U.S. patent application number 14/013670 was filed with the patent office on 2014-01-02 for methods and apparatuses for dilute phase impregnation of a milled sorbent with a chemical compound in an aqueous solution.
This patent application is currently assigned to Cabot Norti Americas, Inc.. The applicant listed for this patent is Cabot Norit Americas, Inc.. Invention is credited to Patton M. Adams, Robert S. Nebergall.
Application Number | 20140004262 14/013670 |
Document ID | / |
Family ID | 44645791 |
Filed Date | 2014-01-02 |
United States Patent
Application |
20140004262 |
Kind Code |
A1 |
Nebergall; Robert S. ; et
al. |
January 2, 2014 |
METHODS AND APPARATUSES FOR DILUTE PHASE IMPREGNATION OF A MILLED
SORBENT WITH A CHEMICAL COMPOUND IN AN AQUEOUS SOLUTION
Abstract
The present disclosure relates to apparatus designed to
impregnate a sorbent. In some embodiments apparatus of the
disclosure may comprise a mixing vessel having either a conical
mixing chamber or an cylindrical mixing chamber designed to
increase the contact surface area and/or contact/residence time of
a sorbent and impregnant to produce compositions comprising an
impregnated sorbent. Apparatus of the disclosure may also comprise
one or more atomizers operable to produce atomized droplets of
impregnant. The disclosure also provides methods for impregnation
of a milled sorbent or an un-milled sorbent. Methods of the
disclosure provide several technical advantages and may be cost
effective. Impregnant sorbent compositions produced by methods
and/or apparatus of the disclosure may have higher concentrations
of an impregnant, a more uniform distribution of an impregnant and
may have a greater sorbent efficiency.
Inventors: |
Nebergall; Robert S.;
(Longview, TX) ; Adams; Patton M.; (Longview,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cabot Norit Americas, Inc. |
Marshall |
TX |
US |
|
|
Assignee: |
Cabot Norti Americas, Inc.
Marshall
TX
|
Family ID: |
44645791 |
Appl. No.: |
14/013670 |
Filed: |
August 29, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12875195 |
Sep 3, 2010 |
|
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|
14013670 |
|
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Current U.S.
Class: |
427/216 ;
427/212; 427/215; 427/222 |
Current CPC
Class: |
A61P 3/10 20180101; B01F
5/205 20130101; B01J 20/20 20130101; A61P 25/00 20180101; A61P
29/00 20180101; B01J 20/3293 20130101 |
Class at
Publication: |
427/216 ;
427/212; 427/215; 427/222 |
International
Class: |
B01J 20/32 20060101
B01J020/32 |
Claims
1. A method for impregnation of a sorbent, comprising: receiving a
milled sorbent in a sorbent delivery chamber; forming a dilute
phase milled sorbent; receiving an impregnant in a container; and
contacting the dilute phase milled sorbent with the impregnant
under conditions to cause impregnation of the impregnant into the
sorbent.
2. The method of claim 1, wherein the impregnant is atomized to
form atomized impregnant droplets prior to contacting.
3. The method of claim 1, wherein the impregnant comprises a
selected one of a halogen, a halogen salt, a halogen acid, a
cation, silver, and sulfur.
4. (canceled)
5. (canceled)
6. The method of claim 3, wherein the halogen is further comprised
in an aqueous solution.
7. The method of claim 1, wherein the milled sorbent comprises an
activated carbon, a non-carbon sorbent or combinations thereof.
8. The method of claim 7, wherein the non-carbon sorbent is
selected from the group consisting of a zeolite, an
aluminosilicate, a polymeric resin, a non-metallic resin, a clay,
or an ion exchange resin.
9. The method of claim 7, wherein the activated carbon is selected
from the group consisting of a powdered activated carbon, a
granular activated carbon, a lignite, a brown coal, an activated
carbon having a diameter to 40 microns or less, an activated carbon
having a diameter of 10 microns to 30 microns, and combinations
thereof.
10. The method of claim 1, wherein the range of particle size of
the milled sorbent is similar to the range of particle size of
impregnant.
11. The method of claim 1, wherein contacting the dilute phase
milled sorbent and the impregnant is performed in a mixing vessel
having a conical chamber.
12. The method of claim 1, wherein contacting the dilute phase
milled sorbent and the impregnant is performed in a mixing vessel
having a cylindrical chamber.
13. A method for impregnation of a sorbent, comprising: receiving a
sorbent having a respective sorbent particle size; atomizing an
aqueous impregnant solution to form an aqueous atomized impregnant
droplets having a respective aqueous atomized impregnant droplet
size; contacting the sorbent with the aqueous atomized impregnant
droplets; mixing the sorbent with the aqueous atomized impregnant
droplets, thereby forming an impregnated sorbent.
14. The method of claim 13, wherein a size range of the sorbent
particle size is similar to a size range of the aqueous atomized
impregnant droplet size.
15. The method of claim 13, wherein contacting the sorbent and the
aqueous atomized impregnant droplets comprises turbulence
formation.
16. The method of claim 13, wherein mixing the sorbent and the
aqueous atomized impregnant droplets comprises turbulent
mixing.
17. The method of claim 13, wherein contacting and mixing the
sorbent with the aqueous atomized impregnant droplets is performed
in a mixing vessel having a conical chamber.
18. The method of claim 13, wherein contacting and mixing the
sorbent with the aqueous atomized impregnant is performed in a
mixing vessel having a cylindrical chamber.
19. The method of claim 13, wherein the sorbent is a milled
sorbent.
20. The method of claim 13, wherein the sorbent is a powdered
sorbent.
21. The method of claim 13, wherein the impregnant comprises a
halogen selected from the group consisting of bromine, chlorine,
iodine and fluorine.
22. The method of claim 21, wherein the halogen comprises a
selected one of a halogen salt and a halogen acid.
23-38. (canceled)
Description
TECHNICAL FIELD
[0001] The present disclosure relates to methods for impregnating a
sorbent with an impregnant and to compositions comprising at least
one sorbent (e.g., a milled sorbent, non-milled sorbent, activated
carbon, non-carbon sorbents) and an impregnant (e.g., a halogen).
In some embodiments, the disclosure relates to apparatuses and
devices designed for impregnating a sorbent and/or for making
compositions of the disclosure.
BACKGROUND OF THE INVENTION
[0002] Contaminants, such as mercury, may be removed from flue
gases and from exhaust emitted from power plants by halogenated
activated carbon sorbents and non-carbon sorbents. Methods to make
halogenated activated carbon comprise halogenating an activated
carbon sorbent and milling the halogenated activated carbon.
[0003] Halogens are typically in an aqueous solution during the
halogenation process and/or milling process. Aqueous halogen
solutions are corrosive and corrode moving parts of mills used to
mill halogenated activated carbons. This adversely affects milling
operations. For example, corroded mill parts do not function well
and repeated replacements and maintenance issues slow down
production. The effects on milling operations result in high costs
associated with part replacement and time lost to shutting down of
production lines for repair or maintenance.
[0004] In addition, present methods of making halogenated activated
carbon sorbents do not produce uniformly halogenated sorbents. This
greatly affects the contaminant removal efficiency of the
halogenated sorbents.
SUMMARY
[0005] The present disclosure, in some embodiments relates to
methods and apparatuses designed to impregnate sorbents.
[0006] Apparatus of the disclosure, according to some embodiments,
may be designed to increase the contact surface area and/or
contact/residence time of a sorbent and an impregnant to produce
compositions comprising an impregnated sorbent.
[0007] In one embodiment, an apparatus of the disclosure may
comprise a mixing vessel having a conical chamber designed to
generate a turbulent formation of inflowing sorbent particles. The
conical chamber may also have at least one atomizer disposed
therein that is operable to produce atomized droplets of
impregnant. In some embodiments, turbulent mixing of atomized
impregnant droplets with particles of sorbent flowing in a
turbulent formation may result in a greater contact time and/or
expose greater surface area of sorbent and impregnant to each other
thereby producing impregnant sorbent having a substantially uniform
impregnant distribution and a substantially high impregnant
incorporation into a sorbent.
[0008] In some embodiments, an apparatus of the disclosure may
comprise a mixing vessel having a cylindrical vessel, also referred
to as an impregnation cylinder, and may have one or more atomizers
disposed therein. The impregnation cylinder may be designed to
generate a turbulent formation of inflowing sorbent particles.
Atomized droplets of impregnant may be sprayed onto the turbulent
flow of sorbent at multiple points allowing contact and mixing of
sorbent and impregnant droplets.
[0009] In some embodiments, components of an apparatus may comprise
devices and/or software to synchronize one or more steps, regulate
reaction conditions and/or perform an operation cycle.
