U.S. patent application number 17/480600 was filed with the patent office on 2022-01-06 for modular co2 sequestration units and systems, and methods for using the same.
The applicant listed for this patent is Blue Planet Systems Corporation. Invention is credited to Brent R. CONSTANTZ.
Application Number | 20220001329 17/480600 |
Document ID | / |
Family ID | 1000005853645 |
Filed Date | 2022-01-06 |
United States Patent
Application |
20220001329 |
Kind Code |
A1 |
CONSTANTZ; Brent R. |
January 6, 2022 |
MODULAR CO2 SEQUESTRATION UNITS AND SYSTEMS, AND METHODS FOR USING
THE SAME
Abstract
Shippable modular units configured for use in sequestering
CO.sub.2 are provided. Aspects of the units include a support
having one or more of: a CO.sub.2 gas/liquid contactor subunit, a
carbonate production subunit and an alkali enrichment subunit;
associated therewith. Also provided are systems made up of one or
more such modular units, and methods for using the units/systems in
CO.sub.2 sequestration protocols.
Inventors: |
CONSTANTZ; Brent R.;
(Portola Valley, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Blue Planet Systems Corporation |
Los Gatos |
CA |
US |
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|
Family ID: |
1000005853645 |
Appl. No.: |
17/480600 |
Filed: |
September 21, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15562405 |
Sep 27, 2017 |
11154813 |
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PCT/US2016/024338 |
Mar 25, 2016 |
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17480600 |
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62139616 |
Mar 27, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02W 10/37 20150501;
B01D 2251/606 20130101; B01D 2258/0233 20130101; C02F 1/444
20130101; Y02A 50/20 20180101; C02F 2103/18 20130101; B01D 2259/455
20130101; B01D 53/62 20130101; C01B 32/60 20170801; C02F 2201/007
20130101; Y02C 20/40 20200801; B01D 2258/0283 20130101; C02F
2101/10 20130101; B01D 2252/103 20130101; C01B 2210/0003 20130101;
C01B 32/50 20170801; C02F 1/441 20130101; B01D 53/78 20130101; C02F
9/005 20130101; C02F 1/442 20130101 |
International
Class: |
B01D 53/62 20060101
B01D053/62; C01B 32/50 20060101 C01B032/50; C01B 32/60 20060101
C01B032/60; B01D 53/78 20060101 B01D053/78; C02F 9/00 20060101
C02F009/00 |
Claims
1. A shippable modular unit configured for use in sequestering
CO.sub.2 from a gaseous source of CO.sub.2, the shippable modular
unit comprising: (a) a support; and (b) at least one type of
subunit selected from the group consisting of: a CO.sub.2
gas/liquid contactor subunit; a carbonate production subunit; an
alkali enrichment subunit; a water softening subunit; a cation
recovery subunit; a heat exchange subunit; a reverse osmosis
subunit; a nanofiltration subunit; a microfiltration subunit; an
ultrafiltration subunit; and a purified CO.sub.2 collection
subunit; associated with the support.
2. The shippable modular unit according to claim 1, wherein the
shippable modular unit includes only one type of subunit selected
from the group consisting of: a CO.sub.2 gas/liquid contactor
subunit; a carbonate production subunit; an alkali enrichment
subunit; a water softening subunit; a cation recovery subunit; a
heat exchange subunit; a reverse osmosis subunit; a nanofiltration
subunit; a microfiltration subunit; an ultrafiltration subunit; and
a purified CO.sub.2 collection subunit; present in the housing.
3. The shippable modular unit according to claim 1 or 2, wherein
the type of subunit is a CO.sub.2 gas/liquid contactor subunit or a
carbonate production subunit or an alkali enrichment subunit.
4. The shippable modular unit according to claim 1, wherein the
modular unit includes at least two types of subunits selected from
the group consisting of: a CO.sub.2 gas/liquid contactor subunit; a
carbonate production subunit; an alkali enrichment subunit; a water
softening subunit; a cation recovery subunit; a heat exchange
subunit; a reverse osmosis subunit; a nanofiltration subunit; a
microfiltration subunit; an ultrafiltration subunit; and a purified
CO.sub.2 collection subunit; present in the housing.
5. The shippable modular unit according to claim 4, wherein the at
least two types of subunits comprise: a CO.sub.2 gas/liquid
contactor subunit and a carbonate production subunit; or a CO.sub.2
gas/liquid contactor subunit and an alkali enrichment subunit; or a
carbonate production subunit and an alkali enrichment subunit.
6. The shippable modular unit according to any of claims 1 to 5,
wherein the shippable modular unit is configured to be operatively
coupled to one or more additional shippable modular units each
comprising: (a) a support; and (b) at least one type of subunit
selected from the group consisting of: a CO.sub.2 gas/liquid
contactor subunit; a carbonate production subunit; and an alkali
enrichment subunit; a water softening subunit; a cation recovery
subunit; a heat exchange subunit; a reverse osmosis subunit; a
nanofiltration subunit; a microfiltration subunit; an
ultrafiltration subunit; and a purified CO.sub.2 collection
subunit; associated with the support.
7. The shippable modular unit according to any of the preceding
claims, wherein the shippable modular unit is configured to be
transported by rail.
8. The shippable modular unit according to any of claims 1 to 7,
wherein the shippable modular unit is configured to be transported
by truck.
9. The shippable modular unit according to any of claims 1 to 7,
wherein the shippable modular unit is configured to be transported
by boat.
10. The shippable modular unit according to any of claims 1 to 9,
wherein the housing has an internal volume ranging from 8 to 30,000
m.sup.3.
11. The shippable modular unit according to any of claims 1 to 10,
wherein the shippable modular unit has a mass ranging from 1 ton to
20,000 tons.
12. A system configured to sequester CO.sub.2 from a gaseous source
of CO.sub.2, the system comprising: two or more operably coupled
shippable modular units, each shippable modular unit comprising:
(a) a housing having at least one material input and least one
product output; and (b) at least one type of subunit selected from
the group consisting of: a CO.sub.2 gas/liquid contactor subunit; a
carbonate production subunit; an alkali enrichment subunit; a water
softening subunit; a cation recovery subunit; a heat exchange
subunit; a reverse osmosis subunit; a nanofiltration subunit; a
microfiltration subunit; an ultrafiltration subunit; and a purified
CO.sub.2 collection subunit; present in the housing.
13. The system according to claim 12, wherein the housing of at
least one of the shippable modular units includes only one type of
subunit selected from the group consisting of: a CO.sub.2
gas/liquid contactor subunit; a carbonate production subunit; an
alkali enrichment subunit; a water softening subunit; a cation
recovery subunit; a heat exchange subunit; a reverse osmosis
subunit; a nanofiltration subunit; a microfiltration subunit; an
ultrafiltration subunit; and a purified CO.sub.2 collection
subunit; present in the housing.
14. The system according to claim 12, wherein the housing of at
least one of the shippable modular units comprises at least two
types of subunits selected from the group consisting of: a CO.sub.2
gas/liquid contactor subunit; a carbonate production subunit; an
alkali enrichment subunit; a water softening subunit; a cation
recovery subunit; a heat exchange subunit; a reverse osmosis
subunit; a nanofiltration subunit; a microfiltration subunit; an
ultrafiltration subunit; and a purified CO.sub.2 collection
subunit; present in the housing.
15. A method for sequestering CO.sub.2 from a gaseous source of
CO.sub.2, the method comprising: (a) introducing a gaseous source
of CO.sub.2 into a system according to any of claims 12 to 14; and
(b) obtaining a carbonate product material from the modular unit.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Pursuant to 35 U.S.C. .sctn. 119(e), this application claims
priority to the filing date of U.S. Provisional Application Ser.
No. 62/139,616 filed on Mar. 27, 2015; the disclosure of which
application is herein incorporated by reference.
INTRODUCTION
[0002] Carbon dioxide (CO.sub.2) is a naturally occurring chemical
compound that is present in Earth's atmosphere as a gas. Sources of
atmospheric CO.sub.2 are varied, and include humans and other
living organisms that produce CO.sub.2 in the process of
respiration, as well as other naturally occurring sources, such as
volcanoes, hot springs, and geysers.
[0003] Additional major sources of atmospheric CO.sub.2 include
industrial plants. Many types of industrial plants (including
cement plants, refineries, steel mills and power plants) combust
various carbon-based fuels, such as fossil fuels and syngases.
Fossil fuels that are employed include coal, natural gas, oil,
petroleum coke and biofuels. Fuels are also derived from tar sands,
oil shale, coal liquids, and coal gasification and biofuels that
are made via syngas.
[0004] The environmental effects of CO.sub.2 are of significant
interest. CO.sub.2 is commonly viewed as a greenhouse gas. Because
human activities since the industrial revolution have rapidly
increased concentrations of atmospheric CO.sub.2, anthropogenic
CO.sub.2 has been implicated in global warming and climate change,
as well as ocean acidification.
[0005] Sequestration of anthropogenic CO.sub.2 is of great global
urgency and is important in efforts to slow or reverse global
warming and ocean acidification.
SUMMARY
[0006] Shippable modular units configured for use in sequestering
CO.sub.2 are provided. Aspects of the units include a support,
e.g., a housing or base, having associated therewith one or more
of: a CO.sub.2 gas/liquid contactor subunit, a carbonate production
subunit, an alkali enrichment subunit, a water softening subunit, a
cation recovery subunit, a heat exchange subunit, a reverse osmosis
subunit, a nanofiltration subunit, a microfiltration subunit, an
ultrafiltration subunit, and a purified CO.sub.2 collection
subunit. Also provided are systems made up of one or more such
modular units. Systems disclosed herein include large capacity
systems, where individual modular units may contain only one type
or more of a given subunit, e.g., a CO.sub.2 gas/liquid contactor
subunit, a carbonate production subunit, an alkali enrichment
subunit, a water softening subunit, a cation recovery subunit, a
heat exchange subunit, a reverse osmosis subunit, a nanofiltration
subunit, a microfiltration subunit, an ultrafiltration subunit, and
a purified CO.sub.2 collection subunit. Aspects of the invention
include larger assemblages of multiple individual modular units
that are engaged and may have one or many individual modular units
that include a CO.sub.2 gas/liquid contactor subunit, a carbonate
production subunit, an alkali enrichment subunit, a water softening
subunit, a cation recovery subunit, a heat exchange subunit, a
reverse osmosis subunit, a nanofiltration subunit, a
microfiltration subunit, an ultrafiltration subunit, and a purified
CO.sub.2 collection subunit. Also provided are methods of using the
units/systems in CO.sub.2 sequestration protocols.
BRIEF DESCRIPTION OF THE FIGURES
[0007] FIG. 1 provides a schematic representation of a shippable
modular CO.sub.2 sequestration unit that includes a CO.sub.2/liquid
contactor subunit.
[0008] FIG. 2 provides a schematic representation of a shippable
modular CO.sub.2 sequestration unit that includes a carbonate
production subunit.
[0009] FIG. 3 provides a schematic representation of a shippable
modular CO.sub.2 sequestration unit that includes alkali enrichment
subunit.
[0010] FIG. 4 provides a schematic representation of a shippable
modular CO.sub.2 sequestration unit that includes a CO.sub.2/liquid
contactor subunit; a carbonate production subunit and an alkali
enrichment subunit.
[0011] FIG. 5 provides a schematic representation of a system made
up of three distinct shippable modular CO.sub.2 sequestration
units, one of which includes a CO.sub.2/liquid contactor subunit;
one of which includes a carbonate production subunit and one of
which includes an alkali enrichment subunit.
DETAILED DESCRIPTION
[0012] Shippable modular units configured for use in sequestering
CO.sub.2 are provided. Aspects of the units may include a support,
e.g., a housing or base, having associated therewith one or more
of: a CO.sub.2 gas/liquid contactor subunit, a carbonate production
subunit, an alkali enrichment subunit, a water softening subunit, a
cation recovery subunit, a heat exchange subunit, a reverse osmosis
subunit, a nanofiltration subunit, a microfiltration subunit, an
ultrafiltration subunit, and a purified CO.sub.2 collection
subunit. Also provided are systems made up of one or more such
modular units. Systems disclosed herein include large capacity
systems, where individual modular units may contain only one type
or more of a given subunit, e.g., a CO.sub.2 gas/liquid contactor
subunit, a carbonate production subunit, an alkali enrichment
subunit, a water softening subunit, a cation recovery subunit, a
heat exchange subunit, a reverse osmosis subunit, a nanofiltration
subunit, a microfiltration subunit, an ultrafiltration subunit, and
a purified CO.sub.2 collection subunit. Aspects of the invention
include larger assemblages of multiple individual modular units
that are engaged and may have one or many individual modular units
that include a CO.sub.2 gas/liquid contactor subunit, a carbonate
production subunit, an alkali enrichment subunit, a water softening
subunit, a cation recovery subunit, a heat exchange subunit, a
reverse osmosis subunit, a nanofiltration subunit, a
microfiltration subunit, an ultrafiltration subunit, and a purified
CO.sub.2 collection subunit. Also provided are methods of using the
units/systems in CO.sub.2 sequestration protocols.
[0013] Before the present invention is described in greater detail,
it is to be understood that this invention is not limited to
particular embodiments described, as such may, of course, vary. It
is also to be understood that the terminology used herein is for
the purpose of describing particular embodiments only, and is not
intended to be limiting, since the scope of the present invention
will be limited only by the appended claims.
[0014] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limit of that range and any other stated or intervening
value in that stated range, is encompassed within the invention.
The upper and lower limits of these smaller ranges may
independently be included in the smaller ranges and are also
encompassed within the invention, subject to any specifically
excluded limit in the stated range. Where the stated range includes
one or both of the limits, ranges excluding either or both of those
included limits are also included in the invention.
[0015] Certain ranges are presented herein with numerical values
being preceded by the term "about." The term "about" is used herein
to provide literal support for the exact number that it precedes,
as well as a number that is near to or approximately the number
that the term precedes. In determining whether a number is near to
or approximately a specifically recited number, the near or
approximating un-recited number may be a number which, in the
context in which it is presented, provides the substantial
equivalent of the specifically recited number.
[0016] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can also be used in the practice or testing of the present
invention, representative illustrative methods and materials are
now described.
[0017] All publications and patents cited in this specification are
herein incorporated by reference as if each individual publication
or patent were specifically and individually indicated to be
incorporated by reference and are incorporated herein by reference
to disclose and describe the methods and/or materials in connection
with which the publications are cited. The citation of any
publication is for its disclosure prior to the filing date and
should not be construed as an admission that the present invention
is not entitled to antedate such publication by virtue of prior
invention. Further, the dates of publication provided may be
different from the actual publication dates which may need to be
independently confirmed.
[0018] It is noted that, as used herein and in the appended claims,
the singular forms "a", "an", and "the" include plural referents
unless the context clearly dictates otherwise. It is further noted
that the claims may be drafted to exclude any optional element. As
such, this statement is intended to serve as antecedent basis for
use of such exclusive terminology as "solely," "only" and the like
in connection with the recitation of claim elements, or use of a
"negative" limitation.
[0019] As will be apparent to those of skill in the art upon
reading this disclosure, each of the individual embodiments
described and illustrated herein has discrete components and
features which may be readily separated from or combined with the
features of any of the other several embodiments without departing
from the scope or spirit of the present invention. Any recited
method can be carried out in the order of events recited or in any
other order which is logically possible.
Modular CO.sub.2 Sequestration Units
[0020] As summarized above, aspects of the invention include
shippable modular CO.sub.2 sequestration units. By CO.sub.2
sequestration unit is meant a structure or device that finds use in
methods of sequestering CO.sub.2, i.e., CO.sub.2 sequestration
processes (i.e., methods, protocols, etc.) that result in CO.sub.2
sequestration. By "CO.sub.2 sequestration" is meant the removal or
segregation of an amount of CO.sub.2 from an environment, such as
the Earth's atmosphere or a gaseous waste stream produced by an
industrial plant, so that some or all of the CO.sub.2 is no longer
present in the environment from which it has been removed. CO.sub.2
sequestering methods of the invention sequester CO.sub.2 in a
number of different ways, e.g., by producing a CO.sub.2
sequestering product, e.g., a carbonate material, and/or by
producing a substantially pure subsurface injectable CO.sub.2
product gas from an amount of initial CO.sub.2, such that the
CO.sub.2 is sequestered. The CO.sub.2 sequestering product may be a
storage stable composition that incorporates an amount of CO.sub.2
into a storage stable form, such as an above-ground storage or
underwater storage stable form, so that the CO.sub.2 is no longer
present as, or available to be, a gas in the atmosphere.
Sequestering of CO.sub.2 according to methods of the invention
results in prevention of CO.sub.2 gas from entering the atmosphere
and allows for long-term storage of CO.sub.2 in a manner such that
CO.sub.2 does not become part of the atmosphere.
[0021] As the CO.sub.2 sequestration units are modular, they are
self-contained units or items that are configured for carrying out
a part of or all of a given CO.sub.2 sequestration process, e.g.,
as described in greater detail below. In some instances, the
modular units are configured so to be combined or interchanged with
other modular CO.sub.2 sequestration units so as to produce a
system configured to carry out a CO.sub.2 sequestration process. In
other instances, modular units are configured so to carry out a
complete CO.sub.2 sequestration process, in that they include all
the components or units necessary to carry out a complete CO.sub.2
sequestration process.
[0022] The modular CO.sub.2 sequestration units are shippable. As
the modular units are shippable, they are readily transportable "as
is" (i.e., without breaking them down into two or more component
parts), between first and second distinct geographical locations
(such as a CO.sub.2 sequestration location and a remote location
thereto), which first and second geographical locations may be
separated from each other by a distance of 100 m or more, including
500 m or more, e.g., 1 km or more, 10 km or more, 100 km or more,
1000 km or more, 10,000 km or more, including 25,000 km or more. By
readily transportable is meant that the units can be conveyed
between the first and second geographic locations using any
convenient transportation means, such as but not limited to: boat,
rail, truck, plane, etc.
[0023] The shippable modular units may have any convenient shape
and dimensions. The modular units may include at least a support,
e.g., skid, platform, housing, etc., for the one or more subunits
that they include, i.e., that are associated therewith. In some
instances, the shippable modular units have conventional shipping
container dimensions, e.g., they have a length ranging from 2 to 50
m, such as 5 to 10 m; a height ranging from 2 to 30 m, such as 3 to
10 m and a width ranging from 2 to 20 m, such as 3 to 15 m. The
shippable modular units are structures which are supports and may
be configured in a number of different ways, e.g., as a housing or
a base skid, that defines an internal volume or footprint, where
one or more CO.sub.2 sequestration subunits or components may be
present. While the internal volume (i.e., the volume defined by the
housing or volume occupied by the components on a base skid) may
vary, in some instances the internal volume ranges from 8 to 30,000
m.sup.3, such as 50 to 10,000 m.sup.3. The mass of the shippable
modular units may vary, ranging in some instances from 1 ton to
20,000 tons, such as 10 to 1000 tons and including 15 to 500
tons.
[0024] In those embodiments where the modular unit includes a
housing, the housing of the container may be fabricated from any
convenient material or combination of different materials, e.g.,
metals, metal alloys, polymeric materials, etc. The housing of the
shippable modular unit includes at least one material input and at
least one product output. A given housing may include a single
material input, or two or more material inputs, e.g., three or
more, four or more, material inputs, as desired. Similarly, a given
housing may include a single product output, or two or more product
outputs, e.g., three or more, four or more, product outputs, as
desired. The material or product that a given input or output is
configured to transfer between internal and external locations
relative to the housing may vary, being solid, liquid or gas,
depending on the particular modular unit and CO.sub.2 sequestration
subunits housed in the container. For example, a given modular unit
may include a liquid input and/or a gas input. A given modular unit
may include a gas output, a solid output and/or a liquid output.
Different configurations of material inputs and product outputs are
further described below.
[0025] In addition to the housing having one or more material
inputs and one or more product outputs, the shippable modular units
further include one or more CO.sub.2 sequestration subunits present
inside of the housing. CO.sub.2 sequestration subunits are
components or devices configured to perform a defined task in a
CO.sub.2 sequestration process. CO.sub.2 sequestration subunits of
interest include, but are not limited to: CO.sub.2 gas/liquid
contactor subunits, carbonate production subunits, alkali
enrichment subunits, etc. A given modular unit may include a single
CO.sub.2 sequestration subunit, or two or more CO.sub.2
sequestration subunits, where the two or more CO.sub.2
sequestration subunits may be the same or different types of
subunits. For example, a given modular unit may include one or more
of the same type of CO.sub.2 sequestration subunits, e.g., one or
more CO.sub.2 gas/liquid contactor subunits, carbonate production
subunits, alkali enrichment subunits, etc. Alternatively, a given
modular unit may include one or more of two or more different types
of CO.sub.2 sequestration subunits, e.g., one or more of at least
two of CO.sub.2 gas/liquid contactor subunits, carbonate production
subunits, alkali enrichment subunits, etc.; including one or more
of each of CO.sub.2 gas/liquid contactor subunits, carbonate
production subunits, alkali enrichment subunits, etc.
[0026] Depending on the configuration of a particular modular
subunit, a given CO.sub.2 sequestration subunit may be operably
coupled directly to a material input(s) and/or product output(s)
and/or operably coupled to one or more additional CO.sub.2
sequestration subunits present within the housing. For example,
where the CO.sub.2 sequestration subunit is a CO.sub.2 gas/liquid
contactor subunit, the CO.sub.2 gas/liquid contactor subunit may be
operably coupled to a liquid material input of the modular unit and
a gas (e.g., gaseous source of CO.sub.2) material input of the
modular unit, and also operably coupled to product outputs of the
housing (e.g., one for product gas and one for CO.sub.2 charged
liquid), or operably coupled to a CO.sub.2 product gas output and a
second CO.sub.2 sequestration subunit, e.g., an alkali enrichment
subunit. In other instances where the CO.sub.2 sequestration
subunit is an alkali enrichment subunit, instead of the above
described configuration, the alkali enrichment subunit may be
operatively coupled to first and second liquid material inputs, as
well as a liquid product output or a second CO.sub.2 sequestration
subunit, e.g., a CO.sub.2 gas/liquid contactor subunit. Whether a
given CO.sub.2 sequestration subunit is operatively coupled to a
material input(s) and/or product output(s) or another CO.sub.2
sequestration subunit in the housing depends on a particular
modular units configuration and the type(s) of CO.sub.2
sequestration subunit(s) present therein.
[0027] The shippable modular units are configured to process
industrial amounts materials. By "industrial amounts" is meant
amounts of materials that are typically processed in an industrial
setting, as opposed to a research setting. Industrial amounts are
at least several fold larger than amounts of materials that are
processed in a research setting. In some instances where the
modular units are configured to process input liquid materials, the
modular units may be configured to process 100 to 10,000,000, such
as 10,000 to 1,000,000 liters/hr. In some instances where the
modular units are configured to process input gaseous materials,
the modular units may be configured to process 1000 to 10,000,000,
such as 10,000 to 1,000,000 scfm.
