US20130228470A1

US20130228470A1 - Method and apparatus for an electrolytic cell including a three-phase interface to react carbon-based gases in an aqueous electrolyte

Info

Publication number: US20130228470A1
Application number: US13/783,102
Authority: US
Inventors: Ed Ite Chen
Original assignee: Viceroy Chemical
Current assignee: VICEROY CHEMICAL Inc; Viceroy Chemical
Priority date: 2012-03-03
Filing date: 2013-03-01
Publication date: 2013-09-05
Also published as: WO2013134078A1; CN104428449A; EP2823091A4; EP2823091A1; CA2866306A1; RU2014139975A

Abstract

A process for converts carbon-based gases such as non-polar organic gases and carbon oxides to longer chained organic gases such as liquid hydrocarbons, longer chained gaseous hydrocarbons, branched-chain liquid hydrocarbons, branched-chain gaseous hydrocarbons, as well as chained and branched-chain organic compounds. In general, the method is for chain modification of hydrocarbons and organic compounds, including chain lengthening, and eventual conversion into liquids including, but not limited to, hydrocarbons, alcohols, and other organic compounds.

Description

The priority of U.S. Application Ser. No. 61/608,583, entitled, “An Electrochemical Process for Direct one step conversion of methane to Ethylene on a Three Phase Gas, Liquid, Solid Interface”, and filed Mar. 8, 2012, in the name of the inventor Ed Chen is hereby claimed pursuant to 35 U.S.C. §119(e). This application is commonly assigned herewith and is also hereby incorporated for all purposes as if set forth verbatim herein.
The priority of U.S. Application Ser. No. 61/639,544, entitled, “Electrochemical Reactor for the use of Aqueous Electrolyte for High Efficiency Reaction of Non Polar Organic Gases”, filed Apr. 27, 2012, in the name of the inventor Ed Chen is hereby claimed pursuant to 35 U.S.C. §119(e). This application is commonly assigned herewith and is also hereby incorporated for all purposes as if set forth verbatim herein.
The priority of U.S. Application Ser. No. 61/606,398, entitled, “A Process, Apparatus, and Components for the Production of High Value Chemicals from carbon dioxide Using Modular, Electrochemical Reduction of CO₂on Three Phase Interphase Gas Diffusion Electrode”, filed Mar. 3, 2012, in the name of the inventor Ed Chen is hereby claimed pursuant to 35 U.S.C. §119(e). This application is commonly assigned herewith and is also hereby incorporated for all purposes as if set forth verbatim herein.
The priority of U.S. Application Ser. No. 61/713,487, entitled, “A Process for Electrochemical Fischer Tropsch”, filed Oct. 13, 2012, in the name of the inventor Ed Chen is hereby claimed pursuant to 35 U.S.C. §119(e). This application is commonly assigned herewith and is also hereby incorporated for all purposes as if set forth verbatim herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

The technique described herein and illustrated in the appended drawings is related by overlapping disclosure to the following applications, each of which is commonly assigned herewith:
U.S. application Ser. No. 13/782,936, entitled “Chained Modification of Gaseous Methane Using Aqueous Electrochemical Activation at a Three Phase Interface”, in the name of Ed Chen on an even date herewith (Attorney Docket No. 2039.000300),

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

This section of this document introduces information about and/or from the art that may provide context for or be related to the subject matter described herein and/or claimed below. It provides background information to facilitate a better understanding of the various is aspects of the claimed subject matter. This is therefore a discussion of “related” art. That such art is related in no way implies that it is also “prior” art. The related art may or may not be prior art. The discussion in this section of this document is to be read in this light, and not as admissions of prior art.
Some common industrial processes involve the conversion of a gas or components of a gaseous mixture into another gas. These types of processes are performed at high pressures and temperatures. Operational considerations such as temperature and pressure requirements frequently make these types of processes energy inefficient and costly. The industries in which these processes are used therefore spend a great deal of effort in improving the processes with respect to these kinds of considerations.
Several configurations of electrolytic cells are available to the art many or all of all of may be competent for their intended purposes. The art, however, is always receptive to improvements or alternative means, methods and configurations. Therefore the art will well receive the launching tool described herein.

SUMMARY

In a first aspect, an electrolytic cell, comprises: at least one reaction chamber into which, during operation, a aqueous electrolyte and a gaseous feedstock including are introduced, wherein the gaseous feedstock comprises a carbon-based gas; and a pair of reaction electrodes disposed within the reaction chamber, at least one of the reaction electrodes including a solid catalyst and defining, in conjunction with the aqueous electrolyte and the gaseous feedstock, a three-phase interface.
In a second aspect, a method for chain modification of hydrocarbons and organic compounds comprises: contacting a gaseous feedstock including a carbon-based gas, an aqueous electrolyte, and a catalyst in a reaction area; and activating the carbon-based gas in an aqueous electrochemical reaction at the reaction electrode and yield a product.
In a third aspect, a method for chain modification of hydrocarbons and organic compounds comprises: contacting an aqueous electrolyte with a a catalyst and a gaseous feedstock including a carbon-based gas within a reaction area; and reacting the aqueous electrolyte, the catalyst, and the gaseous feedstock at temperatures in the range of −10 C to 1000 C and at pressures in the range of 0.1 ATM to 100 ATM to yield a long chained hydrocarbon.
In a third aspect, a gas diffusion electrode, comprises: a hydrophobic layer porous to carbon dioxide and impermeable to aqueous electrolytes; a hydrophilic layer bonded to the hydrophobic layer; and a cuprous halide coating disposed about the bonded hydrophobic and hydrophilic layers.
In a fourth aspect, a method for fabricating a gas diffusion electrode, comprising: bonding a hydrophobic layer porous to carbon dioxide and impermeable to aqueous electrolytes to a hydrophilic layer supporting, a copper catalyst; and treating the copper catalyst to create a cuprous
The above presents a simplified summary of the presently disclosed subject matter in order to provide a basic understanding of some aspects thereof. The summary is not an exhaustive overview, nor is it intended to identify key or critical elements to delineate the scope of the subject matter claimed below. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

The claimed subject matter may be better understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:

FIG. 1 depicts one particular embodiment of an electrolytic cell in accordance with some aspects of the presently disclosed technique.

