U.S. patent application number 14/470700 was filed with the patent office on 2014-12-18 for electrochemical reduction of co2 with co-oxidation of an alcohol.
The applicant listed for this patent is Liquid Light, Inc.. Invention is credited to Andrew B. Bocarsly, Emily Barton Cole, Jerry Kaczur, Paul Majsztrik, Narayanappa Sivasankar, Kyle Teamey.
Application Number | 20140367274 14/470700 |
Document ID | / |
Family ID | 48171282 |
Filed Date | 2014-12-18 |
United States Patent
Application |
20140367274 |
Kind Code |
A1 |
Teamey; Kyle ; et
al. |
December 18, 2014 |
Electrochemical Reduction of CO2 with Co-Oxidation of an
Alcohol
Abstract
The present disclosure is a system and method for producing a
first product from a first region of an electrochemical cell having
a cathode and a second product from a second region of the
electrochemical cell having an anode. The method may include the
step of contacting the first region of the electrochemical cell
with a catholyte comprising an alcohol and carbon dioxide. Another
step of the method may include contacting the second region of the
electrochemical cell with an anolyte comprising the alcohol.
Further, the method may include a step of applying an electrical
potential between the anode and the cathode sufficient to produce a
first product recoverable from the first region and a second
product recoverable from the second region.
Inventors: |
Teamey; Kyle; (Washington,
DC) ; Kaczur; Jerry; (North Miami Beach, FL) ;
Cole; Emily Barton; (Houston, TX) ; Majsztrik;
Paul; (Cranbury, NJ) ; Sivasankar; Narayanappa;
(Plainsboro, NJ) ; Bocarsly; Andrew B.;
(Plainsboro, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liquid Light, Inc. |
Monmouth Junction |
NJ |
US |
|
|
Family ID: |
48171282 |
Appl. No.: |
14/470700 |
Filed: |
August 27, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13724231 |
Dec 21, 2012 |
8845875 |
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14470700 |
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61720670 |
Oct 31, 2012 |
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61703175 |
Sep 19, 2012 |
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61675938 |
Jul 26, 2012 |
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61703229 |
Sep 19, 2012 |
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61703158 |
Sep 19, 2012 |
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61703231 |
Sep 19, 2012 |
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61703232 |
Sep 19, 2012 |
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61703231 |
Sep 19, 2012 |
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61703234 |
Sep 19, 2012 |
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61703238 |
Sep 19, 2012 |
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61703187 |
Sep 19, 2012 |
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Current U.S.
Class: |
205/440 ;
204/265; 204/277; 205/448; 205/450; 205/462; 205/555 |
Current CPC
Class: |
C07C 51/15 20130101;
Y02P 20/127 20151101; Y02P 20/582 20151101; C25B 3/04 20130101;
C25B 15/00 20130101; C07C 67/08 20130101; C25B 3/06 20130101; C07C
1/26 20130101; C25B 1/24 20130101; C25B 3/00 20130101; C25B 9/10
20130101; C07C 29/58 20130101; C25B 15/08 20130101; Y02P 20/10
20151101; C07C 51/367 20130101; Y02P 20/133 20151101; C25B 9/08
20130101; Y02P 20/132 20151101; C25B 13/08 20130101; C07C 51/02
20130101; C25B 3/10 20130101; C07C 29/149 20130101; C25B 1/00
20130101; C25B 3/02 20130101; Y02P 20/129 20151101 |
Class at
Publication: |
205/440 ;
205/555; 205/448; 205/450; 205/462; 204/277; 204/265 |
International
Class: |
C25B 3/02 20060101
C25B003/02; C25B 13/08 20060101 C25B013/08 |
Claims
1. A method for producing a first product from a first region of an
electrochemical cell having a cathode and a second product from a
second region of the electrochemical cell having an anode, the
method comprising the steps of: receiving a feed of carbon dioxide
and methanol at the first region of the electrochemical cell;
contacting the first region with a catholyte comprising carbon
dioxide and methanol; receiving a feed of methanol at the second
region of the electrochemical cell; contacting the second region
with an anolyte comprising methanol; and applying an electrical
potential between the anode and the cathode sufficient to produce
the first product recoverable from the first region and the second
product recoverable from the second region.
2. The method according to claim 1, wherein the anolyte is free of
halide ions.
3. The method according to claim 1, wherein the first product
includes at least one of carbon monoxide, formic acid,
formaldehyde, methanol, oxalate, oxalic acid, glyoxylic acid,
glycolic acid, glyoxal, glycolaldehyde, ethylene glycol, acetic
acid, acetaldehyde, ethanol, ethylene, methane, ethane, lactic
acid, propanoic acid, acetone, isopropanol, 1-propanol,
1,2-propylene glycol, propane, 1-butanol, and 2-butanol.
4. The method according to claim 1, wherein the second product
includes at least one of formaldehyde, formic acid, acetaldehyde,
acetic acid, glycolaldehyde, glyoxal, glycolic acid glyoxylic acid,
oxalic acid, glyceraldehyde, dihydroxyacetone, 2,3
dihydroxypropionic acid, polyol-aldehyde, polyol-ketone,
polyol-carboxylic acid, acetone, propionaldehyde, propanoic acid,
butyraldehyde, butanoic acid, butanone, hydroquinone,
1,2-dihydroxybenzene, 2,5-cyclohexadiene-1-one, benzoquinone,
maleic acid, benzaldehyde, benzoic acid, acrolein, and acrylic
acid.
5. The method according to claim 1, wherein the cathode and the
anode are separated by an ion permeable barrier.
6. The method according to claim 5, wherein the ion permeable
barrier includes one of a polymeric or inorganic ceramic-based ion
permeable barrier.
7. The method according to claim 5, wherein the ion permeable
barrier includes at least one of a solid polymer conductor
electrolyte material and a perfluorinated sulfonic acid based
membrane, a sodium super-conducting ionic conductor type ceramics
or zirconium-yttria and beta-alumina based ceramics.
8. A system for electrochemical co-production of products,
comprising: an electrochemical cell including: a first region; a
cathode associated with the first region; a second region; an anode
associated with the second region; and a separator for selectively
controlling a flow of ions between the first region and the second
region; a carbon dioxide source, the carbon dioxide source in flow
communication with the first region to supply carbon dioxide to the
first region; an alcohol source, the alcohol source in flow
communication with the second region to supply alcohol to the
second region; an energy source for applying a current across the
anode and the cathode, wherein when current is applied, a first
product is recoverable from the first region and a second product
is recoverable from the second region.
