U.S. patent application number 14/203158 was filed with the patent office on 2014-07-10 for method and system for the electrochemical co-production of halogen and carbon monoxide for carbonylated products.
This patent application is currently assigned to Liquid Light, Inc.. The applicant listed for this patent is Liquid Light, Inc.. Invention is credited to Jerry J. Kaczur, Robert Page Shirtum, Kyle Teamey.
Application Number | 20140194641 14/203158 |
Document ID | / |
Family ID | 48171282 |
Filed Date | 2014-07-10 |
United States Patent
Application |
20140194641 |
Kind Code |
A1 |
Teamey; Kyle ; et
al. |
July 10, 2014 |
Method and System for the Electrochemical Co-Production of Halogen
and Carbon Monoxide for Carbonylated Products
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 a step
of contacting the first region with a catholyte including carbon
dioxide and contacting the second region with an anolyte including
a recycled reactant. The method may further include applying an
electrical potential between the anode and the cathode sufficient
to produce carbon monoxide recoverable from the first region and a
halogen recoverable from the second region.
Inventors: |
Teamey; Kyle; (Washington,
DC) ; Kaczur; Jerry J.; (North Miami Beach, FL)
; Shirtum; Robert Page; (Sonora, 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.: |
14/203158 |
Filed: |
March 10, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13724996 |
Dec 21, 2012 |
8691069 |
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14203158 |
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61720670 |
Oct 31, 2012 |
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61703232 |
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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61703175 |
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: |
558/277 ;
205/349; 558/260; 560/347 |
Current CPC
Class: |
C07C 29/58 20130101;
C25B 9/08 20130101; C25B 3/04 20130101; Y02P 20/582 20151101; C25B
1/00 20130101; C25B 3/06 20130101; Y02P 20/132 20151101; Y02P
20/129 20151101; C25B 1/24 20130101; C07C 51/15 20130101; C07C
67/08 20130101; Y02P 20/127 20151101; C25B 9/10 20130101; C07C
51/367 20130101; C07C 1/26 20130101; C25B 3/10 20130101; Y02P
20/133 20151101; Y02P 20/10 20151101; C25B 3/02 20130101; C07C
51/02 20130101; C07C 29/149 20130101; C25B 3/00 20130101; C25B
13/08 20130101; C25B 15/08 20130101; C25B 15/00 20130101 |
Class at
Publication: |
558/277 ;
205/349; 560/347; 558/260 |
International
Class: |
C25B 1/24 20060101
C25B001/24; C25B 1/00 20060101 C25B001/00 |
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: contacting the first region with a
catholyte comprising carbon dioxide; contacting the second region
with an anolyte comprising a recycled reactant and carbon monoxide;
and applying an electrical potential between the anode and the
cathode sufficient to produce carbon monoxide recoverable from the
first region and phosgene recoverable from the second region, the
carbon monoxide recoverable from the first region being recycled as
an input feed to the second region.
2. The method according to claim 1, wherein the recycled reactant
is HX, where X is selected from a group consisting of F, Cl, Br, I
and mixtures thereof.
3. The method according to claim 1, further comprising: reacting
the phosgene recovered from the second region with an additional
reactant to form a third product and the recycled reactant.
4. The method according to claim 3, wherein the additional reactant
includes at least one of an amine, methyl amine, butyl amine,
aniline, a diamine, di amino toluene, diamino benzene, 4,4'
methylene diphenyl diamine, hexamethylenediamine,
meta-tetramethylxylylene-diamine, and toluenediamines, or at least
one of an alcohol, methanol, and ethanol, and mixtures thereof.
5. The method according to claim 3, wherein the third product
includes an isocyanate, methyl isocyanate, butyl isocyanate, phenyl
isocyanate, diisocyanate, methylene-diphenylisocyanate,
phenyl-diisocyanate, hexamethylene-diisocyanate,
toluene-diisocyanate, meta-tetramethylxylylene-diisocyanate, alkyl
carbonate, dimethyl carbonate, ethylmethyl carbonate or diethyl
carbonate.