[0010] In some embodiments, methods for impregnation of a milled
sorbent are described and may comprise contacting a milled sorbent
with an impregnant to allow maximum surface area of a milled
sorbent to be contacted with impregnant. Methods of the disclosure
may result in an increased residence time of reactants.
[0011] In some embodiments, methods for impregnation of an
un-milled sorbent are described and may comprise contacting a
sorbent that is not milled with atomized droplets of an impregnant.
In some embodiments, turbulent mixing of sorbent and impregnant
increase surface area contact as well as increase residence time.
Methods of the disclosure may provide several technical advantages
and may be cost effective.
[0012] The disclosure also describes impregnant sorbent
compositions produced by methods and/or apparatus of the
disclosure. In some embodiments, compositions of the disclosure may
have higher concentrations of an impregnant, a more uniform
distribution of an impregnant and/or may have a greater sorbent
efficiency.
[0013] Some embodiments of the disclosure may provide one or more
of the following technical advantages. A technical advantage of
some embodiments may include uniform impregnation of a milled
sorbent with an impregnant. Additionally, an increase in efficiency
of contaminant removal (e.g., mercury removal) by an impregnated
milled sorbent made by a method of the present disclosure may
occur. Another technical advantage of some embodiments may include
elimination or reduction of damage by aqueous halogens to mill
components. Therefore, time and costs associated with replacement
of mill parts and maintenance of milling operations may be reduced.
Some embodiments may also increase milling capacity and throughput,
which also results in cost savings. Yet another technical advantage
of some embodiments may include elimination of cross contamination
of a mill by a halogen or other impregnant. Therefore, a mill may
be used for multiple processes because halogen contaminants do not
contact mill parts.
[0014] A technical advantage of some embodiments may be a
continuous process that may be efficient, consistent and less
expensive for impregnating a milled sorbent. The adsorption of
impregnant and/or the increased evaporation of moisture may be
increased by a milled sorbent. Additionally, a decrease in caking
and plugging of mill parts by impregnated sorbent may occur. A
technical advantage of certain embodiments may also include an
increase in flowability of the impregnated sorbent.
[0015] Various embodiments of the disclosure may include none,
some, or all of the above technical advantages. One or more other
technical advantages may be readily apparent to one skilled in the
art from the figures, descriptions, and claims included herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] For a more complete understanding of the present disclosure,
its features and advantages, reference is now made to the following
description, taken in conjunction with the accompanying drawings,
in which:
[0017] FIG. 1 illustrates an exemplary apparatus operable to
impregnate a sorbent having a mixing vessel comprising a conical
mixing chamber, according to one example embodiment;
[0018] FIG. 2A illustrates a mixing vessel having a conical mixing
chamber, according to one example embodiment;
[0019] FIG. 2B illustrates a top-view of a mixing vessel having a
conical mixing chamber, according to one example embodiment;
[0020] FIG. 2C depicts an example flange comprised in a mixing
vessel having a conical mixing chamber, according to one example
embodiment;
[0021] FIG. 2D illustrates different parts of a mixing vessel
having a conical mixing chamber of FIG. 2A, according to one
example embodiment;
[0022] FIG. 2E illustrates a three dimensional view of different
parts of a mixing vessel having a conical mixing chamber as shown
in FIG. 2B, according to one example embodiment;
[0023] FIG. 2F illustrates a two-dimensional view of a mixing
vessel having a conical mixing chamber showing handle 56, according
to one example embodiment;
[0024] FIG. 2G illustrates a three-dimensional view of a mixing
vessel having a conical mixing chamber as shown in FIG. 2F,
according to one example embodiment;
[0025] FIG. 3 illustrates an exemplary apparatus operable to
impregnate a sorbent having a mixing vessel having a cylindrical
mixing chamber, according to one example embodiment;
[0026] FIG. 4 illustrates a mixing vessel having a cylindrical
mixing chamber, according to one example embodiment;
[0027] FIG. 5A illustrates an exemplary method for impregnating a
milled sorbent, according to one example embodiment;
[0028] FIG. 5B illustrates an exemplary method for impregnating a
milled sorbent, according to one example embodiment;
[0029] FIG. 6 illustrates an exemplary method for impregnating a
sorbent, according to one example embodiment;
[0030] FIG. 7 illustrates an exemplary method for impregnating a
sorbent using a mixing vessel having a conical mixing chamber,
according to one example embodiment; and
[0031] FIG. 8 illustrates an exemplary method for impregnating a
sorbent using a mixing vessel having a cylindrical mixing chamber,
according to one example embodiment.
DETAILED DESCRIPTION
[0032] It should be understood at the outset that, although example
implementations of embodiments of the disclosure are illustrated
below, embodiments of the present disclosure may be implemented
using any number of techniques, whether currently known or not. The
present disclosure should in no way be limited to the example
implementations, drawings, and techniques illustrated below. Some
embodiments of the disclosure and associated advantages may be best
understood by reference to FIGS. 1-8 wherein like numbers refer to
same and like parts.
[0033] The present disclosure, in some embodiments, relates to
methods and apparatuses and/or devices for making impregnated
sorbent compositions that may be used to decontaminate fluids.
Compositions of the disclosure, i.e., impregnated sorbents, may be
operable to remove, lower, and/or reduce contaminants, hazardous
materials and/or pollutants such as mercury, fly ash, acid gases,
dioxins, furans, mercury-containing compounds, heavy metal
compounds, biological toxins from other polluted/contaminated
fluids such as industrial fluids, exhaust gases, power plant
emissions, contaminated blood or other biological fluids.
[0034] In some embodiments, the disclosure provides apparatuses
designed to impregnate a sorbent. FIG. 1 illustrates a process flow
diagram showing an apparatus 10 comprising a mixing vessel 50
having a conical mixing chamber operable to impregnate sorbent 20
from an impregnated sorbent 165, according to one example
embodiment.
[0035] Sorbent 20 may include any sorbent that may be used for
decontamination applications and may comprise any material operable
to adsorb and/or chemically bind to a hazardous molecule or a
contaminant molecule to remove, reduce, or lower the level of the
hazardous molecule or the contaminant molecule. In some
embodiments, sorbent 20 may be a milled sorbent. Milling a sorbent
greatly increases it surface area thereby allowing for greater
capacity for adsorbing a hazardous molecule or a contaminant. While
several example embodiments are described herein with regard to
milled and/or powdered sorbent 20, teachings recognize that the
present disclosure is not limited to milled sorbents. Accordingly,
sorbents that are not milled or powdered may also be impregnated
using the methods and apparatus described herein. For example, in
some embodiments, sorbents that are not milled or powdered but have
a particle size of from about 10 microns to 30 microns (10.mu. to
30.mu.) may be impregnated by the present methods and devices. In
some embodiments, any sorbent having the ability to fluidize with
air to a turbulent velocity may be used.
[0036] Apparatus 10 as shown in FIG. 1 may comprise sorbent
delivery chamber 30 (also referred to as a sorbent feeder, a silo
or a delivery chute) having sorbent 20.
[0037] Sorbent delivery chamber 30 represents a device to deliver
sorbent 20 to an impregnation chamber, such as mixing vessel 50
having a conical mixing chamber.
[0038] From sorbent delivery chamber 30, sorbent 20 may be
delivered or fed into bottom end 59 of mixing vessel 50 having a
conical mixing chamber via pump 40 as a dilute phase sorbent with
compressed air or low pressure air 60. A dilute phase sorbent
conveying refers to a solid or a sorbent conveyed by a gas where
the gas velocity exceeds the saltation velocity.
[0039] 40 represents a pump that is operable to transfer energy
from one fluid to another. In some embodiments, 40 may be an
eductor or a jet-pump. Pressure valve 91 may regulate the flow.
Component 151 may comprise a thermocouple to measure temperature of
the gas entering mixing vessel 50.
[0040] Mixing vessel 50 having a conical mixing chamber (also
referred to herein as cone 50) is a cone shaped vessel having a
first end or top end 58 and a second end or bottom end 59. Mixing
vessel 50 having a conical mixing chamber may be lined and/or
comprised of a corrosion resistant and temperature transfer
resistant material. Mixing vessel 50 having a conical mixing
chamber may be made from a variety of material including
non-limiting examples such as stainless steel, dual composite
material comprising polyvinyl chloride (PVC), reinforced polyester
or others. In some embodiments, the core of mixing vessel 50 having
a conical mixing chamber may comprise stainless steel. The size and
height of the walls of mixing vessel 50 having a conical mixing
chamber may be designed to maintain sorbent 20 in a dilute
phase.
