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
  • 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
  • C25B1/042—Hydrogen or oxygen by electrolysis of water by electrolysis of steam
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
  • C07C1/02—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon
  • C07C1/04—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon from carbon monoxide with hydrogen
  • C07C1/0405—Apparatus
  • C07C1/041—Reactors
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
  • C07C1/02—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon
  • C07C1/12—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon from carbon dioxide with hydrogen
• • 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
  • C25B1/23—Carbon monoxide or syngas
• • 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
  • C25B15/02—Process control or regulation
  • C25B15/021—Process control or regulation of heating or cooling
• • 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
  • 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
  • C25B15/081—Supplying products to non-electrochemical reactors that are combined with the electrochemical cell, e.g. Sabatier reactor
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M16/00—Structural combinations of different types of electrochemical generators
  • H01M16/003—Structural combinations of different types of electrochemical generators of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
  • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
  • H01M8/0656—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants by electrochemical means
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
  • H01M8/0662—Treatment of gaseous reactants or gaseous residues, e.g. cleaning
  • H01M8/0668—Removal of carbon monoxide or carbon dioxide
• • 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
• • 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
  • Y02E60/50—Fuel cells
• • 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
  • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Definitions

• the object of the invention is to significantly improve the above-mentioned efficiencies for "power-to-gas" technologies with the help of an integrated overall concept, to minimize the investment costs through new circuits and their structural design and thus to contribute to sustainable system integration, which despite fluctuating feed-in guarantees a secure and stable power supply and contributes to sustainable supply and disposal management through CO 2 recycling.
• Problem analysis, solution approaches and task definition A with the help of in (Wolfgang Georg Winkler: Sustainable product development based on second law of thermodynamics. September 2011. Applied Energy 88(9): 3248-3256 DOI: 10.1016/j.apenergy.2011.03.020) indicated methodology of reversible process structures showed that essentially two effects with their impact on further process integration to these lead to relatively low efficiencies.
• low-temperature electrolysis best fulfills the task of converting excess electricity and unusable waste heat into usable chemical potential.
• high-temperature electrolysis is the more suitable process when sufficient high-temperature heat is available and little electrical power is available. If there is a sufficient external heat supply, the necessary evaporation heat can also be provided without any difficulty, without generating additional power consumption. However, it must be taken into account that the use of high-temperature heat for evaporation also leads to considerable exergy losses and thus does not solve the thermodynamic problem.
• the methanation processes commonly used today use H 2 and CO 2 as reactants. The optimization of the electrolysis is therefore today a basic requirement for the further optimization of these processes.
• thermodynamic variables required for balancing are entered for easier orientation.
• the entire product cycle of the H 2 from the removal of the H 2 O in the liquid state to its evaporation, the production of the gaseous products H 2 and O 2 by means of electrolysis with the electrical work supplied, the storage of the products, the subsequent conversion in the fuel cell with the release of the generated electrical work and condensation of the gaseous reaction product H 2 O through to the discharge of the liquid H 2 O. Since reversibility of all processes is assumed, occurring Losses are only caused by faulty system structures that are so easily identifiable. It is then the task to come as close as possible to the technical implementation of these theoretical structures with technically and economically sensible solutions.
• the main components of this isothermal system are the electrolyser (1) and the fuel cell (2), which are connected to each other via the two gas storage tanks (3a) and (4a) and the associated lines (3) and (4) and at temperatures T above the associated saturated steam temperature, practically above 100 °C.
• the line system (3) contains H 2 in an H + conductive electrolyte and O 2 in an O 2- conductive electrolyte and accordingly the line system (4) with O 2 in H + conductive electrolytes and with H 2 in O 2- conductive electrolytes filled.
• this is irrelevant for the thermodynamic consideration as long as H 2 and O 2 remain separate from each other in systems 3 and 4.