6. The method according to claim 1, wherein the cathode and the
anode 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 is liquid
phase and the anolyte is gas phase.
9. 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: contacting the first region with a
catholyte; contacting the second region with an anolyte comprising
a recycled reactant; and applying an electrical potential between
the anode and the cathode sufficient to produce hydrogen
recoverable from the first region and a halogen recoverable from
the second region, where the halogen includes at least one of
F.sub.2, Cl.sub.2, Br.sub.2 or I.sub.2; reacting the hydrogen
recovered from the first region with carbon dioxide to produce
water and carbon monoxide; and reacting the carbon monoxide, the
halogen recovered from the second region and an additional reactant
to form a third product and the recycled reactant.
10. The method according to claim 9, wherein the recycled reactant
is HX, where X is selected from a group consisting of F, Cl, Br, I
and mixtures thereof.
11. The method according to claim 9, wherein the additional
reactant includes at least one of an amine, methyl amine, butyl
amine, aniline, diamine, di amino toluene, diamino benzene, 4,4'
methylene diphenyl diamine, hexamethylenediamine,
meta-tetramethylxylylene diamine, and toluenediamines, or at least
one of an alcohol, methanol, and ethanol, and mixtures thereof.
12. The method according to claim 9, wherein the third product
includes an isocyanate, methyl isocyanate, butyl isocyanate, phenyl
isocyanate, diisocyanate, methylene-diphenylisocyanate,
phenyl-diisocyanate, hexamethylene-diisocyanate,
toluene-diisocyanate, meta-tetramethylxylylene-diisocyanate, alkyl
carbonate, dimethyl carbonate, ethylmethyl carbonate or diethyl
carbonate.
13. 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: contacting the first region with a
catholyte; contacting the second region with an anolyte comprising
a recycled reactant and carbon monoxide; applying an electrical
potential between the anode and the cathode sufficient to produce
hydrogen recoverable from the first region and phosgene recoverable
from the second region; reacting the hydrogen recovered from the
first region with carbon dioxide to produce water and carbon
monoxide, the carbon monoxide being supplied as an input feed to
the second region; and reacting the phosgene recovered from the
second region and an additional reactant to form a third product
and the recycled reactant.
14. The method according to claim 13, wherein the recycled reactant
is HX, where X is selected from a group consisting of F, Cl, Br, I
and mixtures thereof.
15. The method according to claim 13, wherein the additional
reactant includes at least one of an amine, methyl amine, butyl
amine, aniline, diamine, di amino toluene, diamino benzene, 4,4'
methylene diphenyl diamine, hexamethylenediamine,
meta-tetramethylxylylene diamine, and toluenediamines, or at least
one of an alcohol, methanol, and ethanol, and mixtures thereof.
16. The method according to claim 13, wherein the third product
includes an isocyanate, methyl isocyanate, butyl isocyanate, phenyl
isocyanate, diisocyanate, methylene-diphenylisocyanate,
phenyl-diisocyanate, hexamethylene-diisocyanate,
toluene-diisocyanate, meta-tetramethylxylylene-diisocyanate, alkyl
carbonate, dimethyl carbonate, ethylmethyl carbonate or diethyl
carbonate.
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. 13/724,996 filed Dec.
21, 2012. The U.S. patent application Ser. No. 13/724,996 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. 61/703,232 filed Sep.
19, 2012 and U.S. Provisional Application Ser. No. 61/675,938 filed
Jul. 26, 2012. Said U.S. patent application Ser. No. 13/724,996
filed Dec. 21, 2012, U.S. Provisional Application Ser. No.
61/720,670 filed Oct. 31, 2012, U.S. Provisional Application Ser.
No. 61/703,232 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 U.S. patent application Ser. No. 13/724,996 filed Dec.
21, 2012 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. 61/703,234
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. Said 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. 61/703,234 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.
[0003] The present application incorporates by reference co-pending
U.S. patent application Ser. No. 13/724,339, U.S. patent
application Ser. No. 13/724,878, U.S. patent application Ser. No.