[0041] Mixing vessel 50 having a conical mixing chamber may have a
top portion 53 that is a cylindrical chamber (also called a top
chamber) and a bottom portion 54 that is a conical chamber (also
called a bottom chamber). Atomizer 130 may be disposed toward top
end 58 of mixing vessel 50 having a conical mixing chamber. In some
embodiments, mixing vessel 50 having a conical mixing chamber may
comprise multiple atomizers (not expressly depicted). Product
discharge tube 140 may be disposed toward top end 58 of mixing
vessel 50 having a conical mixing chamber. Product discharge tube
140 may also be referred to variously as discharge tube or
discharge chute.
[0042] The shape of mixing vessel 50 having a conical mixing
chamber may be designed to allow for turbulence formation in bottom
portion 54 of vessel 50 following the flow of sorbent 20 and
compressed air 60 through second end 59. In some embodiments,
mixing vessel 50 having a conical mixing chamber may be designed to
generate a turbulence formation having flow and dynamics for
efficient mixing of milled or non-milled sorbent 20 with atomized
droplets of impregnant 100. In some embodiments, construction of
mixing vessel 50 having a conical mixing chamber with temperature
transfer resistant material may be designed to facilitate
maintenance of the temperature of a reaction in cone 50 within a
range where impregnant 100 remains in an aqueous phase and is not
converted into a gaseous phase.
[0043] Mixing vessel 50 having a conical mixing chamber may also be
designed to have a reverse flow for discharging impregnated sorbent
165 via product discharge tube 140 out of cone 50. The shape of
mixing vessel 50 having a conical mixing chamber may be operable to
reduce or prevent caking and plugging of outlets and inlets by
components of the reaction or by a product. In some embodiments,
maintenance of turbulent velocity during the formation and drafting
may reduce or prevent caking or plugging. Other embodiments
relating to mixing vessel 50 having a conical mixing chamber are
described in sections below and in FIGS. 2A-2G.
[0044] Apparatus 10 may also comprise compressed air source 70
having compressed air 60 operable to be delivered (or fed) with
sorbent 20 into bottom end 59 of mixing vessel 50 having a conical
mixing chamber via regulator 81, pressure valve 91, valve 80,
element 85 and through eductor 40.
[0045] In non-limiting examples, compressed air source 70 may be an
air cylinder having air under high pressure (e.g., a high pressure
air compressor), air under low pressure or a blower. In some
embodiments, compressed air 60 may be at a pressure of about 90
ACFM to about 900 ACFM. Compressed air 60 may comprise oxygen,
nitrogen, or combinations thereof.
[0046] Compressed air source 70 may also supply compressed air 60
to atomizer 130 located at top end 58 of mixing vessel 50 having a
conical mixing chamber. Regulator 82, air flow meter 85 and
pressure valve 93 may control the flow of compressed air to
atomizer 130.
[0047] Impregnant 100 may be contained in container 101 and fed via
pump 110 into atomizer 130. Rotameter 120 measures the flow rate of
impregnant 100, and pressure valves 94 and 95 and element 96
regulate the flow of impregnant 100 and compressed air 60 into
atomizer 130.
[0048] Atomizer 130 may be operable to atomize impregnant 100 into
atomized droplets (not expressly shown). In some embodiments,
atomizer 130 may be operable to atomize impregnant 100 into
atomized droplets that are similar in size to the size of milled
sorbent 20. In some embodiments, atomizer 130 may be operable to
atomize impregnant 100 into droplets having a size range of about
10.mu. to about 30.mu.. However, teachings recognize that atomized
droplets of other sizes may be used as well and the present
disclosure is not limited to droplets in the size range of 10.mu.
to 30.mu.. In some embodiments, more than one atomizer 130 may be
used (not expressly depicted).
[0049] Atomizer 130 may be operable to spray atomized aqueous
impregnant at an angle of 10.degree. to 15.degree. relative to the
turbulent flow of sorbent 20. The angle of spray of atomizer 130
may be broad enough to distribute impregnant 100 to substantially
all particles of sorbent 20. The angle of the atomizer spray may
also be designed to avoid spraying the exiting product 165.
[0050] An impregnated sorbent 165, product 165, may exit mixing
vessel 50 having a conical mixing chamber through product discharge
tube 140. Product discharge tube 140 may be attached to collection
chamber 160 where impregnated milled sorbent 165 (product 165) may
be collected following impregnation in mixing vessel 50 having a
conical mixing chamber. Regulatory valve 80 may control the flow of
product 165 into collection chamber 160 (also referred to as dust
collector). Thermocouple 152 may measure exit temperature following
impregnant adsorption for impregnant into sorbent. Rotary valve 170
may control the flow of impregnated sorbent 165 into chamber 180.
Dust collector 160 (also referred to as collection chamber) may
separate air and impregnated sorbent. Dust collector 160 may have
filters, such as but not limited to filter bags, to separate air
and impregnated sorbent. Dust collector 160 may also have a blower.
Chamber 180 may be a storage container or a bulk bag to collect
and/or store impregnated sorbent 165.
[0051] Apparatus 10 may also comprise one or more computers, one or
more process control programs, one or more data input programs,
and/or one or more data output readers (not expressly shown). In
some embodiments, apparatus 10 may be started and shut-down
automatically by an automated process control program. In some
embodiments, apparatus 10 may be started, shut down and controlled
in intermediate steps manually. In some embodiments, apparatus 10
may be started, shut-sown and controlled in intermediate steps by a
combination of automated and manual steps. Manual control may be by
human operators.
[0052] Automated controls, manual controls and/or combinations
thereof may be used for maintenance operations. Maintenance
operations may include washing one or more components of apparatus
10.
[0053] Automated controls may also be used for one or more of the
following including: synchronization of input of sorbent and
compressed air, synchronization of input of aqueous impregnant and
compressed air for atomization, controlling residence time in the
apparatus cone (or mixing vessel 190 comprising a cylindrical
mixing chamber as described later), and exiting of impregnated
product.
[0054] In an exemplary embodiment, sorbent 20 flows through
apparatus 10 to form an impregnated sorbent 165 in mixing vessel 50
having a conical mixing chamber. Teachings of the disclosure may be
used to impregnate any sorbent 20 with any impregnant 100.
Exemplary sorbent 20 that may be impregnated by methods of the
disclosure using apparatus 10 comprising mixing vessel 50 having a
conical mixing chamber (and/or mixing vessel 190 comprising a
cylindrical mixing chamber as described later) may comprise an
activated carbon sorbent such as a lignite, a brown coal, an
activated carbon having an average diameter of less than about
40.mu., a powdered activated carbon sorbent such as but not limited
to a lignite, a brown coal, a powdered activated carbon having an
average diameter of less than about 40.mu., sorbents having an
average diameter of from about 10.mu. to about 30.mu., or any
combinations thereof. A description of various activated carbon
sources is provided below.
[0055] Impregnant 100 may be any chemical or biochemical agent that
may be impregnated into sorbent 20. Impregnant 100 may be operable
to increase adsorption efficiency of a sorbent for one or more
contaminant. In some embodiments, impregnant 100 may be operable to
chemically react with a contaminant and render it less toxic.
Accordingly, impregnant 100, in some embodiments, may be operable
to detoxify a decontaminant or a toxic agent. Impregnant 100 may
have a high affinity for a contaminant and, in some embodiments,
may further be operable to adsorb, chemically bind, capture, and/or
selectively bind a contaminant. Non-limiting examples of
impregnants may include halogens, sulfur, silver, or cations, such
as Al, Mn, Zn, Fe, Li, Ca. In some embodiments, impregnant 100 may
comprise a halogen. Exemplary halogens in aqueous phase may include
fluorine (F), chlorine (Cl), bromine (Br) and iodine (I). Example
halogen impregnants of the disclosure may comprise salts such as
but not limited to sodium (Na) or potassium (K), acids such as but
not limited to hydrochloric acid (HCl), or bases. In some
embodiments, impregnant 100 may be in an aqueous phase. An aqueous
phase may comprise water. For example, in one example embodiment,
an aqueous solution of sodium bromide (NaBr) may be used as an
impregnant.
[0056] In one example embodiment, flow of sorbent 20, through
apparatus 10, may begin with delivery of sorbent 20 from sorbent
delivery chamber 30 into bottom end 59 of mixing vessel 50 having a
conical mixing chamber. Delivery and flow of sorbent 20 into mixing
vessel 50 having a conical mixing chamber may be facilitated by
compressed air source 70 having compressed air 60. Accordingly,
compressed air 60 and sorbent 20 may be delivered simultaneously
into bottom end 59 of mixing vessel 50 having a conical mixing
chamber and may be regulated by one or more of regulator 81,
pressure valve 91, valve 80, and/or element 85 through eductor 40.