FIG. 2 graphically illustrates the electrochemical Fischer-Tropsch process in accordance with other aspects of the presently disclosed technique.

FIG. 3A-FIG. 3B depict a copper mesh reaction electrode as may be used in some embodiments.

FIG. 4A-FIG. 4B depict a gas diffusion electrode as may be used in some embodiments.

FIG. 5A-FIG. 5B depict a gas diffusion electrode as may be used in some embodiments.

FIG. 6 depicts a portion of an embodiment in which the electrodes are electrically short circuited.

FIG. 7 graphically illustrates the process of carbon dioxide to ethylene in accordance with one particular embodiment of the presently disclosed technique.

FIG. 8 depicts another embodiment of an electrolytic cell in accordance with another aspect of the presently disclosed technique.

FIG. 9 depicts another embodiment of an electrolytic cell in accordance with another aspect of the presently disclosed technique.

FIG. 10A-FIG. 10B depict another embodiment of an electrolytic cell in accordance with another aspect of the presently disclosed technique.

FIG. 11 depicts another embodiment of an electrolytic cell in accordance with another aspect of the presently disclosed technique.

While the invention is susceptible to various modifications and alternative forms, the drawings illustrate specific embodiments herein described in detail by way of example. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Illustrative embodiments of the subject matter claimed below will now be disclosed. In the interest of clarity, not all features of an actual implementation are described in this specification. It will be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort, even if complex and time-consuming, would be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
The presently disclosed technique is a process for converting carbon-based gases such as non-polar organic gases and carbon oxides to longer chained organic gases such as liquid hydrocarbons, longer chained gaseous hydrocarbons, branched-chain liquid hydrocarbons, branched-chain gaseous hydrocarbons, as well as chained and branched-chain organic compounds. In general, the method is for chain modification of hydrocarbons and organic compounds, including chain lengthening, and eventual conversion into liquids including, but not limited to, hydrocarbons, alcohols, and other organic compounds.
This process more particularly uses aqueous electrolytes to act as a reducing or oxidizing atmosphere and hydrogen and oxygen source for hydrocarbon gases. The process in the disclosed technique is a chain modification of hydrocarbons and organic compounds using aqueous electrochemical activation of carbon based gases at three-phase interface of a gas-liquid-solid electrode surface. This process turns hydrocarbon gases including, but not limited to, gaseous methane, natural gas, other hydrocarbons, carbon monoxide, carbon dioxide, and/or other organic gases into C₂+ hydrocarbons, alcohols, and other organic compounds. One exemplary product is ethylene (C₂H₄) and alcohols. The process may also turn carbon dioxide (CO₂) into one or more of isopropyl alcohol, hydroxyl-3-methyl-2-butanone, tetrahydrofuran, toluene, 2-heptanone, 2-butoxy ethanol, 1-butoxy-2-propanol, benzaldehyde, 2-ethyl-hexanol, methyl-undecanol, methyl-octanol, 2-heptene, nonanol, diethyl-dodecanol, dimethyl-cyclooctane, dimethyl octanol, dodecanol, ethyl-1,4-dimethyl-cyclohexane, dimethyl-octanol, hexadecene, ethyl-1-propenyl ether, dimethyl-silanediol, toluene, hexanal, methyl-2-hexanone, xylene isomer, methyl-hexanone, heptanal, methyl-heptanone, benzaldehyde, octanal, 2-ethyl-hexanol, nonanal, hexene-2,5-diol, dodecanal, 3,7-dimethyl-octanol, methyl-2,2-dimethyl-1-(2-hydroxy-1-methylethyl)propyl ester propanoic acid, methyl-3-hydroxy-2,4,4-triinethylpentyl ester propanoic acid, phthalic anhydride.
The reaction of carbon based gases may be successfully achieved with an aqueous electrochemical solution serving as a liquid ion source along with the supply for hydrogen or singlet oxygen being provided by the aqueous source through acids and bases. By creating a three phase gas, solid, liquid interface between the carbon-based gases with an electrolyte at a solid phase catalyst which is connected to the reaction electrode of an electrolytic cell. The reaction may also be adjusted with different pHs or any kind of additive in the electrolytic solution.
The reaction utilizes a three phase interface which defines a reaction area. A catalyst, a liquid, and a gas are contacted in the reaction area and an electric potential is applied to make electrons available to the reaction site. When hydrocarbons are used as the reactant gas it is possible to create hydrocarbon radicals which then join with other molecules or parts of molecules or themselves to create longer chained hydrocarbons and/or organic molecules. The reaction site can also cause branched chain production by reacting with a newly created molecule and building on that or continuous chain building. Thus from the simple molecule of propane (C₃H₈) chains of molecules can be built by activating the propane molecule. Existing chained molecules can be lengthened, and existing chained molecules can be branched. A simple example is methane (CH⁴), can be converted to propanol (C₃H₇(OH)). Different voltages create different reaction product distributions or facilitate different reaction types.
This aqueous electrochemical reaction includes a reaction that proceeds at room temperature and pressure, although higher temperatures and pressures may be used. In general, temperatures may range from −10 C to 240 C, or from −10 C to 1000 C, and pressures may range from 0.1 ATM to 10 ATM, or from 0.1 ATM to 100 ATM. The process generates reactive activated carbon-based gases through the reaction on the reaction electrodes. On the reaction electrode, the production of activated carbon-based gases occurs.
In general, the method introduces a liquid ion source and a gaseous feedstock into a chamber in contact with a catalyst supporting reaction electrode submerged in an electrolyte. The reaction electrode is powered.