9. The system according to claim 8, wherein the second region is
free of halide ions.
10. The system according to claim 8, wherein the alcohol includes
at least one of methanol, ethanol, ethylene glycol, glycerol,
1-propanol, 2-propanol, phenol, 1-butanol, 2-butanol, isopropanol,
benzyl alcohol, allyl alcohol, a glycol, and a polyol.
11. The system according to claim 8, wherein the second product
recoverable from the second region includes an aldehyde.
12. The system according to claim 8, wherein the second product
recoverable from the second region includes a carboxylic acid.
13. The system according to claim 8, wherein the second product
recoverable from the second region includes carboxylic acid and an
aldehyde.
14. The system according to claim 8, wherein the second product
recoverable from the second region includes at least one of
formaldehyde, formic acid, acetaldehyde, acetic acid,
glycolaldehyde, glyoxal, glycolic acid glyoxylic acid, oxalic acid,
glyceraldehyde, dihydroxyacetone, 2,3 dihydroxypropionic acid,
polyol-aldehyde, polyol-ketone, polyol-carboxylic acid, acetone,
propionaldehyde, propanoic acid, butyraldehyde, butanoic acid,
butanone, hydroquinone, 1,2-dihydroxybenzene,
2,5-cyclohexadiene-1-one, benzoquinone, maleic acid, benzaldehyde,
benzoic acid, acrolein, and acrylic acid.
15. The system according to claim 8, wherein the first product
recoverable from the first region includes at least one of carbon
monoxide, formic acid, formaldehyde, methanol, oxalate, oxalic
acid, glyoxylic acid, glycolic acid, glyoxal, glycolaldehyde,
ethylene glycol, acetic acid, acetaldehyde, ethanol, ethylene,
methane, ethane, lactic acid, propanoic acid, acetone, isopropanol,
1-propanol, 1,2-propylene glycol, propane, 1-butanol, and
2-butanol.
16. The system according to claim 8, wherein the separator
selectively controls a flow of ions between the first region and
the second region.
17. The system according to claim 8, wherein the catholyte
comprises one or more of water, methanol, ethanol, acetonitrile,
propylene carbonate, ethylene carbonate, dimethyl carbonate,
diethyl carbonate, dimethylsulfoxide, dimethylformamide,
acetonitrile, acetone, tetrahydrofuran, N,N-dimethylacetaminde,
dimethoxyethane, diethylene glycol dimethyl ester, butyrolnitrile,
1,2-difluorobenzene, .gamma.-butyrolactone, N-methyl-2-pyrrolidone,
sulfolane, 1,4-dioxane, nitrobenzene, nitromethane, acetic
anhydride, ionic liquids.
18. The system according to claim 16, wherein the separator
includes an ion permeable barrier.
19. The system according to claim 16, wherein the separator
includes at least one of a solid polymer conductor electrolyte
material and a perfluorinated sulfonic acid based membrane, a
sodium super-conducting ionic conductor type ceramics.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit under 35 U.S.C.
.sctn.120 of U.S. patent application Ser. No. 13/724,231 filed Dec.
21, 2012 and U.S. patent application Ser. No. 13/724,231 filed Dec.
21, 2012 is incorporated by reference in its entirety.
[0002] The U.S. patent application Ser. No. 13/724,231 filed Dec.
21, 2012 claims the benefit under 35 U.S.C. .sctn.119(e) of U.S.
Provisional Application Ser. No. 61/720,670 filed Oct. 31, 2012,
U.S. Provisional Application Ser. No. 61/703,175 filed Sep. 19,
2012 and U.S. Provisional Application Ser. No. 61/675,938 filed
Jul. 26, 2012. Said U.S. Provisional Application Ser. No.
61/720,670 filed Oct. 31, 2012, U.S. Provisional Application Ser.
No. 61/703,175 filed Sep. 19, 2012 and U.S. Provisional Application
Ser. No. 61/675,938 filed Jul. 26, 2012 are incorporated by
reference in their entireties.
[0003] The U.S. patent application Ser. No. 13/724,231 filed Dec.
21, 2012 also claims the benefit under 35 U.S.C. .sctn.119(e) of
U.S. Provisional Application Ser. No. 61/703,229 filed Sep. 19,
2012, U.S. Provisional Application Ser. No. 61/703,158 filed Sep.
19, 2012, U.S. Provisional Application Ser. No. 61/703,231 filed
Sep. 19, 2012, U.S. Provisional Application Ser. No. 61/703,232
filed Sep. 19, 2012, U.S. Provisional Application Ser. No.
61/703,234 filed Sep. 19, 2012, U.S. Provisional Application Ser.
No. 61/703,238 filed Sep. 19, 2012, U.S. Provisional Application
Ser. No. 61/703,187 filed Sep. 19, 2012. The U.S. Provisional
Application Ser. No. 61/703,229 filed Sep. 19, 2012, U.S.
Provisional Application Ser. No. 61/703,158 filed Sep. 19, 2012,
U.S. Provisional Application Ser. No. 61/703,231 filed Sep. 19,
2012, U.S. Provisional Application Ser. No. 61/703,232 filed Sep.
19, 2012, U.S. Provisional Application Ser. No. 61/703,234 filed
Sep. 19, 2012, U.S. Provisional Application Ser. No. 61/703,238
filed Sep. 19, 2012 and U.S. Provisional Application Ser. No.
61/703,187 filed Sep. 19, 2012 are hereby incorporated by reference
in their entireties.
[0004] The U.S. patent application Ser. No. 13/724,231 filed Dec.
21, 2012 incorporates by reference co-pending U.S. patent
application by reference co-pending U.S. patent application Ser.
No. 13/724,339 filed on Dec. 21, 2012, U.S. patent application Ser.
No. 13/724,878 filed on Dec. 21, 2012, U.S. patent application Ser.
No. 13/724,647 filed on Dec. 21, 2012, U.S. patent application Ser.
No. 13/724,807 filed on Dec. 21, 2012, U.S. patent application Ser.
No. 13/724,996 filed on Dec. 21, 2012, U.S. patent application Ser.