Sorbent 20 and air 60 may comprise a dilute phase sorbent. In some
embodiments, sorbent 20 may enter end 59 of mixing vessel 50 having
a conical mixing chamber at a rate of from about 1000 lb/hr to
about 5000 lb/hr.
[0057] Inflow of sorbent 20 simultaneously with compressed air 60
into conical chamber 54 of mixing vessel 50 having a conical mixing
chamber results in a turbulence formation, or a turbulent flow,
comprising particles of sorbent 20 having a turbulent velocity. As
described earlier, the shape of mixing vessel 50 having a conical
mixing chamber facilitates turbulence formation or turbulent flow
in conical chamber 54.
[0058] At the same time, impregnant 100 may be delivered to top end
58 of mixing vessel 50 having a conical mixing chamber via atomizer
130. Delivery of impregnant 100 from container 101 into atomizer
130 may be facilitated by pump 110, pressure valves 94 and 95,
rotameter 120, and element 96. Compressed air 60 from compressed
air source 70 may be delivered into atomizer 130 simultaneously
with impregnant 100. Compressed air 60 along with impregnant 100
enter atomizer 130 and may be atomized into atomized droplets of
impregnant 100 as they enter top end 58 of mixing vessel 50 having
a conical mixing chamber.
[0059] In some embodiments, a finer particle size of atomized
droplets of impregnant 100 formed by atomizer 130 may result in a
larger surface area of impregnant 100 operable to contact sorbent
20. In some embodiments, atomizer 130 may spray atomized impregnant
100 at an angle relative to the turbulent flow of sorbent 20. In
some embodiments, the angle of spray of atomizer 130 may distribute
impregnant to substantially all particles of sorbent 20. The angle
of spray relative to the turbulent flow of sorbent may be but is
not limited to 10.degree. to 15.degree..
[0060] As atomized droplets of impregnant 100 flow in through
atomizer 130 into first end 58 of cone 50, the atomized droplets
come in contact with a turbulent formation comprising milled
sorbent 20 and compressed air 60. This results in mixing sorbent 20
and impregnant 100 in cone 50. In some embodiments, the mixing may
be turbulent mixing (i.e., mixing occurring at turbulent velocities
of one or more of the components being mixed). Mixing results in
adsorption of impregnant 100 into milled sorbent 20 and formation
of impregnated sorbent 165.
[0061] In some embodiments, turbulence formation in mixing vessel
50 having a conical mixing chamber may have flow and dynamics for
efficient mixing of sorbent 20 with atomized droplets of impregnant
100. In embodiments where non-milled sorbents 20 may be impregnated
using cone 50 and/or other parts of apparatus 10, the particle size
of non-milled sorbent 20 may be fine enough to fluidize with
compressed air 60 at a respective velocity of turbulence to allow
mixing of particles of non-milled sorbent 20 with impregnant
100.
[0062] Impregnated sorbent 165 may exit mixing vessel 50 having a
conical mixing chamber by a reverse flow via product discharge tube
140. Product 165 may exit out by drafting through discharge tube
140 into dust collector chamber 160. A draft from dust collector
blower (not expressly shown) may pull air/sorbent through toward
dust collector chamber 165. Impregnated sorbent 165 may be forced
out from mixing vessel 50 by the pressure difference between mixing
vessel 50 and dust collector 160.
[0063] While the velocity of air and sorbent may vary inside mixing
vessel 50 having a conical mixing chamber, the air and sorbent 20
remain in a turbulent regime. Once the gas/sorbent reaches
discharge tube 140, the velocity increases significantly due to the
pressure difference between the mixing vessel 50 and the dust
collector 160. In response to the pressure difference, impregnated
sorbent 165 and air may exit toward the top 58 of mixing vessel 50,
in a dilute phase, via discharge chute 140 that extends down into
the turbulent volume of mixing vessel 50.
[0064] The air may be drafted or pulled through filter bags located
in dust collector 160 and discharged out of a blower (not shown).
Impregnated sorbent 165 now separated from the air, falls to a
bottom hopper in dust collector 160 and may be discharged to a
storage container 180 via a rotary valve 170.
[0065] Milled sorbent 20 impregnated with impregnant 100, also
referred to as impregnated adsorbent 165, made using apparatus 10
of the present disclosure, may have an increased efficiency for
adsorbing and decontaminating a fluid (such as a flue gas or an
exhaust gas) as compared to a milled sorbent 20 that is not
impregnated. In some embodiments, impregnated adsorbent 165 may be
operable to increase sorbent efficiency by detoxifying a
contaminant or a hazardous molecule as compared to milled sorbent
20 that is not impregnated. In one example embodiment, an
impregnated sorbent 165 may comprise impregnant 100 comprising a
halogen and may be operable to oxidize mercury (Hg) from flue gases
and exhaust gases.
[0066] FIG. 2A illustrates an exemplary mixing vessel 50 having a
conical mixing chamber having a top end 58 and a second end 59.
Atomizer 130 and product discharge tube 140 may be located toward
top end 58.
[0067] FIG. 2B illustrates a top-view of mixing vessel 50 having a
conical mixing chamber showing individual parts. In some
embodiments, parts of mixing vessel 50 having a conical mixing
chamber may be releasably attached.
[0068] FIG. 2C depicts an example flange 52 that couples to
cylindrical chamber 53.
[0069] FIG. 2D illustrates a two dimensional representation of
different parts of mixing vessel 50 having a conical mixing chamber
as described in FIG. 2A and shows top flange 51 having atomizer 130
and discharge chute 140 disposed therein, flange 52, cylindrical
chamber 53, bottom conical chamber 54, and bottom flange 55.
Flanges 51 and 52 may facilitate a seal between the various
components.
[0070] FIG. 2E illustrates a three-dimensional view of components
of mixing vessel 50 having a conical mixing chamber as shown in
FIG. 2B. Top flange 51 may be located toward top end 58 of cone 50.
Atomizer 130 and product discharge tube 140 may be attached to top
flange 51. Atomizer 130 and product discharge tube 140 may be
disposed into various elements of flange 51. In other embodiments,
atomizer 130 or discharge tube 40 may be located in different
positions on flange 51.
[0071] Cylindrical chamber 53 and bottom conical chamber 54 are
located below flange 52. Bottom flange 55 is located toward second
end 59 of cone 50 and may be releasably attached to the body.
[0072] FIG. 2F illustrates a two-dimensional view of an exemplary
mixing vessel 50 having a conical mixing chamber showing handle 56.
Handle 56 may be releasably attached to bottom conical chamber 54
to facilitate moving chamber 54. FIG. 2F illustrates a
three-dimensional view of mixing vessel 50 having a conical mixing
chamber as shown in FIG. 2E.
[0073] FIG. 3 illustrates another exemplary apparatus 10 having
mixing vessel 190 comprising a cylindrical mixing chamber operable
to impregnate sorbent 20. Several elements of apparatus 10 of FIG.
3 are similar to apparatus 10 described in FIG. 1, but sorbent 20
impregnation occurs in mixing vessel 190 comprising a cylindrical
mixing chamber rather than in mixing vessel 50 having a conical
mixing chamber.
[0074] Apparatus 10 as shown in FIG. 3 may comprise sorbent
delivery chamber 30 having sorbent 20. Sorbent delivery chamber 30
represents a device to deliver sorbent 20 into mixing vessel 190
comprising a cylindrical mixing chamber.
[0075] Mixing vessel 190 comprising a cylindrical mixing chamber
(also referred to herein as cylinder 190) comprises a cylindrical
vessel having a first end 191 and a second end 192. A first flange
195 may be disposed on first end 191. Flange 195 may have inlet 31
for entry of sorbent 20 and compressed air 60 into cylinder 190. A
second flange 196 may be disposed on second end 192. Flange 192 may
include outlet 140, also described as product discharge tube 140,
to discharge impregnated sorbent 165 from cylinder 190.
[0076] Cylindrical mixing chamber of mixing vessel 190 may have an
external surface 194 and an internal surface 193. Mixing vessel 190
comprising a cylindrical mixing chamber may be lined and/or
comprised of a corrosion resistant and temperature transfer
resistant material. In some embodiments, the core of mixing vessel
190 comprising a cylindrical mixing chamber may comprise stainless
steel. The size and height of the walls of mixing vessel 190
comprising a cylindrical mixing chamber may be designed to maintain
sorbent 20 in a dilute phase. The shape of mixing vessel 190
comprising a cylindrical mixing chamber may be designed to allow
for turbulence formation or turbulent flow in the cylindrical
vessel 190 following in flow of sorbent 20 and compressed air 60
through first end 191 via inlet 31.