[0028] As summarized above, the shippable modular units may include
one or more CO.sub.2 sequestration subunits, which CO.sub.2
sequestration subunits may vary. Each of the subunits may be
present in a subunit housing. Subunit housings may vary depending
the particular subunit housed therein. A subunit housing of a
subunit may be fabricated from any convenient material or
combination of different materials, e.g., metals, metal alloys,
polymeric materials, etc. A subunit housing of the shippable
modular unit includes at least one material input and at least one
product output. A given subunit housing may include a single
material input, or two or more material inputs, e.g., three or
more, four or more, material inputs, as desired. Similarly, a given
subunit housing may include a single product output, or two or more
product outputs, e.g., three or more, four or more, product
outputs, as desired. Subunit housing dimensions may vary depending
on the particular subunit housed therein, and in some instances
subunit housings have a length ranging from 0.1 to 10 m, such as 1
to 5 m; a height ranging from 0.2 to 10 m, such as 0.25 to 15 m and
a width ranging from 0.1 m to 5 m, such as 1 to 4 m. The internal
volume of the subunit housings may vary, ranging in some instances
from 0.2 to 100, such as 2 to 1000 m.sup.3.
[0029] As summarized above, CO.sub.2 sequestration subunits that
may be present in the shippable modular units include, but are not
limited to: CO.sub.2 gas/liquid contactor subunits, carbonate
production subunits, alkali enrichment subunits, water softening
subunits, cation recovery subunits, heat exchange subunits, reverse
osmosis subunits, nanofiltration subunits, microfiltration
subunits, ultrafiltration subunits and purified CO.sub.2 collection
subunits. Each of these CO.sub.2 sequestration subunits is now
reviewed in greater detail.
CO.sub.2 Gas/Liquid Contactor Subunit
[0030] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a CO.sub.2 gas/liquid contactor
subunit. CO.sub.2 gas/liquid contactor subunits are devices or
components that are configured to contact a CO.sub.2 containing gas
with a liquid (e.g., an aqueous medium) under conditions sufficient
to remove CO.sub.2 from the CO.sub.2 containing gas (e.g., a
CO.sub.2 containing gaseous stream), and increase the dissolved
inorganic carbon (including bicarbonate ion) concentration of
liquid (an in some instances produce an LCP containing liquid, as
described in greater detail below). The CO.sub.2 containing gas may
be contacted with the liquid in the subunit using any convenient
protocol. For example, contact protocols of interest include, but
are not limited to: direct contacting protocols, e.g., bubbling the
gas through a volume of the aqueous medium, concurrent contacting
protocols, i.e., contact between unidirectionally flowing gaseous
and liquid phase streams, countercurrent protocols, i.e., contact
between oppositely flowing gaseous and liquid phase streams, and
the like. Contact may be accomplished through use of infusers,
bubblers, fluidic Venturi reactors, spargers, gas filters, sprays,
trays, packed column reactors, aqueous froth filters (e.g., as
described in U.S. Pat. Nos. 7,854,791; 6,872,240; 6,616,733, as
well as Published U.S. Patent Application Nos. 20140245887 and
WO2005/014144; the disclosures of which are herein incorporated by
reference); and the like, as may be convenient.
[0031] In some instances, the contactor subunit is configured so
that the gaseous source of CO.sub.2 is contacted with the liquid
using a microporous membrane contactor. Microporous membrane
contactors of interest include a microporous membrane present in a
suitable housing, where the housing includes a gas inlet and a
liquid inlet, as well a gas outlet and a liquid outlet. The
contactor is configured so that the gas and liquid contact opposite
sides of the membrane in a manner such that molecule may dissolve
into the liquid from the gas via the pores of the microporous
membrane. The membrane may be configured in any convenient format,
where in some instances the membrane is configured in a hollow
fiber format. Hollow fiber membrane reactor formats which may be
employed include, but are not limited to, those described in U.S.
Pat. Nos. 7,264,725; 6,872,240 and 5,695,545; the disclosures of
which are herein incorporated by reference. In some instances, the
microporous hollow fiber membrane contactor that is employed is a
Liqui-Cel.RTM. hollow fiber membrane contactor (available from
Membrana, Charlotte N.C.), which membrane contactors include
polypropylene membrane contactors and polyolefin membrane
contactors.
[0032] CO.sub.2 gas/liquid contactor subunits are further described
in U.S. patent application Ser. No. 14/636,043; the disclosure of
which is herein incorporated by reference.
Carbonate Production Subunit
[0033] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a carbonate production subunit
(i.e., a mineralization subunit). Carbonate production subunits are
devices or components that are configured to manipulate a
bicarbonate-containing liquid, such as a liquid condensed phase
(i.e., LCP) containing liquid (e.g., LCP) to produce solid phase
carbonate composition, and therefore sequester CO.sub.2 from an
initial CO2-containing gas into a solid form and produce a CO.sub.2
sequestering carbonate material. By CO.sub.2 sequestering carbonate
material is meant a material that stores a significant amount of
CO.sub.2 in a storage-stable format, such that CO.sub.2 gas is not
readily produced from the material and released into the
atmosphere. In certain embodiments, the CO.sub.2-sequestering
material includes 5% or more, such as 10% or more, including 25% or
more, for instance 50% or more, such as 75% or more, including 90%
or more of CO.sub.2, e.g., present as one or more carbonate
compounds. The CO.sub.2-sequestering materials produced in
accordance with methods of the invention may include one or more
carbonate compounds, e.g., as described in greater detail below.
The amount of carbonate in the CO.sub.2-sequestering material,
e.g., as determined by coulometry, may be 40% or higher, such as
70% or higher, including 80% or higher.
[0034] CO.sub.2 sequestering materials, e.g., as described herein,
provide for long-term storage of CO.sub.2 in a manner such that
CO.sub.2 is sequestered (i.e., fixed) in the material, where the
sequestered CO.sub.2 does not become part of the atmosphere. When
the material is maintained under conditions conventional for its
intended use, the material keeps sequestered CO.sub.2 fixed for
extended periods of time (e.g., 1 year or longer, 5 years or
longer, 10 years or longer, 25 years or longer, 50 years or longer,
100 years or longer, 250 years or longer, 1000 years or longer,
10,000 years or longer, 1,000,000 years or longer, or even
100,000,000 years or longer) without significant, if any, release
of the CO.sub.2 from the material. With respect to the
CO.sub.2-sequestering materials, when they are employed in a manner
consistent with their intended use and over their lifetime, the
amount of degradation, if any, as measured in terms of CO.sub.2 gas
release from the product will not exceed 10% per year, such as 5%
per year, and in certain embodiments, 1% per year. In some
instances, CO.sub.2-sequestering materials provided by the
invention do not release more than 1%, 5%, or 10% of their total
CO.sub.2 when exposed to normal conditions of temperature and
moisture, including rainfall of normal pH, for there intended use,
for at least 1, 2, 5, 10, or 20 years, or for more than 20 years,
for example, for more than 100 years. Any suitable surrogate marker
or test that is reasonably able to predict such stability may be
used. For example, an accelerated test comprising conditions of
elevated temperature and/or moderate to more extreme pH conditions
is reasonably able to indicate stability over extended periods of
time. For example, depending on the intended use and environment of
the composition, a sample of the composition may be exposed to 50,
75, 90, 100, 120, or 150.degree. C. for 1, 2, 5, 25, 50, 100, 200,
or 500 days at between 10% and 50% relative humidity, and a loss
less than 1%, 2%, 3%, 4%, 5%, 10%, 20%, 30%, or 50% of its carbon
may be considered sufficient evidence of stability of materials of
the invention for a given period (e.g., 1, 10, 100, 1000, or more
than 1000 years).
[0035] In certain instances, the carbonate production subunit is
configured to combine a bicarbonate-containing liquid or component
thereof (e.g., LCP) with a divalent cation source (e.g., a hard
water) under conditions sufficient to produce the desired carbonate
product. Any convenient divalent cation source may be employed.
Divalent cations, such as alkaline earth metal cations, e.g.,
calcium and magnesium cations, are of interest. Cation sources of
interest include, but are not limited to, the brine from water
processing facilities, such as sea water desalination plants,
brackish water desalination plants, groundwater recovery
facilities, wastewater facilities, and the like, which produce a
concentrated stream of solution high in cation contents. Also of
interest as cation sources are naturally occurring sources, such
as, but not limited to, native seawater and geological brines,
which may have varying cation concentrations and may also provide a
ready source of cations to trigger the production of carbonate
solids from a bicarbonate rich product or component thereof (e.g.,
LCP), such as described in greater detail below. In such
embodiments, the carbonate production unit may be operably
connected to a material input for a divalent cation source. A given
divalent cation source may be a solid or liquid, as desired. For
example, a liquid divalent cation source may be employed.
Alternatively, a solid divalent cation source, such as a
particulate source (e.g., a powder) may be employed.
[0036] In some embodiments, the carbonate production subunit is
configured such that, during the production of solid carbonate
compositions from the bicarbonate-containing solution (e.g., an LCP
containing liquid), one mol of CO.sub.2 may be produced for every 2
mols of bicarbonate ion from the bicarbonate-containing solution or
component thereof (e.g., LCP). For example, where solid carbonate
compositions are produced by adding calcium cation to the
bicarbonate-containing solution or component thereof (e.g., LCP),
the production of solid carbonate compositions, e.g., the form of
amorphous calcium carbonate minerals, may proceed according to the
following reaction:
2HCO.sub.3.sup.-+Ca.sup.++CaCO.sub.3.H.sub.2O+CO.sub.2
Ca.sup.++.sub.(aq)+2HCO.sub.3(aq).sup.-CaCO.sub.3(s)+H.sub.2O.sub.(l)+CO-
.sub.2(g)
While the above reaction shows the production of 1 mol of CO.sub.2,
2 moles of CO.sub.2 from the CO.sub.2-containing gas were initially
converted to bicarbonate. As such, the overall process sequesters a
net 1 mol of CO.sub.2 and therefore is an effective CO.sub.2
sequestration process, with a downhill thermodynamic energy profile
of -34 kJ mol.sup.-1 for the above reaction.
[0037] Where carbonate compositions are produced, e.g., as
described above, from the CO.sub.2 sequestration protocol, the
product carbonate compositions may vary greatly. The carbonate
product may include one or more different carbonate compounds, such
as two or more different carbonate compounds, e.g., three or more
different carbonate compounds, five or more different carbonate
compounds, etc., including non-distinct, amorphous carbonate
compounds. Carbonate compounds may be compounds having a molecular
formulation X.sub.m(CO.sub.3).sub.n where X is any element or
combination of elements that can chemically bond with a carbonate
group or its multiple, wherein X is in certain embodiments an
alkaline earth metal and not an alkali metal; wherein m and n are
stoichiometric positive integers. These carbonate compounds may
have a molecular formula of X.sub.m(CO.sub.3).sub.n.H.sub.2O, where
there are one or more structural waters in the molecular formula.
The amount of carbonate in the product, as determined by coulometry
using the protocol described as coulometric titration, may be 40%
or higher, such as 70% or higher, including 80% or higher.
[0038] The carbonate compounds of the precipitated products may
include a number of different cations, such as but not limited to
ionic species of: calcium, magnesium, sodium, potassium, sulfur,
boron, silicon, strontium, and combinations thereof. Of interest
are carbonate compounds of divalent metal cations, such as calcium
and magnesium carbonate compounds. Specific carbonate compounds of
interest include, but are not limited to: calcium carbonate
minerals, magnesium carbonate minerals and calcium magnesium
carbonate minerals. Calcium carbonate minerals of interest include,
but are not limited to: calcite (CaCO.sub.3), aragonite
(CaCO.sub.3), vaterite (CaCO.sub.3), ikaite (CaCO.sub.3.6H.sub.2O),
and amorphous calcium carbonate (CaCO.sub.3). Magnesium carbonate
minerals of interest include, but are not limited to magnesite
(MgCO.sub.3), barringtonite (MgCO.sub.3.2H.sub.2O), nesquehonite
(MgCO.sub.3.3H.sub.2O), lanfordite (MgCO.sub.3.5H.sub.2O),
hydromagnisite, and amorphous magnesium calcium carbonate
(MgCO.sub.3). Calcium magnesium carbonate minerals of interest
include, but are not limited to dolomite (CaMg)(CO.sub.3).sub.2),
huntite (Mg.sub.3Ca(CO.sub.3).sub.4) and sergeevite
(Ca.sub.2Mg.sub.11(CO.sub.3).sub.13.H.sub.2O). The carbonate
compounds of the product may include one or more waters of
hydration, or may be anhydrous. In some instances, the amount by
weight of magnesium carbonate compounds in the precipitate exceeds
the amount by weight of calcium carbonate compounds in the
precipitate. For example, the amount by weight of magnesium
carbonate compounds in the precipitate may exceed the amount by
weight calcium carbonate compounds in the precipitate by 5% or
more, such as 10% or more, 15% or more, 20% or more, 25% or more,
30% or more. In some instances, the weight ratio of magnesium
carbonate compounds to calcium carbonate compounds in the product
ranges from 1.5-5 to 1, such as 2-4 to 1 including 2-3 to 1. In
some instances, the product may include hydroxides, such as
divalent metal ion hydroxides, e.g., calcium and/or magnesium
hydroxides.
[0039] In some instances, the carbonate production subunit is
configured to produce solid carbonate products using a
precipitation protocol, e.g., a protocol which results in the
production of a slurry that includes precipitated carbonate
products. Precipitation of solid carbonate compositions from a
dissolved inorganic carbon (DIC) composition (e.g., an LCP
composition as employed in a bicarbonate-mediated sequestration
protocol), such as described above, results in the production of a
composition that includes both precipitated solid carbonate
compositions, as well as the remaining liquid from which the
precipitated product was produced (i.e., the mother liquor). This
product composition may be present as a slurry of the precipitate
and mother liquor.
[0040] In some instances, the carbonate production subunit is
configured to produce solid carbonate products using a non-slurry
continuous protocols for production of CO.sub.2 sequestering
materials. As the processes of these embodiments are continuous,
they are not batch processes. In practicing continuous processes of
the invention, a divalent cation source, e.g., as described above,
is introduced into a flowing aqueous bicarbonate and/or carbonate
containing liquid (e.g., a bicarbonate rich product containing
liquid as described above) under conditions sufficient such that a
non-slurry solid phase CO.sub.2 sequestering carbonate material is
produced in the flowing aqueous bicarbonate rich product. The
carbonate production unit of these embodiments may be configured as
a continuous reactor. Where the production subunit is a continuous
reactor, the location at which the CO.sub.2 sequestering material
is produced may be a fluidized bed subunit of the continuous
reactor. Fluidized bed reactors of interest are configured to
maintain a region of fluidized solids in a continuously flowing
medium, and may have a fluid inlet, a fluid outlet, and a region of
material production positioned there-between. A given fluidized bed
reactor may have a single change or multiple chambers, as desired.
Where desired, the fluidized bed may include structures, e.g.,
filters, meshes, frits, etc., or other retaining structures which
serve to keep the product material in the fluidize bed.
[0041] Carbonate production subunits are further described in U.S.
patent application Ser. No. 14/636,043; the disclosure of which is
herein incorporated by reference.
Alkali Enrichment Subunit
[0042] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is an alkali enrichment subunit.
Alkali enrichment (AE) subunits are devices or components that are
configured to increase the alkalinity of a liquid, e.g., to produce
a CO.sub.2 capture liquid, to enhance the alkalinity of a CO.sub.2
charged liquid, etc. The alkalinity increase of a given liquid may
be manifested in a variety of different ways. In some instances,
increasing the alkalinity of a liquid is manifested as an increase
the pH of the liquid. For example, a liquid may be processed to
remove hydrogen ions from the liquid to increase the alkalinity of
the liquid. In such instances, the pH of the liquid may be
increased by a desirable value, such as 0.10 or more, 0.20 or more,
0.25 or more, 0.50 or more, 0.75 or more, 1.0 or more, 2.0 or more,
etc. In some instances, the magnitude of the increase in pH may
vary, ranging in some instances from 0.1 to 10, such as 1 to 9,
including 2.5 to 7.5, e.g., 3 to 7. As such, methods may increase
the alkalinity of an initial liquid to produce a product liquid
having a desired pH, where in some instances the pH of the product
liquid ranges from 5 to 14, such as 6 to 13, including 7 to 12,
e.g., 8 to 11, where the product liquid may be viewed as an
enhanced alkalinity liquid. The increase in alkalinity of a liquid
may also be manifested as an increase in the dissolved inorganic
carbon (DIC) content of liquid. The DIC is the sum of the
concentrations of inorganic carbon species in a solution,
represented by the equation:
DIC=[CO.sub.2*]+[HCO.sub.3.sup.-]+[CO.sub.3.sup.2-], where
[CO.sub.2*] is the sum of carbon dioxide ([CO.sub.2]) and carbonic
acid ([H.sub.2CO.sub.3]) concentrations, [HCO.sub.3.sup.-] is the
bicarbonate concentration and [CO.sub.3.sup.2-] is the carbonate
concentration in the solution. The DIC of the alkali enriched
liquid may vary, and in some instances may be 500 ppm or greater,
such as 5,000 ppm or greater, including 15,000 ppm or greater. In
some instances, the DIC of the alkali enriched liquid may range
from 500 to 20,000 ppm, such as 7,500 to 15,000 ppm, including
8,000 to 12,000 ppm. In some instances, alkali enrichment is
manifested as an increase in the concentration of bicarbonate
species, e.g., NaHCO.sub.3, e.g., to a concentration ranging from 5
to 500 mMolar, such as 10 to 200 mMolar.
[0043] In some instances, the alkali enrichment subunit includes a
membrane, such that it is configured for use in a membrane mediated
alkali enrichment protocol. By membrane mediated protocol is meant
a process or method which employs a membrane at some time during
the method. As such, membrane mediated alkali enrichment protocols
are those alkali enrichment processes in which a membrane is
employed at some time during the process. While a given membrane
mediated alkali enrichment protocol may vary, in some instances the
membrane mediated protocol includes contacting a first liquid,
e.g., a feed liquid, and a second liquid, e.g., a draw liquid, to
opposite sides of a membrane. A variety of different types of
membranes, membrane configurations, contact protocols, first and
second liquid pairings, etc., may be employed, where selection of a
particular set of protocol parameters may depend on a number of
different factors, such as the nature of the first and second
liquids that are available, for what purpose the alkali enrichment
protocol is employed (e.g., to produce a CO.sub.2 capture liquid,
to increase the alkalinity of a CO.sub.2 charged liquid, etc.). A
variety of different types of membranes may be employed in a given
alkali enrichment protocol. In some embodiments, a selective
membrane may utilize dialysis diffusion through the membrane to
selectively partition ions between the feed and the draw stream.
Diffusion dialysis membranes are generally permeable to hydrogen
ions and utilize differences in ion solubility and mobility within
the membrane for selective ion separations between different
liquids, e.g., feed and draw liquids. Examples of such membranes
include, but are not limited to those described in: Liu et al., J.
Membrane Science (2014) 451: 18-23; Hao et al., J. Membrane Science
(2013) 425-426: 156-162; Gu et al., Desalination (2012) 304: 25-32;
and Hao et al., J. Hazardous Materials (2013) 244-245: 348-356; as
well as Nafion membranes, e.g., as described in Okada et al.,
Electrochimica Acta (1998) 43: 3741-3747. In some instances, the
diffusion dialysis membrane employed is ion or charge selective
membrane, i.e., a membrane that preferentially allows the passage
of one type of charged species across the membrane relative to
other species, e.g., other charged species and/or neutral species.
For example, membranes of interest include cationic membranes,
i.e., membranes that permit the passage of cations but not of
anions. Any cationic membrane may be employed in cationic membrane
mediated alkali enrichment protocols. Cationic membranes of
interest include, but are not limited to: Selemion.TM. cation
exchange membranes CMV, CMD, HSF, CSO, CMF, and the like. Also of
interest are anionic membranes, i.e., membranes that permit the
passage of cations but not of anions. Anionic membranes of interest
include, but are not limited to: Selemion.TM. anion exchange
membranes AMV, AMT, DSV, AAV, ASV, AHO, APS4, and the like.
Membranes employed in membrane mediated alkali enrichment protocols
may vary with respect to porosity. In some embodiments, employed
membranes may be size-based separators that allow molecules under a
certain size to pass through, while preventing larger molecules
from passing through. In this way, the membranes can be used to
selectively retain molecules that are over a certain size while
allowing other molecules that are below a certain size to pass
through.
[0044] A given membrane may have a variety of different physical
dimensions. In some instances, membranes of interest having
thicknesses ranging from 0.001 mm to 1 mm, such as 0.005 mm to 0.05
mm and including 0.03 mm to 0.3 mm. Membranes in accordance with
embodiments of the invention can have a variety of configurations
including thin films, hollow fiber membranes, spiral wound
membranes, monofilaments and disk tubes. Membranes of interest can
be made of organic or inorganic materials. In some embodiments,
membranes made of materials such as cellulose acetate, cellulose
nitrate, polysulfone, polyvinylidene fluoride, polyamide and
acrylonitrile co-polymers may be used. Other membranes may be
mineral membranes or ceramic membranes made of materials such as
ZrO.sub.2 and TiO.sub.2. The material selected for use as the
membrane may be selected to be able to withstand various process
conditions to which the membrane may be subjected. For example, it
may be desirable that the membrane be able to withstand elevated
temperatures, such as those associated with sterilization or other
high temperature processes. In some embodiments, a membrane module
may be operated at a temperature in the range of 0 to 100.degree.
C., such as 40 to 50.degree. C. Likewise, the membrane may be
selected to be able to maintain integrity under various pH
conditions, such as a pH level ranging from 2 to 11, such as 7 to
10. The thickness of the membrane may vary, ranging in some
instances from 0.01 mm to 0.1 mm, such as 0.02 mm to 0.06 mm and
including 0.03 mm to 0.04 mm.
[0045] Membranes employed in methods of the invention may be
present in distinct alkali enrichment units, which units are
configured produce a desired amount of alkalinity per time. For
example, alkali enrichment units may be configured to produce 0.1
to 10 moles of alkalinity per square meter of membrane per hour
(mol alkalinity/m.sup.2 h), such as 0.5 to 1.5 mol
alkalinity/m.sup.2 h. A given unit may include one or more square
meter (m.sup.2) of membrane, such as two or more m.sup.2 membrane,
e.g., 5 m.sup.2 to 500,000 m.sup.2 membrane, such as 40 m.sup.2 to
400 m.sup.2 membrane, including 50,000 m.sup.2 to 250,000 m.sup.2
membrane, which may be arranged so that the first and second fluids
flow sequentially past each of the membranes, e.g., in a co- or
counter-current fashion. In such units, the one or m.sup.2 membrane
may be positioned within a housing or casing, e.g., in a
plate-and-frame structure or "stack". The housing may be sized and
shaped to accommodate the membrane(s) positioned therein. For
example, the housing may be substantially cylindrical if housing
spirally wound forward osmosis membranes. Alternatively, the
housing may have a box configuration, e.g., where multiple
membranes are arranged therein in a stacked or plate-and-frame
structure. The housing of the membrane module may contain inlets to
provide first and second liquids to the membrane module as well as
outlets for withdrawal of product streams from the membrane module.
In some embodiments, the housing may provide at least one reservoir
or chamber for holding or storing a fluid to be introduced to or
withdrawn from the membrane module. In some embodiments, the
housing may be insulated.