No. 13/724,719 filed on Dec. 21, 2012, U.S. patent application Ser.
No. 13/724,082 filed on Dec. 21, 2012, and U.S. patent application
Ser. No. 13/724,768 filed on Dec. 21, 2012, now U.S. Pat. No.
8,444,844 in their entireties.
TECHNICAL FIELD
[0005] The present disclosure generally relates to the field of
electrochemical reactions, and more particularly to methods and/or
systems for electrochemical reduction of carbon dioxide with
co-oxidation of an alcohol.
BACKGROUND
[0006] The combustion of fossil fuels in activities such as
electricity generation, transportation, and manufacturing produces
billions of tons of carbon dioxide annually. Research since the
1970s indicates increasing concentrations of carbon dioxide in the
atmosphere may be responsible for altering the Earth's climate,
changing the pH of the ocean and other potentially damaging
effects. Countries around the world, including the United States,
are seeking ways to mitigate emissions of carbon dioxide.
[0007] A mechanism for mitigating emissions is to convert carbon
dioxide into economically valuable materials such as fuels and
industrial chemicals. If the carbon dioxide is converted using
energy from renewable sources, both mitigation of carbon dioxide
emissions and conversion of renewable energy into a chemical form
that can be stored for later use will be possible.
SUMMARY
[0008] The present disclosure is directed to a system and method
for producing a first product from a first region of an
electrochemical cell having a cathode and a second product from a
second region of the electrochemical cell having an anode. The
method may include the step of contacting the first region of the
electrochemical cell with a catholyte comprising carbon dioxide and
optionally an alcohol. Another step of the method may include
contacting the second region of the electrochemical cell with an
anolyte comprising an alcohol. Further, the method may include a
step of applying an electrical potential between the anode and the
cathode sufficient to produce a first product recoverable from the
first region and a second product recoverable from the second
region.
[0009] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not necessarily restrictive of the
present disclosure. The accompanying drawings, which are
incorporated in and constitute a part of the specification,
illustrate subject matter of the disclosure. Together, the
descriptions and the drawings serve to explain the principles of
the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The numerous advantages of the disclosure may be better
understood by those skilled in the art by reference to the
accompanying figures in which:
[0011] FIGS. 1A and 1B is a block diagram of a system in accordance
with an embodiment of the present disclosure;
[0012] FIG. 2 is a block diagram of a system in accordance with
another embodiment of the present disclosure;
[0013] FIG. 3 is a block diagram of a system in accordance with an
additional embodiment of the present disclosure;
[0014] FIG. 4 is a block diagram of a system in accordance with
another additional embodiment of the present disclosure;
[0015] FIG. 5 is a flow diagram of a method of electrochemical
co-production of products in accordance with an embodiment of the
present disclosure; and
[0016] FIG. 6 is a flow diagram of a method of electrochemical
co-production of products in accordance with another embodiment of
the present disclosure.
DETAILED DESCRIPTION
[0017] Reference will now be made in detail to the subject matter
disclosed, which is illustrated in the accompanying drawings.
[0018] Referring generally to FIGS. 1-6, systems and methods of
electrochemical co-production of products with a carbon-based
reactant, such as an alcohol, supplied to an anode are disclosed.
It is contemplated that the electrochemical co-production of
products may include a production of a first product, such as
reduction of carbon dioxide to carbon-based products to include
one, two, three, and four carbon chemicals, at a cathode side of an
electrochemical cell with co-production of a second product, such
as an oxidized carbon-based product, at the anode of the
electrochemical cell whereby the anolyte includes an alcohol.
[0019] Before any embodiments of the disclosure are explained in
detail, it is to be understood that the embodiments may not be
limited in application according to the details of the structure or
the function as set forth in the following descriptions or
illustrated in the figures. Different embodiments may be capable of
being practiced or carried out in various ways. Also, it is to be
understood that the phraseology and terminology used herein is for
the purpose of description and should not be regarded as limiting.
The use of terms such as "including," "comprising," or "having" and
variations thereof herein are generally meant to encompass the item
listed thereafter and equivalents thereof as well as additional
items. Further, unless otherwise noted, technical terms may be used
according to conventional usage. It is further contemplated that
like reference numbers may describe similar components and the
equivalents thereof.
[0020] Referring to FIG. 1A, a block diagram of a system 100 in
accordance with an embodiment of the present disclosure is shown.
System (or apparatus) 100 generally includes an electrochemical
cell (also referred as a container, electrolyzer, or cell) 102, a
carbon based reactant source 104, a carbon dioxide source 106, a
first product extractor 110 and a first product 113, a second
product extractor 112, second product 115, and an energy source
114.
[0021] Electrochemical cell 102 may be implemented as a divided
cell. The divided cell may be a divided electrochemical cell and/or
a divided photoelectrochemical cell. Electrochemical cell 102 may
include a first region 116 and a second region 118. First region
116 and second region 118 may refer to a compartment, section, or
generally enclosed space, and the like without departing from the
scope and intent of the present disclosure. First region 116 may
include a cathode 122. Second region 118 may include an anode 124.
First region 116 may include a catholyte whereby carbon dioxide is
dissolved in the catholyte. A heterocyclic catalyst, such as
pyridine, imidazole, lutadines, or bipyridines, may also be in the
catholyte. Second region 118 may include an anolyte which may
include an alcohol. The anolyte may be free of halide ions. Energy
source 114 may generate an electrical potential between the anode
124 and the cathode 122. The electrical potential may be a DC
voltage. Energy source 114 may be configured to implement a
variable voltage or variable current source. Separator 120 may
selectively control a flow of ions between the first region 116 and
the second region 118. Separator 120 may include an ion conducting
membrane or diaphragm material.
[0022] Electrochemical cell 102 is generally operational to reduce
carbon dioxide in the first region 116 to a first product 113
recoverable from the first region 116 while producing a second
product 115 recoverable from the second region 118. Cathode 122 may
reduce the carbon dioxide into a first product 113 that may include
one or more compounds. Examples of the first product 113
recoverable from the first region 116 by first product extractor
110 may include carbon monoxide, formic acid, formaldehyde,
methanol, oxalate, oxalic acid, glyoxylic acid, glycolic acid,
glyoxal, glycolaldehyde, ethylene glycol, acetic acid,
acetaldehyde, ethanol, ethylene, methane, ethane, lactic acid,
propanoic acid, acetone, isopropanol, 1-propanol, 1,2-propylene
glycol, propane, 1-butanol, and 2-butanol.