In the embodiments illustrated herein, the technique employs an electrochemical cell such as the one illustrated in FIG. 1. The electrochemical cell 100 generally comprises a reactor 105 in one chamber 110 of which are positioned two electrodes 115, 116, a cathode and an anode, separated by a liquid ion source, i.e., an electrolyte 120. Those in the art will appreciate that the identity of the electrodes 115, 116 as cathode and anode is a matter of polarity that can vary by implementation. In the illustrated embodiment, the electrode 115 is the anode and the electrode 116 is the cathode. Because of the interchangeability between electrode 115 and 116 and because in some embodiments of the design the electrodes are electrically short circuited, the reaction electrode is considered to be either or both of the electrode 115 and electrode 116.
There is also a second chamber 125 into which a gaseous feedstock 130 is introduced as described below. The gaseous feedstock 130 may be a carbon-based gas, for example, non-polar organic gases, carbon-based oxides, or some mixture of the two. The two chambers are joined by apertures 135 through the wall 140 separating the two chambers 110, 125. The reactor 105 may be constructed in conventional fashion except as noted herein. For example, materials selection, fabrication techniques, and assembly processes in light of the operational parameters disclosed herein will be readily ascertainable to those skilled in the art.
Catalysts will be implementation specific depending, at least in part, on the implementation of the reaction electrode 116. Depending on the embodiment, suitable catalysts may include, but are not limited to, nickel, copper, iron, tin, zinc, ruthenium, palladium, rhenium, or any of the other transition or lanthanide and actinide metals, or a noble metal such as platinum, palladium, gold, or silver. They may also include products thereof, including for example cuprous chloride or cuprous oxide, other inorganic compounds of catalytic metals, as well as organometallic compounds. Exemplary organometallic compounds include, but are not limited to, tetracarbonyl nickel, lithiumdiphenylcuprate, pentamesitylpentacopper, and etharatedimer.
The electrolyte 120 will also be implementation specific depending, at least in part, on the implementation of the reaction electrode 116. Exemplary liquid ionic substances include, but are not limited to, Polar Organic Compounds, such as Glacial Acetic Acid, Alkali or alkaline Earth salts, such as halides, sulfates, sulfites, carbonates, nitrates, or nitrites. The electrolyte 120 may therefore be, depending upon the embodiment, magnesium sulfate (MgS), sodium chloride (NaCl), sulfuric acid (H₂SO₄), potassium chloride (KCl), hydrogen chloride (HCl), hydrogen bromide (HBr), hydrogen fluoride (HF), potassium chloride (KCl), potassium bromide (KBr), and potassium iodide (KI), or any other suitable electrolyte and acid or base known to the art.
The pH of the electrolyte 120 may range from −4 to 14 and concentrations of between 0.1M and 3M inclusive may be used. Some embodiments may use water to control pH and concentration, and such water may be industrial grade water, brine, sea water, or even tap water. The liquid ion source, or electrolyte 120, may comprise essentially any liquid ionic substance. In some embodiments, the electrolyte 120 is a halide to benefit catalyst lifetime.
In addition to the reactor 105, the electrochemical cell 100 includes a gas source 145 and a power source 150, and an electrolyte source 163. The gas source 145 provides the gaseous feedstock 130 while the power source 150 is powering the electrodes 115, 116 at a selected voltage sufficient to maintain the reaction at the three phase interface 155. The three phase interface 155 defines a reaction area. In one example, the reaction pressure might be, for example, 10000 pascals or 0.1 ATM to 10 ATM, or from 0.1 ATM to 100 ATM, and the selected pressure may be, for example, between 0.01 V and 10 V.
The electrolyte source 163 provides adequate levels of the electrolyte 120 to ensure proper operations. The three phases at the interface 155 are the liquid electrolyte 120, the solid catalyst of the reaction electrode 116, and the gaseous feedstock 130 as illustrated in FIG. 6. The reaction products 160 are generated in both the electrolyte 120 and in the chamber 125 and may be collected in a vessel 165 of some kind in any suitable manner known to the art. In some embodiments, the products 160 may be forwarded to yet other processes either after collection or without ever being collected at alt in these embodiments, the products 160 may be streamed directly to downstream processes using techniques well known in the art.
The embodiment of FIG. 1 includes only a single reactor 105. However, in alternative embodiments, multiple units of these may be arranged for greater efficiencies. In a larger single chamber, pressure would more likely have to be adjusted with electrolyte level rather than changes in the pressure of the gaseous feedstock 130 in the chamber 125.
Those in the art will appreciate that some implementation specific details are omitted from FIG. 1. For example, various instrumentation such as flow regulators, mass regulators, a pH regulator, and sensors for temperatures and pressures are not shown but will typically be found in most embodiments. Such instrumentation is used in conventional fashion to achieve, monitor, and maintain various operational parameters of the process. Exemplary operational parameters include, but are not limited to, pressures, temperatures, pH, and the like that will become apparent to those skilled in the art. However, this type of detail is omitted from the present disclosure because it is routine and conventional so as not to obscure the subject matter claimed below.
The reaction is conceptually illustrated in FIG. 2. In this embodiment 200, the feedstock 130′ is natural gas and the electrolyte 120′ is Sodium Chloride. Reactive hydrogen ions (H⁺) are fed to the natural gas stream 130′ through the electrolyte 120′ with an applied cathode potential of The molecules may also in turn react with water on the interface to form alcohols, oxygenates, and ketones. In one example of this reaction, the reaction occurs at room temperature and with an applied cathode potential of 0.01V versus SHE to 1.99V versus SHE.
The voltage level can be used to control the resulting product. A voltage of 0.01V may result in a methanol product whereas a 0.5V voltage may result in butanol as well as higher alcohols such as dodecanol. These specific examples may or may not be reflective of the actual product yield and are meant only to illustrate how a product produced can be altered with a change in voltage.