[0046] Alkali enrichment subunits are further described in U.S.
patent application Ser. No. 14/636,043; the disclosure of which is
herein incorporated by reference.
Water Softening Subunit
[0047] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a water softening subunit. Water
softening subunits are units that are configured to soften an
aqueous medium, e.g., by removing divalent cations, such as calcium
and magnesium ions, from an aqueous medium. In other words, an
initial aqueous medium may be subject to a hardness reduction
protocol prior to being subjected to a hydronium ion removal
protocol, e.g., as described above. Hardness reduction protocols of
interest include removing divalent cations, e.g., alkaline earth
metal divalent cations, from an initial aqueous medium. Water
softening subunits reduce the hardness of a given aqueous medium by
a suitable amount, where in some instances the hardness is reduce
to a level that does not result in any substantial scaling in a
CO.sub.2 gas/liquid contactor subunit. While the amount of hardness
reduction may vary, in some instances the amount of of hardness
reduction is 5% or greater, such as 25% or greater, including 50%
or greater.
[0048] In the water softening subunits, divalents cations may be
removed from an aqueous medium using any convenient protocol. In
some instances, an aqueous medium input is contacted with a
divalent cation selective membrane under conditions sufficient to
separate the liquid component of the feed and smaller molecules
having a diameter that is less than that of a hydrated divalent
cation from a retentate. Processing conditions may include a range
of positive or negative pressures applied to the membrane. Where
desired, positive or negative pressures may be applied to the
membrane such that a pressure differential is established across
the membrane. For example, in some embodiments, a membrane feed is
contacted with a divalent cation selective membrane such that a
pressure differential across the membrane ranges from 1 atmosphere
(ATM) up to 50 ATM, such as 20-30 ATM is established. In some
embodiments, processing conditions may include a range of suitable
temperatures. For example, in some embodiments, a membrane feed is
contacted with a divalent cation selective membrane at a
temperature ranging from 0.degree. C. up to 100.degree. C., such as
40-50.degree. C. Likewise, a membrane may be selected to be able to
maintain integrity under various pH conditions, such as a pH
ranging from 2 to 11, such as 7 to 10. Contacting the aqueous
medium with the divalent cation selective membrane results in the
formation of a permeate having a reduced concentration of divalent
cations relative to the feed, and a retentate having an increased
concentration of divalent cations relative to the feed. Aspects of
the methods involve subjecting the reduced divalent cation
concentration permeate to the hydrogen ion removal process
described above. Aspects of the methods also involve subjecting the
increased divalent cation concentration retentate to further
processing, as described below.
[0049] In some embodiments, the divalent cation selective membrane
is a nanofiltration membrane. In these instances, the water
softening subunit may be viewed as a nanofiltration subunit. By
"nanofiltration membrane" is meant a membrane whose pores range in
diameter from 0.1 to 20 nanometers, such as 0.5 to 10 nanometers,
including 1 to 10 nanometers, such as 1 to 2 nanometers, and are
configured to retain divalent cations, such as Mg.sup.2+ and
Ca.sup.2+ cations, in the retentate, while allowing smaller species
to pass through the membrane with the permeate. For example, in
certain embodiments, a nanofiltration membrane is adapted to retain
hydrated divalent cations (e.g., Ca.sup.2+, Mg.sup.2+) on a first
side of the membrane, while allowing smaller hydrated monovalent
ions to pass to the other side of the membrane. In some
embodiments, a nanofiltration membrane is configured such that in
use, the nanofiltration membrane can retain divalent cations in the
retentate without adding additional ions, such as sodium ions, to
the feed. In some embodiments, a nanofiltration membrane is
configured such that in use, the nanofiltration membrane can retain
divalent cations in the retentate without the need to continuously
heat or cool the solution. Nanofiltration membranes in accordance
with embodiments of the invention may have varying pore density,
and in some instances have a pore density ranging from 1 to 150
pores per square centimeter, such as 50 to 100 pores per square
centimeter. The pore dimensions and pore density may be controlled
using suitable process conditions, such as controlled pH,
temperature and process timing employed during a nanofiltration
membrane fabrication process. The material from which a
nanofiltration membrane is made may be selected to be able to
withstand various process conditions to which the membrane may be
subjected during processing. For example, it may be desirable that
the membrane be able to withstand elevated temperatures, such as
those associated with sterilization or other high temperature
processes, as well as elevated pressures. In some embodiments, a
nanofiltration membrane has a standardized design, such as, e.g., a
spiral wound module design or a tubular module design, having a
range of standard diameters to fit standard pressure vessel sizes
and/or components thereof. In certain embodiments, a standardized
nanofiltration membrane module is configured to facilitate the
connection of multiple membrane modules in series and/or in
parallel within a standardized pressure vessel. In some
embodiments, a nanofiltration membrane may be in the form of a
cartridge that is positioned within a housing or casing. The
housing may be sized and shaped to accommodate the membrane(s)
positioned therein. For example, the housing may be substantially
cylindrical if housing a spirally wound membrane. The housing of
the module may contain inlets or channels to facilitate the
introduction of a membrane feed into the module, as well as outlets
for withdrawal of product streams from the module. In some
embodiments, the housing may provide at least one reservoir or
chamber for holding or storing a fluid to be introduced into or
withdrawn from the module. In some embodiments, the housing may be
insulated.
[0050] Protocols for softening an aqueous medium are further
described in U.S. Provisional Application Ser. No. 62/051,100 filed
on Sep. 16, 2014; the disclosure of which is herein incorporated by
reference. While a given water softening subunit may be positioned
at any convenient location in a modular unit or system of modular
units, in some instances it is positioned upstream of a CO.sub.2
gas/liquid contactor subunit.
Cation Recovery Subunit
[0051] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a cation recovery subunit. Cation
recovery subunits are subunits configured to recover a cation rich
composition for use in another subunit system of a module/system
that includes the cation recovery subunit. The cation recover
subunit may be a simple conveyor the takes the cation rich
retentate from a water softening subunit and transfers it to
another subunit, such as a carbonate production subunit.
[0052] In some instances, cation recovery subunit is a subunit that
is configured to produce a concentrated hard water, where the
concentrated hard water is one that has been produced by contacting
an initial hard water with a divalent cation selective membrane to
produce a concentrated hard water that has an increased
concentration of divalent cations as compared to the initial hard
water. Divalent cation selective membranes that may be used in such
embodiments are configured or adapted to prevent the passage of
divalent cations from one side of the membrane to the other, while
allowing liquid and smaller molecules (e.g., molecules having a
diameter that is smaller than the diameter of a hydrated divalent
cation) to pass from one side of the membrane to the other.
Divalent cation selective membranes in accordance with embodiments
of the invention have pores or passages of a size that allows
liquid and smaller molecules to pass through, but prevents or
blocks the passage of particles having a size equal to or greater
than the diameter of a hydrated divalent cation, such as Ca.sup.2+
or Mg.sup.2+. A membrane "feed" refers to an initial liquid mixture
that is applied to a membrane filter. A membrane "retentate" or
"concentrate" refers to the components of the feed that cannot pass
through the pores or passages of the membrane and are thus retained
on the first side of the membrane. A membrane "permeate" refers to
the components of the feed that are able to pass through the pores
or passages of the membrane to reach the other side of the
membrane. In some embodiments of the methods, a membrane feed is
contacted with a divalent cation selective membrane under
conditions that are sufficient to separate the liquid component of
the feed and smaller molecules having a diameter that is less than
that of a hydrated divalent cation from the retentate. Processing
conditions may include a range of positive or negative pressures
applied to the membrane. Where desired, positive or negative
pressure may be applied to the membrane such that a pressure
differential is established across the membrane. For example, in
some embodiments, a membrane feed is contacted with a divalent
cation selective membrane such that a pressure differential across
the membrane ranges from 1 atmosphere (atm) up to 40 atm, such as
20-30 atm is established. In some embodiments, processing
conditions may include a range of suitable temperatures. For
example, in some embodiments, a membrane feed is contacted with a
divalent cation selective membrane at a temperature ranging from
0.degree. C. up to 100.degree. C., such as 40-50.degree. C.
Likewise, a membrane may be selected to be able to maintain
integrity under various pH conditions, such as a pH ranging from 2
to 11, such as 7 to 10. In some embodiments, the selective membrane
is a nanofiltration membrane, e.g., as described above.
[0053] As used herein, the term "concentrated hard water" means a
solution of aqueous media having a divalent cation concentration of
500 ppm or greater, such as 600 ppm or greater, including 750 ppm
or greater. In some instances, a concentrated hard water has a
divalent cation concentration of 2,500 ppm or greater, e.g., 5,000
ppm or greater, 10,000 ppm or greater, 15,000 ppm or greater,
20,000 ppm or greater, 25,000 ppm or greater, 30,000 ppm or
greater, 40,000 ppm or greater, including 50,000 ppm or greater. In
some embodiments, a concentrated hard water may have a divalent
cation concentration ranging from 500 to 200,000 ppm, such as 1,000
to 200,000 ppm, where in some instances the concentration ranges
from 50,000 to 200,000 ppm, such as 50,000 to 175,000 ppm, an
including 50,000 to 150,000 ppm. While the concentrated hard water
may vary depending on the particular application, concentrated hard
waters of interest include one or more solutes, e.g., divalent
cations, such as alkaline earth metal cations, including but not
limited to Mg.sup.2+, Ca.sup.2+, Be.sup.2+, Ba.sup.2+, Sr.sup.2+,
Pb.sup.2+, Fe.sup.2+, and Hg.sup.2+. The pH of concentrated hard
waters in accordance with embodiments of the invention may vary,
and in some instances ranges from 2 to 12, such as 4 to 10. In such
embodiments, an initial hard water may be naturally occurring or
man-made, as desired. Naturally occurring hard waters include, but
are not limited to, waters obtained from seas, oceans, lakes,
swamps, estuaries, lagoons, brines, alkaline lakes, inland seas,
etc. In certain embodiments, a naturally occurring hard water
source is co-located with a location where a CO.sub.2 sequestration
protocol or process is conducted. Man-made sources of hard waters
may also vary, and may include brines produced by water
desalination plants, mining operations, such as fracking
operations, oil field operations, industrial waste waters, and the
like. Of interest in some instances are waters that provide for
excess alkalinity, which is defined as alkalinity which is provided
by sources other than bicarbonate ion. In these instances, the
amount of excess alkalinity may vary, so long as it is sufficient
to provide 1.0 or slightly less, e.g., 0.9, equivalents of
alkalinity. Hard waters of interest include those that provide
excess alkalinity (meq/liter) of 30 or higher, such as 40 or
higher, 50 or higher, 60 or higher, 70 or higher, 80 or higher, 90
or higher, 100 or higher, etc. In certain embodiments, where such
hard waters are employed, no other source of alkalinity, e.g.,
NaOH, is required. Where desired, methods of such embodiments may
include combining a scaling-retarding amount of an acidic solution
with the concentrated hard water. Acidic solutions in accordance
with embodiments of the invention may be, e.g., aqueous solutions
having a pH ranging from 1 to 7, such as from 3 to 5. In certain
embodiments, an acidic solution may be an acidic by-product of
alkali enrichment protocol, e.g., as described above.
[0054] In some instances, the cation recovery subunit is a
concentrated hard water production unit that producing a
concentrated hard water using a membrane mediated protocol, e.g.,
as described in U.S. Patent Application Ser. No. 62/041,568 filed
on Aug. 25, 2014; the disclosure of which is herein incorporated by
reference).
Heat Exchange Subunit
[0055] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a heat exchange subunit. Heat
exchange subunits of interest are subunits that are configured to
remove heat from a first medium, e.g., liquid or gas, and in some
instances transfer the removed heat to a second medium, e.g.,
liquid or gas, where the second medium is in subunit distinct from
the subunit where the medium is located from which the heat is
removed. In some instances, the heat exchange subunit is a subunit
configured to remove heat from an input gas, e.g., flue gas, and
either discard the heat, e.g., by directing it to an output vent,
or transfer the heat to another subunit, e.g., a carbonate
production subunit.
[0056] The heat exchange subunit may vary. In some instances, the
heat exchange subunit is a gas/liquid heat exchange device. In
certain embodiments, heat exchange subunit may include one or more
channels (e.g., channels having a large interior and/or exterior
surface area) physically integrated with a conduit for a gas, e.g.,
flue gas. Where desired, heat exchange elements are configured such
that water may flow through them and thereby transfer heat away
from the gas and into the water. Examples of heat exchange elements
that may be utilized either wholly or partially in connection with
the disclosed systems are provided by U.S. Pat. Nos. 6,374,627;
8,009,430; 7,525,207; 7,347,058; 8,004,832; 7,810,341; 7,808,780;
6,574,104; 6,859,366; 8,157,626; 7,881,057; 6,980,433; 6,945,058;
6,854,284; 6,834,512; 6,775,997; 6,772,604; 8,113,010; 8,276,397;
the disclosures of each which are incorporated by reference
herein.
Reverse Osmosis Subunit
[0057] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a reverse osmosis subunit. By
reverse osmosis subunit is meant a subunit that is configured to
separate small solutes, e.g., sodium ions, chloride ions, etc.,
from an aqueous medium. Microfiltration subunits of interest may
include a reverse osmosis membrane. Reverse osmosis membranes have
a porosity that may vary, where in some embodiments, the reverse
osmosis membrane has pores ranging in size from 5 Angstroms up to 6
Angstroms, up to 7 Angstroms, up to 8 Angstroms. Configuration of
the membrane may vary, where configurations of interest include
plate and frame (i.e., flat sheet) and spiral-wound. While a
reverse osmosis subunit may be present in any convenient location
of a module/system, in some instances it is present at a position
downstream of a liquid output of another subunit, e.g., so as
remove salt from a liquid output and produce a water suitable for
further use in the system.
Nanofiltration Subunit
[0058] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a nanofiltration subunit. In these
instances, the nanofiltration subunit may be separate or distinct
from a water softening subunit, such that a given module/system may
have both a water softening subunit and a nanofiltration subunit.
Nanofiltration subunits of interest may include a nanofiltration
membrane, e.g., as described above in connection with the water
softening subunit. While a nanofiltration subunit may be present in
any convenient location of a module/system, in some instances it is
present at a position downstream of a liquid output of another
subunit, e.g., so as remove divalent cations from a liquid output
and produce a water suitable for further use in the system.
Microfiltration Subunit
[0059] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is a microfiltration subunit. By
microfiltration subunit is meant a subunit that is configured to
separate particles, such as, sediment, algae, protozoa or large
bacteria, etc., from an aqueous medium. Microfiltration subunits of
interest may include a microfiltration membrane. Microfiltration
membranes have a porosity ranging from 0.1 to 1 .mu.m and may be
fabricated from a variety of different materials, including but not
limited to: polymers, e.g., cellulose acetate (CA), polysulfone,
polyvinylidene fluoride, polyethersulfone and polyamide (as may be
found in organic membranes; and sintered metal or porous alumina
(as may be found in inorganic membranes. Configurations of
membranes may vary, where configurations of interest include plate
and frame (i.e., flat sheet) and spiral-wound. While a
microfiltration subunit may be present in any convenient location
of a module/system, in some instances it is present at a position
upstream of a liquid input of another subunit, e.g., so as remove
larger contaminants from a liquid before the liquid enters the
subunit.
Ultrafiltration Subunit
[0060] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is an ultrafiltration subunit.
Ultrafiltration subunits of interest may include a ultrafiltration
membrane. Ultrafiltration membranes have a porosity ranging 10
nanometers up to 20 nanometers, up to 30 nanometers, up to 40
nanometers, up to 50 nanometers, up to 60 nanometers, up to 70
nanometers, up to 80 nanometers, up to 90 nanometers, up to 100
nanometers, up to 125 nanometers, up to 150 nanometers, up to 175
nanometers, up to 200 nanometers, or more, and may be fabricated
from a variety of different materials, including but not limited
to: polymers, e.g., (polysulfone, polypropylene, cellulose acetate,
PLA); and ceramics. Configurations of membranes may vary, where
configurations of interest include plate and frame (i.e., flat
sheet) and spiral-wound. While a ultrafiltration subunit may be
present in any convenient location of a module/system, in some
instances it is present at a position upstream of a liquid input of
another subunit, e.g., so as remove larger contaminants from a
liquid before the liquid enters the subunit.
Purified CO.sub.2 Collection Subunit
[0061] One type of CO.sub.2 sequestration subunit that may be
present in a shippable module is purified CO.sub.2 collection
subunit. By purified CO.sub.2 collection subunit is meant a subunit
that is configured collect, and in some instances store, purified
CO.sub.2 gas produced by another subunit of the system, e.g., a
carbonate production subunit. Where desired, the purified CO.sub.2
collection subunit may be configured to compress the gas, e.g., for
storage or further processing, including transport to another
location.
Specific Embodiments
[0062] The shippable modular CO.sub.2 sequestration units having
been generally described, various specific illustrative shippable
modular CO.sub.2 sequestration units are now reviewed in greater
detail. FIG. 1 provides a schematic view of a shippable modular
CO.sub.2 sequestration unit that includes a single CO.sub.2
gas/liquid contactor subunit. As shown in FIG. 1, shippable modular
CO.sub.2 sequestration unit 100 includes a housing 110 sized to be
shippable, e.g., as described above. Housing 110 includes a liquid
material input 120, e.g., introducing a liquid material (such as an
aqueous medium) into the interior of the housing. Operatively
coupled to the liquid material input 120 is CO.sub.2 gas/liquid
contactor subunit 130. CO.sub.2 gas/liquid contactor subunit 130 is
also operatively coupled to gas material input 140 which is
configured for receiving a gaseous material (such as a CO.sub.2
containing gaseous material) into the interior of the housing.
CO.sub.2 gas/liquid contactor subunit 130 is operatively coupled to
gaseous product output 150 which is configured to pass treated gas
from the contactor subunit to the outside of the unit. CO.sub.2
gas/liquid contactor subunit 130 is operatively coupled to liquid
product output 160 which is configured to pass CO.sub.2 charged
liquid from the contactor subunit to the outside of the unit. While
only a single contactor subunit is illustrated in the embodiment
shown in FIG. 1, as described above, a given unit may include 2 or
more, such as 3 or more, including 4 or more contactor subunits, as
desired.
[0063] FIG. 2 provides a schematic view of a shippable modular
CO.sub.2 sequestration unit that includes a single carbonate
production subunit. As shown in FIG. 2, shippable modular CO.sub.2
sequestration unit 200 includes a housing 210 sized to be
shippable, e.g., as described above. Housing 210 includes a liquid
material input 220, e.g., introducing a liquid material (such as a
bicarbonate containing, e.g., LCP containing, liquid) into the
interior of the housing. Operatively coupled to the liquid material
input 220 is carbonate production subunit 230. Carbonate production
subunit 230 is also operatively coupled to divalent cation source
input 240 which is configured for receiving a divalent cation
source (such as a concentrated brine) into the interior of the
housing. Carbonate production subunit 230 is operatively coupled to
carbonate product output 260 which is configured to pass the
carbonate product (e.g., slurry of precipitated carbonate solids)
to the outside of the unit. Carbonate production subunit 230 is
also operatively coupled to gaseous product output 265 which is
configured to pass the pure CO.sub.2 gas product to the outside of
the unit. While only a single carbonate production subunit is
illustrated in the embodiment shown in FIG. 2, as described above,
a given unit may include 2 or more, such as 3 or more, including 4
or more carbonate production subunits, as desired.
[0064] FIG. 3 provides a schematic view of a shippable modular
CO.sub.2 sequestration unit that includes a single alkali
enrichment subunit. As shown in FIG. 3, shippable modular CO.sub.2
sequestration unit 300 includes a housing 310 sized to be
shippable, e.g., as described above. Housing 310 includes a first
and second liquid material inputs 320 and 330, e.g., introducing
first and second liquids (such a high salinity water and a low
salinity water) into the housing. Operatively coupled to the liquid
material inputs 320 and 330 is an alkali enrichment subunit 340.
Alkali enrichment subunit 340 is also operatively coupled to
alkalinity enriched liquid product output 350 which is configured
to pass alkalinity enriched liquid product from the alkali
enrichment subunit to the outside of the unit. Alkali enrichment
subunit 340 is also operatively coupled to waste liquid product
output 360 which is configured to pass waste liquid from the alkali
enrichment subunit to the outside of the unit. While only a single
alkali enrichment subunit is illustrated in the embodiment shown in
FIG. 3, as described above, a given unit may include 2 or more,
such as 3 or more, including 4 or more alkali enrichment subunits,
as desired.
[0065] As discussed above, a given shippable modular CO.sub.2
sequestration unit may include a single type of CO.sub.2
sequestration subunit (where the unit may include one or more of
the subunits) or a given shippable modular CO.sub.2 sequestration
unit may include two or more different types, such as three or more
different types of CO.sub.2 sequestration subunits (where the unit
may include one or more of each of the different types of
subunits). For example, a given a given shippable modular CO.sub.2
sequestration unit may include an AE subunit and a CO.sub.2
gas/liquid contactor subunit; a CO.sub.2 gas/liquid contactor
subunit and a carbonate production subunit; a carbonate production
subunit and an AE subunit; all three of an AE subunit, a CO.sub.2
gas/liquid contactor subunit and a carbonate production subunit;
etc.
[0066] An example if a shippable modular CO.sub.2 sequestration
unit that includes all three of an AE subunit, a CO.sub.2
gas/liquid contactor subunit and a carbonate production subunit is
illustrated in FIG. 4. As shown in FIG. 4, shippable modular
CO.sub.2 sequestration unit 400 includes housing 410 having liquid
material inputs 415 and 420 for high salinity and low salinity
waters, respectively. Operatively coupled to liquid material inputs
415 and 420 is alkali enrichment subunit 425. Alkali enrichment
subunit 425 is operatively coupled to waste water output 430
configured to convey water from the AE subunit 425 to the outside
of the container. AE subunit 425 is also operatively coupled to
CO.sub.2 gas/liquid contactor 435 so as to convey alkalinity
enriched liquid from the AE subunit to the contactor 435. Contactor
435 is also operatively coupled to gaseous material input 440.
Contactor 435 is operatively coupled to treated gas output 445
which conveys CO.sub.2 depleted gas from the contactor to outside
the modular unit. Contactor 435 is also operatively coupled to
carbonate production subunit 450 in a manner sufficient to convey
bicarbonate rich liquid produced in the contactor to the carbonate
production subunit 450. Carbonate production subunit 450 is
configured to produce a non-slurry carbonate product from the
bicarbonate rich liquid produced by the contactor subunit and a
divalent cation source, such as hard water. As such, the carbonate
production subunit 450 is operatively coupled to divalent cation
liquid input 455. Carbonate production subunit 450 is operatively
coupled to non-slurry carbonate product (e.g., carbonate coated
sand) output 460 and gas product (e.g., pure CO.sub.2 gas) output
465. Carbonate production subunit 450 is also operatively coupled
to waste water disposal 470.
