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WO2007004997A1 - Procede d'electrolyse en phase gazeuse pour la production d'hydrogene - Google Patents

Procede d'electrolyse en phase gazeuse pour la production d'hydrogene Download PDF

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Publication number
WO2007004997A1
WO2007004997A1 PCT/US2005/019703 US2005019703W WO2007004997A1 WO 2007004997 A1 WO2007004997 A1 WO 2007004997A1 US 2005019703 W US2005019703 W US 2005019703W WO 2007004997 A1 WO2007004997 A1 WO 2007004997A1
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WO
WIPO (PCT)
Prior art keywords
gaseous
sulfur
decomposition
electrolyzer
hydrogen
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2005/019703
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English (en)
Inventor
Edward J. Lahoda
Keith D. Task
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Westinghouse Electric Co LLC
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Co LLC
Westinghouse Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Westinghouse Electric Co LLC, Westinghouse Electric Corp filed Critical Westinghouse Electric Co LLC
Priority to PCT/US2005/019703 priority Critical patent/WO2007004997A1/fr
Publication of WO2007004997A1 publication Critical patent/WO2007004997A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/02—Preparation of oxygen
    • C01B13/0203—Preparation of oxygen from inorganic compounds
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/48—Sulfur dioxide; Sulfurous acid
    • C01B17/50—Preparation of sulfur dioxide
    • C01B17/501—Preparation of sulfur dioxide by reduction of sulfur compounds
    • C01B17/502—Preparation of sulfur dioxide by reduction of sulfur compounds of sulfur trioxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/48—Sulfur dioxide; Sulfurous acid
    • C01B17/50—Preparation of sulfur dioxide
    • C01B17/60—Isolation of sulfur dioxide from gases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/69—Sulfur trioxide; Sulfuric acid
    • C01B17/74—Preparation
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/133—Renewable energy sources, e.g. sunlight