FIG. 7 graphically illustrates the process of carbon dioxide to ethylene in accordance with one particular embodiment of the presently disclosed technique. The gaseous feedstock 730 is carbon dioxide. A voltage is applied across the cathode 716 and the anode 715 or a electrically short circuited reaction electrode illustrated in FIG. 11. The electrochemical interface in this reactor prevents the deactivation of carbon dioxide by providing sufficient reactants to the surface of the catalyst to consistently produce the desired products without the buildup of carbon black. In one example of this reaction, the reaction occurs at a temperature of −10 C to 210 C and a pressure of 0.1 ATM to 10 ATM to yield ethylene product 765 found in both the gas and electrolyte
Returning now to FIG. 1, additional attention will now be directed to the electrochemical cell 100. As noted above, the reactor 105 can be fabricated from conventional materials using conventional fabrication techniques. Notably, the presently disclosed technique operates at room temperatures and pressures whereas conventional processes are performed at temperatures and pressures much higher. Design considerations pertaining to temperature and pressure therefore can be relaxed relative to conventional practice. However, conventional reactor designs may nevertheless be used in some embodiments.
The presently disclosed technique admits variation in the implementation of the electrode at which the reaction occurs, hereafter referred to as the “reaction electrode”. As set forth above, either the electrode 115 or the electrode 116, or both, may be considered to be the reaction electrode depending upon the embodiment.
In one embodiment, an 80 mesh copper mesh is used. This mesh may be plated with high current densities to produce fractal foam structures with high surface areas which may be utilized as catalysts in this reaction. More particularly, the catalyst 305 is supported on a copper mesh 310 embedded in an ion exchange resin 300 as shown in FIG. 3A. The catalyst 305 can be a plated catalyst or powdered catalyst. The metal catalyst 305 is a catalyst capable of reducing carbon-based gases to products of interest. Exemplary metals include, but are not limited to, metals such as copper, silver, gold, iron, tin, zinc, ruthenium, platinum, palladium, rhenium, or any of the other transition or lanthanide and actinide metals. In one embodiment, the metal catalyst is silver, copper, copper chloride or copper oxide. Ion exchange resins are well known in the art and any suitable ion exchange resin known to the art may be used. In one particular embodiment, the ion exchange resin is NAFION 117 by Dupont.
The copper wire mesh 310 can be used to structure the catalyst 305 within the resin 300 or it may be used without a resin. The assembly 315 containing the catalyst 305 can be deposited onto or otherwise structurally associated with an electrically conducting paper 320, as shown in FIG. 3B. Electrical leads (not shown) can then be attached to the copper wire mesh 310 in conventional fashion. The reaction electrode 320 is but one implementation of the reaction electrode 116 in FIG. 1. The electrical leads may also be connected to short circuit the electrodes. Alternative implementations will be discussed below.
The counter electrode 115 and the reaction electrode 116 are disposed within a reactor 105 so that, in use, it is submerged in the electrolyte 120 and the catalyst 305 forms one part of the three-phase interface 155. When electricity is applied to electrodes 115, 116, electrochemical reduction discussed above takes place to produce hydrocarbons and organic chemicals. The reaction electrode 320 receives the electrical power and catalyzes a reaction between the hydrogen in the electrolyte 120 and the gaseous feedstock 130.
As mentioned above, the copper mesh 310 in the illustrated embodiment is a mesh in the range of 1-400 mesh.
In a second embodiment shown in FIG. 4A-FIG. 4B, a gas diffusion electrode 400 comprises a hydrophobic layer 405 that is porous to carbon-based gases but impermeable or nearly impermeable to aqueous electrolytes. In one embodiment of the electrode 400, a 1 mil thick advcarb carbon paper 410 treated with TEFLON® (i.e., polytetrafluoroethylene) dispersion (not separately shown) is coated with activated carbon 415 with copper 420 deposited in the pores of the activated carbon 415. The copper 420 may be deposited through a wet impregnation method, electrolytic reduction, or other means of reduction of copper, silver other transition metals into the porous carbon material.
This material is then mixed with a hydrophilic binding agent (not shown), such as polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), or Nafion. An ink is made from the mixture of impregnated graphite, binding agent, and alcohol or other organic solvent. The ink is painted onto the hydrophobic layer 405 and then bonded through any means, such as atmospheric drying, heat press, or other means of application of heat.
The copper 420 impregnated into the ion electrode 400 is then made into a cuprous halide through any suitable procedure. One embodiment of the procedure to make the cuprous halide is to submerge the electrode in a solution of hydrochloric acid and cupric chloride, heat to 100° C. for 2 hours. Another embodiment submerges the impregnated electrode 400 in 3 M KBr or 3 M Kl and run a 4 V pulse of electricity to the electrode 400 in order to form a thin film of cuprous halide 425, shown in cross-section FIG. 4B, in the electrode 400.
In another embodiment, the copper particles in the electrode are first plated with silver by electroless plating or another method, creating a thin film of silver over the copper. Copper may then be plated onto the silver and transformed into a halide through procedure previously described. In another embodiment, silver particles are deposited into the hydrophilic layer, coated with copper electrolytically, and then the same procedure for the conversion of the copper layer to a copper halide layer is conducted.
