U.S. patent application number 13/724768 was filed with the patent office on 2013-05-09 for electrochemical co-production of a glycol and an alkene employing recycled halide.
This patent application is currently assigned to LIQUID LIGHT, INC.. The applicant listed for this patent is Liquid Light, Inc.. Invention is credited to Emily Barton Cole, Jerry J. Kaczur, Kyle Teamey.
Application Number | 20130116474 13/724768 |
Document ID | / |
Family ID | 48171282 |
Filed Date | 2013-05-09 |
United States Patent
Application |
20130116474 |
Kind Code |
A1 |
Teamey; Kyle ; et
al. |
May 9, 2013 |
Electrochemical Co-Production of a Glycol and an Alkene Employing
Recycled Halide
Abstract
The present disclosure is a method and system for
electrochemically co-producing a first product and a second
product. The system may include a first electrochemical cell, a
first reactor, a second electrochemical cell, at least one second
reactor, and at least one third reactor. The method and system for
co-producing a first product and a second product may include
co-producing a glycol and an alkene employing a recycled
halide.
Inventors: |
Teamey; Kyle; (Washington,
DC) ; Kaczur; Jerry J.; (North Miami Beach, FL)
; Cole; Emily Barton; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liquid Light, Inc.; |
Monmouth Junction |
NJ |
US |
|
|
Assignee: |
LIQUID LIGHT, INC.
Monmouth Junction
NJ
|
Family ID: |
48171282 |
Appl. No.: |
13/724768 |
Filed: |
December 21, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61703187 |
Sep 19, 2012 |
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61720670 |
Oct 31, 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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61703175 |
Sep 19, 2012 |
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61703231 |
Sep 19, 2012 |
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61703232 |
Sep 19, 2012 |
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61703234 |
Sep 19, 2012 |
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61703238 |
Sep 19, 2012 |
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Current U.S.
Class: |
568/852 ;
422/187 |
Current CPC
Class: |
C07C 29/149 20130101;
C07C 51/15 20130101; C25B 3/10 20130101; C25B 15/00 20130101; C25B
3/00 20130101; C25B 13/08 20130101; C25B 9/10 20130101; Y02P 20/127
20151101; C25B 9/08 20130101; C25B 1/00 20130101; Y02P 20/129
20151101; C07C 1/26 20130101; C07C 51/02 20130101; C25B 1/24
20130101; Y02P 20/132 20151101; Y02P 20/133 20151101; Y02P 20/582
20151101; C25B 3/06 20130101; C07C 51/367 20130101; C07C 67/08
20130101; C25B 3/02 20130101; Y02P 20/10 20151101; C25B 15/08
20130101; C25B 3/04 20130101; C07C 29/58 20130101 |
Class at
Publication: |
568/852 ;
422/187 |
International
Class: |
C25B 3/02 20060101
C25B003/02 |
Claims
1. A method for co-producing a first product and a second product,
the method comprising the steps of: contacting a first region of a
first electrochemical cell having an cathode with a catholyte
comprising carbon dioxide; contacting a second region of a first
electrochemical cell having an anode with an anolyte comprising a
MX where M is at least one cation and X is selected from a group
consisting of F, Cl, Br, I, and mixtures thereof; applying an
electrical potential between the anode and the cathode sufficient
to produce M-carboxylate recoverable from the first region of the
first electrochemical cell and a halogen recoverable from the
second region of the first electrochemical cell; reacting the
M-carboxylate with HX via a secondary reactor to produce a
carboxylic acid and MX, the MX being recycled to an input of the
second region of the first electrochemical cell; contacting a first
region of a second electrochemical cell having a cathode with a
catholyte comprising the carboxylic acid; contacting a second
region of a second electrochemical cell having an anode with an
anolyte comprising HX; applying an electrical potential between the
anode of the second electrochemical cell and the cathode of the
second electrochemical cell sufficient to produce at least one of
another carboxylic acid, an aldehyde, a ketone, a glycol or an
alcohol recoverable from the first region of the second
electrochemical cell and a halogen recoverable from the second
region of the second electrochemical cell; reacting the halogen
from the second region of the first electrochemical cell and from
the second region of the second electrochemical cell with an
alkane, aromatic compound, or other carbon compound to produce a
halogenated compound and HX, the HX being recycled back to the
second region of the second electrochemical cell and to the input
of the secondary reactor; and reacting the halogenated compound via
at least one reactor to produce at least one of an alkene, alkyne,
alcohol, phenol, aldehyde, ketone, unsaturated carbon compound, or
longer-chain alkane, and HX, the HX being recycled back to the
second region of the second electrochemical cell and to the input
of the secondary reactor.
2. The method according to claim 1, wherein the halogen includes at
least one of F.sub.2, Cl.sub.2, Br.sub.2, or I.sub.2.
3. The method according to claim 1, wherein the halogen is reacted
with at least one of methane, ethane, propane, butane, isobutane,
benzene, toluene, or xylene.
4. The method according to claim 1, wherein the M-carboxylate is M
oxalate.
5. The method according to claim 1, wherein at least one of
glyoxylic acid, glyoxal, glycolic acid, glycolaldehyde, acetic
acid, acetaldehyde, ethanol, ethane, ethylene, or ethylene glycol
is recoverable from the first region of the second electrochemical
cell.
