U.S. patent application number 12/943180 was filed with the patent office on 2011-05-12 for process for producing renewable gasoline, and fuel compositions produced therefrom.
This patent application is currently assigned to Range Fuels, Inc.. Invention is credited to David T. Gallaspy, Shakeel H. TIRMIZI, John D. Winter.
Application Number | 20110107662 12/943180 |
Document ID | / |
Family ID | 43973095 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110107662 |
Kind Code |
A1 |
TIRMIZI; Shakeel H. ; et
al. |
May 12, 2011 |
PROCESS FOR PRODUCING RENEWABLE GASOLINE, AND FUEL COMPOSITIONS
PRODUCED THEREFROM
Abstract
The present invention provides a process for producing gasoline
components from syngas. Syngas is converted to one or more of
methanol, ethanol, mixed alcohols, and dimethyl ether, followed by
various combinations of separations and reactions to produce
gasoline components with oxygenates, such as alcohols. The syngas
is preferably derived from biomass or another renewable
carbon-containing feedstock, thereby providing a biorefining
process for the production of renewable gasoline.
Inventors: |
TIRMIZI; Shakeel H.;
(Matawan, NJ) ; Winter; John D.; (Broomfield,
CO) ; Gallaspy; David T.; (Church Hill, TN) |
Assignee: |
Range Fuels, Inc.
Broomfield
CO
|
Family ID: |
43973095 |
Appl. No.: |
12/943180 |
Filed: |
November 10, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61260563 |
Nov 12, 2009 |
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61260580 |
Nov 12, 2009 |
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61260611 |
Nov 12, 2009 |
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Current U.S.
Class: |
44/451 |
Current CPC
Class: |
C10G 2400/02 20130101;
C10L 1/06 20130101; C10G 2300/1011 20130101; C10L 1/023 20130101;
C10G 45/02 20130101; C10G 2300/1022 20130101; C10G 3/49 20130101;
C10G 3/50 20130101; C10G 45/58 20130101; Y02P 30/20 20151101 |
Class at
Publication: |
44/451 |
International
Class: |
C10L 1/18 20060101
C10L001/18 |
Claims
1. A process for producing an oxygenated gasoline blendstock, said
process comprising: (a) generating or providing syngas; (b)
dividing said syngas into a first syngas stream and a second syngas
stream; (c) converting at least some of said first syngas stream to
methanol using a methanol-synthesis catalyst; (d) converting at
least some of said methanol to one or more gasoline components
using a zeolite catalyst; (e) converting at least some of said
second syngas stream to two or more C.sub.1-C.sub.4 alcohols using
an alcohol-synthesis catalyst; and (f) combining a portion of said
C.sub.1-C.sub.4 alcohols with a portion of said gasoline
components, thereby producing an oxygenated gasoline
blendstock.
2. The process of claim 1, wherein said syngas is derived from
biomass.
3. The process of claim 1, further comprising removing a portion of
water from a product stream generated in step (e).
4. The process of claim 3, wherein at least some of said water is
not removed.
5. The process of claim 1, wherein said C.sub.1-C.sub.4 alcohols
include methanol, and wherein said process further comprises
recycling at least some of said methanol generated in step (e) to
step (d) for conversion to one or more gasoline components using a
zeolite catalyst.
6. The process of claim 1, further comprising separating a portion
of said C.sub.1-C.sub.4 alcohols prior to step (f).
7. The process of claim 6, additionally comprising combining said
portion of said C.sub.1-C.sub.4 alcohols with said gasoline
components, thereby generating oxygenated gasoline components.
8. The process of claim 1, wherein said C.sub.1-C.sub.4 alcohols
include ethanol, and wherein said process further comprises
separating a portion of said ethanol prior to step (f).
9. The process of claim 8, additionally comprising combining said
portion of said ethanol with said gasoline components, thereby
generating ethanol-containing gasoline components.
10. The process of claim 1, wherein said oxygenated gasoline
blendstock includes at least one C.sub.5-C.sub.10 hydrocarbon.
11. The process of claim 1, further comprising hydrotreating at
least some of said gasoline components.
12. The process of claim 1, further comprising isomerizing at least
some of said gasoline components.
13. The process of claim 1, wherein said oxygenated gasoline
blendstock meets fuel specification ASTM D 4814-09a.
14. The process of claim 1, further comprising blending said
oxygenated gasoline blendstock with another fuel, thereby
generating gasoline.
15. The process of claim 14, wherein said gasoline meets fuel
specification ASTM D 4814-09a.
16. The process of claim 1, wherein the output from step (d)
further includes C.sub.2-C.sub.4 hydrocarbon gases that are
recycled back to step (a).
17. A process for producing an oxygenated gasoline blendstock, said
process comprising: (a) generating syngas from biomass; (b)
dividing said syngas into a first syngas stream and a second syngas
stream; (c) converting said first syngas stream to methanol using a
methanol-synthesis catalyst; (d) converting at least some of said
methanol to one or more gasoline components using a zeolite
catalyst; (e) converting at least some of said second syngas stream
to at least ethanol using an alcohol-synthesis catalyst; and (f)
combining a portion of said ethanol with a portion of said gasoline
components, thereby producing an oxygenated gasoline
blendstock.
