Classifications

• • 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
  • C25B15/00—Operating or servicing cells
  • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
  • C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
  • C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
  • C07C29/1516—Multisteps
  • C07C29/1518—Multisteps one step being the formation of initial mixture of carbon oxides and hydrogen for synthesis
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
  • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
  • C10L3/08—Production of synthetic natural gas
• • 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
• • 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
  • C25B1/04—Hydrogen or oxygen by electrolysis of water
• • 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
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Definitions

• the invention relates to an arrangement for high-temperature electrolysis, which comprises a high-temperature electrolyzer and a reactor, and to a method for the operation thereof.
• a known way to store excess energy from the power grid is the electrolysis, especially of water. This water is converted to hydrogen and oxygen. The excess energy is stored as hydrogen. Furthermore, it is possible to convert hydrogen into synthetic natural gas by means of methanization and to store it, for example, in the natural gas grid. The conversion to other hydrocarbons, in particular to methanol, is possible.
• the electrolysis can take place at different temperature levels. On the one hand, there is the low-temperature electrolyte, in which liquid water is used as starting material.
• the low-temperature electrolyser can be operated dynamically, ie absorb and convert energy at any time, depending on the amount of surplus current, without any special effort.
• a disadvantage is the rather low efficiency of the low-temperature electrolyzer.
• the low-temperature electrolyzer must be cooled to heat, which is produced in the electrolysis due to overvoltages and kinetic losses, dissipate and be operated with liquid water as starting material.
• the electrolysis in Hochtemperaturelektrolyseur has the potential to achieve better efficiency.
• the electrolysis is operated there at temperatures between 650 ° C and 1000 ° C with superheated steam as starting material.
• a disadvantage of the high-temperature electrolyzer is that the dynamic operation is difficult.
• the maximum possible heating rate of the ceramic materials of the high-temperature electrolyzer of about 200 ° C / h leads to a significant duration of startup and shutdown. As a result, excess electricity can not be immediately used for electrolysis and stored. As an alternative to cooling and heating the high-temperature electrolyzer, it can also be heated continuously, in particular electrically. However, not inconsiderable energy is consumed, so that the overall efficiency drops significantly.
• the object of the present invention is to specify an arrangement and a method for high-temperature electrolysis with which the overall efficiency of a high-temperature electrolyzer and a chemical synthesis, in particular of hydrocarbons, is improved.
• a chemical synthesis is carried out in a reactor.
• water is heated to steam.
• the water vapor is then fed into a high temperature electrolyzer.
• carbon dioxide is introduced into the high-temperature electrolyzer and / or into the reactor. leads.
• Hochtemperaturelektrolyseur a first gas flow is generated. At least a portion of the first gas stream is fed to the reactor as a reactant stream for chemical synthesis.
• the arrangement for carrying out a method according to the invention for high-temperature electrolysis comprises a high-temperature electrolyzer and a reactor for chemical synthesis and a heat coupling of the two.
• Carbon dioxide is supplied to the high-temperature electrolyzer and / or the reactor.
• water is heated to steam by means of heat coupling with the chemical synthesis.
• the water vapor is fed to the high-temperature electrolyzer as starting material.
• a first gas flow is generated. This is fed to the reactor as Eduktstrom for chemical synthesis.
• the high-temperature electrolyzer and the reactor are thermally coupled.
• the overall efficiency of high temperature electrolysis is thereby improved. If water vapor is passed into the high-temperature electrolyzer, electrolysis of water vapor to hydrogen and oxygen takes place.
• the hydrogen is fed (with a proportion residual water vapor) as the first gas stream to the reactor.
• the carbon dioxide is fed to the reactor as starting material. Additional hydrogen tanks are advantageously not needed.
• the resulting pure oxygen is stored in at least one tank.
• a tube bundle reactor is used as the reactor.
• a very good heat transfer between water and Edukt- or product gas of the reactor is achieved, so that the heat transfer in a wide temperature range is feasible.
• this reactor design is very compact, so that the space requirement is low.
• a methanization is carried out as a chemical synthesis.
• the synthesis gas which was produced in the high-temperature electrolyzer is thus directly referred to as
• Feedstock gas used for methanation Additional tanks, especially for carbon monoxide or hydrogen, are then saved. Furthermore, the synthetic natural gas generated in the methanation is advantageously stored in the natural gas network. The waste heat of methane synthesis is also used to evaporate the water to steam.
• a methanol synthesis is carried out as a chemical synthesis.
• the synthesis gas produced in the high-temperature electrolyzer is advantageously used as educt gas for the production of methanol.
• the size of the tanks for hydrogen or carbon monoxide is thus minimized. Ideally, the tanks are not needed and will be saved.
• the waste heat of the methanol synthesis is also used to evaporate the water to steam.