• H 2 and O 2 stored separately in the gas storage tanks (3a) and (4a) are fed to the fuel cell (2) if required (lack of electricity) and converted there again to H 2 O and the free enthalpy of reaction - ⁇ R G becomes released as reversible work (here and in the following the resulting signs are put in front for a better understanding and the quantities ⁇ R G , ⁇ R S and ⁇ s v are then to be understood as absolute values).
• H 2 O is condensed in the condenser (5) and fed to the H 2 O tank (6) and the heat of condensation -T .
• ⁇ s v is released to the heat accumulator (7), where ⁇ s v stands for the entropy change due to the phase change.
• the reversible waste heat -T . ⁇ R S produced as a result of the reaction entropy ⁇ R S must be fed from the fuel cell (2) to the heat accumulator (8).
• the liquid H 2 O taken from the H 2 O tank (6) when there is a surplus of electricity is fed to the evaporator (9) and vaporized there by means of the supply of the required heat of vaporization +T . ⁇ s v from the heat accumulator (7) and the electrolyser (1). supplied via the H 2 O line (10).
• the electrolyser (1) receives the free reaction enthalpy + ⁇ R G as reversible work from the outside and the heat input required because of the reaction entropy ⁇ R S + T . ⁇ R S supplied from the heat accumulator (8). This completes the cycle and describes how its components work. If the energy supplied to and removed from the system is now summarized, the energy supplied E to : (3) and for the energy to be dissipated Eab: (4) This process structure is exactly loss-free and losses that actually occur in systems constructed in this way are only due to the imperfection of the practical implementation with real lossy components.
• the electrolyser and fuel cell are operated separately, as mentioned, which means that there is no longer a direct physical connection between the fuel cell and the electrolysis, and the internal heat exchange required for high efficiency is no longer possible.
• the extension to this case is therefore necessary in order to understand and technically implement the design principles of electrolysis, which is essential for every "power-to-gas" technology.
• the closed reversible cycle of an energy storage process based on H 2 described in Fig. 1 does not describe the precise structure of the H 2 O tank (6), the heat recovery via the condenser (5), the heat storage (7) and (8) and the evaporator (9), but only their ideal mode of operation. This means that the system boundary within which these functions must be fulfilled can also be freely selected.
• the environment forms a reversible store for all heat and substances that are exchanged with it, while at the same time a reversible (electrical) energy network is tacitly assumed as a reversible store for the reversible work that is supplied and removed.
• a reversible (electrical) energy network is tacitly assumed as a reversible store for the reversible work that is supplied and removed.
• the choice of the environment as storage there is also no need to include the refilling of the storage in the considerations, because the thermodynamic state of the environment does not change due to the reversible heat and substance removal by the electrolysis system.
• the removal of the required reversible Carnot work for the heat pump does not affect the state of a global reversible power grid with environmental character.
• the electrolysis system for electricity storage is obviously the most thermodynamically advantageous one, which obtains the required heat supply from the environment with the least possible effort and thereby converts the greatest possible amount of electrical work into the thermodynamic potential of the H 2 formed.
• high-temperature electrolysis can be the more advantageous solution when high-temperature heat is sufficiently available and electricity is scarce or too expensive.
• high-temperature heat can be used to generate electricity, so its thermodynamic value is significantly higher than that of low-temperature waste heat.
• This also defines the design principle, as with any isolated synthetic gas generation with H 2 as a reactant, the losses for providing the required heat of vaporization can be minimized.
• the evaporation heat required for low-temperature electrolysers can always be provided more energy-efficiently than is the case with the dissipation of electrical work that is common today.
• the energy requirement of the heat pump can also be further reduced if instead of using ambient heat any waste heat can be used as its heat source.
• the heat pump can be omitted if the temperature of the waste heat is above the required evaporation temperature, usually 100 °C. In the sense of the comparison process, waste heat can be interpreted as any heat that would be dissipated in the environment for evaporation if not used and thus contributes to its entropy increase.
• the second essential influence follows from the separation of substances in thermal processes for CH 4 generation according to Sabatier.
• a scheme as indicated in FIG. 2 serves to analyze the possible process steps.