18. A gasoline composition produced by a process comprising: (a)
generating or providing syngas; (b) dividing said syngas into a
first syngas stream and a second syngas stream; (c) converting at
least some of said first syngas stream to methanol using a
methanol-synthesis catalyst; (d) converting at least some of said
methanol to one or more gasoline components using a zeolite
catalyst; (e) converting at least some of said second syngas stream
to two or more C.sub.1-C.sub.4 alcohols using an alcohol-synthesis
catalyst; (f) combining a portion of said C.sub.1-C.sub.4 alcohols
with a portion of said gasoline components, thereby producing an
oxygenated gasoline blendstock; and (g) blending said oxygenated
gasoline blendstock with another fuel, thereby producing a gasoline
composition.
19. The gasoline composition of claim 18, wherein said composition
comprises durene.
20. The gasoline composition of claim 18, wherein said composition
includes about 2.7 wt % oxygen or less.
21. The gasoline composition of claim 18, wherein said composition
includes greater than 2.7 wt % oxygen.
22. The gasoline composition of claim 18, wherein said composition
includes at least 9 vol % ethanol.
23. The gasoline composition of claim 18, wherein said composition
includes about 0.3 vol % methanol or less.
24. The gasoline composition of claim 18, wherein said composition
includes greater than 0.3 vol % methanol.
Description
PRIORITY DATA
[0001] This patent application claims priority under 35 U.S.C.
.sctn.120 from U.S. Provisional Patent Application Nos. 61/260,563;
61/260,580; and 61/260,611, each filed Nov. 12, 2009, the
disclosures of which are hereby incorporated by reference herein
for all purposes.
FIELD OF THE INVENTION
[0002] The present invention generally relates to processes for the
conversion of synthesis gas into renewable liquid fuels, including
gasoline.
BACKGROUND OF THE INVENTION
[0003] Synthesis gas, which is also known as syngas, is a mixture
of gases comprising carbon monoxide (CO) and hydrogen (H.sub.2).
Generally, syngas may be produced from any carbonaceous material.
In particular, biomass such as agricultural wastes, forest
products, grasses, and other cellulosic material may be converted
to syngas.
[0004] Syngas is a platform intermediate in the chemical and
biorefining industries and has a vast number of uses. Syngas can be
converted into alkanes, olefins, oxygenates, and alcohols such as
ethanol. These chemicals can be blended into, or used directly as,
diesel fuel, gasoline, and other liquid fuels. Syngas can also be
directly combusted to produce heat and power. The substitution of
alcohols and/or derivatives of alcohols in place of petroleum-based
fuels and fuel additives can be particularly environmentally
friendly when the alcohols are produced from feed materials other
than fossil fuels.
[0005] Gasoline is a refined petroleum product which is burned in
the engines powering most of the world's automobiles. Petroleum is
a non-renewable resource of finite supply. Acute shortages and
dramatic price increases in petroleum and the refined products
derived from petroleum have occurred, particularly during the past
several decades. Extensive research is now being directed toward
replacing a portion of petroleum-based gasoline with a
cleaner-burning fuel derived from a renewable resource, such as
biomass in a biorefinery.
[0006] In recent years, considerable research has been devoted to
providing alternative sources and manufacturing routes for liquid
hydrocarbon fuels in recognition of the fact that petroleum is a
non-renewable resource and that petroleum-based fuels such as
gasoline and distillate will ultimately become more expensive.
[0007] A major development within the chemical/petroleum industry
has been the discovery of the special catalytic capabilities of a
family of zeolite catalyst based upon medium-pore size shape
selective metallosilicates. Discoveries have been made leading to a
series of analogous processes drawn from the catalytic capability
of zeolites. Depending upon various conditions of space velocity,
temperature, and pressure, methanol can be converted in the
presence of zeolite-type catalysts to olefins which can oligomerize
to provide gasoline or distillate, or can be converted further to
produce aromatics.
[0008] It has been demonstrated that alcohols, ethers, and
carbonyl-containing compounds can be converted to higher
hydrocarbons, particularly aromatics-rich high-octane gasoline, by
catalytic conversion employing a shape-selective medium pore acidic
zeolite catalyst such as H-ZSM-5. This conversion is described in,
among others, U.S. Pat. Nos. 3,894,103; 3,894,104; 3,894,106;
3,907,915; 3,911,041; 3,928,483; and, 3,969,426. The conversion of
methanol to gasoline in accordance with this technology (the "MTG"
process) produces mainly C.sub.5+ gasoline-range hydrocarbon
products together with C.sub.3-C.sub.4 gases and C.sub.9 heavy
aromatics. The desirable C.sub.6-C.sub.8 aromatics (principally
benzene, toluene and xylenes) can be recovered as a separate
product slate by conventional distillation and extraction
techniques.
[0009] Traditional approaches for converting syngas to gasoline
involve a two-step process comprising converting syngas to methanol
followed by converting methanol to gasoline. What are needed, in
view of the art and commercial drivers, are process configurations,
apparatus, and suitable catalysts for conversion of syngas into
gasoline components as well as oxygenates, such as alcohols, for
blending into oxygenated gasoline. Additionally, methods that
proceed through higher alcohols (ethanol and heavier) are desired
in order to take advantage of the state of the art for ethanol
synthesis and higher-alcohol synthesis from syngas.
SUMMARY OF THE INVENTION
[0010] In some variations, this invention provides a process for
producing gasoline components, the process comprising:
[0011] (a) generating or providing syngas;
[0012] (b) converting the syngas using an alcohol-synthesis
catalyst to a first stream comprising two or more C.sub.1-C.sub.4
alcohols;
[0013] (c) converting at least some of the first stream using an
ether-synthesis catalyst to a second stream comprising one or more
ethers; and
[0014] (d) converting at least some of the second stream using a
zeolite catalyst to a third stream comprising one or more gasoline
components.