6. The method according to claim 1, wherein the cathode and the
anode of the first electrochemical cell and the cathode and the
anode of the second electrochemical cell, are separated by an ion
permeable barrier that operates at a temperature less than 600
degrees C.
7. The method according to claim 6, wherein the ion permeable
barrier includes one of a polymeric or inorganic ceramic-based ion
permeable barrier.
8. The method according to claim 1, wherein the catholyte of the
second electrochemical cell is liquid phase and the anolyte of the
second electrochemical cell is gas phase.
9. The method according to claim 1, wherein at least one of: the
catholyte and the anolyte of the first electrochemical cell; and
the catholyte and the anolyte of the second electrochemical cell;
is non-aqueous.
10. The method according to claim 1, wherein reacting the recovered
halogen from the second region of the first electrochemical cell
and the second region of the second electrochemical cell with an
alkane, aromatic compound, or other carbon compound is performed by
at least a single reactor.
11. The method according to claim 1, wherein reacting the recovered
halogen from the second region of the first electrochemical cell
and the second region of the second electrochemical cell with an
alkane, aromatic compound, or other carbon compound is performed by
at least two reactors.
12. A system for co-producing a first product and a second product,
comprising: a first electrochemical cell, the first electrochemical
cell including a first region, a second region and a separator that
selectively controls a flow of ions between the first region and
the second region, the first region having a cathode with a
catholyte comprising carbon dioxide, the second region having an
anode with an anolyte comprising MX where M is at least one cation
and X is selected from a group consisting of F, Cl, Br, I and
mixtures thereof, wherein when there is an electric potential
applied between the anode and cathode, M-carboxylate is produced in
the first region and a halogen is produced in the second region; a
first reactor, the first reactor reacts the M-carboxylate with HX
to produce carboxylic acid and MX, the MX being recycled to an
input of the second region of the first electrochemical cell; a
second electrochemical cell, the second electrochemical cell
including a first region, a second region and a separator that
selectively controls a flow of ions between the first region and
the second region, the first region having a cathode with a
catholyte comprising the carboxylic acid, the second region having
an anode with an anolyte comprising HX, wherein when there is an
electric potential applied between the anode and cathode, at least
one of another carboxylic acid, an aldehyde, a ketone, a glycol or
an alcohol is produced at the first region of the second
electrochemical cell and a halogen is produced in the second region
of the second electrochemical cell; at least one second reactor,
the at least one second reactor reacts the halogen from the second
region of the first electrochemical cell and the second region of
the second electrochemical cell with an alkane, aromatic compound,
or other carbon compound to produce a halogenated compound and HX,
the HX being recycled back to the second region of the second
electrochemical cell and to the input of the first reactor; and at
least one third reactor, the at least one third reactor reacts the
halogenated compound to produce at least one of an alkene, alkyne,
ketone, alcohol, aldehyde, unsaturated carbon compound, or
longer-chain alkane, and HX, the HX being recycled back to the
second region of the second electrochemical cell and to the input
of the first reactor.
13. The system according to claim 12, wherein the halogen includes
at least one of F.sub.2, Cl.sub.2, Br.sub.2 or I.sub.2.
14. The system according to claim 12, wherein the alkane, aromatic
compound, or other carbon compound includes at least one of
methane, ethane, propane, or butane.
15. The system according to claim 12, wherein the M-carboxylate is
M oxalate.
16. The system according to claim 12, wherein at least one of
glyoxylic acid, glyoxal, glycolic acid, glycolaldehyde, acetic
acid, acetaldehyde, ethanol, ethane, ethylene, or ethylene glycol
is recoverable from the first region of the second electrochemical
cell.
17. The system according to claim 13, wherein the cathode and the
anode of the first electrochemical cell and the cathode and the
anode of the second electrochemical cell, are separated by an ion
permeable barrier that operates at a temperature less than 600
degrees C.
18. The system according to claim 17, wherein the ion permeable
barrier includes one of a polymeric or inorganic ceramic-based ion
permeable barrier.
19. The system according to claim 12, wherein the catholyte of the
second electrochemical cell is liquid phase and the anolyte is gas
phase.
20. The method according to claim 12, wherein at least one of: the
catholyte and the anolyte of the first electrochemical cell; and
the catholyte and the anolyte of the second electrochemical cell;
are non-aqueous.
21. A method for co-producing a first product and a second product,
the method comprising the steps of: applying an electrical
potential between a cathode of a first region of a first
electrochemical cell, including a catholyte comprising carbon
dioxide, and an anode of a second region of a first electrochemical
cell, the second region including an anolyte comprising MX, where M
is at least one cation and X is selected from a group consisting of
F, Cl, Br, I, and mixtures thereof, sufficient to produce
M-carboxylate recoverable from the first region of the first
electrochemical cell and a halogen recoverable from the second
region of the first electrochemical cell; reacting the
M-carboxylate with HX via a secondary reactor to produce a
carboxylic acid and MX, the MX being recycled to an input of the
second region of the first electrochemical cell; applying an
electrical potential between a cathode of a first region of a
second electrochemical cell, including a catholyte comprising the
carboxylic acid, and an anode of a second region of a second
electrochemical cell, including an anolyte comprising HX,
sufficient to produce at least one of another carboxylic acid, an
aldehyde, a ketone, a glycol or an alcohol recoverable from the
first region of the second electrochemical cell and a halogen
recoverable from the second region of the second electrochemical
cell; reacting the halogen from the second region of the first
electrochemical cell and from the second region of the second
electrochemical cell with an alkane, aromatic compound, or other
carbon compound, to produce a halogenated compound and HX, the HX
being recycled back to the second region of the second
electrochemical cell and to the input of the secondary reactor; and
reacting the halogenated compound via at least a third reactor to
produce at least one of an alkene, alkyne, alcohol, aldehyde,
ketone, or longer-chain alkane, and HX, the HX being recycled back
to the second region of the second electrochemical cell and to the
input of the secondary reactor.