In another embodiment, the gas diffusion electrode uses nanoparticles reduced from a solution of Cupric Chloride with an excess of ascorbic acid and 10 grams of carbon graphite. The amalgam was heated to 100° C. for eight hours. It is then mixed with equal amounts in weight of a hydrophilic binder.
In another embodiment, a high mesh copper of 200 mesh is allowed to form cuprous chloride in a solution of cupric chloride and hydrochloric acid. This layer of halide on the surface of the catalyst material allows for catalyst regeneration. This accounts for the abnormally high lifetime of the three phase reaction. The result is then treated in a 0.1 to 3M solution of Cupric Chloride heated to 100° C. This treatment is not necessary for the wire mesh catalyst to function.
In one embodiment the electrode 400 therefore includes a covering or coating 425 of cuprous chloride to prevent “poisoning” or fouling of the electrode 400 during operation. The electrodes in this embodiment must be copper so that no other metals foul the reaction by creating intermediate products which ruin the efficacy of the surface of the copper. Some embodiments also treat the copper with a high surface area powder by electroplating, which will allow for the generation of greater microturbulence, thereby creating more contact and release between the three phase reaction surface. Furthermore, contrary to conventional practice, rather than separate the cathode and anode, the cathode and anode are allowed to remain in the same electrolyte in this embodiment. (The electrolyte is filtered through a pump not shown.) The electrolyte is therefore contacted directly to the gas diffusion electrode 400 rather than through the intercession of a polymer exchange membrane.
Catalysts in this particular embodiment may include copper, silver, gold, iron, tin, zinc, ruthenium, platinum, palladium, rhenium, or any of the other transition or lanthanide and actinide metals. In addition, the catalysts may be formed into a metal foam or alternatively it may be deposited through electroless or electrolytic deposition onto a porous support with a hydrophobic and hydrophilic layer.
In one particular embodiment, the electrodes are electrically short circuited (“shorted”) within the electrolyte while maintaining a three phase interface between carbon-based gases and electrolyte in a mixed slurry pumped through the reactor. In this embodiment, the catalyst in powder form is mixed with the electrolyte to make a slurry. FIG. 6 depicts a portion 600 of an embodiment in which the electrodes are shorted. In this drawing, only a single electrode 605 is shown but the electric potential is drawn across the electrode 605. The companion electrode (not shown) is similarly shorted.
So, turning now to the process again and referring to FIG. 1, carbon-based gases or electrolyte gaseous mixture including gaseous feedstock 130 is introduced into the reaction chamber 125 of the reactor 105 under enough pressure to overcome the gravitational pressure of the column of electrolyte, which depends on the height of the electrolyte, to induce the reaction. The exemplary embodiments discussed below all include the following design characteristics: (1) a three-phase catalytic interface 155 for solid catalyst, gaseous feedstock 130, and liquid ion source (e.g., a liquid electrolyte) 120, (2) a cathode 116 and anode 115 in the same, or a shorted reaction electrode, filtered electrolyte 120, and (3) an electrolyte 120 contacted directly to the reaction electrode, which is the cathode 116.
The method of operation generally comprises introducing the electrolyte 120 into the reaction chamber 110 into direct contact with the powered electrode surfaces 115 and 116. The gaseous feedstock 130 is then introduced into the second chamber 125 under enough pressure to overcome the gravitational pressure of the column of electrolyte, which depends on the height of the electrolyte, to induce the reaction to induce the reaction. During the reaction, the electrolyte 120 is filtered, the gaseous feedstock 130 is maintained at a selected pressure to ensure its presence at the three phase interface 155, and the product 165 is collected. Within this general context, the following examples are implemented.
Above the second chamber 125, but attached to it, is an area for the introduction of a cathode reaction electrode 116 where the three-phase interface 155 will form. Catalysts supported by the reaction electrode 116 include copper, silver, gold, iron, tin, zinc, ruthenium, platinum, palladium, rhenium, or any of the other transition or lanthanide and actinide metals. In addition, the catalysts may be formed into a metal foam or alternatively it may be deposited through electroless or electrolytic deposition onto a porous support with a hydrophobic and hydrophilic layer as previously described above. The electrolyte 120 may comprise, for example, potassium chloride (KCI), potassium bromide (KBr), potassium iodide (Kl), or any other suitable electrolyte known to the art.
This particular embodiment implements the reaction electrode 116 as the gas diffusion electrode described above with the cuprous halide coating. Alternative embodiments may use another cuprous halide coating the surface of the metal. Cuprous Oxide, Cupric Oxide, and other varying valence states of copper will also work in the reaction.
By maintaining a three phase interface between the gaseous feedstock 130 and the electrolyte 120, the carbon-based gases will form organic chemicals and form a nearly complete conversion when there is continuous contact to the gaseous feedstock 130 on the three phase interfaces 155 between the liquid electrolyte 120, the solid catalyst, and the gaseous feedstock 130.
For carbon dioxide, this reaction mechanism also produces organic compounds such as ethers, epoxides, and C5+ alcohols, among other compounds such as ethers, epoxies and long C5+ hydrocarbons which have not been reported in the prior art.
The electrolyte 120 should be relatively concentrated at 0.1M-3M and should be a halide electrolyte as discussed above to increase catalyst lifetime. The higher the surface area between the reaction electrode 116 and the gaseous chamber 125 on one side and the liquid electrolyte 120 on the other side, the higher the conversion rates. Operating pressures could be ranged from only 10000 pascals or 0.1 atm to 10 atm, though Standard Temperature and Pressures (STP) were sufficient for the reaction.