• the starting materials and the thermodynamically possible variants of reactions are shown there in 3 columns, with the corresponding links being indicated by arrows.
• H 2 O and CO 2 enter the system as starting materials.
• the first step before thermal methanation is upstream electrolysis. For methanation, reduction to at least 2 moles of H 2 per mole of CH 4 to be produced is absolutely necessary.
• Eq. (6) H 2 generation is the only electrochemical process that suffices, because CO 2 is a reactant in Eq. (6) is.
• the reduction of CO 2 to CO can also be represented electrochemically and has the advantage that the reaction takes place in ambient conditions without a phase change.
• the thermal methanation reaction Eq. (7) an option that requires only 3 moles of H 2 per mole of CH 4 . This means that the evaporation loss compared to the reaction Eq. (6) Decreased by 25%.
• two different electrolysis processes are then required at the same time: (7) In the third column of FIG. 2, combinations are given only for the methods that are possible with an O 2 -conducting electrolyte, via which O 2 can be electrochemically discharged.
• the working ranges of the electrolysis and the methanation processes are also shown, as well as the discharged O 2 substance quantity as a parameter and the assignment to the electrolysis and methanation processes can be seen via the noted equation numbers. Since the temperature of methanation is usually higher than that of the associated electrolysis, more heat is released than is required for the electrolysis. This results in an excess of heat emission, which can be used to evaporate the water for the electrolysis. This effect arises because the electrolysis, which works at a lower temperature, requires more electrical power than at a higher temperature, where more energy is supplied by heat. These different temperatures are due to the operating temperature of the catalysts and the excess (irreversible) heat can be used as evaporation heat in the system. All methods for methanation according to Eqs.
• the CH 4 -H 2 O mixture is then passed via the heat exchanger (16) for H 2 preheating and the second stage of CO 2 preheating (17) to the condenser (15) for the separation of CH 4 and H 2 O.
• the condensed H 2 O is stored in the container (6) and the CH 4 is discharged separately (14).
• 4 mol H 2 O must be supplied to the electrolyser, half of which is provided by recirculation and the other half from outside.
• the required H 2 O is fed to the evaporator (9) via the condenser (15) and to the electrolyser (1) as vapor via line (10).
• the O 2 emerging from the electrolyzer is conducted via the line (4) to the heat exchanger (17) as the first preheating stage for preheating the incoming CO 2 and is cooled there.
• the tasks to improve the efficiency of the synthetic production of H 2 and CH 4 and other hydrocarbons can be hydrogen, generally hydrocarbon compounds, which are in accordance with the Characteristic fields of FIGS. 3 and 4 behave, and specify their technical implementation in the following points.
• the use of oxygen-ion-conducting electrolytes can also enable direct methanation according to Eq. (5) enable. This means that at least 2 moles of H 2 O must be supplied per mole of CH 4 produced.
• the fuel cell (2) is supplied with H 2 and O 2 from the gas storage tanks (3a) and (4a) when electricity is required and is operated at a higher temperature than the electrolyser (1) that a reliable heat exchange via the heat accumulator (8) is secured.
• the pressure of the exhaust steam from the fuel cell (2) is correspondingly increased with a steam compressor (18) so that the heat accumulator (7) can be supplied by the condenser (5) with waste heat at a sufficiently high temperature during the condensation of the exhaust steam from the fuel cell and the condensate is formed supplied to the H 2 O tank (6).
• the electrolyser (1) is supplied with steam from the H 2 O tank (6) via the feed pump (19), the evaporator (9) and the H 2 O line (10) and then fills the two gas storage tanks (3) and (4) again with H 2 and O 2 .
• the heat required for this is taken from the heat accumulator (7).
• the amount of heat stored in the heat accumulator (8), which results from the release of the reaction entropy of the fuel cell, is relatively small at low operating temperatures of the electrolyzer. It is therefore advisable to check here whether the operating conditions of the electrolyser allow an additional storage tank to be installed economically, or whether it makes more sense to compensate for the heat loss through electrical heating or to look for other solutions.