Modular CO.sub.2 Sequestration Unit Systems
[0067] Aspects of the invention further include systems configured
to sequester CO.sub.2 from a gaseous source of CO.sub.2, where the
systems include a plurality of operably coupled shippable modular
units, e.g., as described above. A given system may include two or
more, such as three or more, four or more, five or more, ten or
more, twenty-five or more, including fifty or more shippable
modular units. The modular units of a given system may be arranged
in parallel and/or in series, as desired. For example, a system may
include two or more AE subunit containing units arranged in
parallel, where the alkalinity enriched liquid out of each of the
AE subunit containing units is combined and then conveyed to a
contactor subunit containing modular unit, where bicarbonate rich
product liquid output of the contactor subunit containing unit is
then conveyed to a carbonate production subunit containing
unit.
[0068] An example of a system made up of multiple shippable modular
units is schematically illustrated in FIG. 5. As shown in FIG. 5,
system 500 includes a first shippable modular unit 510, which
contains an AE subunit. Modular unit 510 is operatively coupled to
first and second liquid inputs 515 and 520, which are configured to
introduce high salinity and low salinity waters into the AE
containing unit, respectively. AE unit 510 includes waste water
product output 525, and is operatively coupled to shippable modular
unit 530 which contains a CO.sub.2 gas/liquid contactor subunit so
as to convey alkalinity enriched liquid from the AE containing unit
510 to the contactor containing unit 530. Contactor unit includes
CO.sub.2 containing gas input 535 and CO.sub.2 deplete gas output
540. Contacting containing unit 530 is operatively coupled go
carbonate production unit 550 in order to convey bicarbonate rich
liquid produced by the contactor unit to the carbonate production
unit 550, which contains a carbonate production subunit, e.g., as
described above. Carbonate production unit 550 is configured to
produce a non-slurry carbonate product from the bicarbonate rich
liquid produced by the contactor unit and a divalent cation source,
such as hard water. As such, the carbonate production subunit 550
is operatively coupled to divalent cation liquid input 555.
Carbonate production subunit 550 is operatively coupled to
non-slurry carbonate product (e.g., carbonate coated sand) output
560 and gas product (e.g., pure CO.sub.2 gas) output 565. Carbonate
production unit 550 is also operatively coupled to waste water
disposal 570.
Methods of Sequestering CO.sub.2
[0069] Also provided are methods of using the shippable modular
CO.sub.2 sequestration units and systems thereof in CO.sub.2
sequestration applications, i.e., methods of sequestering CO.sub.2.
By CO.sub.2 sequestration application is meant a method or process
of sequestering CO.sub.2 which results in CO.sub.2 sequestration.
As reviewed above, by "CO.sub.2 sequestration" is meant the removal
or segregation of an amount of CO.sub.2 from an environment, such
as the Earth's atmosphere or a gaseous waste stream produced by an
industrial plant, so that some or all of the CO.sub.2 is no longer
present in the environment from which it has been removed. CO.sub.2
sequestering methods of the invention sequester CO.sub.2 in a
number of different ways, e.g., by producing a CO.sub.2
sequestering product, e.g., a carbonate material, and/or by
producing a substantially pure subsurface injectable CO.sub.2
product gas from an amount of initial CO.sub.2, such that the
CO.sub.2 is sequestered. The CO.sub.2 sequestering product may be a
storage stable composition that incorporates an amount of CO.sub.2
into a storage stable form, such as an above-ground storage or
underwater storage stable form, so that the CO.sub.2 is no longer
present as, or available to be, a gas in the atmosphere.
Sequestering of CO.sub.2 according to methods of the invention
results in prevention of CO.sub.2 gas from entering the atmosphere
and allows for long-term storage of CO.sub.2 in a manner such that
CO.sub.2 does not become part of the atmosphere.
[0070] Aspects of the methods include introducing a CO.sub.2
containing gas and one or more waters into a CO.sub.2 sequestration
system (which may be made up of either (a) a single shippable
modular unit configured to carry out all tasks in a given CO.sub.2
sequestration process or (b) two or more different shippable
modular units which collectively are configured to carry out all
tasks in a CO.sub.2 sequestration process, e.g., as described
above) and obtaining from the system a CO.sub.2 sequestering
carbonate product, and in some instances one or more byproducts,
e.g., pure CO.sub.2 gas, etc. A given system is configured to at
least contact a CO.sub.2 gas with a liquid to produce a CO.sub.2
charged liquid, as well to manipulate the CO.sub.2 charged liquid
in a manner sufficient to produce a CO.sub.2 sequestering carbonate
product. In some instances where the system includes an AE unit,
the methods of using the systems further include an alkali
enrichment step. Each of these steps is now described in greater
detail.
CO.sub.2 Gas/Liquid Contact
[0071] As the systems include a CO.sub.2 gas/liquid contact
subunit, embodiments of methods as described herein include a step
of contacting a gaseous source of CO.sub.2 with a liquid under
conditions sufficient for CO.sub.2 molecules in the gas to dissolve
into the liquid and thereby be separated from the gas, e.g., to
produce a CO.sub.2 charged liquid, which may be a liquid condensed
phase (LCP) containing liquid. As such, aspects of such embodiments
include contacting a CO.sub.2 containing gas with an aqueous medium
to remove CO.sub.2 from the CO.sub.2 containing gas.
[0072] The CO.sub.2-containing gas that is contacted with the
CO.sub.2 sequestration liquid to produce the high DIC containing
liquid may be pure CO.sub.2 or be combined with one or more other
gasses and/or particulate components, depending upon the source,
e.g., it may be a multi-component gas (i.e., a multi-component
gaseous stream). While the amount of CO.sub.2 in such gasses may
vary, in some instances the CO.sub.2-containing gases have a
pCO.sub.2 of 10.sup.3 or higher, such as 10.sup.4 Pa or higher,
such as 10.sup.5 Pa or higher, including 10.sup.6 Pa or higher. The
amount of CO.sub.2 in the CO.sub.2-containing gas, in some
instances, may be 20,000 or greater, e.g., 50,000 ppm or greater,
such as 100,000 ppm or greater, including 150,000 ppm or greater,
e.g., 500,000 ppm or greater, 750,000 ppm or greater, 900,000 ppm
or greater, up to and including 1,000,000 ppm or greater (in pure
CO.sub.2 exhaust the concentration is 1,000,000 ppm) and in some
instances may range from 10,000 to 500,000 ppm, such as 50,000 to
250,000 ppm, including 100,000 to 150,000 ppm. The temperature of
the CO.sub.2-containing gas may also vary, ranging in some
instances from 0 to 1800.degree. C., such as 100 to 1200.degree. C.
and including 600 to 700.degree. C.
[0073] In some instances, a CO.sub.2-containing gas is not pure
CO.sub.2, in that it contains one or more additional gasses and/or
trace elements. Additional gasses that may be present in the
CO.sub.2-containing gas include, but are not limited to water,
nitrogen, mononitrogen oxides, e.g., NO, NO.sub.2, and NO.sub.3,
oxygen, sulfur, monosulfur oxides, e.g., SO, SO.sub.2 and
SO.sub.3), volatile organic compounds, e.g., benzo(a)pyrene
C.sub.2OH.sub.12, benzo(g,h,l)perylene C.sub.22H.sub.12,
dibenzo(a,h)anthracene C.sub.22H.sub.14, etc. Particulate
components that may be present in the CO.sub.2-containing gas
include, but are not limited to particles of solids or liquids
suspended in the gas, e.g., heavy metals such as strontium, barium,
mercury, thallium, etc.
[0074] In certain embodiments, CO.sub.2-containing gases are
obtained from an industrial plant, e.g., where the
CO.sub.2-containing gas is a waste feed from an industrial plant.
Industrial plants from which the CO.sub.2-containing gas may be
obtained, e.g., as a waste feed from the industrial plant, may
vary. Industrial plants of interest include, but are not limited
to, power plants and industrial product manufacturing plants, such
as but not limited to chemical and mechanical processing plants,
refineries, cement plants, steel plants, etc., as well as other
industrial plants that produce CO.sub.2 as a byproduct of fuel
combustion or other processing step (such as calcination by a
cement plant). Waste feeds of interest include gaseous streams that
are produced by an industrial plant, for example as a secondary or
incidental product, of a process carried out by the industrial
plant.
[0075] Of interest in certain embodiments are waste streams
produced by industrial plants that combust fossil fuels, e.g.,
coal, oil, natural gas, as well as man-made fuel products of
naturally occurring organic fuel deposits, such as but not limited
to tar sands, heavy oil, oil shale, etc. In certain embodiments,
power plants are pulverized coal power plants, supercritical coal
power plants, mass burn coal power plants, fluidized bed coal power
plants, gas or oil-fired boiler and steam turbine power plants, gas
or oil-fired boiler simple cycle gas turbine power plants, and gas
or oil-fired boiler combined cycle gas turbine power plants. Of
interest in certain embodiments are waste streams produced by power
plants that combust syngas, i.e., gas that is produced by the
gasification of organic matter, e.g., coal, biomass, etc., where in
certain embodiments such plants are integrated gasification
combined cycle (IGCC) plants. Of interest in certain embodiments
are waste streams produced by Heat Recovery Steam Generator (HRSG)
plants. Waste streams of interest also include waste streams
produced by cement plants. Cement plants whose waste streams may be
employed in methods of the invention include both wet process and
dry process plants, which plants may employ shaft kilns or rotary
kilns, and may include pre-calciners. Each of these types of
industrial plants may burn a single fuel, or may burn two or more
fuels sequentially or simultaneously. A waste stream of interest is
industrial plant exhaust gas, e.g., a flue gas. By "flue gas" is
meant a gas that is obtained from the products of combustion from
burning a fossil or biomass fuel that are then directed to the
smokestack, also known as the flue of an industrial plant.
[0076] Where the CO.sub.2 containing gas is a multi-component
gaseous medium that includes CO.sub.2 and other gases, e.g., as
described above, the CO.sub.2 containing gas may be processed to
increase the partial pressure of CO.sub.2 in the gas prior to
contact with the CO.sub.2 capture liquid. In such instances, the
magnitude of increase of the CO.sub.2 in the CO.sub.2 containing
gas may vary, where in some instances the increase may be 5% (v/v)
or more, such as 10% (v/v) or more, 20% (v/v) or more, 25% (v/v) or
more or more, 50% (v/v) or more, 75% (v/v) or more, including 80 to
90% (v/v) or more. For example, where the gaseous components of
non-treated flue gas input stream contain <1-20% (v/v) CO.sub.2,
the gaseous stream may be processed to produce a treated flue gas
output stream that contains 30-90% (v/v) CO.sub.2. While separation
of non-CO.sub.2 components from a gaseous stream may be
accomplished using any convenient protocol, in some instances a
membrane mediated gas separation protocol is employed. While such
protocols may vary, a number of CO.sub.2 selective membrane
mediated gas separation protocols may be used, including but not
limited to: those described in Ramasubramian et al., "Membrane
processes for carbon capture from coal-fired power plant flue gas:
A modeling and cost study," J. Membrane Science (2012) 421-422:
299-310; Published PCT Application Serial No. WO/2006/050531 titled
"Membranes, Methods Of Making Membranes, And Methods Of Separating
Gases Using Membranes" and plastic-based, nano-engineered membranes
(e.g., from Membrane Research Group (MEMFO) at the Chemical
Engineering Department of the Norwegian University of Science and
Technology (NTNU)) as described in Biopact at
"http://news.mongabay.com/bioenergy/2007/09/new-plastic-based-nano-engine-
ered-co2.html"; the disclosures of which are herein incorporated by
reference.
[0077] The CO.sub.2 gas/liquid contactor may contact the CO.sub.2
containing gas with a variety of different types of liquids, where
liquids of interest include a variety of different aqueous media.
Aqueous media that may be contacted with the gaseous source of
CO.sub.2 (i.e., the CO.sub.2 containing gas) may vary, ranging from
fresh water to bicarbonate buffered aqueous media. Bicarbonate
buffered aqueous media employed in embodiments of the invention
include liquid media in which a bicarbonate buffer is present. As
such, liquid aqueous media of interest include dissolved CO.sub.2,
water, carbonic acid (H.sub.2CO.sub.3), bicarbonate ions
(HCO.sub.3.sup.-), protons (H.sup.+) and carbonate ions
(CO.sub.3.sup.2-). The constituents of the bicarbonate buffer in
the aqueous media are governed by the equation:
CO.sub.2+H.sub.2OH.sub.2CO.sub.3H.sup.++HCO.sub.3.sup.-2H.sup.++CO.sub.3-
.sup.2-
The pH of the bicarbonate buffered aqueous media may vary, ranging
in some instances from 7 to 11, such as 8 to 11, e.g., 8 to 10,
including 8 to 9. In some instances, the pH ranges from 8.2 to 8.7,
such as from 8.4 to 8.55. The bicarbonate buffered aqueous medium
may be a naturally occurring or man-made medium, as desired.
Naturally occurring bicarbonate buffered aqueous media include, but
are not limited to, waters obtained from seas, oceans, lakes,
swamps, estuaries, lagoons, brines, alkaline lakes, inland seas,
etc. Man-made sources of bicarbonate buffered aqueous media may
also vary, and may include brines produced by water desalination
plants, and the like. Of interest in some instances are waters that
provide for excess alkalinity, which is defined as alkalinity that
is provided by sources other than bicarbonate ion. In these
instances, the amount of excess alkalinity may vary, so long as it
is sufficient to provide 1.0 or slightly less, e.g., 0.9,
equivalents of alkalinity. Waters of interest include those that
provide excess alkalinity (meq/liter) of 30 or higher, such as 40
or higher, 50 or higher, 60 or higher, 70 or higher, 80 or higher,
90 or higher, 100 or higher, etc. Where such waters are employed,
no other source of alkalinity, e.g., NaOH, is required.
[0078] In some instances, the aqueous medium that is contacted with
the CO.sub.2 containing gas is one which, in addition to the
bicarbonate buffering system (e.g., as described above), further
includes an amount of divalent cations. Inclusion of divalent
cations in the aqueous medium can allow the concentration of
bicarbonate ion in the bicarbonate rich product to be increased,
thereby allowing a much larger amount of CO.sub.2 to become
sequestered as bicarbonate ion in the bicarbonate rich product. In
such instances, bicarbonate ion concentrations that exceed 5,000
ppm or greater, such as 10,000 ppm or greater, including 15,000 ppm
or greater may be achieved. For instance, calcium and magnesium
occur in seawater at concentrations of 400 and 1200 ppm
respectively. Through the formation of a bicarbonate rich product
using seawater (or an analogous water as the aqueous medium),
bicarbonate ion concentrations that exceed 10,000 ppm or greater
may be achieved.
[0079] In such embodiments, the total amount of divalent cation
source in the medium, which divalent cation source may be made up
of a single divalent cation species (such as Ca.sup.2+) or two or
more distinct divalent cation species (e.g., Ca.sup.2+, Mg.sup.2+,
etc.), may vary, and in some instances is 100 ppm or greater, such
as 200 ppm or greater, including 300 ppm or greater, such as 500
ppm or greater, including 750 ppm or greater, such as 1,000 ppm or
greater, e.g., 1,500 ppm or greater, including 2,000 ppm or
greater. Divalent cations of interest that may be employed, either
alone or in combination, as the divalent cation source include, but
are not limited to: Ca.sup.2+, Mg.sup.2+, Be.sup.2+, Ba.sup.2+,
Sr.sup.2+, Pb.sup.2+, Fe.sup.2+, Hg.sup.2+ and the like. Other
cations of interest that may or may not be divalent include, but
are not limited to: Na.sup.+, K.sup.+, NH.sup.4+, and Li.sup.+, as
well as cationic species of Mn, Ni, Cu, Zn, Cu, Ce, La, Al, Y, Nd,
Zr, Gd, Dy, Ti, Th, U, La, Sm, Pr, Co, Cr, Te, Bi, Ge, Ta, As, Nb,
W, Mo, V, etc. Naturally occurring aqueous media which include a
cation source, divalent or otherwise, and therefore may be employed
in such embodiments include, but are not limited to: aqueous media
obtained from seas, oceans, estuaries, lagoons, brines, alkaline
lakes, inland seas, etc.
[0080] In some instances, the aqueous medium is one that has been
subjected to an alkali enrichment process, such as a membrane
mediated alkali enrichment process, e.g., by receiving the aqueous
medium from an AE modular unit or subunit, such as described above.
Alkali enrichment processes of interest include, but are not
limited to, those described in U.S. patent application Ser. No.
14/636,043; the disclosures of which are herein incorporated by
reference.
[0081] In some instances, amines, including primary, secondary and
tertiary amines, may be provided as enhancers of CO.sub.2 solvation
and/or catalysts in bicarbonate ion formation. Primary amines of
interest include, but are not limited to: ammonia,
2-amino-2-hydroxymethyl-propane-1,3-diol (TRIS), monoethanolamine
(MEA), 2-amino-2-methyl-1-propanol (AMP), melamine,
amino-2-propanol, arginine, poly-arginine, etc. Secondary amines of
interest include, but are not limited to: diethanolamine (DEA),
morpholine, 2-(tert-butylamino)ethanol (TBAE),
bis(2-hydroxypropyl)amine, piperazine, am inoethylethanolamine,
N-[Tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid (TAPS),
etc. Tertiary amines of interest include, but are not limited to:
2,2',2'',2'''-(ethylenedinitrilo)tetraethanol (THEED),
methyldiethanolamine (MDEA), poly-melamine-formaldehyde (Tysol SM),
triethanolamine (TEOA), triethanolamine acetate,
tris(2-hydroxypropyl)amine, etc. When present, the amount of these
amines may vary, and in some instances ranges from 1% to 80%, such
as 10.2% to 21.7% dry wt. Further details regarding such enhancers
are provided in U.S. patent application Ser. No. 14/112,495; the
disclosures of which are herein incorporated by reference.
[0082] Contact of the CO.sub.2 containing gas and the liquid is
done under conditions sufficient to remove CO.sub.2 from the
CO.sub.2 containing gas (i.e., the CO.sub.2 containing gaseous
stream), and increase the dissolved inorganic carbon (including
bicarbonate ion) concentration of the aqueous medium. The CO.sub.2
containing gas may be contacted with the aqueous medium using any
convenient protocol, which may vary depending on the configuration
of the CO.sub.2/liquid contactor subunit of the system. For
example, contact protocols of interest include, but are not limited
to: direct contacting protocols, e.g., bubbling the gas through a
volume of the aqueous medium, concurrent contacting protocols,
i.e., contact between unidirectionally flowing gaseous and liquid
phase streams, countercurrent protocols, i.e., contact between
oppositely flowing gaseous and liquid phase streams, and the like.
Contact may be accomplished through use of infusers, bubblers,
fluidic Venturi reactors, spargers, gas filters, sprays, trays,
packed column reactors, aqueous froth filters (e.g., as described
in U.S. Pat. Nos. 7,854,791; 6,872,240; 6,616,733, as well as
Published U.S. Patent Application Nos. 20140245887 and
WO2005/014144; the disclosures of which are herein incorporated by
reference); and the like, as may be convenient. The process may be
a batch or continuous process.
[0083] In some instances, the gaseous source of CO.sub.2 is
contacted with the liquid using a microporous membrane contactor.
Microporous membrane contactors of interest include a microporous
membrane present in a suitable housing, where the housing includes
a gas inlet and a liquid inlet, as well a gas outlet and a liquid
outlet. The contactor is configured so that the gas and liquid
contact opposite sides of the membrane in a manner such that
molecule may dissolve into the liquid from the gas via the pores of
the microporous membrane. The membrane may be configured in any
convenient format, where in some instances the membrane is
configured in a hollow fiber format. Hollow fiber membrane reactor
formats which may be employed include, but are not limited to,
those described in U.S. Pat. Nos. 7,264,725; 6,872,240 and
5,695,545; the disclosures of which are herein incorporated by
reference. In some instances, the microporous hollow fiber membrane
contactor that is employed is a Liqui-Cel.RTM. hollow fiber
membrane contactor (available from Membrana, Charlotte N.C.), which
membrane contactors include polypropylene membrane contactors and
polyolefin membrane contactors.
[0084] Contact between the liquid and the CO.sub.2-containing gas
occurs under conditions such that a substantial portion of the
CO.sub.2 present in the CO.sub.2-containing gas goes into solution,
e.g., to produce bicarbonate ions. By substantial portion is meant
10% or more, such as 50% or more, including 80% or more. The
temperature of the capture liquid that is contacted with the
CO.sub.2-containing gas may vary. In some instances, the
temperature ranges from -1.4 to 100.degree. C., such as 20 to
80.degree. C. and including 40 to 70.degree. C. In some instances,
the temperature may range from -1.4 to 50.degree. C. or higher,
such as from -1.1 to 45.degree. C. or higher. In some instances,
cooler temperatures are employed, where such temperatures may range
from -1.4 to 4.degree. C., such as -1.1 to 0.degree. C. In some
instances, warmer temperatures are employed. For example, the
temperature of the capture liquid in some instances may be
25.degree. C. or higher, such as 30.degree. C. or higher, and may
in some embodiments range from 25 to 50.degree. C., such as 30 to
40.degree. C. The CO.sub.2-containing gas and the liquid are
contacted at a pressure suitable for production of a desired
CO.sub.2 charged liquid. In some instances, the pressure of the
contact conditions is selected to provide for optimal CO.sub.2
absorption, where such pressures may range from 1 ATM to 100 ATM,
such as 1 to 50 ATM, e.g., 20-30 ATM or 1 ATM to 10 ATM. Where
contact occurs at a location that is naturally at 1 ATM, the
pressure may be increased to the desired pressure using any
convenient protocol. In some instances, contact occurs where the
optimal pressure is present, e.g., at a location under the surface
of a body of water, such as an ocean or sea. In some instances,
contact of the CO.sub.2-containing gas and the alkaline aqueous
medium occurs a depth below the surface of the water (e.g., the
surface of the ocean), where the depth may range in some instances
from 10 to 1000 meters, such as 10 to 100 meters. In some
instances, the CO.sub.2 containing gas and CO.sub.2 capture liquid
are contacted at a pressure that provides for selective absorption
of CO.sub.2 from the gas, relative to other gases in the CO.sub.2
containing gas, such as N.sub.2, etc. In these instances, the
pressure at which the CO.sub.2 containing gas and capture liquid
are contacted may vary, ranging from 1 to 100 atmospheres (atm),
such as 1 to 10 atm and including 20 to 50 atm.
[0085] Contact between the liquid and the CO.sub.2-containing gas
results in the production of a DIC containing liquid. As such, in
charging the CO.sub.2 capture liquid with CO.sub.2, a CO.sub.2
containing gas may be contacted with CO.sub.2 capture liquid under
conditions sufficient to produce dissolved inorganic carbon (DIC)
in the CO.sub.2 capture liquid, i.e., to produce a DIC containing
liquid. The DIC is the sum of the concentrations of inorganic
carbon species in a solution, represented by the equation:
DIC=[CO.sub.2*]+[HCO.sub.3.sup.-]+[CO.sub.3.sup.2-], where
[CO.sub.2*] is the sum of carbon dioxide ([CO.sub.2]) and carbonic
acid ([H.sub.2CO.sub.3]) concentrations, [HCO.sub.3.sup.-] is the
bicarbonate concentration and [CO.sub.3.sup.2-] is the carbonate
concentration in the solution. The DIC of the aqueous media may
vary, and in some instances may be 5,000 ppm or greater, such as
10,000 ppm or greater, including 15,000 ppm or greater. In some
instances, the DIC of the aqueous media may range from 5,000 to
20,000 ppm, such as 7,500 to 15,000 ppm, including 8,000 to 12,000
ppm. The amount of CO.sub.2 dissolved in the liquid may vary, and
in some instances ranges from 0.05 to 40 mM, such as 1 to 35 mM,
including 25 to 30 mM. The pH of the resultant DIC containing
liquid may vary, ranging in some instances from 4 to 12, such as 6
to 11 and including 7 to 10, e.g., 8 to 8.5.