Definitions

  • the present invention generally relates to a sulfur based method for producing hydrogen, wherein the hydrogen can be used for a variety of uses including transportation fuel, chemicals manufacture and energy storage.
  • the invention relates to a method for producing hydrogen utilizing a sulfur based cycle that dramatically reduces the energy costs of the process by keeping the sulfuric compounds in gaseous phase throughout the cycle, thereby eliminating the energy costs necessary to convert the sulfuric oxide products from liquid to gas and back again.
  • the invention further relates to method for producing hydrogen wherein oxygen is separated from sulfur dioxide with the use of absorbents.
  • thermochemical cycles The production of hydrogen from thermochemical cycles is a science that has been evolving over the past thirty years.
  • sulfur based thermochemical cycles that incorporate sulfuric acid decomposition are now known in the art, such as a Sulfur-Iodine cycle, a Hybrid Sulfur cycle, and a Sulfur-Bromide cycle.
  • a process using sulfuric acid was developed by Westinghouse (Pittsburgh, PA), hereinafter the Westinghouse Sulfur Process.
  • HTGR nuclear High Temperature Gas Cooled Reactor
  • PBMR Pebble Bed Modular Reactor
  • the sulfur dioxide released during the decomposition is absorbed in water at about room temperature and sent to an electrolyzer.
  • the sulfur dioxide and water is then electrolyzed to hydrogen and sulfuric acid in liquid form or sulfur trioxide in liquid form.
  • prior art Figure 1 A more detailed view of the prior art is shown in prior art Figure 1.
  • the process forms sulfur dioxide through decomposition of sulfuric acid at elevated temperatures. This is called an oxygen generation step.
  • the thermal energy required for this step is generally heat at a temperature above 600 0 C, preferably in the range of about 700 to HOO 0 C.
  • the thermal energy is provided by any generator able to produce heat at that temperature level.
  • the reaction for sulfuric acid decomposition and oxygen generation in prior art Figure 1 is:
  • This step is often carried out in concert with a High Temperature Gas Cooled Reactor (HTGR) such as a PBMR to supply heat to the process.
  • HTGR High Temperature Gas Cooled Reactor
  • Various methods are employed to transfer the heat from the nuclear reactor loop to the decomposition reactor.
  • One approach would be to use a bed of alumina or zirconia heat spheres with a catalytic surface that is heated with hot gas from an intermediate loop that is in turn heated by the reactor loop.
  • the catalyst is employed to make the decomposition reaction proceed more quickly to the equilibrium value predicted for the temperature.
  • the sulfur dioxide is cooled in a vaporizer in second step, reference number 4.
  • the vaporizer cools the sulfur dioxide in a heat exchanger, converting it from gas to liquid.
  • residual sulfur dioxide is absorbed in a counter current flow of water at a temperature above 4O 0 F to remove SO 2 from the O 2 .
  • This is referred to as the oxygen recovery step.
  • the system generally operates under increased pressures of about 200 to 1100 psi. In other methods, the pressure of the system in step 3 is increased to between 1450 and 1700 psi, thereby allowing the sulfur dioxide to dissolve in water at higher temperatures or condense as a separate phase.
  • the sulfur dioxide in water is moved to a hydrogen production chamber where hydrogen is produced in a lower temperature step, reference number 8.
  • the hydrogen production chamber is often an electrolyzer, wherein the energy for the reaction is an electrical current.
  • direct current electricity of between about .17 and 1. volt is added to the electrolyzer to react the sulfur dioxide and thereby forming aqueous sulfuric acid and hydrogen.
  • the electrolysis step is generally performed at temperatures of about 20 to 200 0 C.
  • the current density is about 200 ma/sq.cm at about 6O 0 C.
  • electrolysis processes do not present spark sources.
  • the temperatures of the electrolysis step are not potential ignition sources for the produced hydrogen.
  • the aqueous sulfuric acid by-product of the hydrogen production step then re-enters the vaporizer in reference number 10.
  • the vaporizer must vaporize the sulfuric acid, thereby converting it from liquid to gas, for the cycle to be complete.
  • the vaporized gaseous sulfuric acid is thereafter fed back into the oxygen generation system of 2, repeating the cycle.
  • the General Atomics process utilizes iodine and sulfur dioxide to produce sulfuric acid, which is then decomposed to oxygen, water and sulfur dioxide.
  • the iodine process generally uses high temperature thermal energy from a nuclear reactor ( ⁇ 1000 0 C) for the decomposition of sulfuric acid.
  • the process is continually repeated in the aim of producing intermediate HI by-products from the reaction.
  • the process produces hydrogen from the intermediate HI products of the sulfuric acid decomposition by reacting them under elevated temperatures. This hydrogen producing step is typically done at about 400 0 C.
  • an object of the present invention is to provide a method for hydrogen production using sulfur compounds, wherein the sulfur compounds are in a gaseous state throughout the method, including the steps of decomposing gaseous SO 3 into gaseous SO 2 and gaseous O 2 , separating the SO 2 from the O 2 , and oxidizing the SO 2 with gaseous H 2 O to form gaseous SO 3 and gaseous H 2 .
  • FIG. 1 is a process flow diagram of a prior art hydrogen production process.