13/724,647, U.S. patent application Ser. No. 13/724,231, U.S.
patent application Ser. No. 13/724,807, U.S. patent application
Ser. No. 13/724,719, U.S. patent application Ser. No. 13/724,082,
and U.S. patent application Ser. No. 13/724,768 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 halogen and carbon
monoxide for use in carbonylation reactions.
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 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 a step of contacting the first region with a
catholyte including carbon dioxide and contacting the second region
with an anolyte including a recycled reactant. The method may
further include applying an electrical potential between the anode
and the cathode sufficient to produce carbon monoxide recoverable
from the first region and a halogen recoverable from the second
region.
[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;
[0013] FIG. 4 is a block diagram of a system in accordance with
another additional embodiment of the present disclosure;
[0014] FIG. 5 is a block diagram of a system in accordance with
another additional embodiment of the present disclosure; and
[0015] FIG. 6 is a a block diagram of a system in accordance with
another additional embodiment of the present disclosure.
DETAILED DESCRIPTION
[0016] Reference will now be made in detail to the subject matter
disclosed, which is illustrated in the accompanying drawings.
[0017] Referring generally to FIGS. 1-6, systems and methods of
electrochemical co-production of products 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 monoxide, at a cathode side of an
electrochemical cell with co-production of a second product, such
as a halogen, at the anode of the electrochemical cell.
[0018] Additionally, the present disclosure is directed to a system
and method employing an electrochemical cell to to produce a first
product and a second product as intermediate products in the
production of an isocyanate. Advantageously, in one embodiment,
system and method employing an electrochemical cell may produce an
isocyanate without intermediate formation of phosgene. A method for
producing 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 may
include a step of contacting the first region with a catholyte
including carbon dioxide and contacting the second region with an
anolyte including a recycled reactant. The method may further
include applying an electrical potential between the anode and the
cathode sufficient to produce carbon monoxide recoverable from the
first region and a halogen recoverable from the second region.
[0019] The present disclosure is further directed to production of
an additional product, such as isocyanate or alkyl carbonate, via a
further reacting the co-products produced via an electrochemical
cell, such as carbon monoxide and a halogen, with an additional
reactant. It is contemplated that carbon monoxide and halogen may
be dried to a level of to less than 0.10 percent water by weight or
less. The additional reactant may include at least one of an amine,
methyl amine, butyl amine, aniline, diamine, diamino toluene,
diamino benzene, 4,4' methylene diphenyl diamine,
hexamethylenediamine, meta-tetramethylxylylene diamine, and
toluenediamines to form an isocyanate, or at least one of an
alcohol, methanol, and ethanol to form a carbonate, and a recycled
reactant, such as a hydrogen halide. The recycled reactant may be
supplied back to the second region as an input feed. By
co-producing products, and avoiding the formation of phosgene, the
system and method of present disclosure reduces the danger
associated with use of a highly toxic and dangerous chemicals. If
phosgene is formed, it may be done on demand and at a scale
precisely determined by the size of the electrochemical system,
thus mitigating the danger associated with phosgene production. The
recycling of a recycled reactant, such as HCl, is also advantageous
in that it reduces the energy requirement of the overall process,
provides a hydrogen source for CO.sub.2 reduction to CO, and
precludes the need to dispose of the very strong acid HCl.
[0020] In another embodiment of the disclosure, system and method
may be employed to produce in the second region of the
electrochemical cell, prior to reacting the phosgene with an
additional reactant. In another embodiment of the disclosure,
system and method may be employed to produce phosgene in the second
region of the electrochemical cell. The phosgene produced may be
extracted from the second region and the extracted phosgene may be
presented through a port for subsequent storage and/or consumption
by other devices and/or processes. It is contemplated that the
nature of the electrochemical system allows for the production and
control of the required amount of phosgene for the reaction to be
made without any excess.
[0021] 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.
[0022] 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 generally includes an electrochemical
cell (also referred as a container, electrolyzer, or cell) 102, a
carbon dioxide source 106, a reactor 108, a first product extractor
110 and a first product such as carbon monoxide 113, a second
product extractor 112, a second product such as a halogen 115, and
an energy source 114.