[0023] Carbon dioxide source 106 may provide carbon dioxide to the
first region 116 of electrochemical cell 102. In some embodiments,
the carbon dioxide is introduced directly into the region 116
containing the cathode 122.
[0024] First product extractor 110 may implement an organic product
and/or inorganic product extractor. First product extractor 110 is
generally operational to extract (separate) the first product 113
from the first region 116. The extracted first product 113 may be
presented through a port of the system 100 for subsequent storage
and/or consumption by other devices and/or processes.
[0025] Second product extractor 112 may extract the second product
115 from the second region 118. The extracted second product 115
may be presented through a port of the system 100 for subsequent
storage and/or consumption by other devices and/or processes.
[0026] The anode side of the reaction occurring in the second
region 118 may include a carbon-based reactant 104, such as an
alcohol, which may be in the form of a gas phase, liquid phase, or
as a mixed solution phase reactant supplied to the second region
118. The reaction occurring in the second region 118 may include a
variety of oxidations such as the oxidation of a primary alcohol to
an aldehyde or a secondary alcohol to a ketone. The second product
recoverable from the second region 118 may also include a
carboxylic acid, or both a carboxylic acid and an aldehyde. The
carboxylic acid may include formic acid, acetic acid, propanoic
acid, butanoic acid, or acrylic acid. Examples of the second
product 115 recoverable from the second region 118 and the
carbon-based reactant supplied to the second region 118 are in the
table below.
TABLE-US-00001 TABLE 1 Chemical Feed to Anode Oxidation Product(s)
Methanol Formaldehyde, Formic Acid Ethanol Acetaldehyde, Acetic
Acid Ethylene Glycol Glycolaldehyde, Glyoxal, Glycolic Acid,
Glyoxylic Acid, Oxalic Acid Glycerol Glyceraldehyde,
dihydroxyacetone, 2,3 Dihydroxypropionic acid Polyols
Polyol-aldehydes, Polyol-ketones, Polyol-carboxylic acids
2-Propanol 2-Propanone (Acetone) 1-Propanol Propionaldehyde,
Propanoic Acid 1-Butanol Butyraldehyde, Butanoic Acid 2-Butanol
Butanone Phenol Hydroquinone 1-2 dihydrobenzene (Catechol). 2,5
Cyclohexadiene-1-one Benzoquinone, Maleic Acid, Oxalic Acid Benzyl
Alcohol Benzaldehyde, Benzoic Acid Allyl Alcohol Acrolein, Acrylic
Acid
[0027] A glycol or diol or polyol may also serve as a solvent and
reactant in the cell. For instance, ethylene glycol or glycerol
might be a solvent in the electrochemical cell and cathode
reactions involving the reduction of carbon dioxide or other
carbon-based compounds would take place in the ethylene glycol or
glycerol. At the anode, ethylene glycol would be oxidized to a
product or products such as glyoxal or glyoxylic acid, and glycerol
would be oxidized to a product or products such as glyceraldehyde,
glyceric acid, glycolic acid, dihydroxyacetone, or 2,3
dihydroxypropionic acid. Other polyols could be used and would be
oxidized to corresponding, polyol-aldehydes, polyol-ketones, and
polyol-carboxylic acids.
[0028] Through the co-production of a first product 113 and a
second product 115, the overall energy requirement for making each
of the first product 113 and second product 115 may be reduced by
50% or more. In addition, electrochemical cell 102 may be capable
of simultaneously producing two or more products with high
selectivity.
[0029] A preferred embodiment of the present disclosure is the use
of a methanol feed to both the anode and the cathode to make
organic chemicals such as acetic acid at the cathode while
simultaneously making formaldehyde at the anode. Referring to FIG.
2, system 200 for co-production of acetic acid 210 and formaldehyde
212 is shown. The oxidation of alcohol, such as methanol 220 in the
second region 118 produces protons and electrons that are utilized
to reduce carbon dioxide in the first region 116. The hydrogen
resulting from the oxidation reaction at the second region 118 may
be reacted with the carbon dioxide and the methanol provided by
alcohol source 104 to the first region 116 to selectively produce
acetate or acetic acid 210.
[0030] Formaldehyde 212 is produced at the second region 118 from
CO.sub.2 and the methanol provided by alcohol source 104. The
alcohol source 104 is thus used both in the oxidation of the second
product (formaldehyde 212) and in the transfer of hydrogen from the
carbon-based reactant to the first region 116 for CO.sub.2
reduction. The alcohol may serve as the primary hydrogen source for
CO.sub.2 reduction. Both the first region 116 and the second region
118 may utilize the methanol provided by alcohol source 104 as part
of the catholyte or anolyte.
[0031] In one embodiment of the disclosure, when the first product
is acetic acid 210 and the second product is formaldehyde 212 from
methanol provided by alcohol source 104, then the molar ratio of
the products may be 1 acetic acid:4 formaldehyde because acetic
acid production from CO.sub.2 is an 8 electron process and
formaldehyde production from methanol is a two electron process.
Specifically, the anode reaction is:
4CH.sub.3OH=>4CH.sub.2O+8H.sup.++8e.sup.-
[0032] In the anode reaction, methanol is provided by alcohol
source 104 and the methanol is oxidized to formaldehyde, and 2
hydrogen ions are formed which pass through the separator/membrane
separating the first region 116 from the second region 118.
[0033] The cathode reaction is the formation of acetate or acetic
acid as follows:
2CO.sub.2+8H.sup.++8e.sup.-=>CH.sub.3COO.sup.-+H.sup.++2H.sub.2O
[0034] In the cathode reaction, hydrogen ions from the second
region 118 pass through the membrane to the first region 116 to
react with carbon dioxide to form acetic acid or acetate.
[0035] The combined reaction of methanol with carbon dioxide to
form formaldehyde and acetic acid of the embodiment of the system
shown in FIG. 2 is:
4CH.sub.3OH+2CO.sub.2=>4CH.sub.2O+CH.sub.3COO+H.sup.++2H.sub.2O
[0036] The combined reaction for the production of formaldehyde
from methanol oxidation may be controlled through selection of the
anode material, anode material morphology, half-cell potential, the
flow rate, and the concentration of water in the methanol feed, as
well as other factors.