[0086] In some instances where the gaseous source of CO.sub.2 is a
multicomponent gaseous stream, contact occurs in a manner such that
CO.sub.2 is selectively absorbed by the CO.sub.2 absorbing aqueous
medium. By selectively absorbed is meant that the CO.sub.2
molecules preferentially go into solution relative to other
molecules in the multi-component gaseous stream, such as N.sub.2,
O.sub.2, Ar, CO, H.sub.2, CH.sub.4 and the like.
[0087] Where desired, the CO.sub.2 containing gas is contacted with
the capture liquid in the presence of a catalyst (i.e., an
absorption catalyst, either hetero- or homogeneous in nature) that
mediates the conversion of CO.sub.2 to bicarbonate. Of interest as
absorption catalysts are catalysts that, at pH levels ranging from
8 to 10, increase the rate of production of bicarbonate ions from
dissolved CO.sub.2. The magnitude of the rate increase (e.g., as
compared to control in which the catalyst is not present) may vary,
and in some instances is 2-fold or greater, such as 5-fold or
greater, e.g., 10-fold or greater, as compared to a suitable
control. In some instances, the catalyst is a carbon
dioxide-specific catalyst. Examples of carbon dioxide-specific
catalysts of interest include enzymes, such as carbonic anhydrases,
synthetic catalysts, such as those transition metal catalysts
described in Koziol et al., "Toward a Small Molecule, Biomimetic
Carbonic Anhydrase Model: Theoretical and Experimental
Investigations of a Panel of Zinc(II) Aza-Macrocyclic Catalysts,"
Inorganic Chemistry (2012) 51: 6803-6812, colloidal metal
particles, such as those described in Bhaduri and Siller, "Nickel
nanoparticles catalyse reversible hydration of carbon dioxide for
mineralization carbon capture and storage," Catalysis Science &
Technology (2013) DOI: 10.1039/c3cy20791a, and the like, e.g.,
colloidal metal oxide particles. Carbonic anhydrases of interest
include both naturally occurring (i.e., wild-type) carbonic
anhydrase, as well as mutants thereof. Specific carbonic anhydrases
of interest include, but are not limited to: .alpha.-CAs, which
include mammalian carbonic anhydrases, e.g., the cytosolic CAs
(CA-I, CA-II, CA-III, CA-VII and CA XIII) (CA1, CA2, CA3, CA7a,
CA13), mitochondrial CAs (CA-VA and CA-VB) (CA5A, CA5B), secreted
CAs (CA-VI) (CA6), and membrane-associated CAs (CA-IV, CA-IX,
CA-XII, CA-XIV and CA-XV) (CA4, CA9, CA12, CA14); .beta.-CAs, which
include prokaryotic and plant chloroplast CAs; .gamma.-CAs, e.g.,
such as found in methane-producing bacteria; and the like. Carbonic
anhydrases of interest further include those described in U.S. Pat.
No. 7,132,090, the disclosure of which is herein incorporated by
reference. Carbonic anhydrases of interest include those having a
specific activity of 10.sup.3 s.sup.-1 or more, such as 10.sup.4
s.sup.-1 to or more, including 10.sup.5 s.sup.-1 or more. When
employed, the catalyst is present in amount effective to provide
for the desired rate increase of bicarbonate production, e.g., as
described above. In some instances where the catalyst is an enzyme,
the activity of the enzyme in the aqueous media may range from
10.sup.3 to 10.sup.6 s.sup.-1, such as 10.sup.3 to 10.sup.4
s.sup.-1 and including 10.sup.5 to 10.sup.6 s.sup.-1. When
employed, a catalyst, e.g., enzyme such as a carbonic anhydrase,
can be made available in the reaction using any convenient
approach, such as through a solid support (such as a permeable
membrane) to which the catalyst is attached or otherwise with which
the catalyst is stably associated, through porous media and the
like having the catalyst stably associated therewith, large
surfaces with the catalyst immobilized therein (i.e., attached
thereto), or with the catalyst in solution, e.g., which may be
recovered following use. Examples of catalyst formats that may be
employed include, but are not limited to, those described in U.S.
Pat. No. 7,132,090; the disclosure of which is herein incorporated
by reference. Synthetic catalysts of interest include synthetically
prepared transition metal containing complexes, prepared as
biomimetic models of carbonic anhydrase enzymes, e.g., as described
above. Specific synthetic catalysts include, but are not limited
to: transition metal aza-macrocyclic catalysts, e.g., the zinc(II)
aza-macrocyclic catalysts having macrocyclic rings of 9, 12, 13, or
14, as described in Koziol et al., "Toward a Small Molecule,
Biomimetic Carbonic Anhydrase Model: Theoretical and Experimental
Investigations of a Panel of zinc(II) Aza-Macrocyclic Catalysts,"
Inorganic Chemistry (2012) 51: 6803-6812, imidazole- and
indole-based metal catalysts, e.g., the zinc(II) catalysts
described in United States Published Application No. US20110293496,
United States Published Application No. US20120199535 and United
States Published Application No. US20110151537, aminopyridyl-based
catalysts, e.g., as described in Feng et al., "A Highly Reactive
Mononuclear Zn(II) Complex for Phosphodiester Cleavage," Journal of
the American Chemical Society (2005) 127: 13470-13471,
pyrazolylhydroborato- and pyridylthiomethyl-based compounds, e.g.,
as described in Sattler and Parkin, "Structural characterization of
zinc bicarbonate compounds relevant to the mechanism of action of
carbonic anhydrase," Chemical Science (2012) 3: 2105-2109.
Synthetic catalysts of interest include those having a specific
activity of 10.sup.2 or more, such as 10.sup.3 s.sup.-1 or more,
including 10.sup.4 s.sup.-1 or more. When employed, the synthetic
catalyst is present in amount effective to provide for the desired
rate increase of bicarbonate production, e.g., as described above
for carbonic anhydrase. When employed, a synthetic catalyst, e.g.,
aza-macrocyclic transition metal catalyst, can be made available in
the reaction using any convenient approach, e.g., as described
above for carbonic anhydrase. Metal nanoparticles of interest
include commercially available as well as synthetically prepared
colloidal particles of transition metals. Specific colloidal metal
particles include, but are not limited to: metal nanoparticles,
e.g., the nickel nanoparticles (NiNPs) described in Bhaduri and
Siller, "Nickel nanoparticles catalyse reversible hydration of
carbon dioxide for mineralization carbon capture and storage,"
Catalysis Science & Technology (2013) DOI: 10.1039/c3cy20791a.
Colloidal metal particles of interest include those having a
specific activity of 10.sup.2 or more, such as 10.sup.3 s.sup.-1 or
more, including 10.sup.4 s.sup.-1 or more. When employed, the
colloidal metal particles are present in amount effective to
provide for the desired rate increase of bicarbonate production,
e.g., as described above for carbonic anhydrase. When employed, the
colloidal metal particles, e.g., transition metal nanoparticles,
can be made available in the reaction using any convenient
approach, e.g., as described above for carbonic anhydrase. Metal
nanoparticle catalysts finding use in embodiments described herein
are further described in U.S. Provisional Application Ser. No.
61/793,585 filed on Mar. 15, 2013; the disclosure of which is
herein incorporated by reference. Catalysts of interest are further
described in U.S. patent application Ser. No. 14/112,495; the
disclosure of which is herein incorporated by reference.
[0088] The CO.sub.2 gas/liquid contactor unit/subunit produces a
CO.sub.2 charged liquid. In some embodiments, the resultant
CO.sub.2 charged liquid is a bicarbonate-containing liquid, where
in in some instances, the bicarbonate-containing liquid is a two
phase liquid which includes droplets of a liquid condensed phase
(LCP) in a bulk liquid, e.g., bulk solution. By "liquid condensed
phase" or "LCP" is meant a phase of a liquid solution which
includes bicarbonate ions wherein the concentration of bicarbonate
ions is higher in the LCP phase than in the surrounding, bulk
liquid.
[0089] LCP droplets are characterized by the presence of a
meta-stable bicarbonate-rich liquid precursor phase in which
bicarbonate ions associate into condensed concentrations exceeding
that of the bulk solution and are present in a non-crystalline
solution state. The LCP contains all of the components found in the
bulk solution that is outside of the interface. However, the
concentration of the bicarbonate ions is higher than in the bulk
solution. In those situations where LCP droplets are present, the
LCP and bulk solution may each contain ion-pairs and pre-nucleation
clusters (PNCs). When present, the ions remain in their respective
phases for long periods of time, as compared to ion-pairs and PNCs
in solution.
[0090] The bulk phase and LCP are characterized by having different
K.sub.eq, different viscosities, and different solubilities between
phases. Bicarbonate, carbonate, and divalent ion constituents of
the LCP droplets are those that, under appropriate conditions, may
aggregate into a post-critical nucleus, leading to nucleation of a
solid phase and continued growth. While the association of
bicarbonate ions with divalent cations, e.g., Ca.sup.2+, in the LCP
droplets may vary, in some instances bidentate bicarbonate
ion/divalent cation species may be present. For example, in LCPs of
interest, Ca.sup.2+/bicarbonate ion bidentate species may be
present. While the diameter of the LCP droplets in the bulk phase
of the LCP may vary, in some instances the droplets have a diameter
ranging from 1 to 500 nm, such as 10 to 100 nm. In the LCP, the
bicarbonate to carbonate ion ratio, (i.e., the
HCO.sub.3.sup.-/CO.sub.3.sup.2- ratio) may vary, and in some
instances is 10 or greater to 1, such as 20 or greater to 1,
including 25 or greater to 1, e.g., 50 or greater to 1. Additional
aspects of LCPs of interest are found in Bewernitz et al., "A
metastable liquid precursor phase of calcium carbonate and its
interactions with polyaspartate," Faraday Discussions. 7 Jun. 2012.
DOI: 10.1039/c2fd20080e (2012) 159: 291-312. The presence of LCPs
may be determined using any convenient protocol, e.g., the
protocols described in Faatz et al., Advanced Materials, 2004, 16,
996-1000; Wolf et al., Nanoscale, 2011, 3, 1158-1165; Rieger et
al., Faraday Discussions, 2007, 136, 265-277; and Bewernitz et al.,
Faraday Discussions, 2012, 159, 291-312.
[0091] Where the bicarbonate-containing solution has two phases,
e.g., as described above, the first phase may have a higher
concentration of bicarbonate ion than a second phase, where the
magnitude of the difference in bicarbonate ion concentration may
vary, ranging in some instances from 0.1 to 4, such as 1 to 2. For
example, in some embodiments, a bicarbonate rich product may
include a first phase in which the bicarbonate ion concentration
ranges from 1000 ppm to 5000 ppm, and a second phase where the
bicarbonate ion concentration is higher, e.g., where the
concentration ranges from 5000 ppm to 6000 ppm or greater, e.g.,
7000 ppm or greater, 8000 ppm or greater, 9000 ppm or greater,
10,000 ppm or greater, 25,000 ppm or greater, 50,000 ppm or
greater, 75,000 ppm or greater, 100,000 ppm, 500,000 or
greater.
[0092] Where desired, following production of the LCP containing
liquid, the resultant LCP containing liquid may be manipulated to
increase the amount or concentration of LCP droplets in the liquid.
As such, following production of the bicarbonate containing liquid,
the bicarbonate containing liquid may be further manipulated to
increase the concentration of bicarbonate species and produce a
concentrated bicarbonate liquid. In some instances, the bicarbonate
containing liquid is manipulated in a manner sufficient to increase
the pH. In such instances, the pH may be increased by an amount
ranging from 0.1 to 6 pH units, such as 1 to 3 pH units. The pH of
the concentrated bicarbonate liquid of such as step may vary,
ranging in some instances from 5.0 to 13.0, such as 6.5 to 8.5. The
concentration of bicarbonate species in the concentrated
bicarbonate liquid may vary, ranging in some instances from 1 to
1000 mM, such as 20 to 200 mM and including 50 to 100 mM. In some
instances, the concentrated bicarbonate liquid may further include
an amount of carbonate species. While the amount of carbonate
species may vary, in some instances the carbonate species is
present in an amount ranging from 0.01 to 800 mM, such as 10 to 100
mM. The pH of the bicarbonate liquid may be increased using any
convenient protocol. In some instances, an electrochemical protocol
may be employed to increase the pH of the bicarbonate liquid to
produce the concentrated bicarbonate liquid. Electrochemical
protocols may vary, and in some instances include those employing
an ion exchange membrane and electrodes, e.g., as described in U.S.
Pat. Nos. 8,357,270; 7,993,511; 7,875,163; and 7,790,012; the
disclosures of which are herein incorporated by reference.
Alkalinity of the bicarbonate containing liquid may also be
accomplished by adding a suitable amount of a chemical agent to the
bicarbonate containing liquid. Chemical agents for effecting proton
removal generally refer to synthetic chemical agents that are
produced in large quantities and are commercially available. For
example, chemical agents for removing protons include, but are not
limited to, hydroxides, organic bases, super bases, oxides,
ammonia, and carbonates. Hydroxides include chemical species that
provide hydroxide anions in solution, including, for example,
sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium
hydroxide (Ca(OH).sub.2), or magnesium hydroxide (Mg(OH).sub.2).
Organic bases are carbon-containing molecules that are generally
nitrogenous bases including primary amines such as methyl amine,
secondary amines such as diisopropylamine, tertiary such as
diisopropylethylamine, aromatic amines such as aniline,
heteroaromatics such as pyridine, imidazole, and benzimidazole, and
various forms thereof. In some embodiments, an organic base
selected from pyridine, methylamine, imidazole, benzimidazole,
histidine, and a phophazene is used to remove protons from various
species (e.g., carbonic acid, bicarbonate, hydrogen ion, etc.) for
precipitation of precipitation material. In some embodiments,
ammonia is used to raise pH to a level sufficient to precipitate
precipitation material from a solution of divalent cations and an
industrial waste stream. Super bases suitable for use as
proton-removing agents include sodium ethoxide, sodium amide
(NaNH.sub.2), sodium hydride (NaH), butyl lithium, lithium
diisopropylamide, lithium diethylamide, and lithium
bis(trimethylsilyl)amide. Oxides including, for example, calcium
oxide (CaO), magnesium oxide (MgO), strontium oxide (SrO),
beryllium oxide (BeO), and barium oxide (BaO) are also suitable
proton-removing agents that may be used.
[0093] Another type of further manipulation following production
that may be employed is a dewatering of the initial bicarbonate
containing liquid to produce a concentrated bicarbonate containing
liquid, e.g., a concentrated LCP liquid. Dewatering may be
accomplished using any convenient protocol, such as via contacting
the LCP composition with a suitable membrane, such as an
ultrafiltration membrane, to remove water and certain species,
e.g., NaCl, HCl, H.sub.2CO.sub.3 but retain LCP droplets, e.g., as
described in greater detail in U.S. application Ser. No.
14/112,495; the disclosure of which is herein incorporated by
reference.
[0094] As described above, catalysts may be employed in some
embodiments, e.g., where a carbonic anhydrase (CA) is employed to
increase the rate of reaction whereby gaseous carbon dioxide
(CO.sub.2) and water convert to bicarbonate (HCO.sub.3.sup.-) ion
and a proton (H.sup.+), or vice versa. When dissolved in aqueous
solution, for example, in a solution used as a carbon capture
solution and having an alkalinity concentration in the range of,
for example, 1-2,000 millimolar (mM) equivalents, such as but not
limited to 5-50, 75-800 or 900-2,200 mM alkalinity equivalents, CA
significantly increases the rate of formation of HCO.sub.3.sup.-
upon contacting the solution with, for example, flue gas from an
industrial emitter where the partial pressure of CO.sub.2 in the
flue gas is, for example, 0.1-99.9% by weight, such as but not
limited to 0.5-1.5%, 4.0-17% or 45-98% CO2 by weight. Because the
molecular mass of CA enzymes is on the order of kilodaltons (kDa),
for example, 1-70 kDa, such as but not limited to 4-8, 15-30 or
45-65 kDa, soluble CA may be recovered by passing the solution
through a membrane filtration system, for example, loose reverse
osmosis membrane systems, nanofiltration membrane systems or tight
ultrafiltration systems, that reject CA but pass solutions rich in
HCO.sub.3.sup.- ion, such as bicarbonate-rich liquid condensed
phase (LCP) solutions as described above. The reject solution from
the membrane system, one that contains the rejected CA, may be
recirculated as desired in the process so as to continuously
increase the rate of CO.sub.2 conversion to HCO.sub.3.sup.- from
contacting the capture liquid with a CO.sub.2 containing gas. The
permeate solution from the membrane system, e.g., one that contains
the passed LCP, may be further concentrated as desired, e.g.,
through a membrane filtration system (such as described above), for
example, a nanofiltration membrane system, then used in a
mineralization process, e.g., as described below.
CO.sub.2 Sequestering Carbonate Production
[0095] Following preparation of the CO.sub.2 charged liquid, e.g.,
bicarbonate-containing solution, the bicarbonate-containing
solution or component thereof (e.g., LCP) may be manipulated to
produce solid phase carbonate compositions, and therefore sequester
CO.sub.2 from the initial CO.sub.2-containing gas into a solid form
and produce a CO.sub.2 sequestering carbonate material. By CO.sub.2
sequestering carbonate material is meant a material that stores a
significant amount of CO.sub.2 in a storage-stable format, such
that CO.sub.2 gas is not readily produced from the material and
released into the atmosphere. In certain embodiments, the
CO.sub.2-sequestering material includes 5% or more, such as 10% or
more, including 25% or more, for instance 50% or more, such as 75%
or more, including 90% or more of CO.sub.2, e.g., present as one or
more carbonate compounds. The CO.sub.2-sequestering materials
produced in accordance with methods of the invention may include
one or more carbonate compounds, e.g., as described in greater
detail below. The amount of carbonate in the CO.sub.2-sequestering
material, e.g., as determined by coulometry, may be 40% or higher,
such as 70% or higher, including 80% or higher.
[0096] CO.sub.2 sequestering materials, e.g., as described herein,
provide for long-term storage of CO.sub.2 in a manner such that
CO.sub.2 is sequestered (i.e., fixed) in the material, where the
sequestered CO.sub.2 does not become part of the atmosphere. When
the material is maintained under conditions conventional for its
intended use, the material keeps sequestered CO.sub.2 fixed for
extended periods of time (e.g., 1 year or longer, 5 years or
longer, 10 years or longer, 25 years or longer, 50 years or longer,
100 years or longer, 250 years or longer, 1000 years or longer,
10,000 years or longer, 1,000,000 years or longer, or even
100,000,000 years or longer) without significant, if any, release
of the CO.sub.2 from the material. With respect to the
CO.sub.2-sequestering materials, when they are employed in a manner
consistent with their intended use and over their lifetime, the
amount of degradation, if any, as measured in terms of CO.sub.2 gas
release from the product will not exceed 10% per year, such as 5%
per year, and in certain embodiments, 1% per year. In some
instances, CO.sub.2-sequestering materials provided by the
invention do not release more than 1%, 5%, or 10% of their total
CO.sub.2 when exposed to normal conditions of temperature and
moisture, including rainfall of normal pH, for there intended use,
for at least 1, 2, 5, 10, or 20 years, or for more than 20 years,
for example, for more than 100 years. Any suitable surrogate marker
or test that is reasonably able to predict such stability may be
used. For example, an accelerated test comprising conditions of
elevated temperature and/or moderate to more extreme pH conditions
is reasonably able to indicate stability over extended periods of
time. For example, depending on the intended use and environment of
the composition, a sample of the composition may be exposed to 50,
75, 90, 100, 120, or 150.degree. C. for 1, 2, 5, 25, 50, 100, 200,
or 500 days at between 10% and 50% relative humidity, and a loss
less than 1%, 2%, 3%, 4%, 5%, 10%, 20%, 30%, or 50% of its carbon
may be considered sufficient evidence of stability of materials of
the invention for a given period (e.g., 1, 10, 100, 1000, or more
than 1000 years).
[0097] In certain instances of such embodiments, the
bicarbonate-containing liquid or component thereof (e.g., LCP) is
combined with a divalent cation source. Any convenient divalent
cation source may be employed. Divalent cations, such as alkaline
earth metal cations, e.g., calcium and magnesium cations, are of
interest. Cation sources of interest include, but are not limited
to, the brine from water processing facilities, such as sea water
desalination plants, brackish water desalination plants,
groundwater recovery facilities, wastewater facilities, and the
like, which produce a concentrated stream of solution high in
cation contents. Also of interest as cation sources are naturally
occurring sources, such as, but not limited to, native seawater and
geological brines, which may have varying cation concentrations and
may also provide a ready source of cations to trigger the
production of carbonate solids from a bicarbonate rich product or
component thereof (e.g., LCP), such as described in greater detail
below. A given divalent cation source may be a solid or liquid, as
desired. For example, a liquid divalent cation source may be
employed. Alternatively, a solid divalent cation source, such as a
particulate source (e.g., a powder) may be employed.
[0098] During the production of solid carbonate compositions from
the bicarbonate-containing solution or component thereof (e.g.,
LCP), one mol of CO.sub.2 may be produced for every 2 mols of
bicarbonate ion from the bicarbonate-containing solution or
component thereof (e.g., LCP). For example, where solid carbonate
compositions are produced by adding calcium cation to the
bicarbonate-containing solution or component thereof (e.g., LCP),
the production of solid carbonate compositions, e.g., the form of
amorphous calcium carbonate minerals, may proceed according to the
following reaction:
2HCO.sub.3.sup.-+Ca.sup.++CaCO.sub.3.H.sub.2O+CO.sub.2
Ca.sup.++.sub.(aq)+2HCO.sub.3(aq).sup.-CaCO.sub.3(s)+H.sub.2O.sub.(l)+CO-
.sub.2(g)
[0099] While the above reaction shows the production of 1 mol of
CO.sub.2, 2 moles of CO.sub.2 from the CO.sub.2-containing gas were
initially converted to bicarbonate. As such, the overall process
sequesters a net 1 mol of CO.sub.2 and therefore is an effective
CO.sub.2 sequestration process, with a downhill thermodynamic
energy profile of -34 kJ mol.sup.-1 for the above reaction.
[0100] Where carbonate compositions are produced, e.g., as
described above, from the CO.sub.2 sequestration protocol, the
product carbonate compositions may vary greatly. The carbonate
product may include one or more different carbonate compounds, such
as two or more different carbonate compounds, e.g., three or more
different carbonate compounds, five or more different carbonate
compounds, etc., including non-distinct, amorphous carbonate
compounds. Carbonate compounds may be compounds having a molecular
formulation X.sub.m(CO.sub.3).sub.n where X is any element or
combination of elements that can chemically bond with a carbonate
group or its multiple, wherein X is in certain embodiments an
alkaline earth metal and not an alkali metal; wherein m and n are
stoichiometric positive integers. These carbonate compounds may
have a molecular formula of X.sub.m(CO.sub.3).sub.n.H.sub.2O, where
there are one or more structural waters in the molecular formula.