In one embodiment of the was diffusion electrode (GDE) an antioxidant layer of ascorbic acid is mixed with the GDE high porosity carbon. The high porosity carbon includes nanotubes, fullerines, and other specialized formations of carbon as described above. The high porosity carbon is impregnated through reduction of cupric chloride, or other form of carbon. It is then made into a halide by treatment with a chloride solution under the proper pH and temperature of EMF conditions. It also includes a reaction in the solid polymer phase. A paste is made from the impregnated carbon, ascorbic acid, and a hydrophilic binding agent. This paste is painted onto a hydrophobic layer.
The principles discussed above can readily be scaled up to achieve higher yield. Four such embodiments are shown in FIG. 8-FIG. 11.
For example, those in the art having the benefit of the disclosure associated with FIG. 1 will realize that the gaseous feedstock 130 and the electrolyte 120 need not necessarily be introduced into separate chambers. One such example is shown in FIG. 8. in this stacked embodiment 800, reactants 805 (e.g., gaseous feedstock and liquid electrolyte, or gaseous feedstock and a slurry of the catalyst and liquid electrolyte) enter a chamber 810 in which they are mixed, the resulting mixture 835 then entering a reaction chamber 840. A plurality of alternating anodes 820 and cathodes 815 (only one of each indicated) are positioned in the reaction chamber 840. Each of the anodes 820, cathodes 815 is a reaction electrode at which a three-phase reaction area forms as described above. The resultant product 845 is collected in the chamber 825, a portion of which is then recirculated back to the chamber 810 via the line 830.
In the stacked embodiment 900, shown in FIG. 9, the gaseous feedstock 915 and liquid electrolyte 920 are separately introduced at the bottom of the reaction chamber 925. A plurality of chambers 930 (only one indicated) are disposed between respective anodes 820 and cathodes 815. Gaseous feedstock 935 and liquid electrolyte 940 are then reacted in the chambers 930 and the resultant gas product 905 and fouled electrolyte 910 are drawn off the top.
A cylindrical embodiment 1000 is shown in FIG. 10A-FIG. 10B. A mixture 1005 of gaseous feedstock and liquid electrolyte is introduced into the bottom of the embodiment 1000. The embodiment includes a plurality of alternating, nested anodes 1016 and cathodes 1015 (only one of each indicated). As the mixture 1005 bubbles up it reacts with the catalyst (not shown) on the anodes 1016 and cathodes 1015 that define a plurality of three-phase interface as discussed above. Eventually, the product and fouled electrolyte 1020 are drawn off the top.
Another stacked embodiment 1100 is shown in FIG. 11. A mixture 1105 of gaseous feedstock and liquid electrolyte is introduced into a chamber 1110, from which it is then introduced into a reaction chamber 1130 in which a plurality of alternating anodes 1016 and cathodes 1015 are stacked. When the anodes 1016 and cathodes 1015 are powered, they are shorted together. Those in the art will appreciate that, at this point, they lose their identity as a “cathode” or an “anode” because they all have the same polarity and instead all become reaction electrodes. As the mixture 1105 rises in the reaction chamber 1130, it forms a three-phase reaction at each reaction electrode. The gas product 1405 and the fouled electrolyte 1410 are drawn from the chamber 1125 at the top of the embodiment 1100.
Note that not all embodiments will manifest all these characteristics and, to the extent they do, they will not necessarily manifest them to the same extent. Thus, some embodiments may omit one or more of these characteristics entirely. Furthermore, some embodiments may exhibit other characteristics in addition to, or in lieu of, those described herein.
The phrase “capable of” as used herein is a recognition of the fact that some functions described for the various parts of the disclosed apparatus are performed only when the apparatus is powered and/or in operation. Those in the art having the benefit of this disclosure will appreciate that the embodiments illustrated herein include a number of electronic or electro-mechanical parts that, to operate, require electrical power. Even when provided with power, some functions described herein only occur when in operation. Thus, at times, some embodiments of the apparatus of the invention are “capable of” performing the recited functions even when they are not actually performing them—i.e., when there is no power or when they are powered but not in operation.
The following patent, applications, and publications are hereby incorporated by reference for all purposes as if set forth verbatim herein:
U.S. Application Ser. No. 61/608,583, entitled, “An Electrochemical Process for Direct one step conversion of methane to Ethylene on a Three Phase Gas, Liquid, Solid Interface”, and filed Mar. 8, 2012, in the name of the inventor Ed Chen and commonly assigned herewith.
U.S. Application Ser. No. 61/639,544, entitled, “Electrochemical Reactor for the use of Aqueous Electrolyte for High Efficiency Reaction of Non Polar Organic Gases”, filed Apr. 27, 2012, in the name of the inventor Ed Chen and commonly assigned herewith.
U.S. Application Ser. No. 61/606,398, entitled, “A Process, Apparatus, and Components for the Production of High Value Chemicals from carbon dioxide Using Modular, Electrochemical Reduction of CO₂on Three Phase Interphase Gas Diffusion Electrode”, filed Mar. 3, 2012, in the name of the inventor Ed Chen and commonly assigned herewith.
U.S. Application Ser. No. 61/713,487, entitled, “A Process for Electrochemical Fischer Tropsch”, filed Oct. 13, 2012, in the name of the inventor Ed Chen and commonly assigned herewith.
International Application Ser. No. PCT/US2011/064589, entitled, “Porous Metal Dendrites for High Efficiency Aqueous Reduction of CO2 to Hydrocarbons”, filed Dec. 13, 2011, in the name of the inventor Ed Chen and assigned to The Trustees of Columbia University in the City of New York.
To the extent that any patent, patent application, or other reference incorporated herein by reference conflicts with the present disclosure set forth herein, the present disclosure controls.
This concludes the detailed description. The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.