[0037] The concentration of the formaldehyde product leaving the
second region may be from 1 to 50% by weight in one embodiment, and
more preferably 10 to 40% by weight. The methanol concentration may
determine the anolyte conductivity, and should be sufficient in
concentration to maintain low voltages in the second region.
Preferably, the concentration ranges from 1 to 100% and more
preferably from 5 to 90%.
[0038] While system 200 of FIG. 2 is shown with a reactant of
methanol, it is contemplated that other types of alcohols may be
supplied by alcohol source 104 to produce various types of products
(first product and second product) as desired and shown in an
exemplary fashion in Table 1. It is further contemplated that other
types of products may be co-produced by the anode and cathode of an
electrochemical cell without departing from the scope and intent of
the present disclosure.
[0039] Reactions occurring at the first region 116 may occur in a
catholyte which may include water, methanol, ethanol, acetonitrile,
propylene carbonate, ethylene carbonate, dimethyl carbonate,
diethyl carbonate, dimethylsulfoxide, dimethylformamide,
acetonitrile, acetone, tetrahydrofuran, N,N-dimethylacetaminde,
dimethoxyethane, diethylene glycol dimethyl ester, butyrolnitrile,
1,2-difluorobenzene, .gamma.-butyrolactone, N-methyl-2-pyrrolidone,
sulfolane, 1,4-dioxane, nitrobenzene, nitromethane, acetic
anhydride, ionic liquids, or other catholytes in which CO.sub.2 is
soluble. The alcohol source 104 and carbon dioxide source 106 may
be configured to supply the carbon-based reactant and carbon
dioxide separately or jointly. The alcohol source 104 and carbon
dioxide source 106 may be supplied in a solution. The carbon-based
reactant source 104 and carbon dioxide source 106 may also be
configured to supply the alcohol and carbon dioxide in solution
with the catholyte.
[0040] The reactions occurring at the second region 118 may be in a
gas phase, for instance in the case of gas phase reactants such as
methane. The reaction at the second region 118 may also occur in
liquid phase.
[0041] A catalyst may be employed in the second region 118 to
promote the reaction. For example, a metal or metal oxide catalyst
may be incorporated into the anode 124 in order to decrease the
anode 124 potential and/or increase anode 124 current density, in
addition to improving the selectivity of the oxidation reaction to
the products desired. Examples of catalysts may include the metal
and metal oxides of transition metals and their alloys and
mixtures, including those of W, Mo, V, Fe, Ru, Ir, Au, and Pt.
These catalysts may be deposited on the anode structure surfaces
and/or on separate supports located in the second region on
inorganic or carbon based supports. In addition, the catalyst may
also consist of other forms or compositions suitable for the
oxidation of the alcohols such as boron-doped diamond films
deposited on conductive metal or inorganic supports.
[0042] Referring to FIGS. 3-4, block diagrams of systems 300, 400
in accordance with additional embodiments of the present disclosure
are shown. Systems 300, 400 provide additional embodiments to
systems 100, 200 of FIGS. 1A, 1B, and 2 to co-produce a first
product and second product.
[0043] Referring to specifically to FIG. 3, first region 116 may
produce a first product of H.sub.2 310 which is combined with
carbon dioxide 332 in a reactor 330 which may perform a reverse
water gas shift reaction. This reverse water gas shift reaction
performed by reactor 330 may produce water 334 and carbon monoxide
336. Carbon monoxide 336 along with H.sub.2 310 may be combined at
reactor 338. Reactor 338 may cause a reaction, such as a
Fischer-Tropsch synthesis, to reduce carbon monoxide to a product
340. Product 340 may include methane, methanol, hydrocarbons,
glycols. Reactor 338 may also include transition metals such as
iron, cobalt, and ruthenium as well as other transition metal
oxides as catalysts, on inorganic support structures that may
promote the reaction of CO with hydrogen at lower temperatures and
pressures.
[0044] Second region 118 may co-produce formaldehyde 312 from
methanol 304 reactant. It is contemplated that methanol 304 may
include methanol or any other alcohol such as ethanol, 2-propanol,
phenol, 1-propanol, 1-butanol, 2-butanol, isopropanol, benzyl
alcohol, and allyl alcohol without departing from the scope or
intent of the present disclosure. Formaldehyde 312 may also refer
to any type of aldehyde or a carboxylic acid, including for example
formic acid, acetaldehyde, acetic acid, 2-propanone (acetone),
hydroquinone, 1-2 dihydrobenzene (catechol), 2,5
cyclohexadiene-1-one, benzoquinone, maleic acid, oxalic acid,
propionaldehyde, propanoic acid, butyraldehyde, butanoic acid,
butanone, acetone, benzaldehyde, benzoic acid, acrolein, and
acrylic acid, without departing from the scope or intent of the
present disclosure.
[0045] Referring to FIG. 4, first region 116 may produce a first
product of carbon monoxide 410 which is combined with water 432 in
a reactor 430 which may perform a water gas shift reaction. The
water gas shift reaction performed by reactor 430 may produce
carbon dioxide 434 and H.sub.2 436. Carbon monoxide 410 and H.sub.2
436 may be combined at reactor 438. Reactor 438 may cause a
reaction, such as a Fischer-Tropsch synthesis, to reduce carbon
monoxide to methane, methanol, hydrocarbons, glycols, olefins by
utilizing H.sub.2 436. Carbon dioxide 434 may be a byproduct of
water gas shift reaction of reactor 430 and may be recycled as an
input feed to the first region 116. Reactor 438 may also include
transition metals such as iron, cobalt, and ruthenium as well as
other transition metal oxides as catalysts, on inorganic support
structures that may promote the reaction of CO with hydrogen at
lower temperatures and pressures.
[0046] Second region 118 may co-produce formaldehyde 412 from
methanol 404 reactant. It is contemplated that methanol 404 may
include methanol or another alcohol such as ethanol, 2-propanol,
phenol, 1-propanol, 1-butanol, 2-butanol, isopropanol, benzyl
alcohol, and allyl alcohol without departing from the scope or
intent of the present disclosure. Formaldehyde 412 may also refer
to any type of aldehyde or a carboxylic acid, including for example
formic acid, acetaldehyde, acetic acid, 2-propanone (acetone),
hydroquinone, 1-2 dihydrobenzene (catechol), 2,5
cyclohexadiene-1-one, benzoquinone, maleic acid, oxalic acid,
propionaldehyde, propanoic acid, butyraldehyde, butanoic acid,
butanone, acetone, benzaldehyde, benzoic acid, acrolein, and
acrylic acid, without departing from the scope or intent of the
present disclosure.