• the evaporation heat from the heat source (22, 27) is waste heat from processes or waste heat obtained from the environment.
• Waste heat from (industrial) processes is in particular industrial waste heat, preferably with a maximum temperature of 400°C, more preferably not more than 300°C, even more preferably not more than 200°C.
• Waste heat from processes is advantageously external waste heat, ie it is supplied to the device according to the invention from outside and originates, for example, from an external industrial process and not from processes within the device according to the invention, in particular not from the waste heat of a fuel cell in the device according to the invention, unless this heat would otherwise be dissipated into the environment as intended.
• a heat pump can be omitted if the temperature of the waste heat is above the required evaporation temperature.
• a shown in Figure 7 simplified device with the same functionality differs from the basic solution discussed above in that the system of condenser (5), H 2 O tank (6), heat storage (7) and evaporator (9) by a Steam accumulator (20) is replaced, which supplies the electrolyser (1) with steam when there is a surplus of electricity and is recharged when there is a demand for electricity from the exhaust steam of the fuel cell via the steam compressor (18).
• the steam accumulator (20) can be equipped with electrical heating to maintain pressure or a connection to a steam network, if available, or other connected steam accumulators or other heat accumulators and thus be integrated into an industrial sector coupling with a large storage volume .
• the device described can also be used in regenerative fuel cells (1/2), which can also be operated as an electrolyzer, as shown in FIG.
• the steam accumulator (20) is connected to the regenerative fuel cell (1/2) and the steam compressor (18) via a three-way valve (21).
• the three-way valve (21) connects the regenerative fuel cell (1/2) to the vapor compressor (18) and the vapor accumulator (20) is charged with the vaporous H 2 O formed.
• the three-way valve connects the steam accumulator (20) with the regenerative fuel cell (1/2) in electrolysis mode.
• the steam storage tank (20) can also be connected to other steam storage tanks in a steam network and integrated into an industrial sector coupling.
• the possibilities of process improvement shown in Fig.1 can also be used for open circuits for H 2 production and consequently for the CH 4 production and, under certain conditions, also for the production of other hydrocarbons (CnHm) or hydrocarbon compounds.
• the reversible process described above can be approximated thermodynamically if the released during the H 2 oxidation Evaporation heat – be it in a fuel cell or in a combustion reactor – is given off to the environment due to the lack of recuperation options during condensation if, conversely, the evaporation heat of the H 2 O required for electrolysis can be recovered from the environment.
• This can be achieved, or at least approximated, as part of a system integration of the electrolysis (1) with the aid of a circuit as indicated in FIG. H 2 O is fed from the container (6) via the feed pump (19) to the evaporator (23) and supplied there with sufficient evaporation heat from the heat source (22) and the resulting vapor is then fed to the electrolyser (1).
• the design of the evaporator (23) can integrate the vapor accumulator (20) into the evaporator (9). If, for example, the heat source (22) is supplied with solar heat or geothermal heat with heat of vaporization, the requirement for a reversible process would be a good approximation, since this type of heat transfer causes the environment to damage the vaporizer with the entropy released during H 2 oxidation (at least approximately) would have supplied again. Although this ideal case cannot always be achieved, a structure according to FIG supplied H 2 O can be used to significantly reduce the exergy losses of 17% during H 2 production. The advantage of this approach is that industrial plants can use low-exergy steam to save on the dissipation of electrical work.
• the device according to FIG (27) take place in a variety of ways. For example, various heat-emitting fluids can be passed through pipes, or exothermic reactions that need to be cooled can take place there.
• the heat sources (27) are to be arranged in parallel so that a orderly evaporation process and water circulation in the evaporator section (9) can be ensured.
• the electrolyzer (1) consists of cell groups (24) arranged in parallel, which can be designed in the form of plates or tubes, but also as microprocess engineering modules, which are surrounded by a cladding tube (25).