  • FIG. 2 is a process flow diagram of a gas phase SO 3 /SO 2 /H,O electrolyzer process.
  • FIG. 3 is a graph of oxidation of SO 2 to SO 3 by voltage vs. current density.
  • FIG. 4 is a process flow diagram of a gas phase SO 3 /SO 2 and liquid phase H 2 O electrolyzer process.
  • FIG. 1 One embodiment of a hydrogen producing sulfur cycle utilizing the oxidation of sulfur dioxide to sulfur trioxide in their gaseous phases is shown in Figure 2.
  • Sulfur trioxide (SO 3 ) is decomposed under elevated temperatures to sulfur dioxide (SO 2 ) and oxygen (O 2 ), under the reaction SO 3 ⁇ SO 2 + Vi O 2 , in a decomposition reactor as shown in reference number 12.
  • Pressure for this step is kept at normal or slightly elevated pressures such that the sulfuric oxides stay in a gaseous state.
  • the thermal energy required for this step is generally heat in a temperature range of about 600 and 100O 0 C, preferably in the range of about 700 to 900 0 C.
  • the thermal energy may be provided by a heat source, for example, a nuclear reactor.
  • a heat source for example, a nuclear reactor.
  • any other sources known in the art for thermal energy production in excess of 600 0 C may be used.
  • generators that utilize fossil fuels such as coal or oil may be used to derive thermal energy to decompose the sulfur trioxide.
  • gas or solar power may be used.
  • a combination of two or more sources may be used.
  • the heat necessary for the decomposition of sulfur trioxide can be captured from a generator in a transfer of heat known in the art. This may also include alternately heating one cold decomposition reactor with energy from the generator while another hot reactor is used for SO3 decomposition. In alternative embodiments, however, a multiplicity of decomposition reactors may be heated by a single heat generator. In one preferred embodiment, helium is heated in a heat generator and sent to a first decomposition reactor to heat a bed of alumina or zirconia heat spheres with a catalytic surface, wherein the catalytic surface is employed to make the decomposition reaction proceed more quickly to the equilibrium value predicted for the temperature.
  • the helium heats the first decomposition reactor up to a desired temperature, and then is moved to a colder, second decomposition reactor.
  • sulfuric acid or sulfur trioxide is decomposed, gradually cooling the first reactor.
  • the helium still heated, heats up the second decomposition reactor.
  • the hot helium is diverted back to the now cooled first decomposition reactor to reheat it.
  • the sulfuric acid or sulfur trioxide steam is then diverted to the second decomposition reactor to be decomposed in the now heated second reactor.
  • the cycle continues as the second decomposition reactor gradually cools while the first decomposition reactor reheats. The cycle can then repeat.
  • the helium can be fed through a zeolite bed to remove residual sulfur oxide vapors, and/or other variances known in the art.
  • Other decomposition reactor designs can be used including those indirectly heating the sulfuric acid or sulfur trioxide stream through a heat exchange tube.
  • helium is heated in or near the heat generator to a temperature of about 700-1000 0 C and conveyed into the decomposition reactor, thereby providing the heat for the reaction.
  • the helium can be conveyed into the decomposition reactor by any means known in the art, such as piping.
  • the cooled helium is conveyed from the decomposition reactor back to the generator, thereby heating it up to the proper temperature before returning to the decomposition reactor again in a continued cycle.
  • Other compounds other than helium may be used in the process, for example, molten salts or other gases. If other compounds are used, heat may be transferred from the generator helium to these compounds via a suitable heat exchanger.
  • a catalyst is preferably utilized to facilitate the SO 1 ⁇ SO 2 + Vi O 2 reaction within the preferred 600-1000 0 C temperature range.
  • the catalyst is employed to make the decomposition reaction proceed more quickly to the equilibrium value predicted for the temperature.
  • Catalysis known in the art for decomposing sulfuric compounds include platinum, iron, vanadium, held by supports such as the oxides of zirconium, aluminum, titanium and combinations thereof, typically with one of the elements oxidized.
  • Pt/ZrO 2 , Pt/ Al 2 O 3 and Pt/TiO, compounds may be used as catalysts.
  • the catalysts may have varying surface areas under the spirit of the invention.
  • decompositions that use or form water i.e.
  • the sulfuric dioxide, oxygen and any remnant sulfur trioxide that did not decompose exit the decomposition reactor as a heated stream into a conveying means 14, wherein the conveying means is any means known in the art such as insulated piping.
  • the gases are still heated to a temperature range of about 600-1000 0 C.
  • the heated exiting stream of gaseous compounds is split between conveying means 14 and conveying means 16. This can be achieved by two separate conveying means exiting the decomposition reactor or by one conveying means that splits into two, as shown in Figure 2.
  • the majority of the sulfur dioxide, oxygen and remnant sulfur trioxide is moved through conveying means 14 into heat exchanger 18.
  • the gaseous compounds exiting the decomposition reactor are cooled in the heat exchanger by gaseous compounds exiting an electrolyzer as more fully explained below.
  • the sulfuric dioxide, oxygen and any remnant sulfur trioxide compounds are further cooled in steam generator 20 after being conveyed through conveying means 22.