22. The method according to claim 21, wherein the halogen includes
at least one of F.sub.2, Cl.sub.2, Br.sub.2, or I.sub.2.
23. The method according to claim 21, wherein the alkane, aromatic
compound, or other carbon compound includes at least one of
methane, ethane, propane, or butane.
24. The method according to claim 21, wherein the M-carboxylate is
M-oxalate.
25. The method according to claim 21, wherein at least one of
glyoxylic acid, glyoxal, glycolic acid, glycolaldehyde, acetic
acid, acetaldehyde, ethanol, ethane, ethylene, or ethylene glycol
is recoverable from the first region of the second electrochemical
cell.
26. The method according to claim 21, wherein the cathode and the
anode of the first electrochemical cell and the cathode and the
anode of the second electrochemical cell, are separated by an ion
permeable barrier that operates at a temperature less than 600
degrees C.
27. The method according to claim 26, wherein the ion permeable
barrier includes one of a polymeric or inorganic ceramic-based ion
permeable barrier.
28. The method according to claim 21, wherein the catholyte of the
second electrochemical cell is liquid phase and the anolyte of the
second electrochemical cell is gas phase.
29. The method according to claim 21, wherein at least one of: the
catholyte and the anolyte of the first electrochemical cell; and
the catholyte and the anolyte of the second electrochemical cell;
are non-aqueous.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application 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.
61/703,187 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. 61/703,187 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.
[0002] The present application 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. 61/703,175 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. 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. 61/703,175 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 and
U.S. Provisional Application Ser. No. 61/703,238 filed Sep. 19,
2012 are hereby incorporated by reference in their entireties.
[0003] The present application incorporates by reference co-pending
U.S. patent application Attorney Docket 0022, U.S. patent
application Attorney Docket 0023, U.S. patent application Attorney
Docket 0024, U.S. patent application Attorney Docket 0025, U.S.
patent application Attorney Docket 0026, U.S. patent application
Attorney Docket 0027, U.S. patent application Attorney Docket 0028,
and U.S. patent application Attorney Docket 0029 in their
entireties.
TECHNICAL FIELD
[0004] The present disclosure generally relates to the field of
electrochemical reactions, and more particularly to methods and/or
systems for electrochemical co-production of a glycol and an alkene
employing a recycled reactant.
BACKGROUND
[0005] 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.
[0006] 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 OF THE PREFERRED EMBODIMENTS
[0007] The present disclosure includes a system and method for
electrochemically co-producing a first product and a second
product. The system may include a first electrochemical cell, a
first reactor, a second electrochemical cell, at least one second
reactor, and at least one third reactor. The method and system for
co-producing a first product and a second product may include
co-producing a glycol and an alkene employing a recycled
halide.
[0008] 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
[0009] The numerous advantages of the present disclosure may be
better understood by those skilled in the art by reference to the
accompanying figures in which:
[0010] FIG. 1 is a block diagram of a system in accordance with an
embodiment of the present disclosure;
[0011] FIG. 2 is a block diagram of a system in accordance with
another embodiment of the present disclosure;
[0012] FIG. 3 is a block diagram of a system in accordance with an
additional embodiment of the present disclosure; and
[0013] FIG. 4 is a block diagram of a system in accordance with
another additional embodiment of the present disclosure.
DETAILED DESCRIPTION
[0014] Reference will now be made in detail to the subject matter
disclosed, which is illustrated in the accompanying drawings.
[0015] The present disclosure includes a system and method for
electrochemically co-producing a first product and a second
product. The system may include a first electrochemical cell, a
first reactor, a second electrochemical cell, at least one second
reactor, and at least one third reactor. The method and system for
co-producing a first product and a second product may include
co-producing a glycol and an alkene employing a recycled halide. In
one embodiment, the system may co-produce monoethylene glycol (MEG)
and ethylene. An overall equation for the desired reaction is:
2CO.sub.2+5C.sub.2H.sub.6C.sub.2H.sub.4(OH).sub.2+5C.sub.2H.sub.4+2H.sub-
.2O.
[0016] In an advantageous aspect of the present disclosure,
chemicals may be co-produced at both the anode and the cathode of
each electrochemical cell. The cathode may be used to reduce carbon
dioxide to carbon-containing chemicals. The anode may be used to
make an oxidation product for subsequent employment in producing
another carbon compound. By co-producing chemicals, the overall
energy requirement for making each chemical may be reduced by 50%
or more. In addition, the cell may be capable of simultaneously
making two or more products with high selectivity. In another
advantageous aspect of the present disclosure, carbon dioxide may
act to oxidize organic compounds, and the organic compounds may act
to reduce carbon dioxide. The organic compound, such as ethane, may
be the sole source of hydrogen used in the reduction of carbon
dioxide. Halogens utilized to couple the oxidation of organics to
the reduction of carbon dioxide may be recycled in the process.