[0023] 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, the catholyte including
carbon dioxide which may be dissolved in the catholyte. Second
region 118 may include an anolyte which may include a recycled
reactant. 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.
[0024] Electrochemical cell 102 is generally operational to reduce
carbon dioxide in the first region 116 to a first product, such as
carbon monoxide 113 recoverable from the first region 116 while
producing a second product, such as a halogen 115 recoverable from
the second region 118. 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. It is contemplated that
carbon dioxide source 106 may include a source of a mixture of
gases in which carbon dioxide has been filtered from the gas
mixture.
[0025] 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, such
as carbon monoxide 113, from the first region 116. The extracted
carbon monoxide 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 recycled reactant 117 supplied to the
second region 118. The second product recoverable from the second
region 118 may be a halogen 115. Recycled reactant 117 may include
a hydrogen halide, such as HCl, or a halide salt that may be a
byproduct of reactor 108. For example, the recycled reactant may
include AX where A is H, Li, Na, K, Cs, Mg, Ca, or other metal, or
R.sub.4R.sup.+, R.sub.4N.sup.+--where each R is independently alkyl
or aryl--or a cation; and X is F, Cl, Br, I, or an anion; and
mixtures thereof. Examples are in the table below.
TABLE-US-00001 TABLE 1 Chemical Feed to Anode Oxidation Product(s)
Halides (F.sup.-, Cl.sup.-, Br.sup.-, I.sup.-) Halogens (F.sub.2,
Cl.sub.2, Br.sub.2, I.sub.2) Hydrogen halides (HF, HCl, HBr,
Halogens (F.sub.2, Cl.sub.2, Br.sub.2, I.sub.2) HI)
[0027] Second product extractor 112 may extract a the second
product, such as a halogen 115 from the second region 118. The
extracted second product may be presented through a port of the
system 100 for subsequent storage and/or consumption by other
devices and/or processes. It is contemplated that first product
extractor 110 and/or second product extractor 112 may be
implemented with electrochemical cell 102, or may be remotely
located from the electrochemical cell 102. Additionally, it is
contemplated that first product extractor 110 and/or second product
extractor 112 may be implemented in a variety of mechanisms and to
provide desired separation methods, such as fractional distillation
or molecular sieve drying, without departing from the scope and
intent of the present disclosure.
[0028] Carbon monoxide 113 and halogen 115 may be presented to
another reactor, such as a reactor 108, along with an additional
reactant 126. It is contemplated that carbon monoxide 113 and
halogen 115 may be dried to a level of 0.10 percent by weight of
water, preferably less than 0.01 percent weight of water (100 ppm
by weight) or less water content in both the carbon monoxide and
halogen gases to improve the reaction yield at reactor 108.
Additional reactant 126 may include amine, methyl amine, butyl
amine, aniline, diamine, diamino toluene, diamino benzene, 4,4'
methylene diphenyl diamine, hexamethylenediamine,
meta-tetramethylxylylene diamine, and toluenediamines, or at least
one of an alcohol, methanol, and ethanol, and mixtures thereof.
Reactor 108 may produce byproducts, such as a recycled reactant 117
and product 119. Product 119 may be dependent upon the type of
additional reactant 126 and may include isocyanate, methyl
isocyanate, butyl isocyanate, phenyl isocyanate, diisocyanate,
methylene-diphenylisocyanate, phenyl-diisocyanate,
hexamethylene-diisocyanate, toluene-diisocyanate,
meta-tetramethylxylylene-diisocyanate, alkyl carbonate, dimethyl
carbonate, ethylmethyl carbonate or diethyl carbonate.
[0029] Recycled reactant 117 may be recycled back to the second
region 118 as an input feed to the second region 118 of
electrochemical cell 102. Recycled reactant 117 may be recycled
back to the second region 118 of electrochemical cell 102 as either
a pure anhydrous gas or in the liquid phase. The gas phase may be
generally preferred in order to minimize energy requirements.