[0015] The syngas can be derived, for example, from biomass such as
wood chips or from any other carbon-containing feedstock.
[0016] In some embodiments, the method further comprises removing a
portion of water from the first stream prior to step (c) or step
(d). In some embodiments, at least some of this water is not
removed.
[0017] In some embodiments, the method further comprises separating
a portion of the C.sub.1-C.sub.4 alcohols prior to step (c), and/or
a portion of the ethers prior to step (d). The method can
additionally include combining the portion of the C.sub.1-C.sub.4
alcohols and/or the portion of the ethers with the gasoline
components, thereby generating oxygenated gasoline components.
[0018] In some embodiments, the C.sub.1-C.sub.4 alcohols include
ethanol, and a portion of the ethanol is separated prior to step
(c). Optionally, the portion of the ethanol can be combined with
the gasoline components, thereby generating ethanol-containing
gasoline components.
[0019] The gasoline components are not particularly limited but can
include at least one C.sub.5-C.sub.10 hydrocarbon. Gasoline
components can include branched hydrocarbons, olefins, aromatics,
and alcohols.
[0020] Certain methods of the invention further include
hydrotreating, isomerizing, or otherwise catalytically treating at
least some of the gasoline components.
[0021] In some embodiments, the gasoline components meet fuel
specification ASTM D 4814-09a. Gasoline components can be used
directly as gasoline, or blended with another fuel to generate
commercial gasoline meeting fuel specification ASTM D 4814-09a or a
similar specification.
[0022] The third stream can further include non-gasoline components
(such as C.sub.2-C.sub.4 hydrocarbon gases) which are optionally
recycled. Alternatively, or additionally, some of the non-gasoline
components can be converted into syngas, and the syngas is
optionally combined with the syngas provided or generated in step
(a).
[0023] In some variations, the invention provides a process for
producing gasoline components, the process comprising:
[0024] (a) generating or providing syngas;
[0025] (b) converting the syngas using an alcohol-synthesis
catalyst to a first stream comprising two or more C.sub.1-C.sub.4
alcohols;
[0026] (c) converting at least some of the first stream using a
zeolite catalyst to one or more olefins; and
[0027] (d) converting at least some of the one or more olefins
using the zeolite catalyst to a second stream comprising one or
more gasoline components.
[0028] In other variations of the present invention, a process is
provided for producing an oxygenated gasoline blendstock, the
process comprising:
[0029] (a) generating or providing syngas, optionally derived from
biomass;
[0030] (b) dividing the syngas into a first syngas stream and a
second syngas stream;
[0031] (c) converting at least some of the first syngas stream to
methanol using a methanol-synthesis catalyst;
[0032] (d) converting at least some of the methanol to one or more
gasoline components using a zeolite catalyst;
[0033] (e) converting at least some of the second syngas stream to
two or more C.sub.1-C.sub.4 alcohols using an alcohol-synthesis
catalyst; and
[0034] (f) combining a portion of the C.sub.1-C.sub.4 alcohols with
a portion of the gasoline components, thereby producing an
oxygenated gasoline blendstock.
[0035] The process can include removing a portion of water from the
product stream generated in step (e). In some embodiments, at least
some of the water is not removed.
[0036] The C.sub.1-C.sub.4 alcohols include methanol, in some
embodiments, which methanol (or a portion thereof) can be recycled
to step (d) for conversion to one or more gasoline components using
a zeolite or other functionally equivalent catalyst.
[0037] In some embodiments, a portion of the C.sub.1-C.sub.4
alcohols are separated out prior to step (f). This portion of
C.sub.1-C.sub.4 alcohols can be combined with the gasoline
components, thereby generating an oxygenated gasoline
blendstock.
[0038] In some embodiments, the C.sub.1-C.sub.4 alcohols include
ethanol, and the process further comprises separating a portion of
the ethanol prior to step (f). The ethanol can then be combined
with gasoline components, thereby generating ethanol-containing
gasoline components.
[0039] Variations of the invention provide a process for converting
syngas to liquid transportation fuels, the process comprising:
[0040] (a) generating or providing syngas (optionally derived from
biomass);
[0041] (b) dividing the syngas into a first syngas stream and a
second syngas stream;
[0042] (c) converting at least some of the first syngas stream to
methanol using a methanol-synthesis catalyst;
[0043] (d) converting at least some of the methanol to one or more
gasoline components using a zeolite catalyst; and
[0044] (e) converting at least some of the second syngas stream to
ethanol using a biocatalyst, such as suitable yeast or
bacteria.
[0045] A portion of the ethanol can be combined with a portion of
the gasoline components, thereby producing a gasoline blendstock
containing ethanol. In some embodiments, the process further
includes converting at least some of the ethanol to one or more
gasoline components using the zeolite catalyst. The output of step
(d) and the output of step (e) can be, but are not necessarily,
combined.
[0046] Other variations of the invention relate to compositions. In
some embodiments, a composition comprises the gasoline components
produced in accordance with any of the methods described herein. In
some embodiments, a composition consists essentially of the
gasoline components produced in accordance with any of the methods
described herein.
[0047] In some embodiments, compositions include durene or
structurally similar molecules.
[0048] In some embodiments, compositions include about 2.7 wt %
oxygen or less. In other embodiments, compositions include greater
than 2.7 wt % oxygen.
[0049] Compositions of the invention can be ethanol-free, or
include up to about 9-10 vol % ethanol, or can include greater than
10 vol % ethanol, such as about 12 vol %, 15 vol %, 20 vol %, or
more ethanol. In some embodiments, compositions include about 2.75
vol % methanol or less, such as about 0.3 vol % methanol or less.