[0017] Before any embodiments of the disclosure are explained in
detail, it is to be understood that the embodiments may not be
limited in application per 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.
[0018] Referring to FIG. 1, a block diagram of a system 100 in
accordance with an embodiment of the present disclosure is shown.
System (or apparatus) 100 may generally include electrochemical
cells, such as a first electrochemical cell 102A and a second
electrochemical cell 102B, which may also be referred as a
container, electrolyzer, or cell. Electrochemical cells 102A and
102B may be implemented as a divided cells. The divided cells may
be divided electrochemical cells and/or a divided
photo-electrochemical cells. Electrochemical cells 102A and 102B
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 from carbon dioxide source 106 is included
in the catholyte. Second region 118 may include an anolyte which
may include an MX 128 where M is at least one cation and X is
selected from a group consisting of F, Cl, Br, I and mixtures
thereof. An 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 supply
a variable voltage or constant current to electrochemical cell 102.
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.
[0019] A cation, as used above, refers to a positively charged
species including ions such as Li, Na, K, Cs, Be, Mg, Ca, hydrogen
ions, tetraalkyl ammonium ions such as tetrabutylammonium,
tetraethylammonium, and tetraalkylphosphonium ions such as
tetrabutylphosphonium, tetraethylphosphonium, and in general,
R.sub.1R.sub.2R.sub.3R.sub.4N or R.sub.1R.sub.2R.sub.3R.sub.4P
where R.sub.1 to R.sub.4 are independently alkyl, cycloalkyl,
branched alkyl, and aryl.
[0020] First electrochemical cell 102A is generally operational to
reduce carbon dioxide in the first region 116 to a first product
recoverable from the first region 116, such as a carboxylate 130 or
carboxylate salt while producing a halogen 132 recoverable from the
second region 118.
[0021] Carbon dioxide source 106 may provide carbon dioxide to the
first region 116 of first electrochemical cell 102A. In some
embodiments, the carbon dioxide is introduced directly into the
region 116 containing the cathode 122. It is contemplated that
carbon dioxide source may include a source of a mixture of gases in
which carbon dioxide has been filtered or separated from the gas
mixture.
[0022] In one embodiment, carbon dioxide may be reduced to an
oxalate salt at the cathode 122 of the first electrochemical cell
102A while bromine is produced at the anode 124. The two feeds for
the electrochemical cell 102A first region are carbon dioxide and a
bromide salt such as LiBr, NaBr, KBr, MgBr.sub.2, alkylammonium
bromide, tetraalkylammonium salts such as tetramethylammonium
bromide, tetraethylammonium bromide, tetrabutylammonium bromide,
choline bromide, benzyltrimethylammonium bromide, and
butyltrimethylammonium bromide. Oxalate salt produced at cathode
122 of the first electrochemical cell 102A may be
tetrabutylammonium oxalate. However, other organic salts may be
produced to include formates, glyoxylates, glycolates, and
acetates, depending on the solvent utilized. While any solvent or
any mix of solvents may be used, aprotic solvents such as propylene
carbonate may be preferred. A separator 120 may be utilized to
minimize or prevent oxidation of the first region 116 product and
to minimize or prevent mixing of the anode 124 and cathode 122
products. Separator 120 may be a cation exchange membrane, such as
Nafion, or a micro or nanoporous diaphram. Electrochemical cell
102A may be operated in a temperature range from 0.degree. C. to
150.degree. C. Temperatures above 60.degree. C. are preferred for
production of gas phase Br.sub.2. Electrochemical cell 102A may be
operated in a pressure range from 1 to 200 atmospheres, with 1 to
10 atmospheres preferred.
[0023] It is contemplated that each electrochemical cell, 102A and
102B, may include a first product extractor 110 and second product
extractor 113. Product extractors 110, 113 may implement an organic
product and/or inorganic product extractor. First product extractor
110 is generally operational to extract (separate) a product from
the first region 116. Second product extractor 113 may extract the
second product from the second region 118. It is contemplated that
first product extractor and/or second product extractor may be
implemented with electrochemical cells 102A and 102B, or may be
remotely located from the electrochemical cells 102A 102B.
Additionally, it is contemplated that first product extractor
and/or second product extractor may be implemented in a variety of
mechanisms and to provide desired separation methods, such as
fractional distillation, without departing from the scope and
intent of the present disclosure. It is further contemplated that
extracted product may be presented through a port of the system 100
for subsequent storage and/or consumption by other devices and/or
processes.
[0024] An anode side of the reaction occurring in the second region
118 of first electrochemical cell 102A may include a recycled
reactant of MX. Recycled reactant may include an halide salt which
may be a byproduct of a reaction of first reactor 134. For example,
the recycled reactant may include MX where where M is at least one
alkali metal and X is selected from a group consisting of F, Cl,
Br, I and mixtures thereof. M may include H, Li, Na, K, Cs, Mg, Ca,
or other metal, or R.sub.1R.sub.2R.sub.3R.sub.4P.sup.+,
R.sub.1R.sub.2R.sub.3R.sub.4N.sup.+--where each R is independently
alkyl, branched alkyl, cycloalkyl, or aryl--or a cation; and X is
F, Cl, Br, I, or an anion; and mixtures thereof. The anode side of
the reaction may produce a halogen 132 which may be presented to
second reactor 138A.