[0077] Mixing vessel 190 comprising a cylindrical mixing chamber
may have one or more atomizers 130 disposed thereon. Atomizer 130
may be operable to allow atomization of impregnant 100 to form
atomized droplets of impregnant 100. Atomized 130 may be also
operable to allow inflow of atomized droplets. Mixing vessel 190
comprising a cylindrical mixing chamber may be operable to allow
inflow and mixing of sorbent 20 and atomized droplets of impregnant
100 to form impregnated sorbent 165 also referred to as product
165. Product discharge tube 140 (also called outlet 140) may be
disposed on flange 196 at second end 191 of mixing vessel 190
comprising a cylindrical mixing chamber.
[0078] In some embodiments, mixing vessel 190 comprising a
cylindrical mixing chamber is designed to generate a turbulence
formation having flow and dynamics for efficient mixing of milled
or non-milled sorbent 20 with atomized droplets of impregnant 100.
In some embodiments, construction of mixing vessel 190 comprising a
cylindrical mixing chamber with temperature transfer resistant
material may be designed to facilitate maintenance of the
temperature of a reaction in cylinder 190 within a range where
impregnant 100 (e.g., aqueous impregnant) remains in an aqueous
phase and is not converted into a gaseous phase.
[0079] Mixing vessel 190 comprising a cylindrical mixing chamber
may also be designed to have a reverse flow for discharging
impregnated sorbent 165 via product discharge tube 140 out of the
cylinder 190. The shape of mixing vessel 190 comprising a
cylindrical mixing chamber may be operable to reduce or prevent
caking and plugging of outlets and inlets by components of the
reaction or by product. In some embodiments, maintenance of
turbulent velocity during formation and drafting of impregnant
sorbent 165 may reduce or prevent caking or plugging. Additional
details regarding mixing vessel 190 comprising a cylindrical mixing
chamber are described in FIG. 4.
[0080] In apparatus 10, delivery of sorbent 20 into first end 191
of mixing vessel 190 comprising a cylindrical mixing chamber via
inlet 31 may be facilitated by eductor 40. Apparatus 10 may
comprise compressed air source 70 having compressed air 60 operable
to be delivered with sorbent 20 into bottom end 59 of mixing vessel
50 having a conical mixing chamber via regulator 81, pressure valve
91, valve 80, element 85. In some embodiments a rotary valve and a
tee may be used for conveying dilute phase sorbent. In some
embodiments, pump 40 may be used. Compressed air source 70 may in
non-limiting embodiments comprise an air cylinder having air under
pressure, a source having air under low pressure or an air
blower.
[0081] Container 101 may contain impregnant 100 and may be operable
to deliver or feed sorbent 20 via pump 110 into atomizers 130.
Rotameter 120 may be connected to pressure valve 94 and element 96
operable to regulate inflow of impregnant 100 into atomizers
130.
[0082] Compressed air source 70 may be designed to supply
compressed air 60 to one or more atomizers 130 located at one or
more locations on the surface of mixing vessel 190 comprising a
cylindrical mixing chamber via inlets 32. Regulator 82 may control
the flow of compressed air to atomizers 130. Pressure valve 93 and
air flow meter 85 may regulate the flow of compressed air 60.
[0083] FIG. 3 depicts four atomizers 130. However, teachings
recognize that apparatus 10 is not limited to the number of
atomizers or the location of atomizers. More or fewer atomizers 130
may be present and may be located at several locations on the
surface of mixing vessel 190 comprising a cylindrical mixing
chamber (although not expressly depicted). In some embodiments,
atomizer 130 may be operable to atomize impregnant 100 into
atomized droplets that are similar in size to the size of milled
sorbent 20. In some embodiments, atomizer 130 may be operable to
atomize impregnant 100 into atomized droplets having a size range
of, but not limited to, from about 10.mu. to about 30.mu..
[0084] Atomizer 130 may be designed to spray atomized droplets of
aqueous impregnant at an angle relative to the turbulent flow of
sorbent 20. The angle of spray of atomizer 130 may be broad enough
to distribute impregnant 100 to substantially all particles of
sorbent 20. The angle of the atomizer spray may also be designed to
avoid spraying the exiting product 165.
[0085] An impregnated sorbent 165, or product 165, may exit mixing
vessel 190 comprising a cylindrical mixing chamber through product
discharge tube 140. Regulatory valve 80 may control the flow of
product 165 into collection chamber 160.
[0086] 152 may be a temperature indicator to measure the
temperature of exiting impregnated sorbent 165 and air in dilute
phase.
[0087] Product discharge tube 140 may be attached to collection
chamber 160 (also referred to as dust collector 160) wherein
impregnated milled sorbent 165 may be collected following
impregnation in mixing vessel 190 comprising a cylindrical mixing
chamber. Dust collector 160 may be similar to that described in
sections above and may comprise elements such as but not limited to
filters, blower, and/or a bottom hopper. Rotary valve 170 may
control the flow of impregnated sorbent 165 into chamber 180.
[0088] Automated and manual controls of apparatus 10 shown in FIG.
3 may be similar to those described for apparatus 10 of FIG. 1.
[0089] In an exemplary embodiment, sorbent 20 flows through
apparatus 10 of FIG. 3 to form an impregnated sorbent 165 in mixing
vessel 190 comprising a cylindrical mixing chamber. In some
embodiments, sorbent 20 may be a milled sorbent. Teachings
recognize that any sorbent, milled, powdered or un-milled sorbent
may be used in conjunction with apparatus 10 of FIG. 3 and the
apparatus and/or apparatus design does not limit the usage of a
particular sorbent type. In one example embodiment, flow of sorbent
20, through apparatus 10, may begin with delivery of sorbent 20
from sorbent delivery chamber 30 into first end 191 of mixing
vessel 190 comprising a cylindrical mixing chamber via inlet 31.
Delivery and flow of sorbent 20 into mixing vessel 190 comprising a
cylindrical mixing chamber may be facilitated by compressed air
source 70 having compressed air 60. Accordingly, compressed air 60
and sorbent 20 may be delivered (or fed) simultaneously into first
end 191 of mixing vessel 190 comprising a cylindrical mixing
chamber via inlet 31 located on first end 191 and may be regulated
by one or more of regulator 81, pressure valve 91, valve 80, and/or
element 85 through eductor 40. Sorbent 20 with air 60 may comprise
a dilute phase sorbent. In some embodiments, sorbent 20 may enter
end 59 of mixing vessel 190 comprising a cylindrical mixing chamber
at a rate of from about 1000 lb/hr to about 5000 lb/hr.
[0090] Inflow of sorbent 20 with compressed air 60 into the
cylindrical chamber mixing vessel 190 comprising a cylindrical
mixing chamber may result in a turbulence formation or a turbulent
flow comprising particles of sorbent 20 having a turbulent
velocity. At the same time, impregnant 100 may be delivered into
the cylindrical chamber of mixing vessel 190 comprising a
cylindrical mixing chamber via atomizers 130. Delivery of
impregnant 100 from container 101 into atomizers 130 may be
facilitated by pump 110, pressure valves 94 and 95, element 96, and
rotameter 120. Compressed air 60 from compressed air source 70 may
be delivered into atomizers 130 simultaneously as impregnant 100.
Compressed air 60 along with impregnant 100 enters an atomizer 130
and may be atomized into atomized droplets of impregnant 100 which
may be sprayed onto the turbulent flow of sorbent and compressed
air in mixing vessel 190 comprising a cylindrical mixing
chamber.
[0091] In some embodiments a finer particle size of atomized
droplets of impregnant 100 formed by atomizer 130 may result in a
larger surface area of impregnant 100 operable to contact sorbent
20. In some embodiments, atomizer 130 may spray atomized droplets
of impregnant 100 at an angle relative to the turbulent flow of
sorbent 20. In some embodiments, the angle of spray of atomizer 130
may distribute impregnant to substantially all particles of sorbent
20. In some embodiments, multiple atomizers maximize the contact
and mixing of sorbent 20 with impregnant 100.
[0092] As atomized droplets of impregnant 100 flow in through
atomizers 130 into cylinder 190, impregnant 100 comes in contact
with a turbulent formation comprising milled sorbent 20 and
compressed air 60. This results in mixing sorbent 20 and impregnant
100 in cylinder 190. In some embodiments, the mixing may be
turbulent mixing (i.e., mixing occurring at turbulent velocities of
one or more of the components being mixed). Mixing results in
adsorption of impregnant 100 into milled sorbent 20 and formation
of impregnated sorbent 165.