The amount of carbonate in the product, as determined by coulometry
using the protocol described as coulometric titration, may be 40%
or higher, such as 70% or higher, including 80% or higher.
[0101] The carbonate compounds of the precipitated products may
include a number of different cations, such as but not limited to
ionic species of: calcium, magnesium, sodium, potassium, sulfur,
boron, silicon, strontium, and combinations thereof. Of interest
are carbonate compounds of divalent metal cations, such as calcium
and magnesium carbonate compounds. Specific carbonate compounds of
interest include, but are not limited to: calcium carbonate
minerals, magnesium carbonate minerals and calcium magnesium
carbonate minerals. Calcium carbonate minerals of interest include,
but are not limited to: calcite (CaCO.sub.3), aragonite
(CaCO.sub.3), vaterite (CaCO.sub.3), ikaite (CaCO.sub.3.6H.sub.2O),
and amorphous calcium carbonate (CaCO.sub.3). Magnesium carbonate
minerals of interest include, but are not limited to magnesite
(MgCO.sub.3), barringtonite (MgCO.sub.3.2H.sub.2O), nesquehonite
(MgCO.sub.3.3H.sub.2O), lanfordite (MgCO.sub.3.5H.sub.2O),
hydromagnisite, and amorphous magnesium calcium carbonate
(MgCO.sub.3). Calcium magnesium carbonate minerals of interest
include, but are not limited to dolomite (CaMg)(CO.sub.3).sub.2),
huntite (Mg.sub.3Ca(CO.sub.3).sub.4) and sergeevite
(Ca.sub.2Mg.sub.11(CO.sub.3).sub.13.H.sub.2O). The carbonate
compounds of the product may include one or more waters of
hydration, or may be anhydrous. In some instances, the amount by
weight of magnesium carbonate compounds in the precipitate exceeds
the amount by weight of calcium carbonate compounds in the
precipitate. For example, the amount by weight of magnesium
carbonate compounds in the precipitate may exceed the amount by
weight calcium carbonate compounds in the precipitate by 5% or
more, such as 10% or more, 15% or more, 20% or more, 25% or more,
30% or more. In some instances, the weight ratio of magnesium
carbonate compounds to calcium carbonate compounds in the product
ranges from 1.5-5 to 1, such as 2-4 to 1 including 2-3 to 1. In
some instances, the product may include hydroxides, such as
divalent metal ion hydroxides, e.g., calcium and/or magnesium
hydroxides.
Carbonate Precipitation
[0102] In some instances, solid carbonate products are produced
using a precipitation protocol, e.g., a protocol which results in
the production of a slurry that includes precipitated carbonate
products. Precipitation of solid carbonate compositions from a
dissolved inorganic carbon (DIC) composition (e.g., an LCP
composition as employed in a bicarbonate-mediated sequestration
protocol), such as described above, results in the production of a
composition that includes both precipitated solid carbonate
compositions, as well as the remaining liquid from which the
precipitated product was produced (i.e., the mother liquor). This
composition may be present as a slurry of the precipitate and
mother liquor. The resultant slurry is then output from the modular
system, e.g., for storage or further manipulation, as desired. For
example, the resultant precipitated product (i.e., solid carbonate
composition) may be separated from the resultant mother liquor,
e.g., by drying the solid carbonate composition to produce a dried
solid carbonate composition, by subjecting the resultant slurry to
a dewatering protocol to produce a solid carbonate material, etc.
The term solid carbonate material refers to a variety of non-liquid
formulations, such as paste like, putty like and dry compositions.
In some instances, the dewatering includes contacting the
precipitated carbonate composition with a membrane, e.g., an
ultrafiltration membrane, to produce the solid carbonate material.
In some instances, the method further includes producing unit sized
objects from the paste, which unit sized objects may be cured, as
desired, e.g., by contacting the objections with a setting
solution. In some instances, the dewatering includes extruding the
precipitated carbonate composition. In some instances, the
extruding includes applying pressure to remove liquid from the
paste. In some instances, the extruding includes applying negative
pressure to remove air from the paste. In some instances, the
method further includes introducing one or more property modulators
into the process so that the solid carbonate material comprises the
property modulator. Property modulators of interest may vary, and
include but are not limited to reflectance modulators, pigments,
biocides etc. The resultant product may further be disposed of or
refined, e.g., to make various building materials, etc. Further
details of carbonate precipitation protocols, products produced
thereby and further uses thereof are described in U.S. patent
application Ser. No. 14/636,043; the disclosure of which is herein
incorporated by reference.
Non-Slurry Continuous Production Protocols
[0103] Instead of precipitation protocols, e.g., as described
above, also of interest are non-slurry continuous protocols for
production of CO.sub.2 sequestering materials. As the processes are
continuous, they are not batch processes. In practicing continuous
processes of the invention, a divalent cation source, e.g., as
described above, is introduced into a flowing aqueous bicarbonate
and/or carbonate containing liquid (e.g., a bicarbonate rich
product containing liquid as described above) under conditions
sufficient such that a non-slurry solid phase CO.sub.2 sequestering
carbonate material is produced in the flowing aqueous bicarbonate
rich product.
[0104] By "flowing" aqueous liquid is meant a liquid (such as
described above) that is moving in or as in a stream, such that it
is not stationary. The flow rate of the liquid, e.g., as determined
relative to the site or location at which the divalent cations are
introduced into the liquid, may vary. In some instances, the flow
rate of the liquid ranges from 0.1 to 10 m/second, such as 0.2 to
2.0 m/s. In some instances, the flow rate of the liquid ranges from
10 LPD to 40B LPD (liters per day), such as 400,000 LPD to 12M LPD.
In some instances, the liquid is flowing through a housing or
containment structure, where the length of the flow path of the
liquid may vary. In some instances, the flow path ranges in length
from 0.10 m to 100 m, such as 1 m to 10 m and including 1 m to 5.0
m. Along a given flow path, the flow rate of the liquid may be
constant or varied, as desired. For example, the flow rate may be
faster at the site of divalent cation introduction relative to the
site of CO.sub.2 sequestering carbonate material production. The
magnitude of any change in flow rate may vary, where the magnitude
of such change, if present, ranges in some instances from 2 to 100
times, such as 5 to 20 times. The flow rate may be varied using any
convenient protocol, e.g., by placing barriers in the flow path,
adjusting the elevation of the flow path, etc.
[0105] The amount of divalent cation source that is introduced into
the liquid is sufficient to provide for the desired solid phase
CO.sub.2 sequestering carbonate material. While the amount may
vary, in some instances the amount that is introduced into the
liquid is sufficient to provide a concentration of divalent cation
in the liquid at a location in the flow path just before material
production that ranges from 10 ppm to 10,000 ppm, such as 200 ppm
to 2,000 ppm. Where the divalent cation source is a liquid source
having a divalent cation concentration ranging from 500 ppm to
20,000 ppm, such as 1000 ppm to 5000 ppm, the liquid divalent
cation source may be introduced into the flowing liquid at a rate
ranging from 0.1 m/s to 10 m/s, such as 0.2 m/s to 4 m/s.
Alternatively, where the divalent cation source is a dry powder
having a divalent cation concentration of 10 to 80% wt/wt., the
power divalent cation source may be introduced into the flowing
liquid at a rate ranging from 0.2 m/s to 10 m/s, such as 0.2 m/s to
4 m/s.
[0106] As the process is a continuous process, upon initiation of
the process no solid carbonate material product, apart from any
seed structure (e.g., as described below), will be present in the
production zone of the flow path before introduction of the
divalent cations into the flowing liquid. In some embodiments, at a
time following the initial introduction of the divalent cations, a
precursor composition forms at location downstream from the
divalent cation introduction site. While the time between initial
introduction and the formation of the non-solid precursor structure
may vary, in some instances the time ranges from 0.001 sec to 10
min, such as 0.1 sec to 1 min. In these embodiments, the precursor
composition forms at a distance from the divalent cation
introduction site, where the location may be downstream from the
divalent cation introduction site by a varying distance, where this
distance may range in some instances from 1 cm to 10 m, such as 2
cm to 2 m. The precursor composition may be characterized as a
transient zone where the initial clusters of carbonate mineral have
not yet formed a polytype of the carbonate mineral and are highly
unstable, making them more likely to accrete on to a solid surface
than to homogeneously crystallize in solution to become part of a
slurry.
[0107] The zone of accretion (carbonate growth) is defined by
saturation index where:
SI=log(IAP/Ksp)
[0108] (IAP is the ion activity product over Ksp solubility
product) in relation to the activation energy (Stumm & Morgan
1981) where:
.DELTA.G=16.pi..sigma.{circumflex over ( )}3v{circumflex over (
)}2/[3(kT Ln 5){circumflex over ( )}2
[0109] where .sigma. is the interfacial energy, v is the molecular
volume, k is Boltzmann's constant, T is the absolute temperature,
Ln is the natural logarithm operator, S is the relative
supersatruation.
[0110] The zone of accretion can furthermore be modified by
pressure, temperature and flow rate. Supersaturated solutions
between 1.times. and 1000.times. supersaturation are of interest,
such as 10.times. and 500.times. super saturation and including
11.times. and 300.times. supersaturation. The zone of accretion may
be of a transient nature such that periodic dosing of various
divalent cations results in periodicity of saturation index flows
through the system. Also periodic alkaline component solutions can
be introduced to brine solutions or solutions containing divalent
cations creating similar response. Periodicity similar to diurnal
cyclic variance seen in geologic settings where beach rock forms
(Ref. Sedimentary Geology, 33 (1982) 157-172.
[0111] The system may be catalyzed by pH modification in the acidic
or basic direction or using any convenient protocol. Introduction
of CO.sub.2 or carbonic acid into the reactor vessel is one
modality of acidifying the system and modifying the zone of
accretion. Another modality is the introduction of acid, e.g.,
hydrochloric acid (HCl). In such instances, HCl concentrations
between 0.01 and 20%, such as between 0.5 and 10%, including
between 1 and 3% may be employed. In some instances, an
electrochemical protocol may be employed to increase the pH of the
bicarbonate liquid to produce the concentrated bicarbonate liquid.
Electrochemical protocols may vary, and in some instances include
those employing an ion exchange membrane and electrodes, e.g., as
described in U.S. Pat. Nos. 8,357,270; 7,993,511; 7,875,163; and
7,790,012; the disclosures of which are herein incorporated by
reference. Alkalinity modulation, e.g., increase or decrease, of
the bicarbonate containing liquid may also be accomplished by
adding a suitable amount of a chemical agent to the bicarbonate
containing liquid. Chemical agents for effecting proton removal
generally refer to synthetic chemical agents that are produced in
large quantities and are commercially available. For example,
chemical agents for removing protons include, but are not limited
to, hydroxides, organic bases, super bases, oxides, ammonia, and
carbonates. Hydroxides include chemical species that provide
hydroxide anions in solution, including, for example, sodium
hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide
(Ca(OH).sub.2), or magnesium hydroxide (Mg(OH).sub.2). Organic
bases are carbon-containing molecules that are generally
nitrogenous bases including primary amines such as methyl amine,
secondary amines such as diisopropylamine, tertiary such as
diisopropylethylamine, aromatic amines such as aniline,
heteroaromatics such as pyridine, imidazole, and benzimidazole, and
various forms thereof. In some embodiments, an organic base
selected from pyridine, methylamine, imidazole, benzimidazole,
histidine, and a phophazene is used to remove protons from various
species (e.g., carbonic acid, bicarbonate, hydrogen ion, etc.) for
precipitation of precipitation material. In some embodiments,
ammonia is used to raise pH to a level sufficient to precipitate
precipitation material from a solution of divalent cations and an
industrial waste stream. Super bases suitable for use as
proton-removing agents include sodium ethoxide, sodium amide
(NaNH.sub.2), sodium hydride (NaH), butyl lithium, lithium
diisopropylamide, lithium diethylamide, and lithium
bis(trimethylsilyl)amide. Oxides including, for example, calcium
oxide (CaO), magnesium oxide (MgO), strontium oxide (SrO),
beryllium oxide (BeO), and barium oxide (BaO) are also suitable
proton-removing agents that may be used.
[0112] Various condition parameters may be modulated during a given
method to achieve a desired production of CO.sub.2 sequestering
carbonate material. For example, pressure may be maintained at a
constant level along the flow path, or pressure may be modulated
(i.e., varied) along the flow path, as desired. While the pressure
may vary in a given method, in some instances the pressure ranges
from 0.1 atm to 100 atm, such as 1 atm to 10 atm. In some
embodiments, the pressure is varied, e.g., decreased, along the
flow path. The magnitude of any change in pressure may vary, where
the magnitude of such change, if present, ranges in some instances
from 2 to 100 times, such as 5 to 10 times. The pressure may be
varied using any convenient protocol, e.g., by reducing or
increasing the volume of the flow path at a given location, fluid
regime, etc. In some instances, the pressure is reduced at the
location of CO.sub.2 sequestering carbonate material relative to
the divalent cation introduction site, e.g., where the magnitude of
reduction may range from 0% to 100 or more %, such as 10% to
100%.
[0113] Alternatively or in addition, the temperature may be
maintained at a constant level along the flow path, or modulated
(i.e., varied) along the flow path, as desired. While the
temperature may vary in a given method, in some instances the
temperature ranges from -4.degree. C. to +99.degree. C., such as
0.degree. C. to 80.degree. C. In some embodiments, the temperature
is varied, e.g., decreased or increased, along the flow path. The
magnitude of any change in temperature may vary, where the
magnitude of such change, if present, ranges in some instances from
1 to 50.degree. C., such as 2 to 25.degree. C. The temperature may
be varied using any convenient protocol, e.g., by heating or
cooling the liquid at various location(s) of the flow path.
[0114] In some instances, the solid phase CO.sub.2 sequestering
carbonate material is produced at a location that is downstream
from the divalent cation source introduction site. By downstream is
meant a location along the flow path in the direction of fluid flow
that is separated from the divalent cation introduction site. The
distance between the divalent cation introduction site and the
material production site may vary, ranging in some instances from 1
cm to 2.5 km, such as 5 cm to 100 m.
[0115] Introduction of the divalent cation source into the flowing
aqueous bicarbonate rich product containing liquid as described
above results in the production of a non-slurry solid phase
CO.sub.2 sequestering carbonate material. By non-slurry solid phase
is meant a solid phase that is not a slurry, i.e., if maintained
under static conditions it would not be a suspension of small
particles in a liquid. As such, upon cessation of flowing liquid
through the material production zone, the solid phase material
produced according to embodiments of the methods settles (i.e.,
falls) out of suspension in 10 min or less, such as 5 min or less,
and in some instances 1 min or less. As the material is a
non-slurry solid phase, in some instances the longest dimension of
a given amount of the produced material is 30 .mu.m or greater,
such as 100 .mu.m or greater, including 1000 .mu.m or greater. In
some instances the product material is a particulate composition
that is made up of a plurality of distinct particles. In such
instances, the plurality of distinct particles may vary in size,
ranging in some instances from 10 to 1,000,000 .mu.m, such as 1,000
to 100,000 .mu.m and including 5,000 to 50,000 .mu.m. In such
compositions, the mean diameter of the particles may vary, and in
some instances ranges from 20 to 20,000 .mu.m, such as 200 to 8,000
.mu.m. The particles of such compositions may be regular or
irregular, where in some instances the particles are ooids. In
these embodiments, the carbonate material may be produced by
successive coating of carbonate compounds onto growing particles,
resulting in production of particulates as described above. In some
instances, the non-slurry solid phase CO.sub.2 sequestering
carbonate material is a lithified unitary object. While the
dimensions of such an object may vary, in some instances the object
has a longest dimension ranging from 1,000 to 100,000, such as
5,000 to 50,000 .mu.m. In these instances, the lithified object(s)
produced in the production zone may be produced by carbonate
materials forming in pores or interstices of pre-existing
structures, uniting and agglomerating such structures into
lithified masses.
[0116] The CO.sub.2 sequestering carbonate material produced as
described above is a freshwater stable carbonate. By freshwater
stable is meant that the carbonate material is a meta-stable
carbonate compound(s) that, upon combination with fresh water,
dissolves and produces a different mineral that is more stable in
fresh water. The solubility of the product material in freshwater
may vary, but in some instances has a Ksp of 10.sup.-7 or less,
such as 10.sup.-6 or less, including 10.sup.-5 or less.
[0117] In some instances, the method includes producing the solid
phase CO.sub.2 sequestering carbonate material in association with
a seed structure. By seed structure is meant a solid structure or
material that is present flowing liquid, e.g., in the material
production zone, prior to divalent cation introduction into the
liquid. By "in association with" is meant that the material is
produced on at least one of a surface of or in a depression, e.g.,
a pore, crevice, etc., of the seed structure. In such instances, a
composite structure of the carbonate material and the seed
structure is produced. In some instances, the product carbonate
material coats a portion, if not all of, the surface of a seed
structure. In some instances, the product carbonate materials fills
in a depression of the seed structure, e.g., a pore, crevice,
fissure, etc.
[0118] Seed structures may vary widely as desired. The term "seed
structure" is used to describe any object upon and/or in which the
product carbonate material forms. Seed structures may range from
singular objects or particulate compositions, as desired. Where the
seed structure is a singular object, it may have a variety of
different shapes, which may be regular or irregular, and a variety
of different dimensions. Shapes of interest include, but are not
limited to, rods, meshes, blocks, etc. Also of interest are
particulate compositions, e.g., granular compositions, made up of a
plurality of particles. Where the seed structure is a particulate
composition, the dimensions of particles may vary, ranging in some
instances from 0.01 to 1,000,000 .mu.m, such as 0.1 to 100,000
.mu.m.
[0119] The seed structure may be made up of any convenient material
or materials. Materials of interest include both carbonate
materials, such as described above, as well as non-carbonate
materials. The seed structures may be naturally occurring, e.g.,
naturally occurring sands, shell fragments from oyster shells or
other carbonate skeletal allochems, gravels, etc., or man-made,
such as pulverized rocks, ground blast furnace slag, fly ash,
cement kiln dust, red mud, and the like. For example, the seed
structure may be a granular composition, such as sand, which is
coated with the carbonate material during the process, e.g., a
white carbonate material or colored carbonate material, e.g., as
described above.
[0120] In some instances, seed structure may be coarse aggregates,
such as friable Pleistocene coral rock, e.g., as may be obtained
from tropical areas (e.g., Florida) that are too weak to serve as
aggregate for concrete. In this case the friable coral rock can be
used as a seed, and the solid CO.sub.2 sequestering carbonate
mineral may be deposited in the internal pores, making the coarse
aggregate suitable for use in concrete, allowing it to pass the LA
Rattler abrasion test. In some instances, where a light weight
aggregate is desired, the outer surface will only be penetrated by
the solution of deposition, leaving the inner core relatively
`hollow` making a light weight aggregate for use in light weight
concrete.
[0121] Methods as described herein may be carried out in a variety
of different carbonate production subunit continuous reactors.
Examples of continuous reactors of interest are further described
below and in the Experimental section. Where a continuous reactor
is employed, the location at which the CO.sub.2 sequestering
material is produced may be a fluidized bed subunit of the
continuous reactor. Fluidized bed reactors of interest are
configured to maintain a region of fluidized solids in a
continuously flowing medium, and may have a fluid inlet, a fluid
outlet, and a region of material production positioned
there-between. A given fluidized bed reactor may have a single
change or multiple chambers, as desired. Where desired, the
fluidized bed may include structures, e.g., filters, meshes, frits,
etc., or other retaining structures which serve to keep the product
material in the fluidize bed.
[0122] Methods as described herein may further include separating
the non-slurry solid phase CO.sub.2 sequestering carbonate material
from the aqueous bicarbonate rich product containing liquid. Any
convenient separation protocol may be employed to remove the
product material from the liquid. As such, the product material may
be pulled out of the liquid, the liquid may be drained from the
product material, etc., as desired. In some instances, the material
is removed from the liquid while the liquid is still moving. In yet
other instances the material is removed from the liquid after
movement of the liquid has been stopped. Compared with protocols
that produce slurry products, the energy associated with drying the
product materials produced according to the methods described
herein is much lower. While the magnitude of difference in energy
usage may vary, in some instances the difference ranges from 2 to
100 times, such as 10 to 50 times per ton of material produced. One
specific challenge inherent to the field of CO.sub.2 sequestering
material production is reducing the amount of energy consumed
during the carbonation of CO.sub.2. Common extraneous sources of
energy use in production methods that produce a CO.sub.2
sequestering precipitate material include the removal of water from
the precipitated materials after formation. Reducing energy needs
normally required to separate and potentially dry precipitated
material form the bulk solution is important. As compared to
process in which CO.sub.2 sequestering precipitate materials are
produced, embodiments of the present methods produce dried tons of
CO.sub.2 sequestering material using 2 to 100 times less energy,
such as 10 to 50 times less energy, in the water separation/drying
step.
[0123] Continuous processes for producing CO.sub.2 sequestering
non-slurry compositions as well as uses for the resultant products
are further described in U.S. Provisional Application Ser. No.
62/062,084 (BLUE-021PRV) filed on Oct. 9, 2014, the disclosure of
which is herein incorporated by reference and in U.S. Patent
Application Ser. No. 62/096,340 (Attorney Docket No. BLUE-012PRV2);
the disclosure of which is herein incorporated by reference.
Alkali Enrichment
[0124] As summarized above, CO.sub.2 sequestration methods of the
invention may optionally include an alkali enrichment step or
protocol. The alkali enrichment protocol may be employed once or
two or more times during a given method, and at different stages of
a given method. For example, an alkali enrichment protocol may be
performed before and/or after a CO.sub.2 capture liquid production
step, e.g., as described in greater detail below.
[0125] By "alkali enrichment protocol" is meant a method or process
of increasing the alkalinity of a liquid. The alkalinity increase
of a given liquid may be manifested in a variety of different ways.
In some instances, increasing the alkalinity of a liquid is
manifested as an increase the pH of the liquid. For example, a
liquid may be processed to remove hydrogen ions from the liquid to
increase the alkalinity of the liquid. In such instances, the pH of
the liquid may be increased by a desirable value, such as 0.10 or
more, 0.20 or more, 0.25 or more, 0.50 or more, 0.75 or more, 1.0
or more, 2.0 or more, etc. In some instances, the magnitude of the
increase in pH may vary, ranging in some instances from 0.1 to 10,
such as 1 to 9, including 2.5 to 7.5, e.g., 3 to 7. As such,
methods may increase the alkalinity of an initial liquid to produce
a product liquid having a desired pH, where in some instances the
pH of the product liquid ranges from 5 to 14, such as 6 to 13,
including 7 to 12, e.g., 8 to 11, where the product liquid may be
viewed as an enhanced alkalinity liquid. The increase in alkalinity
of a liquid may also be manifested as an increase in the dissolved
inorganic carbon (DIC) content of liquid. The DIC is the sum of the
concentrations of inorganic carbon species in a solution,
represented by the equation:
DIC=[CO.sub.2*]+[HCO.sub.3.sup.-]+[CO.sub.3.sup.2], where
[CO.sub.2*] is the sum of carbon dioxide ([CO.sub.2]) and carbonic
acid ([H.sub.2CO.sub.3]) concentrations, [HCO.sub.3.sup.-] is the
bicarbonate concentration and [CO.sub.3.sup.2-] is the carbonate
concentration in the solution. The DIC of the alkali enriched
liquid may vary, and in some instances may be 500 ppm or greater,
such as 5,000 ppm or greater, including 15,000 ppm or greater. In
some instances, the DIC of the alkali enriched liquid may range
from 500 to 20,000 ppm, such as 7,500 to 15,000 ppm, including
8,000 to 12,000 ppm. In some instances, alkali enrichment is
manifested as an increase in the concentration of bicarbonate
species, e.g., NaHCO.sub.3, e.g., to a concentration ranging from 5
to 500 mMolar, such as 10 to 200 mMolar.