Claims

What is claimed:

1. An electrolytic cell, comprising:

at least one reaction chamber into which, during operation, a aqueous electrolyte and a gaseous feedstock including are introduced, wherein the gaseous feedstock comprises a carbon-based gas; and

a pair of reaction electrodes disposed within the reaction chamber, at least one of the reaction electrodes including a solid catalyst and defining, in conjunction with the aqueous electrolyte and the gaseous feedstock, a three-phase interface.

2. The electrolytic cell of claim 1, wherein the aqueous electrolyte is mixed with the gaseous feedstock when the aqueous electrolyte has been introduced into the reaction chamber.

3. The electrolytic cell of claim 1, wherein the aqueous electrolyte directly contacts the reaction electrode without the intercession of a polymer exchange membrane when the aqueous electrolyte has been introduced into the first chamber and mixed with the gaseous feedstock.

4. The electrolytic cell of claim 1, wherein the aqueous electrolyte is selected from potassium chloride, potassium bromide, potassium iodide, or hydrogen chloride.

5. The electrolytic cell of claim 1, wherein the solid catalyst contains an element selected from copper, silver, gold, iron, tin, zinc, ruthenium, platinum, palladium, rhenium, or a lanthanide metal.

6. The electrolytic cell of claim 5, wherein the copper containing solid catalyst is Cuprous Chloride or Cuprous Oxide.

7. The electrolytic cell of claim 1, wherein the carbon-based gas comprises a non-polar gas, a carbon oxide, or a mixture of the two.

8. The electrolytic cell of claim 7, wherein the non-polar gases include a hydrocarbon gas.

9. The electrolytic cell of claim wherein the carbon oxide includes carbon monoxide, carbon dioxide, or a mixture of the two.

10. The electrolytic cell of claim 1, further wherein the catalyst is powdered and mixed in a slurry with the aqueous electrolyte.

11. A method for chain modification of hydrocarbons and organic compounds comprising:

contacting a gaseous feedstock including a carbon-based gas, an aqueous electrolyte, and a catalyst in a reaction area; and

activating the carbon-based gas in an aqueous electrochemical reaction at the reaction electrode and yield a product.

12. The method of claim 11, wherein reacting the aqueous electrolyte, the catalyst, and the gaseous feedstock includes powering a pair of reaction electrodes.

13. The method of claim 11, wherein reacting the aqueous electrolyte, the catalyst, and the gaseous feedstock includes electrically short circuiting a pair of reaction electrodes within the electrolyte while maintaining a three phase interface.

14. The method of claim 11, wherein contacting the aqueous electrolyte with the catalyst and the gaseous feedstock includes introducing the aqueous electrolyte into direct contact with a gas diffusion electrode.

15. The method of claim 11, wherein contacting the aqueous electrolyte with the catalyst and the gaseous feedstock includes introducing liquid reactants into direct contact with a gas diffusion electrode.

16. The method of claim 11, wherein:

the catalyst is a solid; and

the reaction occurs at a three-phase interface between the aqueous electrolyte, the solid catalyst, and the gaseous feedstock.

17. The method of claim 11, further comprising leaving the aqueous electrolyte unfiltered during the reaction.

18. The electrolytic cell of claim 11, wherein the carbon-based gas comprises a non-polar gas, a carbon oxide, or a mixture of the two.

19. The electrolytic cell of claim 18, wherein the non-polar gases include a hydrocarbon gas.

20. The electrolytic cell of claim 18, wherein the carbon oxide includes carbon monoxide, carbon dioxide, or a mixture of the two.

21. The method of claim 11, wherein the catalyst comprises a metal, an inorganic salt of a metal, or an organometallic compound.

22. The method of claim 11, wherein the catalyst is powdered and mixed in a slurry with the aqueous electrolyte.

23. The method of claim 11, wherein the aqueous electrolyte is selected from magnesium sulfate, sodium chloride, sulfuric acid, potassium chloride, hydrogen chloride), potassium chloride, potassium bromide, potassium iodide, sea salt or brine.

24. The method of claim 11, wherein the aqueous electrolyte has a concentration of between 0.1M-3M.

25. A method for chain modification of hydrocarbons and organic compounds comprising:

contacting an aqueous electrolyte with a a catalyst and a gaseous feedstock including a carbon-based gas within a reaction area; and

reacting the aqueous electrolyte, the catalyst, and the gaseous feedstock at temperatures in the range of −10 C to 1000 C and at pressures in the range of 0.1 ATM to 100 ATM to yield a long chained hydrocarbon.

26. The method of claim 25, wherein reacting the aqueous electrolyte, the catalyst, and the gaseous feedstock includes powering a pair of reaction electrodes.