  • the compounds are moved into heat exchange relation with pumped in water 24 in steam generator 20, such that the compounds are cooled by the water and the water is heated by the compounds. Note that the water and compounds do not mix, they are only in heat exchange relation.
  • the water is heated by the compounds enough to become steam, and exits the steam generator as steam through conveying means 26 in a gaseous state. Meanwhile, the compounds are cooled by the water to a temperature range between about 4 and 60 0 C, although this can vary somewhat within the spirit of the invention. Note that any other heat source may be used to produce all or any portion of the steam that is required for operation of the steam side of the electrolyzer 46.
  • oxygen is separated from sulfur dioxide and any remnant sulfur trioxide. It is important to note that any process known in the art that separates oxygen from sulfur dioxide can be utilized in the hydrogen production method of the present invention. For example, a membrane system that separates O 2 and SO 2 and remnant SO 3 can be used.
  • the cooled SO 2 , SO 3 and O 2 from the steam generator are conveyed to one of the multiplicity of absorption tanks, for example, tank 30, through a valve or valves.
  • the valve is a typical valve known in the art, wherein adjustment of the valve can control the movement of the compounds from the steam generator into tank 30, tank 32, both tank 30 or 32, or neither. If a greater number of tanks are used, the valve can similarly control movement of the compounds to any combination of the tanks. Additional conveying means may be located after the valve to bring the compounds to the desired tanks.
  • valves are not a prerequisite of the invention. Any apparatus known in the art that conveys the gasses to the proper tank or tanks at the proper time may be used. Thus, other controlling means known in the art other than valves may be used to control the movement of the compounds to the desired absorption tanks.
  • Conveying means 16 carries a 'hot stream' of SO 2 , O 2 and SO 3 gases from the decomposition tank.
  • the hot stream gases are conveyed directly from the decomposition tank to the absorption tank and therefore have not been cooled by heat exchanges in heat exchanger 18 or steam generator 20. Thus the temperature of these hot stream gases typically remains in the 600-1000 0 C range.
  • the hot stream gases are similarly connected to the absorption tanks through a valve, wherein the valve can be adjusted to control the movement of the hot stream into none, one, or a multiplicity of absorption tanks.
  • Additional conveying means may be located after the valve to bring the compounds to the desired tanks. These means may alternatively be fully or partially common to those used with the cooled gasses. Further, other controlling means known in the , aside from and in addition to valves, may be used to control the movement of : compounds to the desired absorption tanks.
  • the cooled sulfur dioxide and oxygen is exposed to a bed of absorbent thin the absorption tanks, wherein the bed of absorbent is an absorbent known in i art for absorbing sulfur compounds such as molecular sieves, zeolites or tivated carbon.
  • the temperature of the absorbing tank during absorption is nerally ambient temperature or slightly elevated, between about 10-50 0 C.
  • the essure of the absorbent tank is similarly atmospheric or slightly elevated. Under ⁇ se conditions, the absorbent will generally absorb the SO 2 and remnant SO 3 while wing the oxygen free to exit through outlet 34. Thus, the gases are separated.
  • the absorbent is thereafter regenerated.
  • the particular absorbent tank holding the full absorbent is ken off-line, that is to say, the valve, valves or other apparatus is/are adjusted ch that the cooled gases from heat generator 18 and steam generator 20 via mveying means 22 and 28 are no longer entering the tank.
  • the control ilve/valves or other apparatus is/are adjusted such that the hot stream of gases om conveying means 16 enter the tank.
  • the hot stream releases the absorbed ilfur compounds from the absorbent, thereby 1) freeing the sulfur oxide gases to ⁇ conveyed through optional outlet 36, fan 38 and into conveying means 40, and 2) eeing the absorbent to absorb more sulfur oxide gasses once the absorption tank is >oled again.
  • the gases exiting the off-line absorption tank will have some oxygen resent from the oxygen that was present in the hot stream.
  • the vast lajority of the gases will be sulfur oxide gases, mainly SO 2 .
  • the absorption tanks 30 and 32 function such that 'hen one tank is absorbing sulfur oxide gasses, the other may be regenerating.
  • the vo absorption tanks may alternate back and forth such that when one is absorbing, ie other is regenerating, and vice versa.
  • both tanks can bsorb or regenerate at the same time.
  • any combination of the tanks may be absorbing or ⁇ generating at any one time.
  • gases can travel between the iultiplicity of absorption tanks, and/or the varying conveying means could only onnect to a single or less than the entire number of absorption tanks.
  • Each tank may have its own outlet 34 for exiting oxygen during the bsorption phase, or the tanks may be aligned such that they share one outlet, or in tie case of more than two absorption tanks, any combination thereof.
  • ach tank may have its own sulfur oxide outlet 36 and/or fan 38, or they may share the same one in a common header, or in the case of more than two absorption tanks, any combination thereof.
  • the oxygen of the of the cooled oxygen-sulfur dioxide-sulfur trioxide stream may be absorbed in an absorbent.