[0126] In some instances, the alkali enrichment protocol is a
membrane mediated protocol. By membrane mediated protocol is meant
a process or method which employs a membrane at some time during
the method. As such, membrane mediated alkali enrichment protocols
are those alkali enrichment processes in which a membrane is
employed at some time during the process. While a given membrane
mediated alkali enrichment protocol may vary, in some instances the
membrane mediated protocol includes contacting a first liquid,
e.g., a feed liquid, and a second liquid, e.g., a draw liquid, to
opposite sides of a membrane.
[0127] Membrane mediated alkali enrichment protocols may vary, so
long as they produce an enhanced alkalinity liquid from an initial
liquid, as described above. As such, a variety of different types
of membranes, membrane configurations, contact protocols, first and
second liquid pairings, etc., may be employed, where selection of a
particular set of protocol parameters may depend on a number of
different factors, such as the nature of the first and second
liquids that are available, for what purpose the alkali enrichment
protocol is employed (e.g., to produce a CO.sub.2 capture liquid,
to increase the alkalinity of a CO.sub.2 charged liquid, etc.).
[0128] The conditions of the alkali enrichment step may vary as
desired. The temperature of the liquids may vary, ranging in some
instances from 0 to 100.degree. C., such as 4 to 80.degree. C. The
temperatures of the liquids may be the same or different. When
different, the magnitude of any temperature variation may vary,
ranging in some instances from 0.1 to 95.degree. C., such as 30 to
45.degree. C. The pressure of the liquids may also vary, ranging in
some instances from 1 to 30 bar, such as 1.5 to 2 bar. When
different, the magnitude of any pressure variation may vary,
ranging in some instances from 0.1 to 30 bar, such as 0.5 to 1 bar.
The flow rates of the liquids may be the same or different, and in
some instances range from 0.25 to 10 gallon/min, such as 0.5 to 1
gallon/min. When different, the magnitude of any flow rate
variation between the draw and feed may vary, and in some instances
ranges from 0.05 to 9.75 gallon/min, such as 1 to 3 gallon/min.
Forward osmosis mediated alkali enrichment protocols (also referred
to sometimes as alkali recovery protocols) are further described in
U.S. Provisional Application Ser. No. 61/990,486 (BLUE-018PRV)
filed on May 8, 2014, the disclosure of which is herein
incorporated by reference.
[0129] The nature of the first (i.e., initial) and second liquids
that are processed in methods of the invention may vary. The
initial liquid may be any liquid for which an increase in
alkalinity is desired. The initial liquid may be an aqueous medium
that may vary depending on the specific protocol being performed.
Aqueous media of interest include pure water (e.g., fresh water) as
well as water that includes one or more solutes, e.g., divalent
cations, e.g., Ca.sup.2+, Mg.sup.2+, Be.sup.2+, Ba.sup.2+,
Sr.sup.2+, counterions, e.g., carbonate, hydroxide, etc. The
aqueous medium may be a naturally occurring or man-made medium, as
desired. Naturally occurring aqueous media include, but are not
limited to, waters obtained from seas, oceans, lakes, swamps,
estuaries, lagoons, brines, geological brines, alkaline lakes,
inland seas, brackish waters, etc. Man-made sources of aqueous
media may also vary, and may include brines produced by water
desalination plants, waste waters, and the like. First and second
liquid pairings of interest include, but are not limited to: fresh
and salt water (e.g., river water and seawater), salt water and
desalination waste water (e.g., RO retentate), fresh water charged
with CO.sub.2-containing gas, e.g., industrial flue gas, and salt
water, fresh water and salt water charged with CO.sub.2-containing
gas, e.g., industrial flue gas, acidic salt water and fresh water
and the like, or any combination of the waters disclosed
herein.
[0130] In some embodiments, the first liquid is a carbonate
buffered aqueous medium. Carbonate buffered aqueous media employed
in methods of the invention include liquid media in which a
carbonate buffer is present. As such, liquid aqueous media of
interest include dissolved CO.sub.2, water, carbonic acid
(H.sub.2CO.sub.3), bicarbonate ions (HCO.sub.3.sup.-), hydrogen
ions (H.sup.+) and carbonate ions (CO.sub.3.sup.2-). The
constituents of the carbonate buffer in the aqueous media are
governed by the equation:
CO.sub.2+H.sub.2OH.sub.2CO.sub.3H.sup.++HCO.sub.3.sup.-2H.sup.++CO.sub.3-
.sup.2-
[0131] Where desired, the initial liquid may be one that has been
contacted with a CO.sub.2-containing gas. In words, the initial
liquid is one to which a gaseous source of CO.sub.2 has been
contacted such that the initial liquid that is subjected to the
alkali enrichment protocol is one that includes an amount of
dissolved inorganic carbon (DIC), i.e., it is a CO.sub.2 charged
liquid. In such instances, the CO.sub.2 charged liquid includes an
amount of dissolved CO.sub.2. The amount of CO.sub.2 dissolved in
the liquid may vary, and in some instances ranges from 0.05 to 40
mM, such as 1 to 35 mM, including 25 to 30 mM. In this case, a
CO.sub.2 capture solution can be generated based on carbonate ion
alkalinity. In some instances, carbonate ion alkalinity will be 100
mM or greater, such as 250 mM, and including 500-1,000 mM, or more.
Such instances are described in greater detail below.
[0132] The second liquid employed in methods of the invention may
vary. In some instances, the second liquid differs from the first
liquid in terms of osmotic potential, where the osmotic potential
of a given second liquid may be higher or lower relative to the
initial liquid with which it is employed, depending on the
particular alkali recover protocol that is used (e.g., as described
above). The magnitude of the difference in osmotic potential
between any two given liquid pairs may vary, and in some instances
ranges from 0.1 bar to 150 bar, such as 20 bar to 60 bar, including
25 bar to 35 bar.
[0133] Any convenient liquid may be employed as the second liquid.
In some embodiments, a second liquid may include a high ionic
strength medium. In some embodiments, the second liquid contains
non-hydrogen monovalent cations that are capable of crossing the
membrane system to provide for charge balance and thereby facility
in the alkalinity increase of the first liquid. In certain
embodiments, the non-hydrogen monovalent cations include, but are
not limited to: Na.sup.+, K.sup.+, and NH.sub.4.sup.+. Second
liquids of interest include aqueous media having a salinity of 2
ppt or more, such as 5 ppt or more, including 10 ppt or more. In
some instances the second liquid is an aqueous medium having a
salinity that ranges from 3 to 50 ppt, such as 5 to 35 ppt. The pH
of the second liquid may vary, and in some instances ranges from 4
to 12, such as 5 to 10 and including 6 to 9. In some instances, the
second liquid may be referred to as a brine draw liquid. The term
"brine" refers to water saturated or nearly saturated with salt and
has a salinity that is 50 ppt (parts per thousand) or greater, such
as 60 ppt or greater, and including 95 ppt or greater. Brine draw
liquids of interest include, but are not limited to: man-made
brines, such as geothermal plant wastewaters, oil field produced
brines, fracking operation produced waters, desalination waste
waters, etc., as well as natural brines, such as surface brines
found in bodies of water on the surface of the earth and deep
brines, found underneath the earth, as well as other liquids having
a salinity as described above. In some embodiments, a draw liquid
includes a geological brine or a brine discharge from a
desalination plant.
[0134] Introduction of the first liquid and the second liquid into
a membrane system, e.g., as described above, results in the
production of a product liquid (i.e., enhanced alkalinity liquid)
from the first liquid, where the product liquid has an increased
alkalinity as compared to the first liquid, i.e., the product
liquid is an enhanced alkalinity liquid. As summarized above, while
the increase in alkalinity may vary, in some instances the
magnitude of the increase in pH ranges from 0.1 to 10, such as 1 to
9, including 2.5 to 7.5, e.g., 3 to 7. While the pH of the product
liquid may vary, in some instances the pH of the product liquid
ranges from 5 to 14, such as 6 to 13, including 7 to 12, e.g., 8 to
11.
[0135] In addition, methods of the invention may produce an acidic
by-product liquid. The acidic by-product liquid may vary, and is
one that is produced from the second. The pH of the acidic
by-product liquid ranges in some instances from 0 to 8, such as 3
to 5. The nature of the acidic by-product liquid may vary, where in
some instances the acidic by-product liquid includes HCl.
[0136] Alkali enrichment protocols and systems for practicing the
same that may be adapted for use methods of the invention, e.g., as
described above, include those described in U.S. Patent Application
No. 61/990,486 (BLUE-018PRV) filed on May 8, 2014, U.S. Patent
Application Ser. No. 62/051,100 (BLUE-015PRV) filed on Sep. 16,
2014 and U.S. Patent Application No. 62/096,340 (BLUE-012PRV2)
filed on Dec. 29, 2014; the disclosures of which are herein
incorporated by reference. As indicated above, an alkali enrichment
protocol (e.g., as described above) may be employed at one or more
times during a CO.sub.2 sequestration process, e.g., in producing a
CO.sub.2 capture liquid, to increase the alkalinity of a CO.sub.2
contacted liquid (i.e., a liquid that includes dissolved inorganic
carbon derived from CO.sub.2), etc.
Production of Materials from the CO.sub.2 Sequestering Carbonate
Products
[0137] The product carbonate materials produced by the systems and
methods, e.g., as described above, may be further manipulated
and/or combined with other compositions to produce a variety of
end-use materials. In certain embodiments, the product carbonate
composition is refined (i.e., processed) in some manner. Refinement
may include a variety of different protocols. In certain
embodiments, the product is subjected to mechanical refinement,
e.g., grinding, in order to obtain a product with desired physical
properties, e.g., particle size, etc. In certain embodiments, the
product is combined with a hydraulic cement, e.g., as a sand, a
gravel, as an aggregate, etc., e.g., to produce final product,
e.g., concrete or mortar.
[0138] Also of interest are formed building materials. The formed
building materials of the invention may vary greatly. By "formed"
is meant shaped, e.g., molded, cast, cut or otherwise produced,
into a man-made structure defined physical shape, i.e.,
configuration. Formed building materials are distinct from
amorphous building materials, e.g., particulate (such as powder)
compositions that do not have a defined and stable shape, but
instead conform to the container in which they are held, e.g., a
bag or other container. Illustrative formed building materials
include, but are not limited to: bricks; boards; conduits; beams;
basins; columns; drywalls etc. Further examples and details
regarding formed building materials include those described in
United States Published Application No. US20110290156; the
disclosure of which is herein incorporated by reference.
[0139] Also of interest are non-cementitious manufactured items
that include the product of the invention as a component.
Non-cementitious manufactured items of the invention may vary
greatly. By non-cementitious is meant that the compositions are not
hydraulic cements. As such, the compositions are not dried
compositions that, when combined with a setting fluid, such as
water, set to produce a stable product. Illustrative compositions
include, but are not limited to: paper products; polymeric
products; lubricants; asphalt products; paints; personal care
products, such as cosmetics, toothpastes, deodorants, soaps and
shampoos; human ingestible products, including both liquids and
solids; agricultural products, such as soil amendment products and
animal feeds; etc. Further examples and details non-cementitious
manufactured items include those described in U.S. Pat. No.
7,829,053; the disclosure of which is herein incorporated by
reference.
[0140] In some instances, the solid carbonate product may be
employed in albedo enhancing applications. Albedo, i.e., reflection
coefficient, refers to the diffuse reflectivity or reflecting power
of a surface. It is defined as the ratio of reflected radiation
from the surface to incident radiation upon it. Albedo is a
dimensionless fraction, and may be expressed as a ratio or a
percentage. Albedo is measured on a scale from zero for no
reflecting power of a perfectly black surface, to 1 for perfect
reflection of a white surface. While albedo depends on the
frequency of the radiation, as used herein Albedo is given without
reference to a particular wavelength and thus refers to an average
across the spectrum of visible light, i.e., from about 380 to about
740 nm.
[0141] As the methods of these embodiments are methods of enhancing
albedo of a surface, the methods in some instances result in a
magnitude of increase in albedo (as compared to a suitable control,
e.g., the albedo of the same surface not subjected to methods of
invention) that is 0.05 or greater, such as 0.1 or greater, e.g.,
0.2 or greater, 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6
or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater,
including 0.95 or greater, including up to 1.0. As such, aspects of
the subject methods include increasing albedo of a surface to 0.1
or greater, such as 0.2 or greater, e.g., 0.3 or greater, 0.4 or
greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or
greater, 0.9 or greater, 0.95 or greater, including 0.975 or
greater and up to approximately 1.0.
[0142] Aspects of the methods include associating with a surface of
interest an amount of a highly reflective microcrystalline or
amorphous material composition effective to enhance the albedo of
the surface by a desired amount, such as the amounts listed above.
The material composition may be associated with the target surface
using any convenient protocol. As such, the material composition
may be associated with the target surface by incorporating the
material into the material of the object having the surface to be
modified. For example, where the target surface is the surface of a
building material, such as a roof tile or concrete mixture, the
material composition may be included in the composition of the
material so as to be present on the target surface of the object.
Alternatively, the material composition may be positioned on at
least a portion of the target surface, e.g., by coating the target
surface with the composition. Where the surface is coated with the
material composition, the thickness of the resultant coating on the
surface may vary, and in some instances may range from 1 micron to
100 mm, such as 10 microns to 50 mm, e.g., 0.1 mm to 25 mm, such as
2 mm to 20 mm and including 5 mm to 10 mm. Applications in use as
highly reflective pigments in paints and other coatings like
photovoltaic solar panels are also of interest.
[0143] The albedo of a variety of surfaces may be enhanced.
Surfaces of interest include at least partially facing skyward
surfaces of both man-made and naturally occurring objects. Man-made
surfaces of interest include, but are not limited to: roads,
sidewalks, buildings and components thereof, e.g., roofs and
components thereof (roof shingles, roofing granules, etc.) and
sides, runways, and other man-made structures, e.g., walls, dams,
monuments, decorative objects, etc. Naturally occurring surfaces of
interest include, but are not limited to: plant surfaces, e.g., as
found in both forested and non-forested areas, non-vegetated
locations, water, e.g., lake, ocean and sea surfaces, etc.
[0144] Methods of using the carbonate precipitate compounds
described herein in varying applications as described above,
including albedo enhancing applications, as well as compositions
produced thereby, are further described in U.S. application Ser.
Nos. 14/112,495 and 14/214,129; the disclosures of which
applications are herein incorporated by reference.
Production of Pure Product CO.sub.2 Gas
[0145] As described above, during the production of solid carbonate
compositions from the bicarbonate rich product or component thereof
(e.g., LCP), one mol of CO.sub.2 may be produced for every 2 mols
of bicarbonate ion from the bicarbonate rich product or component
thereof (e.g., LCP). For example, where solid carbonate
compositions are produced by adding calcium cation to the
bicarbonate rich product or component thereof (e.g., LCP), the
production of solid carbonate compositions, e.g., the form of
amorphous calcium carbonate minerals, may proceed according to the
following reaction:
2HCO.sub.3.sup.-+Ca.sup.++CaCO.sub.3.H.sub.2O+CO.sub.2
Ca.sup.++.sub.(aq)+2HCO.sub.3(aq).sup.-CaCO.sub.3(s)+H.sub.2O.sub.(l)+CO-
.sub.2(g)
While the above reaction shows the production of 1 mol of CO.sub.2,
2 moles of CO.sub.2 from the CO.sub.2 containing gas were initially
converted to bicarbonate. As such, the overall process sequesters a
net 1 mol of CO.sub.2 in a carbonate compound and produces 1 mol of
substantially pure CO2 product gas, which may be sequestered by
injection into a subsurface geological location, as described in
greater detail below. Therefore, the process is an effective
CO.sub.2 sequestration process. Contact of the bicarbonate rich
product with the cation source results in production of a
substantially pure CO.sub.2 product gas. The phrase "substantially
pure" means that the product gas is pure CO.sub.2 or is a CO.sub.2
containing gas that has a limited amount of other, non-CO.sub.2
components.
[0146] Following production of the CO.sub.2 product gas, aspects of
the invention may include recovering the gas from the system and
injecting the product CO.sub.2 gas into a subsurface geological
location to sequester CO.sub.2. By injecting is meant introducing
or placing the CO.sub.2 product gas into a subsurface geological
location. Subsurface geological locations may vary, and include
both subterranean locations and deep ocean locations. Subterranean
locations of interest include a variety of different underground
geological formations, such as fossil fuel reservoirs, e.g., oil
fields, gas fields and un-mineable coal seams; saline reservoirs,
such as saline formations and saline-filled basalt formations; deep
aquifers; porous geological formations such as partially or fully
depleted oil or gas formations, salt caverns, sulfur caverns and
sulfur domes; etc.
[0147] In some instances, the CO.sub.2 product gas may be
pressurized prior to injection into the subsurface geological
location. To accomplish such pressurization the gaseous CO.sub.2
can be compressed in one or more stages with, where desired, after
cooling and condensation of additional water. The modestly
pressurized CO.sub.2 can then be further dried, where desired, by
conventional methods such as through the use of molecular sieves
and passed to a CO.sub.2 condenser where the CO.sub.2 is cooled and
liquefied. The CO.sub.2 can then be efficiently pumped with minimum
power to a pressure necessary to deliver the CO.sub.2 to a depth
within the geological formation or the ocean depth at which
CO.sub.2 injection is desired. Alternatively, the CO.sub.2 can be
compressed through a series of stages and discharged as a super
critical fluid at a pressure matching that necessary for injection
into the geological formation or deep ocean. Where desired, the
CO.sub.2 may be transported, e.g., via pipeline, rail, truck or
other suitable protocol, from the production site to the subsurface
geological formation.
[0148] In some instances, the CO.sub.2 product gas is employed in
an enhanced oil recovery (EOR) protocol. Enhanced Oil Recovery
(abbreviated EOR) is a generic term for techniques for increasing
the amount of crude oil that can be extracted from an oil field.
Enhanced oil recovery is also called improved oil recovery or
tertiary recovery. In EOR protocols, the CO.sub.2 product gas is
injected into a subterranean oil deposit or reservoir.
[0149] CO.sub.2 gas production and sequestration thereof is further
described in U.S. Provisional Application 62/054,322 (BLUE-024PRV)
filed on Sep. 23, 2014, the disclosure of which is herein
incorporated by reference.
Methods of Producing CO.sub.2 Sequestering Systems
[0150] Also provided are methods of producing (i.e., installing or
fabricating) a CO.sub.2 sequestration system at a CO.sub.2
sequestration location. Aspects of these methods may include
assessing the CO.sub.2 sequestration requirements of a CO.sub.2
sequestration location and then determining the configuration of a
CO.sub.2 sequestration system sufficient to meet the requirements
of the CO.sub.2 sequestration location. CO.sub.2 sequestration
locations may vary and include, but are not limited to, industrial
sources of CO.sub.2 gas, such as fossil fuel power plants, cement
fabrication plants, etc., such as described above. In assessing the
CO.sub.2 sequestration requirements of a given CO.sub.2
sequestration location, various parameters of the CO.sub.2
sequestration location may be considered, including but not limited
to, types of CO.sub.2 containing gases that need to be treated,
volumes of CO.sub.2 contacting gas that need to be processed to
remove CO.sub.2, types of waters that may be available at the
CO.sub.2 sequestration location, power available at the location,
desired type of carbonate product, etc.
[0151] After the CO.sub.2 sequestration requirements of the
CO.sub.2 sequestration location are assessed or determined, a
CO.sub.2 sequestration system made up of a one or more shippable
modular units, e.g., as described above, may be identified or
determined which is sufficient to meet the requirements. The
identification step may include considering the available different
types of modular units and selecting a system of one or more units
from the available units. For example, a given location may have
CO.sub.2 sequestration requirements that can be met by a single
modular unit that includes AE, contact and carbonate production
subunits and the determining step in such an instance may then
include concluding that a single such modular unit can meet the
requirements of the location or that the requirements can be made
up of three separate modular units, i.e., one containing an AE
subunit, one containing a contactor subunit and one containing a
carbonate production subunit. Alternatively, a given location may
have CO.sub.2 sequestration requirements that can be met by two or
more modular units each of which includes a different type of
subunit. For example, the determined requirements of a given
location may require the CO.sub.2 gas processing capacity of three
contactor modular units, two AE modular units and three carbonate
production units. A suitable system made up of two or more distinct
modular units may then be identified from the available modular
units, e.g., a system that includes three contactor modular units,
two AE modular units and three carbonate production units or a
system that includes two AE modular units, and three modular units
that each contain contactor and carbonate production subunits.
[0152] Aspects of the methods may include transporting the system
of one or more modular units to the CO.sub.2 sequestration location
from a remote location, which remote location may be a fabrication
and/or storage location. In such instances the remote location may
be a variety of distances from the CO.sub.2 sequestration location,
e.g., 1 km or more, 5 km or more, 50 km or more, 100 km or more,
500 km or more, 1000 km or more, 5000 km or more, 10,000 km or
more, etc. In such instances, the system of one or more modular
units may be transported or shipped from the remote location to the
sequestration location using any convenient transportation route,
e.g., by boat, truck, train, plane, etc.
[0153] Aspects of embodiments of the methods of installing the
systems may include operably coupling one or more modular units to
each other and/or one or more sources of input materials, e.g.,
water(s), CO.sub.2 containing gases, sources of divalent cations,
etc. For example, where a system includes three distinct modular
units, i.e., an AE unit, a contact unit and a carbonate production
unit, the methods may include operably coupling the AE unit to
first and second sources of water (e.g., high and low salinity
waters), operably coupling the contactor unit to the alkalinity
enriched liquid output of the AE unit and a source of CO.sub.2
containing gas, and operably coupling the carbonate production unit
to the bicarbonate containing liquid output of the contactor unit
and the a divalent source of cations. Installation may include
operably coupling two or more units to each other, e.g., an AE unit
with the contactor unit, a contactor unit with a carbonate
production unit, etc. Installation may further include operatively
coupling the one or more units of the system with one or more
receivers for products of the units, e.g., a carbonate product
receiver, a pure CO.sub.2 gas receiver, an acidic byproduct liquid
receiver, a CO.sub.2 depleted gas receiver, etc.