Certain compositions contain greater than 2.75 vol % methanol.
BRIEF DESCRIPTION OF THE FIGURES
[0050] FIG. 1 is a block-flow diagram depicting an exemplary
process for conversion of syngas to methanol and ethanol,
conversion of methanol to gasoline, and optional combination of
gasoline and ethanol into oxygenated blends, according to some
embodiments of the invention.
[0051] FIG. 2 is a block-flow diagram depicting an exemplary
process for conversion of syngas to methanol and mixed alcohols,
conversion of methanol to gasoline, and optional combination of
gasoline and mixed alcohols into oxygenated blends, according to
some embodiments.
[0052] FIG. 3 is a block-flow diagram depicting an exemplary
process for conversion of syngas to methanol plus mixed alcohols,
separation of some methanol from the mixed alcohols, conversion of
methanol to gasoline, and optional combination of gasoline and
mixed alcohols into oxygenated blends, according to some
embodiments.
[0053] FIG. 4 is a block-flow diagram depicting an exemplary
process for conversion of syngas to mixed alcohols, separation of
some methanol from mixed alcohols, conversion of methanol to
gasoline, and optional combination of gasoline and mixed alcohols
into oxygenated blends, according to some embodiments.
[0054] FIG. 5 is a block-flow diagram depicting an exemplary
process for conversion of syngas to mixed alcohols, separation of
some ethanol out of the mixed-alcohol mixture, conversion of the
remainder of the mixed-alcohol mixture to gasoline, and optional
combination of gasoline with the separated ethanol (or part
thereof) into oxygenated blends, according to some embodiments.
[0055] FIG. 6 is a block-flow diagram depicting an exemplary
process for conversion of syngas to mixed alcohols which are
optionally dehydrated and then converted directly to gasoline
components, according to some embodiments of the invention.
[0056] FIG. 7 is a block-flow diagram depicting an exemplary
process for conversion of syngas to dimethyl ether and mixed
alcohols, which are both converted to gasoline components with an
optional separation step or steps to recover a portion of dimethyl
ether or a portion of ethanol, according to some embodiments of the
invention.
[0057] These and other embodiments, features, and advantages of the
present invention will become more apparent to those skilled in the
art when taken with reference to the following detailed description
of the invention in conjunction with the accompanying drawings.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0058] Certain embodiments of the present invention will now be
further described in more detail, in a manner that enables the
claimed invention so that a person of ordinary skill in this art
can make and use the present invention.
[0059] Unless otherwise indicated, all numbers expressing reaction
conditions, stoichiometries, concentrations of components, and so
forth used in the specification and claims are to be understood as
being modified in all instances by the term "about." Accordingly,
unless indicated to the contrary, the numerical parameters set
forth in the following specification and attached claims are
approximations that may vary depending at least upon the specific
analytical technique. Any numerical value inherently contains
certain errors necessarily resulting from the standard deviation
found in its respective testing measurements.
[0060] As used in this specification and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless
the context clearly indicates otherwise. Unless defined otherwise,
all technical and scientific terms used herein have the same
meaning as is commonly understood by one of ordinary skill in the
art to which this invention belongs. If a definition set forth in
this section is contrary to or otherwise inconsistent with a
definition set forth in patents, published patent applications, and
other publications that are herein incorporated by reference, the
definition set forth in this specification prevails over the
definition that is incorporated herein by reference.
[0061] Variations of this invention are premised, at least in part,
on the conversion of syngas into gasoline components as well as one
or more alcohols, in various combinations. A "gasoline component"
as used herein means any molecule capable of being combusted in an
internal-combustion engine to provide power for an automobile or
other machine burning gasoline for energy. Gasoline components
include alkanes, olefins, cyclic hydrocarbons, aromatics, and
various oxygenates such as alcohols, ethers, ketones, and
aldehydes.
[0062] Some variations of the invention relate to an integrated
biorefinery capable of producing one or more liquid transportation
fuels, including oxygenated fuels. In some embodiments, the
invention provides a process that converts syngas into gasoline
components. In some embodiments, the invention provides a process
that converts syngas into alcohol fuels such as methanol, ethanol,
propanol, butanol, and/or heavier alcohols, including various
isomers. Certain embodiments also produce dimethyl ether (DME) from
syngas; the DME itself is a suitable liquid fuel (e.g., diesel
fuel), can be combined with other liquids, or can be chemically
converted into gasoline components.
[0063] In some variations, syngas is produced or otherwise provided
in a biorefinery. The syngas can be divided into a plurality of
streams and fed to several unit operations. Biorefinery
optimization can be carried out to adjust the splits to the
different units, for economic reasons. Syngas can be a fuel itself
to provide internal process energy, or sold directly as a
co-product, or converted into electricity for external sale. At
least a portion of the syngas, in the context of the present
invention, is converted to liquid fuels.
[0064] Engineering optimization can be conducted to achieve energy
integration. For example, energy requirements for product
separations can be reduced by combining portions of the product
streams from individual processes into a single unit, such as
distillation and drying. Various levels of heat recovery can be
employed to meet drying and separation requirements.