[0025] System 100 may include second reactor 138A which may receive
halogen 132 produced by the second region 118 of first
electrochemical cell 102A. Second reactor 138A may react halogen
132 with an alkane or aromatic compound or other carbon compounds
that can be partially oxidized with a halogen or mixtures thereof
140 to produce a halogenated compound 144 and HX 148. HX 148 may be
another recycled reactant which may be recycled back to the second
region 118 as an input feed to the second region 118 of second
electrochemical cell 102B and as an input of first reactor 134.
[0026] In one embodiment, the alkane 140 may be ethane and second
reactor 138A may produce bromoethane. While selectivity for
1-bromoethane is generally greater than 85%, some dibromoethane may
also be produced. The dibromoethane may be sold as a separate
product, converted to a secondary product such as acetylene,
recycled back to the secondary reactor 138A in order to improve
selectivity for 1-bromoethane, and/or catalytically converted into
1-bromoethane. HBr will be co-produced with bromoethane and may be
recycled back to first reactor 134 or the second region 118 of
electrochemical cell 102B. In another embodiment, the aromatic
compound may be ethylbenzene which may be brominated to make
bromoethylbenzene and HBr.
[0027] Halogenated compound 144 may be fed to third reactor 152A.
Third reactor 152A may perform a dehydrohalogenation reaction or
another chemical reaction of halogenated compound 144 to produce a
second product 156. In one embodiment, halogen may refer to
Br.sub.2 which may react with ethane to produce bromoethane. The
dehydrohalogenation reaction of bromoethane may produce ethylene
and HBr. The dehydrohalogenation reaction of dibromoethane or
dichloroethane may produce acetylene. The dehydrohalogenation of
bromopropane may produce propylene. The dehydrohalogenation of
bromobutane may produce 1-butene, 2-butene, butadiene, or a mix
thereof. The dehydrohalogenation of bromoisobutane or iodoisobutane
may produce isobutylene. The dehydrohalogenation reaction of
bromoethylbenzene may produce styrene.
[0028] First reactor 134 may receive an input feed of carboxylate
130 or carboxylate salt along with recycled input feed of HX 148 to
produce carboxylic acid 160. Second electrochemical cell 102B may
receive carboxylic acid 160 as a catholyte feed to the first region
116 of the second electrochemical cell 102B. An anode side of the
reaction occurring in the second region 118 of second
electrochemical cell 102B may include a recycled reactant of HX
149. Recycled reactant may include a hydrogen halide and may
include byproducts of at least one second reactor 138A, 138B, and
third reactor 152A, 152B.
[0029] A cathode reaction of the first region 116 may produce a
first product 164 recoverable from the first region 116 of the
second electrochemical cell 102B after extractor 110. First product
may include at least one of another carboxylic acid, an aldehyde, a
ketone, a glycol, or an alcohol. Additional examples of first
product 164 may include glyoxylic acid, glyoxal, glycolic acid,
glycolaldehyde, acetic acid, acetaldehyde, ethanol, ethane,
ethylene or ethylene glycol. An anode reaction of the second region
118 of the second electrochemical cell 102B may produce a halogen
132. Halogen may include Br.sub.2 and may be fed to second reactor
138B.
[0030] In one embodiment, oxalic acid may be produced by first
reactor 134 and first region 116 of second electrochemical cell
102B may reduce the oxalic acid to monoethylene glycol while HBr is
oxidized to Br.sub.2 in the second region 118. Catholyte of first
region 116 may preferably utilize water as solvent, but may include
a non-aqueous solvent or mix of solvents. The electrolyte in the
cathode compartment is preferably an acid such as HBr, HCl, HI, HF,
or H.sub.2SO.sub.4, but may include any mixture of salts or acids.
The catholyte pH may be less than 7 and preferably between 1 and 5.
A homogenous heterocyclic catalyst may be employed in the
catholyte. The anolyte may be solely anhydrous gas-phase HBr or HCl
or may include a liquid solvent, such as water, in which HBr or HCl
is dissolved. In the case of a liquid anolyte, the HBr anolyte
concentration may be in the range of 5 wt % to 50 wt %, more
preferably in the range of 10 wt % to 40 wt %, and more preferably
in the 15 wt % to 30 wt % range, with a corresponding 2 to 30 wt %
bromine content as HBr.sub.3 in the solution phase. The HBr content
in the anolyte solution may control the anolyte solution
conductivity, and thus the anolyte region IR voltage drop. If the
anode is run with gas phase HBr, then HBr concentrations may
approach 100% by wt % and may be run in anhydrous conditions. The
cell temperature may range from 10.degree. C. to 100.degree. C.,
but temperatures less than 60.degree. C. are preferred to produce
Br.sub.2 in the liquid phase.