Utility
[0154] Modular units, systems thereof and methods as described
herein find use in CO.sub.2 sequestration applications. As reviewed
above, by "CO.sub.2 sequestration" is meant the removal or
segregation of an amount of CO.sub.2 from an environment, such as
the Earth's atmosphere or a gaseous waste stream produced by an
industrial plant, so that some or all of the CO.sub.2 is no longer
present in the environment from which it has been removed. CO.sub.2
sequestering methods of the invention sequester CO.sub.2, producing
a storage stable carbon dioxide sequestering product from an amount
of CO.sub.2 such that the CO.sub.2 from which the product is
produced is then sequestered in that product. The storage stable
CO.sub.2 sequestering product is a storage stable composition that
incorporates an amount of CO.sub.2 into a storage stable form, such
as an above-ground storage or underwater storage stable form, so
that the CO.sub.2 is no longer present as, or available to be, a
gas in the atmosphere. Depending on the particular embodiment, the
storage stable form may be a liquid or a solid. Sequestering of
CO.sub.2 according to methods of the invention results in
prevention of CO.sub.2 gas from entering the atmosphere and allows
for long-term storage of CO.sub.2 in a manner such that CO.sub.2
does not become part of the atmosphere.
[0155] Notwithstanding the appended clauses, the disclosure is also
defined by the following clauses:
1. A shippable modular unit configured for use in sequestering
CO.sub.2 from a gaseous source of CO.sub.2, the shippable modular
unit comprising:
[0156] (a) a support; and
[0157] (b) at least one type of subunit selected from the group
consisting of: a CO.sub.2 gas/liquid contactor subunit; a carbonate
production subunit; an alkali enrichment subunit; a water softening
subunit; a cation recovery subunit; a heat exchange subunit; a
reverse osmosis subunit; a nanofiltration subunit; a
microfiltration subunit; an ultrafiltration subunit; and a purified
CO.sub.2 collection subunit;
[0158] associated with the support.
2. The shippable modular unit according to Clause 1, wherein the
shippable modular unit includes only one type of subunit selected
from the group consisting of: a CO.sub.2 gas/liquid contactor
subunit; a carbonate production subunit; an alkali enrichment
subunit; a water softening subunit; a cation recovery subunit; a
heat exchange subunit; a reverse osmosis subunit; a nanofiltration
subunit; a microfiltration subunit; an ultrafiltration subunit; and
a purified CO.sub.2 collection subunit;
[0159] present in the housing.
3. The shippable modular unit according to Clauses 1 or 2, wherein
the type of subunit is a CO.sub.2 gas/liquid contactor subunit. 4.
The shippable modular unit according to Clauses 1 or 2, wherein the
type of subunit is a carbonate production subunit. 5. The shippable
modular unit according to Clauses 1 or 2, wherein the type of
subunit is an alkali enrichment subunit. 6. The shippable modular
unit according to Clause 1, wherein the modular unit includes at
least two types of subunits selected from the group consisting of:
a CO.sub.2 gas/liquid contactor subunit; a carbonate production
subunit; and an alkali enrichment subunit; a water softening
subunit; a cation recovery subunit; a heat exchange subunit; a
reverse osmosis subunit; a nanofiltration subunit; a
microfiltration subunit; an ultrafiltration subunit; and a purified
CO.sub.2 collection subunit;
[0160] present in the housing.
7. The shippable modular unit according to Clause 6, wherein the at
least two types of subunits comprise: a CO.sub.2 gas/liquid
contactor subunit; and a carbonate production subunit. 8. The
shippable modular unit according to Clause 6, wherein the at least
two types of subunits comprise: a CO.sub.2 gas/liquid contactor
subunit; and an alkali enrichment subunit. 9. The shippable modular
unit according to Clause 6, wherein the at least two types of
subunits comprise: a carbonate production subunit; and an alkali
enrichment subunit. 10. The shippable modular unit according to any
of Clauses 1 to 9, wherein the shippable modular unit is configured
to be operatively coupled to one or more additional shippable
modular units each comprising:
[0161] (a) a support; and
[0162] (b) at least one type of subunit selected from the group
consisting of: a CO.sub.2 gas/liquid contactor subunit; a carbonate
production subunit; an alkali enrichment subunit; a water softening
subunit; a cation recovery subunit; a heat exchange subunit; a
reverse osmosis subunit; a nanofiltration subunit; a
microfiltration subunit; an ultrafiltration subunit; and a purified
CO.sub.2 collection subunit; [0163] associated with the support.
11. The shippable modular unit according to any of the preceding
clauses, wherein the shippable modular unit is configured to be
transported by rail. 12. The shippable modular unit according to
any of Clauses 1 to 10, wherein the shippable modular unit is
configured to be transported by truck. 13. The shippable modular
unit according to any of Clauses 1 to 10, wherein the shippable
modular unit is configured to be transported by boat. 14. The
shippable modular unit according to any of Clauses 1 to 13, wherein
the housing has an internal volume ranging from 8 to 30,000
m.sup.3. 15. The shippable modular unit according to any of Clauses
1 to 14, wherein the shippable modular unit has a mass ranging from
1 ton to 20,000 tons. 16. A system configured to sequester CO.sub.2
from a gaseous source of CO.sub.2, the system comprising:
[0164] two or more operably coupled shippable modular units, each
shippable modular unit comprising:
[0165] (a) a housing having at least one material input and least
one product output; and
[0166] (b) at least one type of subunit selected from the group
consisting of: a CO.sub.2 gas/liquid contactor subunit; a carbonate
production subunit; an alkali enrichment subunit; a water softening
subunit; a cation recovery subunit; a heat exchange subunit; a
reverse osmosis subunit; a nanofiltration subunit; a
microfiltration subunit; an ultrafiltration subunit; and a purified
CO.sub.2 collection subunit;
[0167] present in the housing.
17. The system according to Clause 16, wherein the housing of at
least one of the shippable modular units includes only one type of
subunit selected from the group consisting of: a CO.sub.2
gas/liquid contactor subunit; a carbonate production subunit; an
alkali enrichment subunit; a water softening subunit; a cation
recovery subunit; a heat exchange subunit; a reverse osmosis
subunit; a nanofiltration subunit; a microfiltration subunit; an
ultrafiltration subunit; and a purified CO.sub.2 collection
subunit; present in the housing. 18. The system according to Clause
17, wherein the type of subunit is a CO.sub.2 gas/liquid contactor
subunit. 19. The system according to Clause 17, wherein the type of
subunit is a carbonate production subunit. 20. The system according
to Clause 17, wherein the type of subunit is an alkali enrichment
subunit. 21. The system according to Clause 16, wherein the housing
of at least one of the shippable modular units comprises at least
two types of subunits selected from the group consisting of: a
CO.sub.2 gas/liquid contactor subunit; a carbonate production
subunit; an alkali enrichment subunit; a water softening subunit; a
cation recovery subunit; a heat exchange subunit; a reverse osmosis
subunit; a nanofiltration subunit; a microfiltration subunit; an
ultrafiltration subunit; and a purified CO.sub.2 collection
subunit;
[0168] present in the housing.
22. The system according to Clause 21, wherein the at least two
types of subunits comprise: a CO.sub.2 gas/liquid contactor
subunit; and a carbonate production subunit. 23. The system
according to Clause 21, wherein the at least two types of subunits
comprise: a CO.sub.2 gas/liquid contactor subunit; and an alkali
enrichment subunit. 24. The system according to Clause 21, wherein
the at least two types of subunits comprise: a carbonate production
subunit; and an alkali enrichment subunit. 25. The system according
to any of Clauses 16 to 24, wherein the system is configured to
process 1,000 to 10,000,000 scfm of a gaseous source of CO.sub.2.
26. The system according to any of Clauses 16 to 25, wherein the
gaseous source of CO.sub.2 is a multicomponent gaseous stream. 27.
The system according to Clause 16, wherein the multicomponent
gaseous stream is a flue gas. 28. The system according to any of
Clauses 16 to 26, wherein the system is configured to process 100
to 10,000,000 liters/hr of an input liquid material. 29. The system
according to any of Clauses 16 to 28, wherein the system is
operably coupled to a source of an initial liquid. 30. The system
according to Clause 29, wherein the initial liquid is selected from
the group consisting of freshwater, seawater, brine water, produced
water and waste water. 31. The system according to any of Clauses
16 to 30, wherein the system is operatively coupled to a gaseous
source of CO.sub.2. 32. The system according to Clause 31, wherein
the gaseous source of CO.sub.2 is a multi-component gaseous stream.
33. The system according to Clause 32, wherein the gaseous source
of CO.sub.2 is a flue gas. 34. The system according to Clause 33,
wherein the flue gas is obtained from an industrial source. 35. The
system according to Clause 34, wherein the industrial source is a
power plant. 36. A method of producing a system configured to
sequester CO.sub.2 from a gaseous source of CO.sub.2 at a CO.sub.2
sequestration location, the method comprising:
[0169] assessing the CO.sub.2 sequestration requirements of the
CO.sub.2 sequestration location; and
[0170] determining the configuration of a CO.sub.2 sequestration
system sufficient to meet the requirements of the CO.sub.2
sequestration location.
37. The method according to Clause 36, wherein the CO.sub.2
sequestration system comprises one or more shippable modular
CO.sub.2 sequestration units. 38. The method according to Clause
37, wherein the CO.sub.2 sequestration system comprises a shippable
modular CO.sub.2 sequestration unit comprising each of a CO.sub.2
gas/liquid contactor subunit; a carbonate production subunit; and
an alkali enrichment subunit. 39. The method according to Clause
37, wherein the CO.sub.2 sequestration system comprises a two or
more shippable modular CO.sub.2 sequestration units each comprising
at least one of: a CO.sub.2 gas/liquid contactor subunit; a
carbonate production subunit; and an alkali enrichment subunit. 40.
The method according to any of Clauses 36 to 39, wherein the method
further comprises operably coupling the two or more shippable
modular units at the CO.sub.2 sequestration location to produce the
system. 41. The method according to any of Clauses 36 to 40,
wherein the method further comprises operably coupling the system
to a gaseous source of CO.sub.2. 42. The method according to Clause
41, wherein the gaseous source of CO.sub.2 is a multi-component
gaseous stream. 43. The method according to Clause 42, wherein the
gaseous source of CO.sub.2 is a flue gas. 44. The method according
to Clause 43, wherein the flue gas is obtained from an industrial
source. 45. The method according to Clause 44, wherein the
industrial source is a power plant. 46. The method according to any
of Clauses 36 to 45, wherein the method further comprises shipping
the determined CO.sub.2 sequestration system to the CO.sub.2
sequestration location from a remote location. 47. The method
according to Clause 46, wherein the shipping is by rail. 48. The
method according to Clause 46, wherein the shipping is by truck.
49. The method according to Clause 46, wherein the shipping is by
boat. 50. The method according to any of Clauses 46 to 49, wherein
the method further comprises fabricating the system at the remote
location. 51. A method for sequestering CO.sub.2 from a gaseous
source of CO.sub.2, the method comprising:
[0171] (a) introducing a gaseous source of CO.sub.2 into a system
according to any of Clauses 16 to 35; and
[0172] (b) obtaining a carbonate product material from the modular
unit.
52. The method according to Clause 51, wherein the method comprises
processing 1,000 to 10,000,000 scfm of a gaseous source of
CO.sub.2. 53. The method according to any of Clauses 51 to 52,
wherein the gaseous source of CO.sub.2 is a multi-component gaseous
stream. 54. The method according to Clause 53, wherein the gaseous
source of CO.sub.2 is a flue gas. 55. The method according to
Clause 54, wherein the flue gas is obtained from an industrial
source. 56. The method according to any of Clauses 51 to 55,
wherein the method comprises processing 1,000 to 10,000,000
liters/hr of an input liquid. 57. The method according to Clause
56, wherein the carbonate product material comprises a slurry. 58.
The method according to Clause 56, wherein the carbonate product
material comprises a non-slurry. 59. A shippable modular unit
configured to sequester CO.sub.2 from a gaseous source of CO.sub.2,
the modular unit comprising:
[0173] a housing containing: [0174] a CO.sub.2 gas/liquid contactor
subunit operatively connected to a first input for a liquid and a
second input for a gaseous source of CO.sub.2; and [0175] a
carbonate production subunit in fluidic communication with the
contactor unit;
[0176] wherein the carbonate production unit is operatively
connected to a CO.sub.2 product gas output and a carbonate product
material output.
60. The shippable modular unit according to Clause 59, wherein the
modular unit is configured to process 1,000 to 10,000,000 scfm of a
gaseous source of CO.sub.2. 61. The shippable modular unit
according to Clauses 59 or 60, wherein the gaseous source of
CO.sub.2 is a multicomponent gaseous stream. 62. The shippable
modular unit according to Clause 61, wherein the multicomponent
gaseous stream is a flue gas. 63. The shippable modular unit
according to any of Clauses 59 to 62, wherein the modular unit is
configured to process 1,000 to 10,000,000 liters/hr of an input
liquid. 64. The shippable modular unit according to any of Clauses
59 to 62, wherein the modular unit further comprises an alkali
enrichment subunit. 65. The shippable modular unit according to
Clause 64, wherein the alkali enrichment subunit is operatively
coupled to the CO.sub.2 gas/liquid contactor subunit and configured
to produce an enhanced alkalinity liquid from an initial liquid for
use as a CO.sub.2 capture liquid in the CO.sub.2 gas/liquid
contactor unit. 66. The shippable modular unit according to Clause
65, wherein the alkali enrichment subunit is configured to receive
CO.sub.2 charged liquid from the CO.sub.2 gas/liquid contactor
subunit and produce an enhanced alkalinity liquid from the received
CO.sub.2 charged liquid. 67. The shippable modular unit according
to any of Clauses 64 to 66, wherein the alkali enrichment subunit
is operatively coupled to a first input for a first liquid and a
second input for a second liquid. 68. The shippable modular unit
according to any of Clause 59 to 67, wherein the carbonate
production subunit is operatively coupled to an input for a
divalent cation source. 69. The shippable modular unit according to
Clause 68, wherein the divalent cation source is a hard water
source. 70. The shippable modular unit according to any of Clauses
59 to 69, wherein the housing has a volume ranging from 8 to 30,000
m.sup.3. 71. A shippable modular unit configured to sequester
CO.sub.2 from a gaseous source of CO.sub.2, the modular unit
comprising:
[0177] a housing comprising: [0178] an alkali enrichment subunit
configured to produce an enhanced alkalinity liquid from an initial
liquid, wherein the alkali enrichment subunit is operatively
coupled to a first input for the initial liquid and a second input
for a second liquid; [0179] a CO.sub.2 gas/liquid membrane
contactor subunit configured to receive an enhanced alkalinity
liquid from the alkali enrichment subunit and produce a liquid
condensed phase (LCP) containing liquid, wherein the CO.sub.2
gas/liquid membrane contactor subunit is operatively coupled to an
input for a gaseous source of CO.sub.2 and an output for treated
gas; and [0180] a carbonate production subunit in fluidic
communication with the CO.sub.2 gas/liquid membrane contactor
subunit, wherein the carbonate production subunit is operatively
coupled to an input for a liquid divalent cation source, a CO.sub.2
product gas output and a carbonate product material output. 72. The
shippable modular unit according to Clause 71, wherein the modular
unit is configured to process 1,000 to 10,000,000 scfm of a gaseous
source of CO.sub.2. 73. The shippable modular unit according to
Clauses 71 or 72, wherein the gaseous source of CO.sub.2 is a
multicomponent gaseous stream. 74. The shippable modular unit
according to any of Clauses 73, wherein multicomponent gaseous
stream is a flue gas. 75. The shippable modular unit according to
any of Clauses 71 to 74, wherein the first and second inputs of the
alkali enrichment subunit are respectively operatively coupled to a
source of the initial liquid and a source of the second liquid. 76.
The shippable modular unit according to Clause 75, wherein the
initial liquid and second liquid are selected from the group
consisting of freshwater, seawater, brine water, produced water and
waste water. 77. The shippable modular unit according to any of
Clauses 71 to 76, wherein the input for a gaseous source of
CO.sub.2 is operatively coupled to a gaseous source of CO.sub.2.
78. The shippable modular unit according to any of Clauses 71 to
76, wherein the gaseous source of CO.sub.2 is a multi-component
gaseous stream. 79. The shippable modular unit according to Clause
78, wherein the gaseous source of CO.sub.2 is a flue gas. 80. The
shippable modular unit according to Clause 79, wherein the flue gas
is obtained from an industrial source. 81. The shippable modular
unit according to any of Clauses 71 to 80, wherein the CO.sub.2
gas/liquid membrane contactor subunit comprises a hollow fiber
membrane. 82. The shippable modular unit according to any of
Clauses 71 to 81, wherein the carbonate production subunit is
configured to introduce the liquid divalent cation source into a
flowing LCP containing liquid produced by the contactor subunit
under conditions sufficient such that a non-slurry solid phase
CO.sub.2 sequestering carbonate material is produced in the flowing
LCP containing liquid. 83. The shippable modular unit according to
any of Clauses 71 to 82, wherein the carbonate production subunit
comprises a fluidized bed. 84. The shippable modular unit according
to any of Clauses 71 to 83, wherein the carbonate production
subunit is configured to introduce the liquid divalent cation
source into a LCP containing liquid produced by the contactor unit
under conditions sufficient such that a slurry CO.sub.2
sequestering carbonate material is produced from the LCP containing
liquid. 85. The shippable modular unit according to any of Clauses
71 to 84, wherein the carbonate production subunit is operatively
coupled to a waste liquid disposal output. 86. A shippable modular
unit configured to sequester CO.sub.2 from a gaseous source of
CO.sub.2, the modular unit comprising:
[0181] a housing containing: [0182] a CO.sub.2 gas/liquid membrane
contactor subunit configured to produce a liquid CO.sub.2 charged
liquid, wherein the CO.sub.2 gas/liquid membrane contactor subunit
is operatively coupled to an input for a gaseous source of
CO.sub.2, an input for an initial liquid, a first output for a
CO.sub.2 charged liquid and a second output for treated gas; [0183]
an alkali enrichment subunit operatively coupled to the first
output of the CO.sub.2 gas/liquid membrane contactor subunit and
configured to produce an enhanced alkalinity liquid from CO.sub.2
charged liquid received from the CO.sub.2 gas/liquid membrane
contactor subunit, wherein the alkali enrichment subunit is
operatively coupled to a first input for the initial liquid and a
second input for a second liquid; and [0184] a carbonate production
subunit configured to receive an enhanced alkalinity liquid from
the alkali enrichment subunit and operatively coupled to an input
for a liquid divalent cation source, a CO.sub.2 product gas output
and a carbonate product material output. 87. The shippable modular
unit according to Clause 86, wherein the modular unit is configured
to process 1,000 to 10,000,000 scfm of a gaseous source of
CO.sub.2. 88. The shippable modular unit according to any of
Clauses 86 or 87, wherein the initial liquid and second liquid are
selected from the group consisting of freshwater, seawater, brine
water, produced water and waste water. 89. The shippable modular
unit according to any of Clauses 86 to 88, wherein the input for a
gaseous source of CO.sub.2 is operatively coupled to a gaseous
source of CO.sub.2. 90. The shippable modular unit according to any
of Clauses 86 to 89, wherein the gaseous source of CO.sub.2 is a
multi-component gaseous stream. 91. The shippable modular unit
according to Clause 90, wherein the gaseous source of CO.sub.2 is a
flue gas. 92. The shippable modular unit according to Clause 91,
wherein the flue gas is obtained from an industrial source. 93. The
shippable modular unit according to any of Clauses 86 to 92,
wherein the CO.sub.2 gas/liquid membrane contactor subunit
comprises a hollow fiber membrane. 94. The shippable modular unit
according to any of Clauses 86 to 93, wherein the carbonate
production subunit is configured to introduce the liquid divalent
cation source into a flowing LCP containing liquid produced by the
contactor subunit under conditions sufficient such that a
non-slurry solid phase CO.sub.2 sequestering carbonate material is
produced in the flowing LCP containing liquid. 95. The shippable
modular unit according to any of Clauses 86 to 94, wherein the
carbonate production unit comprises a fluidized bed. 96. The
shippable modular unit according to any of Clauses 86 to 95,
wherein the carbonate production subunit is configured to introduce
the liquid divalent cation source into a LCP containing liquid
produced by the contactor unit under conditions sufficient such
that a slurry CO.sub.2 sequestering carbonate material is produced
from the LCP containing liquid. 97. The shippable modular unit
according to any of Clauses 86 to 96, wherein the carbonate
production subunit is operatively coupled to a waste liquid
disposal output. 98. A method for sequestering CO.sub.2 from a
gaseous source of CO.sub.2, the method comprising:
[0185] (a) introducing a gaseous source of CO.sub.2 into a
shippable modular unit configured to sequester CO.sub.2 from a
gaseous source of CO.sub.2, the modular unit comprising a housing
containing: [0186] a CO.sub.2 gas/liquid contactor subunit
operatively connected to a first input for a liquid and a second
input for a gaseous source of CO.sub.2; and [0187] a carbonate
production subunit in fluidic communication with the contactor
subunit,
[0188] wherein the carbonate production subunit is operatively
connected to a CO.sub.2 product gas output and a carbonate product
material output; and
[0189] (b) obtaining a carbonate product material from the modular
unit.
99. The method according to Clause 98, wherein the method comprises
processing 1,000 to 10,000,000 scfm of a gaseous source of
CO.sub.2. 100. The method according to Clause 99, wherein the
gaseous source of CO.sub.2 is a multi-component gaseous stream.
101. The method according to Clause 100, wherein the gaseous source
of CO.sub.2 is a flue gas. 102. The method according to Clause 101,
wherein the flue gas is obtained from an industrial source. 103.
The method according to any of Clauses 98 to 102, wherein the
modular unit further comprises an alkali enrichment subunit and the
method further comprises producing an enhanced alkalinity liquid.
104. The method according to any of Clauses 98 to 103, wherein the
modular unit is configured to process 1,000 to 10,000,000 liters/hr
of an input liquid. 105. The method according to any of Clauses 98
to 104, wherein the carbonate product material comprises a slurry.
106. The method according to any of Clauses 98 to 104, wherein the
carbonate product material comprises a non-slurry.
[0190] Although the foregoing invention has been described in some
detail by way of illustration and example for purposes of clarity
of understanding, it is readily apparent to those of ordinary skill
in the art in light of the teachings of this invention that certain
changes and modifications may be made thereto without departing
from the spirit or scope of the appended claims.
[0191] Accordingly, the preceding merely illustrates the principles
of the invention. It will be appreciated that those skilled in the
art will be able to devise various arrangements which, although not
explicitly described or shown herein, embody the principles of the
invention and are included within its spirit and scope.
Furthermore, all examples and conditional language recited herein
are principally intended to aid the reader in understanding the
principles of the invention and the concepts contributed by the
inventors to furthering the art, and are to be construed as being
without limitation to such specifically recited examples and
conditions. Moreover, all statements herein reciting principles,
aspects, and embodiments of the invention as well as specific
examples thereof, are intended to encompass both structural and
functional equivalents thereof.
[0192] Additionally, it is intended that such equivalents include
both currently known equivalents and equivalents developed in the
future, i.e., any elements developed that perform the same
function, regardless of structure. The scope of the present
invention, therefore, is not intended to be limited to the
exemplary embodiments shown and described herein. Rather, the scope
and spirit of present invention is embodied by the appended
claims.
* * * * *
References