[0093] In some embodiments, turbulence formation in mixing vessel
190 comprising a cylindrical mixing chamber may have flow and
dynamics for efficient mixing of sorbent 20 with atomized droplets
of impregnant 100. In embodiments where non-milled sorbents 20 may
be impregnated using cylinder 190 and/or other parts of apparatus
10, particle size of non-milled sorbent 20 may be fine enough to
fluidize with compressed air 60 at a respective velocity of
turbulence to allow mixing of non-milled sorbent particles 20 with
impregnant 100.
[0094] Impregnated sorbent 165 may exit mixing vessel 190
comprising a cylindrical mixing chamber by a reverse flow via
product discharge tube 140. Product 165 may exit by drafting of
discharge tube 140.
[0095] FIG. 4 depicts a three-dimensional view of mixing vessel 190
comprising a cylindrical mixing chamber. Mixing vessel 190
comprising a cylindrical mixing chamber is a cylindrical chamber
having a first end 191 and a second end 192. A first flange 195 may
be disposed on first end 191. Flange 195 may have inlet 31 for
entry of sorbent 20 and compressed air 60 into cylinder 190.
[0096] One or more atomizers 130 may be disposed on the surface of
mixing vessel 190 comprising a cylindrical mixing chamber at
various locations as described earlier. Impregnant 100 and
compressed air 60 may enter atomizer 130 through inlets 32 located
toward outer surface 194 of mixing vessel 190 comprising a
cylindrical mixing chamber. Atomized droplets of impregnant 100 may
enter mixing vessel 190 comprising a cylindrical mixing chamber
through atomizer 130 toward inner surface 193.
[0097] Mixing vessel 190 comprising a cylindrical mixing chamber
may have a second flange 196 located on second end 192. Product
discharge tube 140 may be disposed in second flange 196 of mixing
vessel 190 comprising a cylindrical mixing chamber.
[0098] In some embodiments, the shape of mixing vessel 190
comprising a cylindrical mixing chamber may be designed to allow
for turbulence formation in cylinder 190 following flow of sorbent
20 and compressed air 60 through inlet 31.
[0099] In some embodiments, mixing vessel 190 comprising a
cylindrical mixing chamber is designed to generate a turbulence
formation having flow and dynamics for efficient mixing of milled
sorbent 20 with atomized droplets of impregnant 100. In embodiments
where non-milled sorbents may be impregnated using cylinder 190
and/or other parts of apparatus 10, the particle size of non-milled
sorbent 20 may be fine enough to fluidize with compressed air 60 at
a respective velocity of turbulence to allow mixing of non-milled
sorbent particles 20 with impregnant 100.
[0100] In some embodiments, mixing vessel 190 comprising a
cylindrical mixing chamber may be designed to control the
temperature of a reaction. In some embodiments, the temperature of
components in cylinder 190 may be maintained within a range where
impregnant 100 remains in an aqueous phase and is not converted
into a gaseous phase.
[0101] Apparatus 10 of the disclosure as shown in FIGS. 1-4 may, in
some embodiments, be designed to generate turbulence when the ratio
of the inertial force of a fluid stream (e.g., of sorbent 20 and
compressed air 60) to its viscous force exceeds a critical value.
In some embodiments, apparatus design of the present disclosure may
result in an increased residence time, which is the time of contact
between an impregnant 100 and a sorbent 20. An increased residence
time may a facilitate distribution of an impregnant 100 uniformly
across the particles of a sorbent 20 allowing for increased
adsorption.
[0102] In some embodiments, apparatus 10 of the disclosure may be
designed to produce turbulence and residence times that allow for
uniform distribution of impregnant 100 across sorbent 20 to allow
sufficient time for the moisture in an impregnant 100 (e.g.,
aqueous impregnant such as a halogen solution) to be either
adsorbed onto pores of a sorbent and/or evaporate such that it does
not condense on the surface of an impregnant sorbent 165.
[0103] Apparatus 10 as shown in FIG. 1 and FIG. 3 as well as
embodiment devices shown in FIGS. 2A-2G and FIG. 4 may be used to
make compositions of the disclosure in accordance methods of the
disclosure. The present disclosure provides several methods to make
an impregnant sorbent 165.
[0104] Some exemplary methods of the disclosure relate to
impregnating a milled (or powdered) sorbent. One such exemplary
method is illustrated in FIG. 5 and begins at step 300 when a
milled sorbent is received. At step 301, milled sorbent is formed
into a dilute phase milled sorbent. This may comprise mixing milled
sorbent with a gas, such as air, to a conveying velocity that
exceeds the saltation velocity of the sorbent. Step 302 comprises
receiving an impregnant, and step 303 comprises contacting the
dilute phase milled sorbent with the impregnant under conditions to
cause impregnation of the impregnant into the milled sorbent.
[0105] In some embodiments, a method as described above may be
performed in apparatus 10 of the disclosure comprising a mixing
vessel 50 having a conical mixing chamber or an mixing vessel 190
comprising a cylindrical mixing chamber. In some embodiments, the
particle size of a milled sorbent may be similar to the particle
size of an impregnant during the contacting step.
[0106] Exemplary conditions under which impregnation may occur may
include one or more of the following: atomizing an impregnant to
form atomized impregnant droplets; generating a turbulent velocity
of dilute phase milled sorbent; contacting atomized impregnant and
dilute phase milled sorbent by spraying atomized droplets of
impregnant into a turbulent flow of dilute phase milled sorbent;
turbulently mixing atomized impregnant and dilute phase sorbent;
and/or controlling temperature of the mixing; synchronization of
spraying by atomizer and turbulent flow of sorbent; and/or
preventing spraying by atomizer onto formed product.
[0107] In some embodiments, an atomized impregnant may be an
aqueous impregnant. Accordingly, in some embodiments of the method,
a liquid phase (aqueous impregnant) may be mixed with a fluid phase
comprising dilute phase sorbent at a turbulent velocity. In one
embodiment, where an aqueous impregnant may be used, a condition
may comprise maintaining or controlling the temperature to avoid
evaporation of liquid from the aqueous sorbent.
[0108] In some embodiments, a non-aqueous impregnant may be used.
In such embodiments, a gas phase impregnant may be mixed with a
liquid phase (or dilute phase) milled sorbent.
[0109] Another method of the disclosure operable to impregnate a
milled or powdered sorbent is illustrated in FIG. 5B and starts
with step 310 when a milled sorbent is received. At step 311,
milled sorbent is formed into a dilute phase milled sorbent. Step
312 comprises receiving an impregnant, and step 313 comprises
atomizing the impregnant to form atomized impregnant droplets. At
step 314, the dilute phase milled sorbent is contacted with the
atomized impregnant under conditions to cause impregnation of the
impregnant into the milled sorbent.
[0110] In some embodiments, a method as described in FIG. 5B may be
performed in apparatus 10 of the disclosure comprising mixing
vessel 50 having a conical mixing chamber or mixing vessel 190
comprising a cylindrical mixing chamber. In some embodiments,
particle size of a milled sorbent may be similar to the particle
size of an impregnant during the contacting step.
[0111] In the two exemplary methods described above, an example
sorbent that may be used may comprise a milled or powdered
activated carbon. Powdered activated carbon may currently be the
Best Available Control Technology ("BACT") for the removal of
mercury, particularly elemental mercury, from the exhaust gases of
mercury emitting facilities such as coal-fired power plants. An
example impregnant may be a halogen, such as bromine, for the
removal of contaminating mercury from flue gases or exhausts from
coal power plants. In some embodiments, the halogen may be in an
aqueous phase. In other embodiments, the halogen may be a gas.
[0112] For applications relating to removal of mercury and/or
elemental mercury from coal-fired power plants, other methods have
shown significantly better mercury removal using a halogenated
activated carbon than with a non-halogenated activated carbon.
However, all of these methods involve first halogenating a granular
activated carbon followed by milling the halogenated granular
carbon to obtain halogenated powdered activated carbon. For
example, in some methods, a halogen compound is dissolved in an
aqueous solution to impregnate the carbon in its granular form
prior to milling it into a powder. In some other methods, sorbents
may be impregnated with halogens by spraying granular activated
carbon with an aqueous NaBr solution immediately prior to feeding
it into a mill where it is ground into powdered activated
carbon.
[0113] An attempt to impregnate powdered activated carbon with an
aqueous halogen solution may involve mixing a halogen solution into
powdered activated carbon in batches and then drying the batches.
However, these efforts are inefficient, expensive and inconsistent
in the composition and quality of product formed.