Chlorine or a similar halogen is thereby recycled, while carbon
monoxide 113 is produced at the first region 116 from CO.sub.2. The
use of CO.sub.2 as a feed for making carbon monoxide is
advantageous in that CO.sub.2 is safe to store and handle and does
not require the large steam reforming infrastructure normally
needed to make carbon monoxide from natural gas.
[0030] It is contemplated that an additional source of recycled
reactant may be further supplied as an input feed to the second
region 118 of the electrochemical cell 102 without departing from
the scope and intent of the present disclosure.
[0031] Through the co-production of a first product and a second
product, such as carbon monoxide 113 and halogen 115, the overall
energy requirement for making each of the first product and second
product 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.
[0032] The oxidation of the recycled reactant, such as hydrogen
halides, produces protons and electrons that are utilized to reduce
carbon dioxide. Reactions occurring at the cathode will generally
take place in a solvent which may include water, methanol,
acetonitrile, propylene carbonate, ionic liquids, or other solvents
in which CO.sub.2 is soluble. It may also occur in the gas phase as
long as water vapor is present in the gas stream. An anode reaction
may occur in gas phase, for instance in the case of gas phase
reactant such as a hydrogen halide. The anode reaction may also
occur in liquid phase, such as the case of a hydrogen halide in
solution.
[0033] In a preferred embodiment, isocyanates such as methylene
diphenyl diisocyanate (MDI) or toluene diisocyanate (TDI) may be
produced, with the recycled reactant 117 byproduct of HCl from
formation of the isocyanate recycled back to the second region 118
of the electrochemical cell 102 where it may be utilized again in
the evolution of carbon monoxide and Cl.sub.2. Separation steps may
be utilized to dry the carbon monoxide gas stream and to separate
unreacted HCl from Cl.sub.2.
[0034] As one embodiment of a recycled reactant 117, HCl may be a
feed going into the second region 118 of the electrochemical cell
102. Recycled reactant 117 may be circulated with a pump in an
anolyte circulation loop where HCl is converted to Cl.sub.2 as a
gas or liquid and W ions may cross the separator 120 into the first
region 116.
[0035] On the cathode side, carbon dioxide may be reacted on a high
surface area cathode to produce, in this example, carbon monoxide.
A circulation pump may be used to provide mass transfer to obtain a
high Faradaic efficiency conversion to carbon monoxide.
[0036] Electrochemical cell 102 may be operated at a current
density of >3 kA/m.sup.2 (300 mA/cm.sup.2), or in suitable range
of 0.5 to 5 kA/m.sup.2 or higher if needed. The current density of
the formation of chlorine from HCl may be operated at even higher
current densities. Electrochemical cell 102 may be liquid phase in
both the first region 116 and second region 118, or in the
preferred embodiment, may be liquid phase in the first region 116
and with a gas phase second region 118 wherein gas phase HCl is fed
directly to the anolyte of the second region 118.
[0037] The operating voltage of the electrochemical cell 102 at a
current density of 1 kA/m.sup.2 is estimated to be somewhere
between 1.0-2.5 volts, because the half cell voltage of an anolyte
reaction is expected to be between 0.6V and 1.2V. In comparison,
the comparable cell voltage using a 1 M sulfuric acid anolyte with
the formation of oxygen operating at 1 kA/m.sup.2 will likely be
between 2.0V and 4V.
[0038] In the case of a liquid anolyte, the HCl 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 %
chlorine content in the solution phase. The HCl content in the
anolyte solution may affect the anolyte solution conductivity, and
thus the second region 118 IR voltage drop. If the anode is run
with gas phase HCl, then HCl concentrations may approach 100% by wt
% and be run in anhydrous conditions.
[0039] The anode preferably has a polymeric bound carbon current
distributor anode and may use a carbon felt with a specific surface
area of 50 cm.sup.2/cm.sup.3 or more that fills a gap between the
cathode backplate and the membrane, thus having a zero gap anode.