[0031] Second reactor 138B may react halogen 132 with a carbon
compound 140, as described above, to produce a halogenated compound
144 and HX 149. HX 149 may be another recycled reactant which may
be recycled back to the second region 118 as an input feed to the
second region 118 of second electrochemical cell 102B and as an
input of first reactor 134. Halogenated compound 144 may be fed to
third reactor 152B.
[0032] Third reactor 152A may perform a dehydrohalogenation
reaction or another chemical reaction of halogenated compound 144
to produce a second product 157. Second product 157 may include an
alkene, alkyne, alcohol, aldehyde, ketone, or longer-chain alkane.
It is contemplated that the reaction may occur at elevated
temperatures and may include the use of a metal or metal oxide
catalyst to reduce the thermal energy required. Temperature ranges
for the reaction are from 25.degree. C. to 1,000.degree. C., with
temperatures below 500.degree. C. preferable.
[0033] In one embodiment, halogen may refer to Br.sub.2 which may
react with ethane to produce bromoethane. The dehydrohalogenation
reaction of bromoethane may produce ethylene and HBr. It is
contemplated that a diverter, or diverter valve may be inserted in
the feed for the HX 148 feed between the second reactor 138A, 138B
and the third reactors 152A and 152B and an input of the first
reactor 134 and the input to the second region 118 of the second
electrochemical cell 102B to ensure a proper amount of HX is
supplied to each of the first reactor 134 and the input to the
second region 118 of the second electrochemical cell 102B.
[0034] Referring to FIG. 2, a block diagram of a system 200 in
accordance with another embodiment of the present disclosure is
shown. System 200 may be substantially similar to system 100 of
FIG. 1. However, system 200 may include a second reactor 138
implemented as a single reactor and third reactor 152 implemented
as a single reactor, rather than as two or more reactors as shown
in system 100 of FIG. 1. It is contemplated that system 200 may
also include a diverter, or diverter valve inserted in the feed for
the HX 148 feed between the second reactor 138 and the third
reactor 152 and an input of the first reactor 134 and the input to
the second region 118 of the second electrochemical cell 102B to
ensure a proper amount of HX is supplied to each of the first
reactor 134 and the input to the second region 118 of the second
electrochemical cell 102B. Second product 157 from third reactor
152 may include an alkene, alkyne, alcohol, aldehyde, ketone, or
longer-chain alkane.
[0035] Referring to FIG. 3, a block diagram of a system 300 in
accordance with an additional embodiment of the present disclosure
is shown. System 300 may include a single electrochemical cell 102.
Carbon dioxide source 106 may provide carbon dioxide to the first
region 116 of first electrochemical cell 102. Cathode reaction may
reduce carbon dioxide to a carbon dioxide reduction product such as
CO 310. An anode side of the reaction occurring in the second
region 118 of first electrochemical cell 102 may include a recycled
reactant of HX where H is hydrogen and X is selected from a group
consisting of F, Cl, Br, I and mixtures thereof. The anode side of
the reaction may produce a halogen 132 which may be provided to
first reactor 138.
[0036] First reactor 138 may react halogen 132, such as Br.sub.2
with a compound 140, as described above, such as ethane, to produce
a halogenated compound 144, such as bromoethane and HX 148, such as
HBr. HX 148 may be recycled reactant which may be recycled back to
the second region 118 of electrochemical cell 102. Halogenated
compound 144 may be fed to second reactor 152 to produce a second
product 156. Second product 156 may include an alkene, alkyne,
alcohol, aldehyde, ketone, or longer-chain alkane, such as
ethylene.
[0037] CO 310 may be fed to third reactor 312. Third reactor 312
may perform a water gas shift reaction and react CO 310 and water
316 to produce carbon dioxide 320 and H.sub.2 324. Carbon dioxide
320 may be recycled back to the input of the first region 116 of
electrochemical cell 102. H.sub.2 324 may be fed to fourth reactor
344. Fifth reactor 328 may receive CO 310 from the first region 116
of electrochemical cell 102 and may receive an O.sub.2 332 input
and a methanol input 336 supplied by a methanol source 334 to
produce an intermediate product 340. In one embodiment,
intermediate product 340 may be dimethyl oxalate. The intermediate
product 340, such as dimethyl oxalate, may be fed to fourth reactor
344. Fourth reactor 344 may react intermediate product 340 with
H.sub.2 324 reduce the intermediate product 340 to produce a first
product 164 and a methanol 336 byproduct which is recycled back to
reactor 328. First product 164 may include an glyoxylic acid,
glyoxal, glycolic acid, glycolaldehyde, acetic acid, acetaldehyde,
ethanol, ethane, ethylene, or ethylene glycol.
[0038] Referring to FIG. 4, a block diagram of a system 400 in
accordance with another additional embodiment of the present
disclosure is shown. System 400 may include a single
electrochemical cell 102. A water source 406, which may include HX
where H is hydrogen and X is selected from a group consisting of F,
Cl, Br, I and mixtures thereof, may be provided to the first region
116 of electrochemical cell 102. Water with HX 406 may be produced
at the first region 116 and recycled back to an input of the first
region 116. Cathode reaction may also produce H.sub.2 410. An anode
side of the reaction occurring in the second region 118 of first
electrochemical cell 102 may include a recycled reactant of HX 148.
The anode side of the reaction may produce a halogen 132 which may
be provided to first reactor 138.