• the ratio of carbon dioxide, which is led into the high-temperature electrolyzer, to carbon dioxide, which is fed into the reactor chosen such that upper limit values for the carbon dioxide, carbon monoxide and hydrogen content of the generated by means of the methanization synthetic natural gas are as far as possible.
• the synthetic natural gas thus produced is fed into the existing natural gas network without additional cleanings, since the country-specific natural gas specifications of the natural gas network are complied with.
• further characteristics and substance data, in particular the Wobbe index and the relative density of the gas are advantageously influenced.
• the ratio of carbon dioxide, which is fed into the high-temperature electrolyzer, to carbon dioxide, which is fed into the reactor chosen such that the yield of methanol is maximum.
• the ratio of carbon dioxide, which is fed into the high-temperature electrolyzer, to carbon dioxide, which is fed into the reactor is selected such that by means of the heat of reaction exactly the amount of water vapor is generated, the high-temperature electrolyzer needed for electrolysis.
• this improves the overall efficiency of the high-temperature electrolysis. There is no need for additional heating of the water vapor and no unnecessary waste heat is generated.
• the first gas stream heats the water vapor and / or the water before entering the high-temperature electrolyzer in a first heat exchanger and / or heating heats the water vapor.
• the high-temperature electrolyzer is operated at temperatures between 650 ° C and 1000 ° C.
• the heat recovery in the first heat exchanger leads to an improved overall efficiency.
• the first gas stream heats the carbon dioxide in the first heat exchanger. As a result, it is advantageously achieved that the carbon dioxide has already been preheated, so that a heat sink in the high-temperature electrolyzer and an associated altered composition of the synthesis gas are avoided. Furthermore, heat of the process is recovered, so that the overall efficiency is improved.
• a portion of the first gas stream is returned to the high-temperature electrolyzer. This improves the lifetime of the typically nickel-containing hydrogen electrode.
• the high-temperature electrolyzer is supplied to an air flow.
• the air stream is heated and / or heated in a second heat exchanger before it is fed to the high temperature electrolyzer.
• the high-temperature electrolyzer comprises an electrolysis membrane, through which oxygen ions permeate, so that an oxygen stream is formed.
• oxygen-enriched air leaves the high-temperature electrolyzer as the second gas stream and is released into the environment.
• the addition of the air stream advantageously serves for further thermal regulation of the high-temperature electrolyzer. Furthermore, the addition of air reduces the corrosion of metallic components.
• the tube bundle reactor comprises an outer shell with intermediate space, wherein the intermediate space is filled with water.
• this space at least one gas line is passed through which a third gas stream of products the chemical synthesis flows and the water heats up.
• the water is advantageously first fed to the intermediate space between the outer shell and the shell of the tube bundle reactor and preheated there.
• the liquid and / or gaseous water is then passed into the interior of the tube bundle reactor. If the water flow is increased in such a way that it comes to a damming of liquid water in the intermediate space, this leads to an additional cooling of the inner container.
• the higher the water level in the gap the higher the cooling capacity.
• the water flow can be further increased so that liquid water enters the container.
• the water is supplied to the upper and / or lower edge of the outer container.
• Figure 1 shows a flow diagram for a high-temperature electro lysis
• FIG. 2 shows schematically the construction of the tube bundle reactor.
• the arrangement shown in Figure 1 comprises a tube bundle reactor 1, a high-temperature electrolyzer 2, a first heat exchanger 3 and a second heat exchanger 11.
• the tube bundle reactor 1 is carried out as a chemical synthesis methanation.
• methanation synthesis gas is converted to methane and water.
• the product gas 18 thus comprises methane (synthetic natural gas) and water.
• the waste heat of the exothermic syn- is used to heat a stream of water 4 to a steam stream 5.
• the water vapor stream 5 thus produced is mixed with a first carbon dioxide stream 8 and fed to the first heat exchanger 3. There, the water vapor and carbon dioxide stream is further heated and fed to the Hochtemperaturelektrolyseur 2 as superheated water vapor and carbon dioxide stream 7.
• synthesis gas 6 and oxygen are produced.
• the synthesis gas 6 comprises predominantly hydrogen and carbon monoxide, but also small residual amounts of water vapor and carbon dioxide.
• the synthesis gas 6 is supplied to the first heat exchanger 3. There, it serves to heat the steam stream 5 and first carbon dioxide stream 8.
• the synthesis gas 6 is then fed to the tube bundle reactor 1 as Eduktstrom.
• a second carbon dioxide stream 9 is fed directly to the tube bundle reactor 1.
• the two carbon dioxide streams 8, 9 are fed from the same carbon dioxide tank 21.
• the high-temperature electrolyzer 2 is additionally rinsed with an air stream 13.