  • Any oxygen absorbent known in the art, such as zeolites or molecular sieves can be used.
  • the oxygen is absorbed in the oxygen absorbent in at least one of the absorption tanks, and the remaining SO, and SO 3 is directed through fan 38 and into conveying means 40.
  • the oxygen can then be released by taking the absorption tank off-line.
  • the hot stream of gases or steam enters the absorption tank, heating the tank and releasing the oxygen to exit through outlet 34.
  • This has the additional purpose of regenerating the absorbent such that it can begin to absorb oxygen again once the tank is cooled by the re-entry of the cooled gases.
  • all or none of the multiplicity of absorption tanks can be absorbing or regenerating at any time, or any combination thereof.
  • a stream of sulfur dioxide and remnant O 2 and SO 3 is conveyed through conveying means 40 into a hydrogen production cell 42 for a hydrogen producing step.
  • the hydrogen producing cell 42 is an electrolysis unit.
  • the hydrogen producing step generally utilizes an electrical current to oxidize sulfuric dioxide into sulfuric trioxide while simultaneously reducing steam into H 2 .
  • sulfuric dioxide is conveyed from conveying means 40 into a first side 44 of the cell, wherein side 44 includes an anode.
  • gaseous H 2 O is conveyed in from steam generator 16 through conveying means 26, wherein second side 46 contains a cathode.
  • Hydrated ion transfer membrane 48 can be any hydrated ion transfer membrane known in the art, for example, Nafion (DuPont, Wilmington, Delaware), a poly(perfluorosulfonic acid) ion exchange membrane.
  • An electrical current is provided through two electrodes 50 to the electrolysis unit 44.
  • the source of the electrical power can come from any source that produces electrical power. Preferably, however, it would come from the same source that is producing the high temperate input to the decomposition reactor 12. In the present example, both the temperature input and the electrical input are provided by a nuclear reactor.
  • the temperature of the hydrogen producing cell during the electrolysis is typically room temperature or slightly elevated, for example, from about 20 to 200 0 C, preferably between about 40 and 15O 0 C.
  • the current density is above 200 ma/sq.cm at above 60 0 C and preferably above 500 ma/sq. cm and above 80 0 C.
  • the pressure is moderate, typically below 1000 psi. to avoid condensation of the
  • the steam inside 46 begins to move away from the cathode and toward the anode in side 44, diffusing across ion exchange membrane 48 in the process.
  • the oxygen in the steam oxidizes sulfur dioxide into sulfur trioxide, thereby releasing hydrogen ions.
  • the reaction for this step in side 44 is SO 2 +H 2 O ⁇ SO 3 + 2H + + 2e " .
  • the current used is high enough to make water diffusion the limiting factor in the oxidization Of SO 2 .
  • the voltage and current density is to low, the steam moves over too fast, and excess water would build up on side 44 and react with the SO 3 to form a condensed phase of H 2 SO 4 .
  • the hydrogen ions diffuse back over membrane 48 toward the cathode in side 46.
  • the hydrogen ions then react at the cathode where they are reduced to hydrogen gas in the reaction 2H + + 2e " ⁇ H 2 .
  • the hydrogen can then exit through outlet 52 to be captured and utilized as desired.
  • the hydrogen would be purified by any means known in the art to eliminate possible contaminants, such as stray steam or sulfur gases.
  • the resultant SO 3 of the reaction on first side 44 exits through conveying means 56 to heat exchanger 18, wherein the SO 3 is heated and wherein gases from the decomposition reactor are cooled. Essentially, within heat exchanger 18, the
  • the gases that exit decomposition reactor 12 enters into a heat exchange relationship with the gases that exit decomposition reactor 12.
  • the SO 3 gases prior to entry into the heat exchanger are at or close to ambient temperature.
  • the gases that exit the decomposition reactor are elevated, typically to about 600-1000 0 C.
  • the heated decomposition reactor gases are used to heat the SO 3 from the electrolyzer, while the SO 3 simultaneously cools the decomposition reactor gases.
  • the SO 3 does not mix with the decomposition reactor gases, only a heat exchange relationship is maintained.
  • the decomposition tank gases, once cooled, are thereafter moved into the steam generator for further cooling or directly into the absorption tanks as shown in Figure 4.
  • the SO 3 now heated, is moved into the decomposition reactor for decomposition, completing the cycle.
  • supplementary heat may be added to the SO 3 stream from any heat source to make sure that the desired temperature of the SO 3 that enters the decomposition reactor is met.
  • FIG. 4 An alternate embodiment of the method is shown in Figure 4.
  • liquid H 2 O is used instead of gaseous H 2 O.
  • Operation of the embodiment shown in Figure 4 generally requires a small increase in voltage during the electrolysis step, about 0.5-0.8v. However, this cost is more than offset by the costs saved through elimination of the steam generator. Further, as noted above, operation at these higher voltage levels may also result in a smaller electrolysis unit 42 due to the high current density that is achieved.
  • the electrolysis step in this embodiment is similarly performed at temperatures of about 20 to 200 0 C, preferably between about 30 and HO 0 C.
  • the current density is preferably above 500 ma/sq.cm at about 100 0 C.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