[0039] First reactor 138 may react halogen 132, such as Br.sub.2
with a compound 140, as described above, such as ethane, to produce
a halogenated compound 144, such as bromoethane and HX 148, such as
HBr. HX 148 may be a recycled reactant which may be recycled back
to the second region 118 of electrochemical cell 102. Halogenated
compound 144 may be fed to second reactor 152 to produce a second
product 156. Second product 156 may include an alkene, alkyne,
alcohol, aldehyde, ketone, or longer-chain alkane, such as
ethylene.
[0040] H.sub.2 410 may be fed to third reactor 412. Reactor 412 may
perform a reverse water gas shift reaction and react H.sub.2 410
and carbon dioxide 316 to produce water 420 and CO 424. Water may
be recycled to an input of the first region 116 of electrochemical
cell. CO 424 may be fed to fourth reactor 428. Fourth reactor 428
may react CO 424 with O.sub.2 432 and methanol 436 supplied from
methanol source 434 to produce an intermediate product 440.
Intermediate product 440 may be dimethyl oxalate. The intermediate
product 440, such as dimethyl oxalate, may be fed to fifth reactor
444. Reactor 444 may react intermediate product 440 with H.sub.2
410 from second region 116 of electrochemical cell 102 to reduce
the intermediate product to produce a first product 164 and a
methanol 336 byproduct which is recycled back to fourth reactor
428. First product 164 may include an glyoxylic acid, glyoxal,
glycolic acid, glycolaldehyde, acetic acid, acetaldehyde, ethanol,
ethane, ethylene, or ethylene glycol.
[0041] In addition to the systems 300, 400 of FIG. 3 and FIG. 4,
another system to produce ethylene glycol may include producing
oxalate in a first electrochemical cell from carbon dioxide and
Br.sub.2 from MBr, where M is a cation. A second electrochemical
cell may utilize HBr at the anode. The second electrochemical cell
may produce H.sub.2 at the cathode and Br.sub.2 at the anode.
Br.sub.2 may be used in the thermal processes to make HBr, which
may be recycled to the HBr electrochemical cell and also used to
acidify oxalate to oxalic acid. The oxalic acid may be reduced to
ethylene glycol in a thermal process utilizing H.sub.2 from the HBr
electrolyzer. Oxalic acid may also be reduced to glyoxylic acid,
glycolic acid, glyoxal, glycolaldehyde, acetic acid, acetaldehyde,
and/or ethanol.
[0042] It is contemplated that a receiving feed may include various
mechanisms for receiving a supply of a product, whether in a
continuous, near continuous or batch portions.
[0043] It is further contemplated that the structure and operation
of the electrochemical cell 102, which includes electrochemical
cells 102A and 102B, and 102 in FIGS. 1-4, may be adjusted to
provide desired results. For example, the electrochemical cell 102
may operate at higher pressures, such as pressure above atmospheric
pressure which may increase current efficiency and allow operation
of the electrochemical cell at higher current densities.
[0044] Additionally, the cathode 122 and anode 124 may include a
high surface area electrode structure with a void volume which may
range from 30% to 98%. The electrode void volume percentage may
refer to the percentage of empty space that the electrode is not
occupying in the total volume space of the electrode. The advantage
in using a high void volume electrode is that the structure has a
lower pressure drop for liquid flow through the structure. The
specific surface area of the electrode base structure may be from 2
cm.sup.2/cm.sup.3 to 500 cm.sup.2/cm.sup.3 or higher. The electrode
specific surface area is a ratio of the base electrode structure
surface area divided by the total physical volume of the entire
electrode. It is contemplated that surface areas also may be
defined as a total area of the electrode base substrate in
comparison to the projected geometric area of the current
distributor/conductor back plate, with a preferred range of
2.times. to 1000.times. or more. The actual total active surface
area of the electrode structure is a function of the properties of
the electrode catalyst deposited on the physical electrode
structure which may be 2 to 1000 times higher in surface area than
the physical electrode base structure.
[0045] Cathode 122 may be selected from a number of high surface
area materials to include copper, stainless steels, transition
metals and their alloys and oxides, carbon, and silicon, which may
be further coated with a layer of material which may be a
conductive metal or semiconductor. The base structure of cathode
122 may be in the form of fibrous, reticulated, or sintered powder
materials made from metals, carbon, or other conductive materials
including polymers. The materials may be a very thin plastic screen
incorporated against the cathode side of the membrane to prevent
the membrane 120 from directly touching the high surface area
cathode structure. The high surface area cathode structure may be
mechanically pressed against a cathode current distributor
backplate, which may be composed of material that has the same
surface composition as the high surface area cathode. In addition,
cathode 122 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 p-Si, degenerately doped p-Si:As, degenerately
doped p-Si:B, degenerately doped n-Si, degenerately doped n-Si:As,
and degenerately doped n-Si:B. These metals and their alloys may
also be used as catalytic coatings on the various metal substrates.
Other conductive electrodes may be implemented to meet the criteria
of a particular application. For photo-electrochemical reductions,
cathode 122 may be a p-type semiconductor electrode, such as
p-GaAs, p-GaP, p-InN, p-InP, p-CdTe, p-GalnP.sub.2 and p-Si, or an
n-type semiconductor, such as n-GaAs, n-GaP, n-InN, n-InP, n-CdTe,
n-GalnP.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, WSi2, CoSi.sub.2, Ti.sub.4O.sub.7, SnO.sub.2, GaAs,
GaSb, Ge, and CdSe.