[0065] Also, specifications on intermediate streams can be relaxed
to reduce energy requirements. For example, the mixed-alcohol
stream can be fed to an alcohol-to-gasoline process without
separation of individual alcohols. In some embodiments, mixed
alcohols or individual alcohols stream are partially (but not
completely) dried for feeding into an alcohols-to-gasoline step,
thereby reducing drying requirements and costs. In some
embodiments, a methanol stream is allowed to contain ethanol in
excess of that described in an ASTM specification, such as 1-2 vol
%, for feeding to an alcohol-to-gasoline step, thereby reducing
energy costs. In some embodiments, ethanol is substantially
separated from mixed alcohols, and the methanol and C.sub.3+
alcohols are fed to an alcohols-to-gasoline step. The methanol and
mixed alcohols optionally are partially dehydrated.
[0066] In the present invention, it may be preferable to use
alcohols larger than methanol to conduct the reactions to produce
components or precursors of gasoline. Alcohols such as ethanol,
propanol, butanol, and C.sub.5+ alcohols (including all isomers)
are desirable in some embodiments.
[0067] Various embodiments of the invention produce one or more
gasoline components selected from the group consisting of 1-butene,
2-methylpropene, 2-methylbutane, 4-methylpentene,
methylcyclopentane, benzene, toluene, ethylbenzene, m-xylene,
p-xylene, o-xylene, 1-ethyl-4-methylbenzene,
1,2,4-trimethylbenzene, 1-methyl-4-(ethylmethyl)-benzene,
1,2-diethylbenzene, 1-ethyl-2,4-dimethylbenzene,
2,3-dihydro-1-methyl-1-indene, naphthalene, 2-methylnaphthalene,
1,8-dimethylnaphthalene, 2-(1-methylethyl)-naphthalene, methanol,
ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol,
t-butanol, dimethyl ether, diethyl ether, and methylethyl ether.
Other alkanes, olefins, cyclic hydrocarbons, aromatics, and
oxygenates (such as alcohols and ethers) can be produced.
[0068] Also, in some embodiments, light components (such as
methane, ethane, and propane) may be recovered as fuel gas suitable
for energy requirements within the biorefinery. In certain
embodiments, crude gasoline components may be distilled to produce
a fuel-grade LPG-type stream and a gasoline stream.
[0069] The present invention will now be further described by
reference to the figures. This exemplary detailed description
illustrates by way of example, not by way of limitation, the
principles of the invention.
[0070] In FIGS. 1 to 7, process block-flow diagrams are depicted
for various processes of the invention.
[0071] FIG. 1 is a block-flow diagram depicting an exemplary
process for conversion of syngas to methanol and ethanol,
conversion of methanol to gasoline, and optional combination of
gasoline and ethanol into oxygenated blends, according to some
embodiments of the invention. In this variation, a starting syngas
stream is provided (e.g., produced from biomass or otherwise
received). The starting syngas stream can be divided into at least
two streams, with a first stream for catalytic conversion to
methanol and a second stream for catalytic or biocatalytic
conversion to ethanol. The methanol can be converted to gasoline
components, which can then be combined with some or all of the
ethanol produced (for example, at about 10 vol % or another
commercially relevant concentration of ethanol).
[0072] FIG. 2 is a block-flow diagram depicting an exemplary
process for conversion of syngas to methanol and mixed alcohols,
conversion of methanol to gasoline, and optional combination of
gasoline and mixed alcohols into oxygenated blends, according to
some embodiments. In this variation, a starting syngas stream is
provided. The starting syngas stream can be divided into at least
two streams, with a first stream for catalytic conversion to
methanol and a second stream for catalytic conversion to mixed
alcohols (e.g., C.sub.1-C.sub.4 alcohols). The methanol can be
converted to gasoline components, which can then be combined with
some or all of the mixed alcohols produced.
[0073] FIG. 3 is a block-flow diagram depicting an exemplary
process for conversion of syngas to methanol plus mixed alcohols,
separation of some methanol from the mixed alcohols, conversion of
methanol to gasoline, and optional combination of gasoline and
mixed alcohols into oxygenated blends, according to some
embodiments. In this variation, a starting syngas stream is
provided. The starting syngas stream can be divided into at least
two streams, with a first stream for catalytic conversion to
methanol and a second stream for catalytic conversion to mixed
alcohols. From the mixed-alcohol stream, at least some of the
methanol can be removed. Methanol from either or both streams can
be converted to gasoline components and optionally combined with
some or all of the remaining mixed alcohols.
[0074] FIG. 4 is a block-flow diagram depicting an exemplary
process for conversion of syngas to mixed alcohols, separation of
some methanol from mixed alcohols, conversion of methanol to
gasoline, and optional combination of gasoline and mixed alcohols
into oxygenated blends, according to some embodiments. In this
variation, a starting syngas stream is provided. The starting
syngas stream is fed (without separation into multiple syngas
streams) to a unit for catalytic conversion to mixed alcohols. From
the mixed-alcohol stream, at least some of the methanol can be
removed. Methanol can be converted to gasoline components and
optionally combined with some or all of the remaining mixed
alcohols.
[0075] FIG. 5 is a block-flow diagram depicting an exemplary
process for conversion of syngas to mixed alcohols, separation of
some ethanol out of the mixed-alcohol mixture, conversion of the
remainder of the mixed-alcohol mixture to gasoline, and optional
combination of gasoline with the separated ethanol (or part
thereof) into oxygenated blends, according to some embodiments. In
this variation, a starting syngas stream is provided. The starting
syngas stream is fed (without separation into multiple syngas
streams) to a unit for catalytic conversion to mixed alcohols. From
the mixed-alcohol stream, at least some of the ethanol can be
removed. The remaining mixed alcohols are converted to gasoline
components and optionally combined with some or all of the ethanol
that was removed.