• the oxygen produced in the electrolysis can pass through the ceramic electrolysis membrane 12 in ion form and leaves the high-temperature electrolyzer 2 as an oxygen-rich gas stream 14.
• the air stream 13 is preheated in the second heat exchanger 11 with the oxygen-rich gas stream 14.
• a part of the synthesis gas 6 produced in the electrolysis is fed to the first heat exchanger 3 via a return line 10. This prevents oxidation of the nickel-containing hydrogen electrode.
• the thermal integration of the production of water vapor from water by the methanation in the tube bundle reactor 1 significantly increases the efficiency. This thermal integration is achieved by adjusting the ratio of the first
• Carbon dioxide stream 8 to the second carbon dioxide stream 9 further optimized.
• the quality of the product gas 18 produced in the methanation can also be Influence the position of this relationship.
• the sole supply of carbon dioxide via the first carbon dioxide stream 8 to the high-temperature electrolyzer 2 represents a first limiting case of this ratio.
• carbon dioxide is fed exclusively to the tube bundle reactor 1 via the second carbon dioxide stream 9.
• the composition of the product gas 18 is also improved via the ratio of the carbon dioxide streams 8, 9 in such a way that the methane content increases.
• the methanation of carbon monoxide from the synthesis gas results in a different gas composition of the synthetic natural gas than the feeding of carbon dioxide directly to the methanation.
• a defined ratio carbon dioxide high temperature electrolyzer to carbon dioxide shell and tube reactor
• FIG. 2 shows a tube bundle reactor 1 which comprises an inner shell 19, an outer shell 15 and a gap 16.
• reactor tubes 20 are filled with catalyst in the form of a fixed bed.
• the reactor tubes 20 may alternatively be coated on the inside with catalyst or filled with a catalyst suspension.
• the outside of the reactor tubes 20 and the gas line 17 is provided with ribs. This improves the heat transfer.
• the outdoor side of the reactor tubes 20 and / or the gas line 17 nubs or fins.
• the reactor tubes 20 are heat-compensated complained, so that the thermal expansion of the reactor tubes 20 is compensated by suitable intermediate elements, such as hoses and flexible metal compensators.
• the produced natural gas is collected from the reactor tubes 20 in a product gas collector.
• the intermediate space there is at least one interspace gas line 17, through which the product gas 18 leaves the tube bundle reactor 1 via the product gas collector.
• the water and / or the water vapor flow in countercurrent to the water and / or water vapor in the intermediate space 16.
• the synthesis gas 6 produced in the high-temperature electrolyzer 2 is mixed with the second carbon dioxide stream 9 and fed to the tube bundle reactor 1. There, the gas stream is distributed to the reactor tubes 20.
• the conversion of synthesis gas 6 to product gas 18, which comprises methane and water, takes place by means of the methanation.
• the waste heat produced during methanation is used directly to heat water to steam.
• the water is first supplied to the intermediate space 16 as a water stream 4. Here it is preheated by means of the generated product gas 18 in the interspace gas line 17. If the water from the product gas 18 condenses in the interspace gas line 17, then the preheating is rendered particularly effective by the heat of condensation released.
• the water now flows as water and as water vapor into the inner shell 19 of the tube bundle reactor 1. There, the water is heated further. Internals in the inner shell 19 distribute the water and water vapor evenly. Alternatively, the distribution takes place by means of a filling body fill in the inner shell 19.
• the water vapor which arises in the process leaves the tube bundle reactor 1 as a water vapor stream 5.
• the temperature of the tube bundle reactor 1 can be adjusted via the water flow 4. Will the water flow 4 so high If water flow 4 is chosen to be so high that liquid water gets into the inner shell 19, water evaporates in the inner shell 19, if water flow 4 is chosen to be high enough to cause liquid water to build up in the interspace 16, this water will cool the inner shell 19 and the reactor tubes 20. which additionally increases the cooling of the reactor tubes 20.
• Another way to influence the temperature in the tube bundle reactor 1 is the choice of operating pressure. As the pressure increases, the boiling point of the water rises. As a result, the temperature level in the entire tube bundle reactor 1 increases.
• the temperature of the tube bundle reactor 1 can alternatively be influenced via a return of the cold product gas 18 to the reactor inlet.
• the temperature in the tube bundle reactor 1 can be influenced by removing liquid water from the intermediate space 16 above the addition of the water stream 4 to the tube bundle reactor 1. This liquid water is mixed with the water stream 4 and fed to the tube bundle reactor 1 again.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Inorganic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

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• 2012
  • 2012-04-20 DE DE102012206541A patent/DE102012206541A1/de not_active Withdrawn
• 2013
  • 2013-04-18 WO PCT/EP2013/058069 patent/WO2013156558A1/fr not_active Ceased

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