[0046] Catholyte may include a pH range from 1 to 12 when an
aqeuous solvent is employed, preferably from pH 4 to pH 10. The
selected operating pH may be a function of any catalysts utilized
in operation of the electrochemical cell 102. Preferably, catholyte
and catalysts may be selected to prevent corrosion at the
electrochemical cell 102. Catholyte may include homogeneous
catalysts. Homogeneous catalysts are defined as aromatic
heterocyclic amines and 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., C1-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 include 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.
[0047] The catholyte may include an electrolyte. Catholyte
electrolytes may include alkali metal bicarbonates, carbonates,
sulfates, phosphates, borates, and hydroxides. 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, an 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. In one embodiment, bromide salts such as NaBr or KBr may
be preferred.
[0048] The catholyte may further include an aqueous or non-aqueous
solvent. An aqueous solvent may include greater than 5% water. A
non-aqueous solvent may include as much as 5% water. A solvent may
contain one or more of water or a non-aqueous solvent.
Representative solvents include methanol, ethanol, acetonitrile,
propylene carbonate, ethylene carbonate, dimethyl carbonate,
diethyl carbonate, dimethylsulfoxide, dimethylformamide,
acetonitrile, acetone, tetrahydrofuran, N,N-dimethylacetamide,
dimethoxyethane, diethylene glycol dimethyl ester, butyronitrile,
1,2-difluorobenzene, .gamma.-butyrolactone, N-methyl-2-pyrrolidone,
sulfolane, 1,4-dioxane, nitrobenzene, nitromethane, acetic
anhydride, hexane, heptane, octane, kerosene, toluene, xylene,
ionic liquids, and mixtures thereof.
[0049] 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 120 or membrane separating the two
regions. 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.
[0050] In another embodiment, a portion of a catholyte recycle
stream may be separately pressurized using a flow restriction with
backpressure or using a pump, with CO.sub.2 injection, such that
the pressurized stream is then injected into the catholyte region
of the electrochemical cell which may increase the amount of
dissolved CO.sub.2 in the aqueous solution to improve the
conversion yield. In addition, micro-bubble generation of carbon
dioxide can be conducted by various means in the catholyte recycle
stream to maximize carbon dioxide solubility in the solution.
[0051] 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 an aqueous solution phase of the
catholyte, which 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 a
portion, or all, of the catholyte through the heat exchanger and
using cooling water to remove the heat and control the catholyte
temperature.
[0052] 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 a portion, or
all, of the anolyte through the heat exchanger and using cooling
water to remove the heat and control the anolyte temperature.
[0053] Electrochemical cells may include various types of designs.
These designs may include zero gap designs with a finite or zero
gap between the electrodes and membrane, flow-by and flow-through
designs with a recirculating catholyte electrolyte utilizing
various high surface area cathode materials. The electrochemical
cell may include flooded co-current and counter-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.
[0054] Anode electrodes may be the same as cathode electrodes or
different. Anode 124 may include electrocatalytic coatings applied
to the surfaces of the base anode structure. Anolytes may be the
same as catholytes or different. Anolyte electrolytes may be the
same as catholyte electrolytes or different. Anolyte may comprise
solvent. Anolyte solvent may be the same as catholyte solvent or
different. For example, for HBr, 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 material 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 electrochemical 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, such as
metal halide or metal oxide catalysts such as iron halides, zinc
halides, aluminum halides, cobalt halides, for the reactions
between the bromine and the carbon-based reactant. For other
anolytes comprising alkaline, or hydroxide electrolytes, anodes may
include carbon, cobalt oxides, stainless steels, and their alloys
and combinations.
[0055] Separator 120, also referred to as a membrane, between a
first region 118 and second region 118, may include cation ion
exchange type membranes. Cation ion exchange membranes which have a
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.RTM. 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 a 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 Ionac.RTM., AGC Engineering (Asahi
Glass) under their Selemion.RTM. trade name, 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 polyphosphazene and sulfonated
polyphosphazene membranes in addition to crown ether based
membranes. 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.
[0056] A rate of the generation of reactant formed in the anolyte
compartment from the anode reaction, such as the oxidation of HBr
to bromine, is contemplated to be proportional to the applied
current to the electrochemical cell 102B. The anolyte product
output in this range can be such that the output stream contains
little or no free bromine in the product output, or it may contain
unreacted bromine. The operation of the extractor and its selected
separation method, for example fractional distillation, the actual
products produced, and the selectivity may be adjusted to obtain
desired characteristics. Any of the unreacted components would be
recycled to the second region 118.
[0057] Similarly, a rate of the generation of the formed
electrochemical carbon dioxide reduction product, such as CO, is
contemplated to be proportional to the applied current to
electrochemical cells 102, 102A, and 102B. The rate of the input or
feed of the carbon dioxide source 106 into the first region 116
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. It is
contemplated that the ratio of carbon dioxide feed to the
theoretical moles of potentially formed carbon dioxide reduction
product 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 and recycled back to the first
region 116.
[0058] 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.
[0059] 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.
* * * * *