The carbon felt may also be electrically and physically bonded to
the carbon current distributor anode by a carbon conductive bonding
agent. Metal and/or metal oxide catalysts may be added to the anode
in order to decrease anode potential and/or to increase the
operating anode current density. An example is the use of a
RuO.sub.2 catalyst.
[0040] The cathode may be a number of high surface area materials
to include copper and copper alloys, bronze and its alloys,
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 against the cathode side
of the membrane may be employed to prevent the membrane from
touching the high surface area cathode structure. The high surface
area cathode structure is 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.
[0041] Faradaic current efficiency of the anode is preferably
between 90 to 100%, and the acetate Faradaic current efficiency is
preferably between 25 and 100%. The flow circulation of the anolyte
and catholyte is such that it provides sufficient flow for the
reactions.
[0042] Referring to FIG. 2, a block diagram of a system in
accordance with another embodiment of the present disclosure is
shown. System 200 may include electrochemical cell 102 may operate
for co-production of a first product and second product, such as
carbon monoxide 113 and halogen 115 as intermediate products
employed for production of a product 228, such as an acrylic acid
or acrylic acid esters. In an advantageous aspect of the
disclosure, acrylic acid or acrylic acid esters may be produced
using a phosgene-free electrochemical process. Additionally,
precursors needed for acrylic acid or acrylic acid esters may be
co-produced from the electrochemical cell 102.
[0043] Halogen 115 may be presented to another reactor, such as a
reactor 208, along with an additional reactant, such as an alkane
204. Alkane 204 may be ethane. Reactor 208 may produce byproducts,
such as a recycled reactant 117 and a dihalogenated alkane 210,
such as a dihalogenated ethane. Recycled reactant 117, such as HCl
may be recycled back to the second region 118 as an input feed to
the second region 118 of electrochemical cell 102. Dihalogenated
alkane 210 may be presented to dehydrohalogenation reactor 212.
Dehydrohalogenation reactor 212 may conduct a dehydrohalogenation
reaction to produce products which may include additional recycled
reactant 117 and acetylene 216. Additional recycled reactant 117,
such as HCl, may be recycled back to the second region 118 as an
input feed to the second region 118 of electrochemical cell
102.
[0044] Acetylene 216 may be reacted with carbon monoxide 113
co-produced with water and/or alcohol from carbon dioxide at the
first region at reactor 220. Reactor 220 may produce a product 228.
Product 228 may include an acrylic acid or acrylic acid esters.
[0045] Referring to FIG. 3, a block diagram of a system 300 in
accordance with an additional embodiment of the present disclosure
is shown. In an alternative embodiment for production of a product,
such as isocyanate or alkyl carbonate, phosgene may be produced
entirely within the electrochemical cell 102. System 300 may
include electrochemical cell 102 which may operate for
co-production of a first product and second product, such as carbon
monoxide 113 and phosgene 313 as intermediate products employed for
production of a product 319. Carbon monoxide 113 may be supplied as
an additional input feed to second region 118.
[0046] Phosgene 313 may react with an additional reactant 326 at
reactor 308 to produce byproducts of a recycled reactant 117 and
product 319. Recycled reactant 117, such as HCl, may be recycled
back to the second region 118 as an input feed to the second region
118 of electrochemical cell 102. Additional reactant 326 may
include an amine, methyl amine, butyl amine, aniline, diamine,
diamino toluene, diamino benzene, 4,4' methylene diphenyl diamine,
hexamethylenediamine, meta-tetramethylxylylene diamine, and
toluenediamines, or at least one of an alcohol, methanol, and
ethanol, and mixtures thereof. Product 319 may be dependent upon
the type of additional reactant 326 and may include isocyanate,
methyl isocyanate, butyl isocyanate, phenyl isocyanate,
diisocyanate, methylene-diphenylisocyanate, phenyl-diisocyanate,
hexamethylene-diisocyanate, toluene-diisocyanate,
meta-tetramethylxylylene-diisocyanate, alkyl carbonate, dimethyl
carbonate, ethylmethyl carbonate or diethyl carbonate.