[0114] Accordingly, while sorbents such as granular activated
carbon may be impregnated by halogenation, the halogenated granular
carbon may be milled later to obtain halogenated powdered activated
carbon. Milling an impregnated sorbent is associated with several
problems. For example, halogens used for impregnation are corrosive
and corrode and damage mill parts. Accordingly, such methods result
in repeated replacement of mill parts and downtime of milling
operations due to maintenance- and/or repair-related shut
downs.
[0115] Another problem associated with methods where halogen
impregnation is followed by milling of the impregnated sorbent is
contamination by halogenated activated carbon. Moving parts of
mills used for milling get contaminated with toxic halogens, which
render the mill unusable for milling other products. Accordingly,
previous methods have imposing limitations of exclusive use of a
mill for halogen impregnated sorbents pose drawbacks.
[0116] Methods that use milling following impregnation are also
plagued with flowability issues. Lines often are caked or plugged
by the activated carbon, the impregnant and/or by the impregnant
sorbent product which may have poor flowability. This reduces
milling capacity.
[0117] In contrast, present methods for impregnation of a milled
sorbent may be operable to impregnate a large surface area since a
milled sorbent has a greater surface area to adsorb/trap in more
impregnant. For example, each grain of granular activated carbon
may become approximately 472,000 particles of powdered activated
carbon. One technical advantage of methods of the present
disclosure may be the formation of a product having a higher
concentration of impregnant as compared to a product formed by
other methods that perform the milling step following
halogenation/impregnation. In some embodiments, the present methods
may produce impregnated sorbents having substantially higher
concentrations of impregnants. In some embodiments, a method of the
disclosure may comprise impregnating a sorbent with from about 3%
to about 4% of Br.
[0118] Use of an atomizer and turbulent flow as described in some
embodiments ensures better contact and mixing of a sorbent with an
impregnant and results in uniformity of impregnation. Accordingly,
in some embodiments, the present methods produce substantially
uniformly impregnated sorbent.
[0119] In some embodiments, methods of the disclosure relate to
impregnation of non-milled sorbents. An exemplary method operable
to impregnate an un-milled sorbent is illustrated in FIG. 6 and
starts from step 320 where an un-milled sorbent having a respective
sorbent particle size is received. The un-milled sorbent may be in
a dilute phase. At step 321, an aqueous impregnant solution is
atomized to form an aqueous atomized impregnant having a respective
aqueous atomized impregnant particle size. Step 322 comprises
contacting the sorbent with the aqueous atomized impregnant, and
step 323 comprises mixing the sorbent with the aqueous atomized
impregnant, thereby forming impregnated sorbent.
[0120] In some embodiments, a method as described in FIG. 6 may be
performed in apparatus 10 of the disclosure comprising mixing
vessel 50 having a conical mixing chamber or mixing vessel 190
comprising a cylindrical mixing chamber. Contacting may comprise
generating a turbulent velocity of sorbent particles and spraying
impregnant using one or more atomizers. Mixing the sorbent may
comprise turbulent mixing.
[0121] In some embodiments of this method, the particle size of an
un-milled sorbent may be substantially similar to the particle size
of aqueous atomized impregnant. In some embodiments, the particle
size of an un-milled sorbent may be in the range of from about
10.mu. to about 30.mu., and the size range of an aqueous atomized
impregnant droplet size may be from about 10.mu. to about 30.mu..
However, the present methods are not limited to these atomized
droplet size ranges and other sizes of droplets may be used as
well.
[0122] In some embodiments, the disclosure relates to methods for
making impregnated sorbents using apparatus 10 of the disclosure.
FIG. 7 illustrates an exemplary method for impregnating sorbent 20
using mixing vessel 50 having a conical mixing chamber and begins
at step 330, which comprises receiving a dilute phase sorbent 20.
At step 331, the dilute phase sorbent 20 and compressed air 60 are
transporting into the bottom of conical chamber 54 of mixing vessel
50 having a conical mixing chamber to form a turbulent formation
comprising sorbent 20 and compressed air 60. At step 332, an
aqueous impregnant 100 is received; and at step 333, the aqueous
impregnant 100 and compressed air 60 are transported into one or
more atomizers 130 located in mixing vessel 50 having a conical
mixing chamber. Step 334 comprises atomizing the aqueous impregnant
100 to form an atomized impregnant. Step 335 comprises contacting
the turbulent formation with the atomized impregnant in the conical
chamber 54 of mixing vessel 50 having a conical mixing chamber.
Step 336 comprises mixing the turbulent formation with the atomized
impregnant in conical chamber 54 of mixing vessel 50 having a
conical mixing chamber to allow adsorption of impregnant 100 into
sorbent 20 to form impregnated sorbent 165. Mixing may comprise
contacting the surface of sorbent with impregnant. Mixing may in
some embodiments comprise adsorption of impregnant 100 into
sorbent. Step 337 comprises drafting impregnated sorbent 165 to
discharge tube 140 on top portion 58 of mixing vessel 50 having a
conical mixing chamber to remove impregnated sorbent 165 from a
mixing vessel having a conical mixing chamber 50.
[0123] In some embodiments, a turbulent formation may comprise
sorbent 20 and compressed air 60. In some embodiments, a turbulent
formation may comprise sorbent 20, atomized impregnant, and
compressed air 60. Turbulence formation used for mixing a milled
sorbent 20 with an impregnant 100 may be referred to as turbulent
mixing.
[0124] In some embodiments, a method of the disclosure may use a
mixing vessel having a cylindrical mixing chamber 195 as described
in FIGS. 3 and 4. FIG. 8 illustrates an example method and starts
at step 350 where a dilute phase sorbent 20 is received. In step
351, dilute phase sorbent 20 and compressed air 60 are transported
into a cylindrical chamber of mixing vessel 190 comprising a
cylindrical mixing chamber to form a turbulent formation comprising
sorbent 20 and compressed air 60. Step 352 comprises receiving an
aqueous impregnant 100, and step 353 comprises transporting the
aqueous impregnant 100 and compressed air 60 into one or more of
the plurality of atomizers 130 of mixing vessel 190 comprising a
cylindrical mixing chamber. Step 354 comprises atomizing the
aqueous impregnant 100 to form an atomized impregnant, and step 355
comprises contacting the turbulent formation with the atomized
impregnant in cylindrical chamber of mixing vessel 190 comprising a
cylindrical mixing chamber. Step 356 comprises mixing the turbulent
formation with the atomized impregnant in cylindrical chamber of
mixing vessel 190 comprising a cylindrical mixing chamber to allow
contact of impregnant into the sorbent to form impregnated sorbent
165. Mixing at step 356 may comprise contacting the surface of
sorbent with impregnant. Mixing at step 356 may in some embodiments
comprise adsorption of impregnant 100 into sorbent. Step 357
comprises drafting impregnated sorbent 165 to discharge tube 140 on
second end 192 of mixing vessel 190 comprising a cylindrical mixing
chamber to remove impregnated sorbent 165 from mixing vessel 190
comprising a cylindrical mixing chamber.
[0125] Methods of the present disclosure may advantageously result
in impregnant sorbents 165 having a higher concentration of
impregnant as compared to a product formed by other methods. For
example, in embodiments where milled sorbents are impregnated,
greater surface area of sorbent is impregnated. In embodiments
where non-milled sorbents are impregnated, the use of atomized
impregnant solution greatly increases the contact between sorbent
and impregnant molecules. In addition, apparatus 10 of the
disclosure are designed for turbulent mixing, which greatly
enhances contacting and mixing of sorbent and impregnant molecules.
Accordingly, methods of the disclosure may produce impregnated
sorbents having substantially higher concentrations of impregnants.
In some embodiments, a method of the disclosure may comprise
increasing Br distribution. In some embodiments, the present
methods produce substantially uniformly impregnated sorbent 165. In
some embodiments, a method of the disclosure may be a continuous
process.
[0126] Embodiments of the disclosure also relate to impregnant
sorbents produced by methods of the disclosure. Compositions of the
disclosure may comprise impregnated sorbents 165 made by a method
and/or in an apparatus of the disclosure.
[0127] An impregnated sorbent composition 165 of the disclosure may
comprise a porous sorbent 20 having one or more inorganic
impregnants 100 such as but not limited to a halogen, silver or a
cation such as Al, Mn, Zn, Fe, Li, Ca. In some embodiments, a
composition of the disclosure may comprise a sorbent comprising an
activated carbon and an impregnant comprising a halogen. One
example embodiment composition may comprise a powdered activated
carbon impregnated with bromine
[0128] In some embodiments, a composition of the disclosure may
comprise a sorbent substantially uniformly impregnated with an
impregnant. In some embodiments, a composition of the disclosure
may comprise a sorbent with a high concentration of impregnant per
unit of sorbent. Additionally, a composition of the disclosure may
have a more uniform distribution of impregnant as compared to an
impregnated sorbent made by other methods. One technical advantage
of an impregnant of the disclosure may be an improved sorbent
efficiency.