[0047] Referring to FIG. 5 a flow diagram of a method 500 of
electrochemical co-production of products in accordance with an
embodiment of the present disclosure is shown. It is contemplated
that method 500 may be performed by system 100 and system 200 as
shown in FIGS. 1A, 1B, and 2. Method 500 may include producing a
first product from a first region of an electrochemical cell having
a cathode and a second product from a second region of the
electrochemical cell having an anode.
[0048] Method 500 of electrochemical co-production of products may
include a step of contacting the first region with a catholyte
comprising carbon dioxide and an alcohol 510. Next, method 500 may
include the step of contacting the second region with an anolyte
comprising alcohol 520. The method 500 may further include the step
of applying an electrical potential between the anode and the
cathode sufficient to produce the first product recoverable from
the first region and the second product recoverable from the second
region. Advantageously, a first product produced at the first
region may be recoverable from the first region and a second
product produced at the second region may be recoverable from the
second region.
[0049] Referring to FIG. 6 a flow diagram of a method 600 of
electrochemical co-production of products in accordance with an
embodiment of the present disclosure is shown. It is contemplated
that method 600 may be performed by system 100 and system 200 as
shown in FIGS. 1A, 1B, and 2. Method 600 may include steps for
producing a first product from a first region of an electrochemical
cell having a cathode and a second product from a second region of
the electrochemical cell having an anode.
[0050] Method 600 may include the step of receiving a feed of
carbon dioxide and methanol at the first region of the
electrochemical cell 610. A further step of method 600 may include
contacting the first region with a catholyte comprising carbon
dioxide and methanol 620. The method 600 also includes the step of
receiving a feed of methanol at the second region of the
electrochemical cell 630 and contacting the second region with an
anolyte comprising methanol 610. The method also includes the step
of applying an electrical potential between the anode and the
cathode sufficient to produce the first product recoverable from
the first region and the second product recoverable from the second
region 650.
[0051] It is contemplated that receiving a feed may include various
mechanisms for receiving a supply of a reactant, whether in a
continuous, near continuous or batch portions. Similarly, the
reactant (such as the alcohol or carbon dioxide) may be jointly fed
with additional reactants, the anolyte or catholyte, or may be fed
separately into either the first region or second region.
[0052] It is further contemplated that the structure and operation
of the electrochemical cell may be adjusted to provide desired
results. For example, the electrochemical cell may operate at
higher pressures, such as pressures above atmospheric pressure
which may increase current efficiency and allow for operation of
the electrochemical cell at higher current densities.
[0053] The first product and the second product may be mixed with
other products. For example, the second product may include a
methanol/formaldehyde mixture, or a methanol/carboxylic acid
mixture. These mixtures may be separated outside of the
electrochemical cell using conventional separation techniques,
including distillation and esterification.
[0054] In one embodiment, the Faradaic current efficiency of the
anode could be between 90 to 100%, and the acetate Faradaic current
efficiency could be between 25 and 100%. The flow circulation of
the anolyte and catholyte is such that it provides sufficient flow
for the reactions. The flow rate may be varied to select for the
production of different products, such as formaldehyde instead of
formic acid, CO, and CO.sub.2 from methanol oxidation.
[0055] Additionally, the cathode and anode may comprise a high
surface area with a void volume which may range from 30% to 98%.
The surface area may be from 2 cm.sup.2/cm.sup.3 to 500
cm.sup.2/cm.sup.3 or higher. It is contemplated that surface areas
also may be defined as a total area in comparison to the current
distributor/conductor back plate, with a preferred range of
2.times. to 1000.times. or more.
[0056] The anode may comprise a polymeric bound carbon current
distributor anode employing a carbon felt with a specific surface
area of 50 cm.sup.2/cm.sup.3 or more that fills the gap between a
cathode backplate and the membrane, resulting in a zero gap
anode.
[0057] The cathode may comprise a number of high surface area
materials to include copper, stainless steels, carbon, and silicon,
which may be further coated with a layer of material which may be a
conductive metal or semiconductor. A very thin plastic screen may
be incorporated against the cathode side of the membrane to prevent
the membrane from touching the high surface area cathode structure.
The high surface area cathode structure may be mechanically pressed
against the cathode current distributor backplate, which may be
composed of material that has the same surface composition as the
high surface area cathode. For electrochemical reductions, the
cathode electrode may be a suitable conductive electrode, such as
Al, Au, Ag, Bi, C, Cd, Co, Cr, Cu, Cu alloys (e.g., brass and
bronze), Ga, Hg, In, Mo, Nb, Ni, NiCo.sub.2O.sub.4, Ni alloys
(e.g., Ni 625, NiHX), Ni--Fe alloys, Pb, Pd alloys (e.g., PdAg),
Pt, Pt alloys (e.g., PtRh), Rh, Sn, Sn alloys (e.g., SnAg, SnPb,
SnSb), Ti, V, W, Zn, stainless steel (SS) (e.g., SS 2205, SS 304,
SS 316, SS 321), austenitic steel, ferritic steel, duplex steel,
martensitic steel, Nichrome (e.g., NiCr 60:16 (with Fe)), elgiloy
(e.g., Co--Ni--Cr), degenerately doped n-Si, degenerately doped
n-Si:As, degenerately doped n-Si:B, degenerately doped n-Si,
degenerately doped n-Si:As, and degenerately doped n-Si:B. Other
conductive electrodes may be implemented to meet the criteria of a
particular application. For photoelectrochemical reductions, the
electrode may be a p-type semiconductor, such as p-GaAs, p-GaP,
p-InN, p-InP, p-CdTe, p-GaInP.sub.2 and p-Si, or an n-type
semiconductor, such as n-GaAs, n-GaP, n-InN, n-InP, n-CdTe,
n-GaInP.sub.2 and n-Si. Other semiconductor electrodes may be
implemented to meet the criteria of a particular application
including, but not limited to, CoS, MoS.sub.2, TiB, WS.sub.2, SnS,
Ag.sub.2S, CoP.sub.2, Fe.sub.3P, Mn.sub.3P.sub.2, MoP, Ni.sub.2Si,
MoSi.sub.2, WSi.sub.2, CoSi.sub.2, Ti.sub.4O.sub.7, SnO.sub.2,
GaAs, GaSb, Ge, and CdSe.