[0047] In one embodiment, carbon monoxide 113 may be dried and fed
into the second region 118 with recycled reactant 117, such as
anhydrous HCl. The anhydrous HCl and carbon monoxide may react in
the second region to form phosgene 313.
[0048] Referring to FIGS. 4-6, block diagrams of systems 400, 500
and 600 show alternative embodiments of systems 100, 200 and 300 of
FIGS. 1-3, respectively. Referring specifically to FIG. 4, first
region 116 of electrochemical cell 102 may produce a first product
of H.sub.2 410 which is combined with carbon dioxide 432 in a
reactor 430 which may perform a reverse water gas shift reaction.
This reverse water gas shift reaction performed by reactor 430 may
produce water 434 and carbon monoxide 436. Carbon monoxide 436 may
be fed to reactor 438.
[0049] Second region 118 may co-produce a halogen 115 that is
supplied to reactor 408. It is contemplated that carbon monoxide
113 and halogen 115 may be dried to a level of 0.10 percent by
weight of water, preferably less than 0.01 percent weight of water
(100 ppm by weight) or less water content in both the carbon
monoxide and halogen gases to improve the reaction at reactor 408.
Reactor 408 may react carbon monoxide 113, halogen 115 and
additional reactant 426. Additional reactant 126 may include amine,
methyl amine, butyl amine, aniline, diamine, di amino toluene,
diamino benzene, 4,4' methylene diphenyl diamine,
hexamethylenediamine, meta-tetramethylxylylene diamine, and
toluenediamines, or at least one of an alcohol, methanol, and
ethanol,and mixtures thereof. Reactor 408 may produce byproducts,
such as a recycled reactant 117 and product 419. Product 419 may be
dependent upon the type of additional reactant 426 and may include
isocyanate, methyl isocyanate, butyl isocyanate, phenyl isocyanate,
diisocyanate, methylene-diphenylisocyanate, phenyl-diisocyanate,
hexamethylene-diisocyanate, toluene-diisocyanate,
meta-tetramethylxylylene-diisocyanate, alkyl carbonate, dimethyl
carbonate, ethylmethyl carbonate or diethyl carbonate.
[0050] Referring specifically to FIG. 5, first region 116 of
electrochemical cell 102 may produce a first product of H.sub.2 410
which is combined with carbon dioxide 432 in a reactor 430 which
may perform a reverse water gas shift reaction. This reverse water
gas shift reaction performed by reactor 430 may produce water 434
and carbon monoxide 436. Carbon monoxide 436 may be fed to reactor
536.
[0051] Second region 118 of electrochemical cell 102 may co-produce
a halogen 115 that is supplied to reactor 408. Halogen 115 may be
presented to reactor 508, along with an additional reactant, such
as an alkane 526. Alkane 526 may be ethane. Reactor 508 may produce
byproducts, such as a recycled reactant 117 and a dihalogenated
alkane 530, such as a dihalogenated ethane. Recycled reactant 117,
such as HCl may be recycled back to the second region 118 as an
input feed to the second region 118 of electrochemical cell 102.
Dihalogenated alkane 530 may be presented to dehydrohalogenation
reactor 532. Dehydrohalogenation reactor 532 may perform a
dehydrohalogenation reaction to produce products which may include
additional recycled reactant 117 and acetylene 534. Additional
recycled reactant 117, such as HCl, may be recycled back to the
second region 118 as an input feed to the second region 118 of
electrochemical cell 102.
[0052] Acetylene 534 may be reacted with carbon monoxide 113
produced via the reverse water gas shift reaction of reactor 430.
Reactor 536 may produce a product 538. Product 538 may include
acrylic acid or acrylic acid esters.
[0053] Referring specifically to FIG. 6, first region 116 of
electrochemical cell 102 may produce a first product of H.sub.2 410
which is combined with carbon dioxide 432 in a reactor 430 which
may perform a reverse water gas shift reaction. This reverse water
gas shift reaction performed by reactor 430 may produce water 434
and carbon monoxide 436. Carbon monoxide 436 may be supplied to the
second region 118 of electrochemical cell 102.