[0129] Sorbent efficiency of an impregnated sorbent according to
the disclosure, (also referred to herein variously as "adsorption
efficiency of a sorbent and/or an impregnated sorbent," "efficiency
of sorbent," or "sorbent efficacy") may be the ability of an
impregnated sorbent to remove substantially all molecules of a
contaminant (e.g., a hazardous molecule) from contaminated fluid
(liquid or gas). An impregnated sorbent made by the methods and/or
apparatuses of the disclosure may remove a contaminant by
adsorbing, binding to, or sequestering a contaminant from a
contaminated fluid. In some embodiments, an impregnated sorbent of
the disclosure may chemically modify a contaminant which may render
a contaminant less toxic. For example, in an example embodiment, an
impregnated sorbent comprising a halogen (e.g., bromine (Br)) may
oxidize mercury from a flue gas or an exhaust gas thereby
decontaminating it.
[0130] In some embodiments, sorbent efficiency may be the ability
of an impregnated sorbent of the disclosure to remove, reduce, or
lower a contaminant from contaminated fluid to a legally acceptable
level. In other embodiments, sorbent efficiency may be the ability
of an impregnated sorbent to remove a substantial portion of a
contaminant from a contaminated fluid. Sorbent efficiency may also
represent the ability of an impregnated sorbent to remove from
about 20% to about 100% of a contaminant from contaminated fluid.
In some embodiments, sorbent efficiency may be the ability of an
impregnated sorbent to lower the levels of a contaminant in a
contaminated fluid from about 20% to about 99.9%. In some
embodiments, sorbent efficiency may be the ability of an
impregnated sorbent to lower the levels of a contaminant in a
contaminated fluid from about 20% to about 99.9%. In some
embodiments, an impregnated sorbent comprising an activated carbon
sorbent and a halogen as described herein may have a sorbent
efficiency may be the ability to lower the levels of mercury in a
contaminated fluid from about 20% to about 99.9%.
[0131] An impregnated sorbent of the disclosure may comprise a
variety of carbon sorbents and/or non-carbon sorbents. Exemplary
non limiting examples of non-carbon adsorbents may include a
zeolite (aluminosilicate), a polymeric resin, a non-metallic resin,
a clay, and/or an ion exchange resin. The section below describes
different sources and types of carbon sorbent materials that may be
used to form a composition of the disclosure. However, teachings
recognize that impregnant sorbent compositions of the present
disclosure are not limited to the described sorbents.
[0132] In some embodiments, activated carbon sorbents may be
impregnated by apparatuses and methods described herein to arrive
at some example compositions of the disclosure. Activated carbons
may be used as sorbents to decontaminate hazardous agents or
contaminants such as but not limited to hydrogen sulfide
(H.sub.2S), ammonia (NH.sub.3), formaldehyde (HCOH), radioisotopes
iodine-131 (.sup.131I) and mercury (Hg). An activated carbon (also
known as activated charcoal or activated coal) may be a powdered,
granular, briquetted and/or pelleted form of an amorphous carbon
and is generally characterized by a large surface area per unit
volume due to the presence of numerous fine pores on the surface of
the activated carbon. Activated carbons are capable of sequestering
gases, liquids, and/or dissolved substances on the surface of its
pores primarily by adsorption. Activated carbons have a broad
spectrum of adsorptive activity, excellent physical and chemical
stability, and ease of production from readily available materials
including waste materials. A variety of carbonaceous raw materials
may be used for the manufacture of activated carbon including, but
not limited to, wood, peat, lignite, coir, bone char made by
calcining bones, nut shells (e.g., coconut), coal, petroleum coke
and petroleum pitch.
[0133] Activation may comprise treating carbon to open many pores
having a diameter that ranges from about 1.2 nanometers (nm) to
about 20 nm (e.g., gas-adsorbent carbon) or up to about 100
nm-diameter range (e.g., decolorizing carbons). Following
activation, an activated carbon may have a large surface area
(typically 500-1500 m.sup.2/g) rendering it operable to adsorb one
or more hazardous agents or contaminants
[0134] A variety of activation methods may be used to activate a
carbon. Exemplary non-limiting methods used to activate carbons may
comprise subjecting the carbon to selective oxidation using steam,
carbon dioxide, flue gas, or air to open the pore structure. Other
methods of activation may include mixing chemicals, such as metal
chlorides (e.g., zinc chloride), metal sulfides, metal phosphates,
potassium sulfide, potassium thiocyanate, and/or phosphoric acid
with a carbonaceous matter followed by calcining and washing the
residue. In addition to high surface area, certain chemical
treatments may be used enhance the absorbing properties of
activated carbon sorbents. Teachings of the present disclosure
recognize that the present embodiments are not limited to any
particular methods of activation or to any particular raw material
sources and/or formulations of activated carbon sorbents.
[0135] Under an electron microscope, high surface-area structures
of activated carbon reveal intensely convoluted individual
particles displaying various kinds of porosity. Micropores are seen
as areas where flat surfaces of graphite-like material run parallel
to each other, separated by only a few nanometers. Micropores may
provide superior conditions for adsorption since adsorbing material
can interact with many surfaces simultaneously. Activated carbon
may bind or adsorb materials (such as a contaminant) by van der
Waals force or London dispersion force. In some instances activated
carbons may bind or adsorb certain contaminant materials by
chemosorption.
[0136] Activated carbons are complex products which are difficult
to classify on the basis of their behavior, surface characteristics
and preparation methods. However, some example activated carbons
classified broadly based on their physical characteristics that may
be used as sorbents in non-limiting embodiments of the present
disclosure may include: powdered activated carbon (PAC), granular
activated carbon (GAC), extruded activated carbons (EAC),
impregnated carbons, and polymer coated carbons. Some embodiments
of the disclosure may use activated carbon aerogels having even
higher surface areas as sorbents for some applications.
[0137] Exemplary PAC's may comprise active carbons as powders or
fine granules less than 1.0 millimeters (mm) in size with an
average diameter between 0.15 mm and 0.25 mm. PAC's may have a
large surface to volume ratio with a small diffusion distance. PAC
may comprise crushed or ground carbon particles, 95-100% of which
are passed through a designated mesh sieve.
[0138] GAC's have a relatively larger particle size compared to PAC
and therefore may have a smaller external surface. GAC's may
function via adsorbate diffusion and may be used for adsorption of
gases and vapors as their rate of diffusion are faster. Granulated
carbons may be used for water treatment, deodorisation and
separation of components of flow system. GAC may be either in
granular form or extruded. GAC are typically designated by sizes
such as 8.times.20, 20.times.40, or 8.times.30 for liquid phase
applications and 4.times.6, 4.times.8 or 4.times.10 for vapor phase
applications. A 20.times.40 carbon is made of particles that pass
through a U.S. Standard Mesh Size Number 20 sieve (0.84 mm)
(generally specified as 85% passing), but are retained on a U.S.
Standard Mesh
[0139] Size Number 40 sieve (0.42 mm) (generally specified as 95%
retained). American Water Works Association (AWWA) (1992) B604 uses
the 50-mesh sieve (0.297 mm) as the minimum GAC size.
[0140] A GAC may comprise activated carbon retained on a 50-mesh
sieve (0.297 mm) and PAC material as finer material, while The
American Society for Testing and Materials (ASTM) classifies
particle sizes corresponding to an 80-mesh sieve (0.177 mm) and
smaller as PAC.
[0141] An EAC may comprise a combination of a PAC with a binder,
fused together and extruded into a cylindrical shaped activated
carbon block having diameters from 0.8 mm to 130 mm. EAC's may be
used for gas phase applications because of their low pressure drop,
high mechanical strength and low dust content.
[0142] Polymer coated carbon may comprise a porous carbon coated
with a biocompatible polymer to give a smooth and permeable coat
without blocking the pores. The resulting activated carbon may be
useful for hemoperfusion. Hemoperfusion is a treatment technique in
which large volumes of the patient's blood are passed over an
adsorbent substance in order to remove toxic substances from the
blood.
[0143] Some embodiments relate to compositions of the disclosure
comprising an activated carbon sorbent that may be milled.
[0144] Although several embodiments have been illustrated and
described in detail, it will be recognized that substitutions and
alterations are possible without departing from the spirit and
scope of the present disclosure, as defined by the appended
claims.
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