27. The method of claim 25, wherein reacting the aqueous electrolyte, the catalyst, and the gaseous feedstock includes electrically short circuiting a pan of reaction electrodes within the electrolyte while maintaining a three phase interface.

28. The method of claim 25, wherein contacting the aqueous electrolyte with the catalyst and the gaseous feedstock includes introducing: the aqueous electrolyte into direct contact with a gas diffusion electrode.

29. The method of claim 25, wherein contacting the aqueous electrolyte with the catalyst and the gaseous feedstock includes introducing liquid reactants into direct contact with a gas diffusion electrode.

30. The method of claim 25, wherein:

the catalyst is a solid; and

31. The method of claim 25, further comprising leaving the aqueous electrolyte unfiltered during the reaction.

32. The electrolytic cell of claim 25, wherein the carbon-based gas comprises a non-polar gas, a carbon oxide, or a mixture of the two.

33. The electrolytic cell of claim 32, wherein the non-polar gases include a hydrocarbon gas.

34. The electrolytic cell of claim 32, wherein the carbon oxide includes carbon monoxide, carbon dioxide, or a mixture of the two.

35. The method of claim 25, wherein the catalyst comprises a metal, an inorganic salt of a metal, or an organometallic compound.

36. The method of claim 35, wherein the catalyst contains an element selected from copper, silver, gold, nickel, iron, tin, zinc, ruthenium, platinum, palladium, rhenium, or a lanthanide metal.

37. The method of claim 35, wherein the catalyst contains an organometallic salt of an element selected from copper, silver, gold, nickel, iron, tin, zinc, ruthenium, platinum, palladium, rhenium, or a lanthanide metal.

38. The method of claim 25, wherein the catalyst is powdered and mixed in a slurry with the aqueous electrolyte.

39. The method of claim 35, wherein the aqueous electrolyte includes Alkali or Alkaline Earth Salts.

40. The method of claim 39, wherein the Alkali or alkaline Earth Salts include Halides, Sulfates, sulfites, Carbonates, Nitrates or Nitrites.

40. The method of claim 39, wherein the aqueous electrolyte is selected from magnesium sulfate, sodium chloride, sulfuric acid, potassium chloride, hydrogen chloride), potassium chloride, potassium bromide, potassium iodide, sea salt, or brine.

41. The method of claim 25, wherein the aqueous electrolyte is selected from magnesium sulfate, sodium chloride, sulfuric acid, potassium chloride, hydrogen chloride), potassium chloride, potassium bromide, potassium iodide, sea salt, or brine.

42. The method of claim 25, wherein the aqueous electrolyte has a concentration of between 0.1M-3M.

43. A gas diffusion electrode, comprising:

a hydrophobic layer porous to carbon dioxide and impermeable to aqueous electrolytes;

a hydrophilic layer bonded to the hydrophobic layer; and

a cuprous halide coating disposed about the bonded hydrophobic and hydrophilic layers.

44. The gas diffusion electrode of claim 43, further comprising:

a high surface area powder electroplated to the cuprous halide coating; and

a capping reducing agent.

45. The gas diffusion electrode of claim 43, wherein the hydrophilic layer includes:

a hydrophilic carbon paper with a polytetrafluoroethylene dispersion;

an activated carbon coating on the polytetrafluoroethylene dispersion; and

the copper catalyst deposited into the pores of the activated carbon.

46. The gas diffusion electrode of claim 43, wherein the copper catalyst is plated onto particles of silver.

47. A method for fabricating a gas diffusion electrode, comprising:

bonding a hydrophobic layer porous to carbon dioxide and impermeable to aqueous electrolytes to a hydrophilic layer supporting a copper catalyst; and

treating the copper catalyst to create a cuprous halide.

48. The method of claim 47, further comprising;

electroplating the cuprous halide with a high surface area powder; and

using a capping reducing agent to create nanoparticles.

49. The method of claim 47, further comprising preparing the hydrophilic layer, wherein preparing the hydrophilic layer includes:

treating a hydrophilic carbon paper with a polytetrafluoroethylene dispersion;

coating the polytetrafluoroethylene dispersion with a porous activated carbon; and

depositing the copper catalyst into the pores of the activated carbon.

50. The method of claim 49, further comprising:

mixing the treated, coated hydrophilic carbon paper with the deposited copper catalyst with a hydrophilic binding agent; and

creating an ink from the mixture and an organic solvent;

painting the mixture onto the hydrophobic layer.

51. The method of claim 50, wherein the organic solvent includes PVA, PVAc, or Nafion.

52. The method of claim 47, wherein treating the copper catalyst to create a cuprous halide includes:

submerging the bonded hydrophobic layer and hydrophilic layer in a solution of hydrochloric acid and cupric chloride; and

heating the submerged the bonded hydrophobic layer and hydrophilic layer to approximately 100° C. for approximately 2 hours.

53. The method of claim 52, wherein treating the copper catalyst further includes:

plating particles of the copper catalyst with silver; and

plating the silver plated particles with the copper catalyst prior to submerging the bonded hydrophobic layer and hydrophilic layer.

54. The method of claim 52, wherein treating the copper catalyst further includes:

impregnating the hydrophilic layer with silver; and

plating the impregnated silver with the copper catalyst prior to submerging the bonded hydrophobic layer and hydrophilic layer.

55. The method of claim 47, wherein treating the copper catalyst to create a cuprous halide includes:

submerging the bonded hydrophobic layer and hydrophilic layer in 3 M KBr or 3 M KI; and

running a 4V pulse of electricity to the the bonded hydrophobic layer and hydrophilic layer.