[0054] Second region 118 of electrochemical cell 102 may co-produce
phosgene 313. Phosgene may react with an additional reactant 626 at
reactor 608 to produce byproducts of a recycled reactant 117 and
product 619. Recycled reactant 117, such as HCl, may be recycled
back to the second region 118 as an input feed to the second region
118 of electrochemical cell 102. Additional reactant 626 may
include amine, methyl amine, butyl amine, aniline, diamine, diamino
toluene, diamino benzene, 4,4' methylene diphenyl diamine,
hexamethylenediamine, meta-tetramethylxylylene diamine, and
toluenediamines, or at least one of an alcohol, methanol, and
ethanol, and mixtures thereof. Product 619 may be dependent upon
the type of additional reactant 626 and may include isocyanate,
methyl isocyanate, butyl isocyanate, phenyl isocyanate,
diisocyanate, methylene-diphenylisocyanate, phenyl-diisocyanate,
hexamethylene-diisocyanate, toluene-diisocyanate,
meta-tetramethylxylylene-diisocyanate, alkyl carbonate, dimethyl
carbonate, ethylmethyl carbonate or diethyl carbonate.
[0055] It is contemplated that a receiving a feed may include
various mechanisms for receiving a supply of a product, whether in
a continuous, near continuous or batch portions.
[0056] It is further contemplated that the structure and operation
of the electrochemical cell 102 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.
[0057] 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.
[0058] Cathode 122 may be selected from a number of high surface
area materials to include copper and copper alloys, stainless
steels, transition metals and their alloys, 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.
[0059] 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. Other conductive electrodes may be implemented to meet the
criteria of a particular application. For photoelectrochemical
reductions, cathode 122 may be a p-type semiconductor electrode,
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, WSi2, CoSi.sub.2, Ti.sub.4O.sub.7,
SnO.sub.2, GaAs, GaSb, Ge, and CdSe.
[0060] Catholyte may include a pH range from 1 to 12, 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-C10) 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.
[0061] 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, 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. In one
embodiment, bromide salts such as NaBr or KBr may be preferred.
[0062] 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, a protic solvent, or an aprotic polar
solvent. Representative solvents include 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, and mixtures thereof.
[0063] 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.
[0064] 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, microbubble generation of carbon
dioxide can be conducted by various means in the catholyte recycle
stream to maximize carbon dioxide solubility in the solution.
[0065] 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.
[0066] 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.
[0067] 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.
[0068] 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 palladium, 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, metallic foams, 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, such as metal halide or metal oxide catalysts
such as iron halides, zinc halides, aluminum halides, cobalt
halides, for reactions between bromine and a carbon-based reactant.
For other anolytes comprising alkaline, or hydroxide electrolytes,
anodes may include carbon, cobalt oxides, stainless steels, and
their alloys and combinations.
[0069] Separator 120, also referred to as a membrane, between a
first region 116 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., Engineering (Asahi Glass)
under their trade name 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.
[0070] A rate of the generation of reactant formed in the anolyte
compartment from the anode reaction, such as the oxidation of HCl
to chlorine, is contemplated to be proportional to the applied
current to the electrochemical cell 102. The rate of the input or
feed of the carbon-based reactant, for example CO, into the anolyte
region 118 should then be fed in proportion to the generated
reactant. The molar ratio of the carbon-based reactant to the
generated anode reactant may be in the range of 100:1 to 1:10, and
more preferably in the range of 50:1 to 1:5. The anolyte product
output in this range can be such that the output stream contains
little or no free chlorine in the product output to the second
product extractor 112, or it may contain unreacted chlorine. The
operation of the extractor 112 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 generated
reactant in the anode compartment. Any of the unreacted components
would be recycled to the second region 118.
[0071] Similarly, a rate of the generation of the formed
electrochemical carbon dioxide reduction product, such as carbon
monoxide, is contemplated to be proportional to the applied current
to the electrochemical cell 102. 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 in the extractor 110 and recycled back to the first
region 116.
[0072] 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.
[0073] 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.
* * * * *