[0076] FIG. 6 is a block-flow diagram depicting an exemplary
process for conversion of syngas to mixed alcohols which are
optionally dehydrated and then converted directly to gasoline
components, according to some embodiments of the invention. In this
variation, a starting syngas stream is provided. The starting
syngas stream is fed (without separation into multiple syngas
streams) to a unit for catalytic conversion to mixed alcohols. The
mixed alcohols are converted to gasoline components.
[0077] FIG. 7 is a block-flow diagram depicting an exemplary
process for conversion of syngas to dimethyl ether and mixed
alcohols, which are both converted to gasoline components with an
optional separation step or steps to recover a portion of dimethyl
ether or a portion of ethanol, according to some embodiments of the
invention. In this variation, a starting syngas stream is provided.
The starting syngas stream can be divided into at least two
streams, with a first stream for catalytic conversion to dimethyl
ether and a second stream for catalytic conversion to mixed
alcohols. The dimethyl ether can be converted to gasoline
components, which can then be combined with some or all of the
mixed alcohols produced. Or, both of the dimethyl ether and the
mixed alcohols can be converted to gasoline components. Optionally,
an alcohol (such as ethanol) is removed from the mixed alcohols
prior to an alcohol-to-gasoline step, wherein at least some of that
ethanol can be later combined with the produced gasoline
components. As another option, some dimethyl ether can be captured
as a co-product in the process.
[0078] The syngas can be produced from biomass, but that is not
necessary for this invention. Other sources of syngas include, for
example, natural gas, coal, crude oil, and any other carbonaceous
material.
[0079] In some embodiments, the syngas provided or generated for
methods of this invention is produced from one or more
carbon-containing feedstocks selected from timber harvesting
residues, softwood chips, hardwood chips, tree branches, tree
stumps, leaves, bark, sawdust, paper pulp, corn stover, wheat
straw, rice straw, sugarcane bagasse, switchgrass, miscanthus,
animal manure, municipal solid waste, municipal sewage, commercial
waste, used tires, grape pumice, almond shells, pecan shells,
coconut shells, coffee grounds, grass pellets, hay pellets, wood
pellets, cardboard, paper, plastic, rubber, cloth, coal, lignite,
coke, lignin, and/or petroleum. Mixtures of any of these feedstocks
can be used.
[0080] Syngas can be produced by any known means, such as by one or
more of gasification, pyrolysis, devolatilization, steam reforming,
and partial oxidation of one or more feedstocks recited herein.
[0081] The syngas-generation unit or step may be a gasifier, such
as a fluidized-bed gasifier. In variations, the gasifier type may
be entrained-flow slagging, entrained flow non-slagging, transport,
bubbling fluidized bed, circulating fluidized bed, or fixed bed.
Some embodiments employ known gasification catalysts.
"Gasification" and "devolatilization" generally refer herein to the
reactive generation of a mixture of at least CO, CO.sub.2, and
H.sub.2, using oxygen, air, and/or steam as the oxidant(s).
[0082] In some embodiments, syngas is produced by the methods
taught in U.S. patent application Ser. No. 12/166,167, entitled
"METHODS AND APPARATUS FOR PRODUCING SYNGAS," filed Jul. 1, 2008,
whose assignee is the same as the assignee of this patent
application, and which is hereby incorporated herein by
reference.
[0083] Syngas can be efficiently converted to methanol according to
well-known techniques known in the art. Carbon monoxide and
hydrogen react over commercially available catalysts to produce
methanol. Today, a widely used catalyst is a mixture of copper,
zinc oxide, and alumina first used by ICI in 1966. At 50-100 atm
and 250.degree. C., the production of methanol from carbon monoxide
and hydrogen proceeds with high selectivity.
[0084] Syngas can be selectively converted to mixed C.sub.1-C.sub.4
alcohols by means of a chemical catalyst, such as described in U.S.
patent application Ser. No. 12/166,203, entitled "METHODS AND
APPARATUS FOR PRODUCING ALCOHOLS FROM SYNGAS," filed Jul. 1, 2008,
whose assignee is the same as the assignee of this patent
application, and which is hereby incorporated herein by
reference.
[0085] Any suitable catalyst or combination of catalysts may be
used in reactors for producing alcohols. Suitable catalysts may
include, but are not limited to, one or more of
ZnO/Cr.sub.2O.sub.3, Cu/ZnO, Cu/ZnO/Al.sub.2O.sub.3,
Cu/ZnO/Cr.sub.2O.sub.3, Cu/ThO.sub.2, Co/Mo/S, Co/S, Mo/S, Ni/S,
Ni/Mo/S, Ni/Co/Mo/S, Rh, Ti, Fe, Ir, and any of the foregoing in
combination with Mn and/or V. The addition of basic promoters (e.g.
K, Li, Na, Rb, Cs, and Fr) increases the activity and selectivity
of some of these catalysts for alcohols. Basic promoters include
alkaline-earth and rare-earth metals. Non-metallic bases can also
serve as effective promoters, in some embodiments.
[0086] In certain embodiments, such as that shown in FIG. 1, syngas
is fermented to ethanol in a process step. Bioconversion of CO or
H.sub.2/CO.sub.2 to acetic acid, ethanol, or other products is well
known. For example, syngas biochemical pathways and energetics of
such bioconversions are summarized by Das and Ljungdahl, "Electron
Transport System in Acetogens" and by Drake and Kusel, "Diverse
Physiologic Potential of Acetogens," appearing respectively as
Chapters 14 and 13 of Biochemistry and Physiology of Anaerobic
Bacteria, L. G. Ljungdahl eds., Springer (2003).