[0058] Catholyte may include a pH range from 1 to 12, and more
specifically from 4 to 10. The pH may be a function of the desired
product and whether any catalysts are utilized in operation of the
electrochemical cell. Preferably, catholyte and catalysts may be
selected to prevent corrosion at the electrochemical cell.
Catholyte may include homogeneous catalysts such as pyridine,
2-picoline, and the like. Catholyte electrolytes may include alkali
metal bicarbonates, carbonates, sulfates, phosphates, borates, and
hydroxides. Non-aqueous solvents, such as propylene carbonate,
methanesulfonic acid, methanol, and other ionic conducting liquids
may be used rather than water. The electrolyte may comprise one or
more of Na.sub.2SO.sub.4, KCl, NaNO.sub.3, NaCl, NaF, NaClO.sub.4,
KClO.sub.4, K.sub.2SiO.sub.3, CaCl.sub.2, a guanidinium cation, a H
cation, an alkali metal cation, an ammonium cation, an
alkylammonium cation, a tetraalkyl ammonium cation, a halide anion,
an alkyl amine, a borate, a carbonate, a guanidinium derivative, a
nitrite, a nitrate, a phosphate, a polyphosphate, a perchlorate, a
silicate, a sulfate, and a hydroxide.
[0059] The catholyte may comprise a homogeneous catalyst.
Homogeneous catalysts comprising aromatic heterocyclic amines may
include, but are not limited to, unsubstituted and substituted
pyridines and imidazoles. Substituted pyridines and imidazoles may
include, but are not limited to mono and disubstituted pyridines
and imidazoles. For example, suitable catalysts may include
straight chain or branched chain lower alkyl (e.g.,
C.sub.1-C.sub.10) mono and disubstituted compounds such as
2-methylpyridine, 4-tertbutyl pyridine, 2,6 dimethylpyridine
(2,6-lutidine); bipyridines, such as 4,4'-bipyridine;
amino-substituted pyridines, such as 4-dimethylamino pyridine; and
hydroxyl-substituted pyridines (e.g., 4-hydroxy-pyridine) and
substituted or unsubstituted quinoline or isoquinolines. The
catalysts may also suitably substituted or unsubstituted dinitrogen
heterocyclic amines, such as pyrazine, pyridazine and pyrimidine.
Other catalysts generally include azoles, imidazoles, indoles,
oxazoles, thiazoles, substituted species and complex multi-ring
amines such as adenine, pterin, pteridine, benzimidazole,
phenonthroline and the like.
[0060] In one embodiment, a catholyte/anolyte flow rate may include
a catholyte/anolyte cross sectional area flow rate range such as
2-3,000 gpm/ft.sup.2 or more (0.0076-11.36 m.sup.3/m.sup.2). A flow
velocity range may be 0.002 to 20 ft/sec (0.0006 to 6.1 m/sec).
Operation of the electrochemical cell catholyte at a higher
operating pressure allows more dissolved carbon dioxide to dissolve
in the aqueous solution. Typically, electrochemical cells can
operate at pressures up to about 20 to 30 psig in multi-cell stack
designs, although with modifications, the electrochemical cells may
operate at up to 100 psig. The electrochemical cell may operate
anolyte at the same pressure range to minimize the pressure
differential on a separator or membrane separating the cathode and
the anode. Special electrochemical designs may be employed to
operate electrochemical units at higher operating pressures up to
about 60 to 100 atmospheres or greater, which is in the liquid
CO.sub.2 and supercritical CO.sub.2 operating range.
[0061] The catholyte may be operated at a temperature range of -10
to 95.degree. C., more preferably 5-60.degree. C. The lower
temperature will be limited by the catholytes used and their
freezing points. In general, the lower the temperature, the higher
the solubility of CO.sub.2 in the aqueous solution phase of the
catholyte, and would help in obtaining higher conversion and
current efficiencies. The drawback is that the operating
electrochemical cell voltages may be higher, so there is an
optimization that would be done to produce the chemicals at the
lowest operating cost. In addition, the catholyte may require
cooling, so an external heat exchanger may be employed, flowing the
catholyte through the heat exchanger and using cooling water to
remove the heat and control the catholyte temperature.
[0062] The anolyte operating temperatures may be in the same ranges
as the ranges for the catholyte, and may be in a range of 0.degree.
C. to 95.degree. C. In addition, the anolyte may require cooling,
so an external heat exchanger may be employed, flowing the anolyte
through the heat exchanger and using cooling water to remove the
heat and control the anolyte temperature.
[0063] Electrochemical cells may include various types of designs.
These designs may include Zero Gap, flow-through with a
recirculating catholyte electrolyte with various high surface area
cathode materials. The electrochemical cell may include flooded
co-current packed and trickle bed designs with the various high
surface area cathode materials. Also, bipolar stack cell designs
and high pressure cell designs may also be employed for the
electrochemical cells.
[0064] Anodes may include electrocatalytic coatings applied to the
surfaces of the base anode structure. For example, for acid
anolytes and oxidizing water generating oxygen, the preferred
electrocatalytic coatings may include precious metal oxides such as
ruthenium and iridium oxides, as well as platinum and gold and
their combinations as metals and oxides on valve metal substrates
such as titanium, tantalum, zirconium, or niobium. For bromine and
iodine anode chemistry, carbon and graphite are particularly
suitable for use as anodes. Polymeric bonded carbon materials may
also be used. For other anolytes comprising alkaline or hydroxide
electrolytes, anodes may include carbon, cobalt oxides, stainless
steels, transition metals, and their alloys and combinations. High
surface area anode structures that may be used which would help
promote the reactions at the anode surfaces. The high surface area
anode base material may be in a reticulated form composed of
fibers, sintered powder, sintered screens, and the like, and may be
sintered, welded, or mechanically connected to a current
distributor back plate that is commonly used in bipolar cell
assemblies. In addition, the high surface area reticulated anode
structure may also contain areas where additional applied catalysts
on and near the electrocatalytic active surfaces of the anode
surface structure to enhance and promote reactions that may occur
in the bulk solution away from the anode surface such as the
reaction between bromine and the carbon based reactant being
introduced into the anolyte. The anode structure may be gradated,
so that the density of the may vary in the vertical or horizontal
direction to allow the easier escape of gases from the anode
structure. In this gradation, there may be a distribution of
particles of materials mixed in the anode structure that may
contain catalysts for the bulk reaction of the carbon based
reactant.