La présente invention a trait à un procédé pour un cycle de production d'hydrogène à base de soufre dans lequel les produits soufrés sont maintenus dans un état gazeux pendant toute la durée du cycle. Le cycle comprend la décomposition d'un trioxyde de soufre en phase gazeuse en dioxyde de soufre et de l'eau dans un réacteur de décomposition et une oxydation de trioxyde de soufre gazeux avec du H2O dans un électrolyseur pour la formation de trioxyde de soufre et de l'hydrogène. Les coûts sont réduits par l'élimination des coûts d'énergie précédemment nécessaires pour la conversion de produits sulfuriques de l'état liquide à l'état gazeux et la transformation inverse et par l'extension de la durée de vie des catalyseurs de décomposition grâce à l'élimination de l'eau dans un flux de SO2/SO3.
PCT/US2005/019703 2005-06-30 2005-06-30 Procede d'electrolyse en phase gazeuse pour la production d'hydrogene Ceased WO2007004997A1 (fr)

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PCT/US2005/019703 WO2007004997A1 (fr) 2005-06-30 2005-06-30 Procede d'electrolyse en phase gazeuse pour la production d'hydrogene

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2017371A1 (fr) * 2007-07-17 2009-01-21 Westinghouse Electric Company LLC Procédé de génération d'hydrogène avec électrolyse à double pression à étapes multiples
WO2009026640A1 (fr) * 2007-08-28 2009-03-05 Commonwealth Scientific And Industrial Research Organisation Production d'hydrogène par l'électrolyse solaire d'acide sulfureux
US8956526B2 (en) 2012-08-09 2015-02-17 Savannah Nuclear Solutions, Llc Hybrid sulfur cycle operation for high-temperature gas-cooled reactors

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4124695A (en) * 1976-08-05 1978-11-07 University Of Southern California Process for the oxidation of sulfur dioxide to sulfur trioxide
US4332650A (en) * 1981-01-21 1982-06-01 Gas Research Institute Thermoelectrochemical process using copper oxide for producing hydrogen and oxygen from water
US4778536A (en) * 1985-06-13 1988-10-18 Purusar Corporation Sulfur trioxide vapor phase stripping

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4124695A (en) * 1976-08-05 1978-11-07 University Of Southern California Process for the oxidation of sulfur dioxide to sulfur trioxide
US4332650A (en) * 1981-01-21 1982-06-01 Gas Research Institute Thermoelectrochemical process using copper oxide for producing hydrogen and oxygen from water
US4778536A (en) * 1985-06-13 1988-10-18 Purusar Corporation Sulfur trioxide vapor phase stripping

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7976693B2 (en) 2006-07-17 2011-07-12 Westinghouse Electric Company Llc Hydrogen generation process with dual pressure multi stage electrolysis
EP2017371A1 (fr) * 2007-07-17 2009-01-21 Westinghouse Electric Company LLC Procédé de génération d'hydrogène avec électrolyse à double pression à étapes multiples
JP2009023905A (ja) * 2007-07-17 2009-02-05 Westinghouse Electric Co Llc デュアル・プレッシャー多段電解による水素発生方法
WO2009026640A1 (fr) * 2007-08-28 2009-03-05 Commonwealth Scientific And Industrial Research Organisation Production d'hydrogène par l'électrolyse solaire d'acide sulfureux
US8956526B2 (en) 2012-08-09 2015-02-17 Savannah Nuclear Solutions, Llc Hybrid sulfur cycle operation for high-temperature gas-cooled reactors

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