[0087] Any suitable microorganisms may be utilized that have the
ability to convert CO, H.sub.2, or CO.sub.2, individually or in
combination with each other or with other components that are
typically present in syngas. A large number of anaerobic organisms
including carboxydotrophic, photosynthetic, methanogenic, and
acetogenic organisms have been shown to metabolize CO to various
end products. Anaerobic bacteria, such as those from the genus
Clostridium, have been demonstrated to produce ethanol from CO,
H.sub.2, or CO.sub.2 via the acetyl CoA biochemical pathway. For
example, various strains of Clostridium ljungdahlii that produce
ethanol from gases are described in U.S. Pat. Nos. 5,173,429,
5,593,886, and 6,368,819.
[0088] Generally speaking, microorganisms suitable for syngas
fermentation in the context of the present invention may be
selected from many genera including Clostridium, Moorella,
Carboxydothermus, Acetogenium, Acetobacterium, Butyribacterium,
Peptostreptococcus, and Geobacter. Microorganism species suitable
for syngas fermentation in this invention may be selected from
Clostridium ljungdahli, Clostridium autoethanogenum, Clostridium
ragsdalei, Clostridium carboxidivorans, Butyribacterium
methylotrophicum, Eurobacterium limosum, and genetically
engineered, mutated, or evolved variations thereof. Microorganisms
that are engineered, created, or provided in the future will be
applicable to the present invention, provided such new
microorganisms can convert one or more of CO, H.sub.2, or CO.sub.2
to a product of interest.
[0089] Reactors for conversion of one or more alcohols to gasoline
components are any type of reactor suitable for carrying out
alcohol-to-gasoline chemistry. Preferably, alcohol-to-gasoline
reactors include one or more zeolite catalysts effective for
conversion of alcohols to gasoline components. A "zeolite catalyst"
as used herein includes molecular sieves and other equivalent
functional forms.
[0090] Zeolitic materials, both natural and synthetic, have been
demonstrated in the past to have catalytic properties for various
types of hydrocarbon conversion. Certain zeolitic materials are
ordered, porous crystalline aluminosilicates having a definite
crystalline structure as determined by X-ray diffraction, within
which there are a large number of smaller cavities which may be
interconnected by a number of still smaller channels or pores.
These cavities and pores are uniform in size within a specific
zeolitic material. These materials have come to be known as
"molecular sieves" and are utilized in a variety of ways to take
advantage of these properties.
[0091] Molecular sieves, both natural and synthetic, include a wide
variety of positive ion-containing crystalline silicates. These
silicates can be described as a rigid three-dimensional framework
of SiO.sub.4 and Periodic Table Group IIIA element oxide, e.g.,
AlO.sub.4, in which the tetrahedra are cross-linked by the sharing
of oxygen atoms whereby the ratio of the total Group IIIA element,
e.g., aluminum, and silicon atoms to oxygen atoms is 1:2. The
electrovalence of the tetrahedra containing the Group IIIA element,
e.g., aluminum, is balanced by the inclusion in the crystal of a
cation, e.g., an alkali metal or an alkaline earth metal
cation.
[0092] One type of cation may be exchanged either entirely or
partially with another type of cation utilizing ion-exchange
techniques in a conventional manner. By means of such cation
exchange, it has been possible to vary the properties of a given
silicate by suitable selection of the cation. The spaces between
the tetrahedra are occupied by molecules of water prior to
dehydration.
[0093] Prior art techniques have resulted in the formation of a
great variety of synthetic zeolites. Many of the zeolites have come
to be designated by letter or other convenient symbols, as
illustrated by zeolite Z (U.S. Pat. No. 2,882,243); zeolite X (U.S.
Pat. No. 2,882,244); zeolite Y (U.S. Pat. No. 3,130,007); zeolite
ZK-5 (U.S. Pat. No. 3,247,195); zeolite ZK-4 (U.S. Pat. No.
3,314,752); zeolite ZSM-5 (U.S. Pat. No. 3,702,886); zeolite ZSM-11
(U.S. Pat. No. 3,709,979); zeolite ZSM-12 (U.S. Pat. No.
3,832,449), zeolite ZS-20 (U.S. Pat. No. 3,972,983); zeolite ZSM-35
(U.S. Pat. No. 4,016,245); and zeolite ZSM-23 (U.S. Pat. No.
4,076,842), for example.
[0094] The SiO.sub.2/Al.sub.2O.sub.3 ratio of a given zeolite is
variable. For example, zeolite X can be synthesized with
SiO.sub.2/Al.sub.2O.sub.3 ratios of from 2 to 3; zeolite Y, from 3
to about 6. In some zeolites, the upper limit of the
SiO.sub.2/Al.sub.2O.sub.3 ratio is unbounded. ZSM-5 is one such
example wherein the SiO.sub.2/Al.sub.2O.sub.3 ratio is at least 5
and up to the limits of present analytical measurement
techniques.
[0095] A "reactor" described herein may be any type of catalytic
reactor suitable for the conversion of syngas to alcohol mixtures.
A reactor may, for example, be any suitable fixed-bed reactor. In
some variations, a reactor comprises tubes filled with one or more
catalysts. Syngas passing through the tubes undergoes catalyzed
reactions to form alcohols or other products.
[0096] The reactor for converting syngas into alcohols can be
engineered and operated in a wide variety of ways. The reactor
operation can be continuous, semicontinuous, or batch. Operation
that is substantially continuous and at steady state is preferable.
The flow pattern can be substantially plug flow, substantially
well-mixed, or a flow pattern between these extremes. The flow
direction can be vertical-upflow, vertical-downflow, or horizontal.