[0065] The separator, also referred as a membrane, between the
cathode and the anode, may include cation ion exchange type
membranes. Cation ion exchange membranes which have an high
rejection efficiency to anions may be preferred. Examples of such
cation ion exchange membranes may include perfluorinated sulfonic
acid based ion exchange membranes such as DuPont Nafion brand
unreinforced types N117 and N120 series, more preferred PTFE fiber
reinforced N324 and N424 types, and similar related membranes
manufactured by Japanese companies under the supplier trade names
such as AGC Engineering (Asahi Glass) under their trade name
Flemion.RTM.. Other multi-layer perfluorinated ion exchange
membranes used in the chlor alkali industry may have a bilayer
construction of a sulfonic acid based membrane layer bonded to a
carboxylic acid based membrane layer, which efficiently operates
with an anolyte and catholyte above a pH of about 2 or higher.
These membranes may have an higher anion rejection efficiency.
These are sold by DuPont under their Nafion.RTM. trademark as the
N900 series, such as the N90209, N966, N982, and the 2000 series,
such as the N2010, N2020, and N2030 and all of their types and
subtypes. Hydrocarbon based membranes, which are made from of
various cation ion exchange materials can also be used if the anion
rejection is not as desirable, such as those sold by Sybron under
their trade name Lonac.RTM., Engineering (Asahi Glass) under their
trade name Selemion.RTM., and Tokuyama Soda, among others on the
market. Ceramic based membranes may also be employed, including
those that are called under the general name of NASICON (for sodium
super-ionic conductors) which are chemically stable over a wide pH
range for various chemicals and selectively transports sodium ions,
the composition is Na.sub.1+xZr.sub.2Si.sub.xP.sub.3-xO.sub.12, and
well as other ceramic based conductive membranes based on titanium
oxides, zirconium oxides and yttrium oxides, and beta aluminum
oxides. Alternative membranes that may be used are those with
different structural backbones such as potyphosphazene and
sulfonated polyphosphazene membranes in addition to crown ether
based membranes. Preferably, the membrane or separator is
chemically resistant to the anolyte and catholyte. Preferably, the
membrane or separator is chemically resistant to the anolyte and
catholyte and operates at temperatures of less than 600 degrees C.,
and more preferably less than 500 degrees C.
[0066] A catholyte or an anolyte may comprise an aqueous solvent, a
non-aqueous solvent, or a mixture of solvents containing one or
more of water as well as protic or aprotic polar solvents such as
methanol, ethanol, acetonitrile, propylene carbonate, ethylene
carbonate, dimethyl carbonate, diethyl carbonate,
dimethylsulfoxide, dimethylformamide, acetonitrile, acetone,
tetrahydrofuran, N,N-dimethylacetaminde, dimethoxyethane,
diethylene glycol dimethyl ester, butyrolnitrile,
1,2-difluorobenzene, .gamma.-butyrolactone, N-methyl-2-pyrrolidone,
sulfolane, 1,4-dioxane, nitrobenzene, nitromethane, acetic
anhydride, and ionic liquids. An aqueous solvent comprises at least
5% water. A non-aqueous solvent comprises less than 5% water.
[0067] The rate of the generation of the second product formed in
the second region from the anode reaction, such as the oxidation of
methanol to formaldehyde, is contemplated to be proportional to the
applied Faradaic current to the electrochemical cell. The rate of
the input or feed of the carbon based reactant into the second
region should then be fed in proportion to the applied Faradaic
current or amperage rate to the electrochemical cell. The anode
reaction efficiency would determine the maximum theoretical
formation in moles of the alcohol oxidation product at the applied
current. It is contemplated that the molar ratio of alcohol feed to
the theoretical moles of potentially formed alcohol oxidation
product would be in a range of 500:1 to 2:1, and preferably in the
range of 200:1 to 10:1, where the alcohol is in excess of the
theoretical required for the anode reaction. In this contemplated
mode of operation, there is an excess of alcohol in the anolyte
during operation. The operation of an extractor and its selected
separation method--for example fractional distillation--the actual
products produced, and the selectivity of the wanted reaction would
determine the optimum molar ratio of the carbon based reactant to
the applied Faradaic current rate applied in the second region. Any
of the unreacted components could be recycled to the second
region.
[0068] Similarly, the rate of the generation of the formed
electrochemical carbon dioxide reduction product in the first
(catholyte) compartment, such as CO, is contemplated to be
proportional to the applied current to the electrochemical cell.
The rate of the input or feed of the carbon dioxide source into the
first compartment should be fed in a proportion to the applied
current. The cathode reaction efficiency would determine the
maximum theoretical formation in moles of the carbon dioxide
reduction product at the applied current. It is contemplated that
the ratio of carbon dioxide feed to the theoretical moles of
potentially formed carbon dioxide reduction product based on the
applied current, would be in a range of 100:1 to 2:1, and
preferably in the range of 50:1 to 5:1, where the carbon dioxide is
in excess of the theoretical required for the cathode reaction. The
carbon dioxide excess would then be separated in the extractor and
recycled back to the second compartment.
[0069] In the present disclosure, the methods disclosed may be
implemented as sets of instructions or software readable by a
device. Further, it is understood that the specific order or
hierarchy of steps in the methods disclosed are examples of
exemplary approaches. Based upon design preferences, it is
understood that the specific order or hierarchy of steps in the
method can be rearranged while remaining within the disclosed
subject matter. The accompanying method claims present elements of
the various steps in a sample order, and are not necessarily meant
to be limited to the specific order or hierarchy presented.
[0070] It is believed that the present disclosure and many of its
attendant advantages will be understood by the foregoing
description, and it will be apparent that various changes may be
made in the form, construction and arrangement of the components
without departing from the disclosed subject matter or without
sacrificing all of its material advantages. The form described is
merely explanatory, and it is the intention of the following claims
to encompass and include such changes.
* * * * *