A vertical configuration can be preferable.
[0097] Any "reactor" used herein can in fact be a series or network
of several reactors in various arrangements. For example, in some
variations, the reactor comprises a large number of tubes filled
with one or more catalysts.
[0098] The catalyst phase can be a packed bed or a fluidized bed.
The catalyst particles can be sized and configured such that the
chemistry is, in some embodiments, mass-transfer-limited or
kinetically limited. The catalyst can take the form of a powder,
pellets, granules, beads, extrudates, and so on. When a catalyst
support is optionally employed, the support may assume any physical
form such as pellets, spheres, monolithic channels, etc. The
supports may be coprecipitated with active metal species; or the
support may be treated with the catalytic metal species and then
used as is or formed into the aforementioned shapes; or the support
may be formed into the aforementioned shapes and then treated with
the catalytic species.
[0099] Reactors can consist of a simple vessel or tank, which can
be stirred or unstirred. Preferably, reactors are closed reaction
vessels, to prevent loss of chemicals to the atmosphere. The
reactions may be conducted batch-wise, continuously, or
semi-continuously.
[0100] The reaction temperature, pressure, and residence time for
each process step are each not regarded as critical, provided that
overall conditions are suitable for a desired conversion.
[0101] In general, solid, liquid, and gas streams produced or
existing within the process can be independently passed to
subsequent steps or removed/purged from the process at any point.
Also, any of the streams or materials present may be subjected to
additional processing, including heat addition or removal, mass
addition or removal, mixing, various measurements and sampling, and
so forth.
[0102] In some embodiments, the process is controlled or adjusted
to attain certain gasoline properties. As is known, relevant
gasoline properties can include flash point, octane number, energy
content, water content, sediment content, ash content, sulfur
content, nitrogen content, phosphorus content, pH, density,
viscosity, and so on.
[0103] Other variations of this invention relate to compositions.
Some variations provide a gasoline composition in accordance with
any of the processes described herein. Other variations provide per
se novel gasoline compositions, regardless of the process used to
produce those compositions.
[0104] In some embodiments, gasoline components are provided by a
process comprising converting a mixed-alcohol stream containing
methanol, ethanol, propanol, butanol, and heavier alcohols. The
mixed-alcohol stream, in some embodiments, contains a Schulz-Flory
distribution of alcohols. In certain embodiments, the mixed-alcohol
stream contains less ethanol than predicted by a Schulz-Flory
distribution of alcohols, i.e. a portion or all of the ethanol can
be removed from the stream prior to conversion to gasoline
components. A mixed-alcohol stream can contain less than 1 vol %,
between about 1-5 vol %, between about 5-10 vol %, or more than 10
vol % ethanol prior to conversion to gasoline components, in
various embodiments.
[0105] Some variations produce or provide gasoline mixed with
alcohols, which alcohols can be (but are not necessarily) produced
by the methods of the invention.
[0106] Some compositions of the invention relate to gasoline
produced primarily from methanol, and containing small amounts of
heavier alcohols such as ethanol, propanol, and butanol.
[0107] Some compositions of this invention are cellulosic gasoline
blends comprising gasoline components plus cellulosic ethanol at a
concentration such as 5-15 vol %, e.g. about 10 vol % ethanol.
[0108] Some compositions provided herein include cellulosic
gasoline components derived from an alcohol-to-gasoline crude
stream and requiring no further processing such as
hydrotreatment.
[0109] Some compositions produced by methods of this invention
include durenes. In some embodiments, compositions are provided
that discourage or eliminate precipitation of durene crystals out
of the liquid composition.
[0110] Preferred compositions are capable of burning in an internal
combustion engine. Preferred compositions are suitable directly as
a gasoline fuel, or as components of gasoline
[0111] In some embodiments, the gasoline composition meets the
specification set forth in ASTM D 4814 as amended, e.g. D 4814-09a
which is hereby incorporated by reference herein. Certain preferred
compositions exceed current fuel-grade blended gasoline
requirements such as octane number, benzene content, Reid vapor
pressure, and sulfur content.
[0112] The present invention has utility with respect to
biorefinery concepts. Final product mixes from a biorefinery can be
optimized for maximum profitability and/or minimum carbon
footprint, for example, by known techniques. Preferred embodiments
of the invention can reduce overall energy intensity and/or reduce
the number of processing steps to manufacture renewable
gasoline.
[0113] All publications, patents, and patent applications cited in
this specification are incorporated herein by reference in their
entirety as if each publication, patent, or patent application was
specifically and individually put forth herein. All ASTM
specifications recited herein are also incorporated by
reference.
[0114] In this detailed description, reference has been made to
multiple embodiments of the invention and non-limiting examples
relating to how the invention can be understood and practiced.
Other embodiments that do not provide all of the features and
advantages set forth herein may be utilized, without departing from
the spirit and scope of the present invention. This invention
incorporates routine experimentation and optimization of the
methods and systems described herein. Such modifications and
variations are considered to be within the scope of the invention
defined by the claims.
[0115] Where methods and steps described above indicate certain
events occurring in certain order, those of ordinary skill in the
art will recognize that the ordering of certain steps may be
modified and that such modifications are in accordance with the
variations of the invention. Additionally, certain of the steps may
be performed concurrently in a parallel process when possible, as
well as performed sequentially.
[0116] Therefore, to the extent that there are variations of the
invention, which are within the spirit of the disclosure or
equivalent to the inventions found in the appended claims, it is
the intent that this patent will cover those variations as well.
The present invention shall only be limited by what is claimed.
* * * * *