• the steam is conducted via the steam dome (28), the steam line (29) to the distributors (30) and then to the cell groups (24) located in the cladding tube (25).
• the parallel flow distributors (30) connect the cell groups (24) and the associated cladding tubes (25) to the parallel headers (31) and (32).
• the gases of the systems (3) and (4) then exit from the collectors (31) and (32).
• H 2 emerges as a gas in (4) and O 2 as a gas in (3).
• the H 2 O is supplied via the inlet connection (33), whereby the incoming water should already be preheated to almost the saturated steam temperature.
• the inlet socket (33) can also be used to feed in external steam to maintain the temperature of the system during standstills and also, depending on the options for system integration, for steam heating instead of the heat source (27). Electrical heating of the evaporator is also possible for commissioning and as an emergency supply.
• the individual fuel cell groups (2) are surrounded analogously to the electrolytic cells (24) with or without cladding tubes (25) and the circuit shown in FIG. 7 is retained at the same time used as a heat source (27).
• the gases H 2 and O 2 involved in the fuel cell process enter the fuel cell via two separate flow distributors and the product H 2 O via an outlet collector, corresponding to the process-related reversal of flow direction to the vapor compressor (18) and then via the inlet (33) into the integrated evaporator (26).
• the steam compressor (18) injects the higher-tension steam not only into the evaporator section (9) but also into the vapor space (35a).
• FIG. 11 shows a variation of the device according to FIG.
• FIG. 10 in which the flow distributors (30) and the collectors (31) and (32) are replaced by chambers.
• the two collectors (31) and (32) are replaced by the two gas chambers (36) and (37), which are formed with the tube sheets (35).
• the flow guidance and gas distribution is analogous to what was said in relation to FIG. In the case of an integrated H 2 power store according to the variants presented in FIG. 7 or 8, what was said above in the description of FIG. 10 applies.
• FIG. 12 A further simplification of the construction of the device is shown in FIG. 12.
• the electrolyzer is constructed as in FIGS.
• FIG. 13 shows the heating (11) of the integrated evaporator using the example of the variant shown in FIG. 12 by means of an exothermic reaction based on the methanation reaction Eq. (6) instead of or in addition to the general heat source (27).
• Eq. (6) instead of or in addition to the general heat source (27).
• this also shows the basic structure of the associated further necessary system integration for an integrated CH 4 generator.
• Eqs. (6) to (10) specified methanation reactions are exothermic and therefore suitable in principle for heating the evaporator, as already explained in FIG.
• the system structure corresponds to the rules formulated in (Wolfgang Georg Winkler: Sustainable product development based on second law of thermodynamics. September 2011. Applied Energy 88(9): 3248-3256 DOI: 10.1016/j.apenergy.2011.03.020).
• reactants and products for heat recovery must first be used and the individual temperature levels of the reactions concerned must be taken into account before additional heat can be supplied.
• the products H 2 and O 2 are obtained from the reactant H 2 O.
• the reactants H 2 and CO 2 according to Eq. (6) CH 4 and H 2 O generated. This results in the three different temperature levels of the environment, evaporator/electrolyser and methanation between where the heat recovery shown here takes place.
• the CH 4 -H 2 O mixture is fed via line (13) according to Eq. (6) discharged from the methanation reactor (11).
• the CH 4 -H 2 O mixture is then passed through the heat exchanger (16) for H 2 preheating and the second stage of CO 2 preheating (17) and finally to the condenser (15) for the separation of CH 4 and H 2 O.
• the condensed H 2 O is stored in the container (6) and the CH 4 is discharged separately (14).
• the electrolyser requires 4 moles of H 2 O to produce 1 mole of CH 4 , half of which is provided by recirculation and the other half from outside.
• FIG. 14 shows a corresponding addition to the system structure of the device shown in FIG. However, the changes in the system only affect the area of the device that includes the supply line of the CO 2 (12) and the components connected thereto.
• the CO 2 is fed via the line (12) to the distributor (38) of the CO 2 electrolyzer (39) and converted there into CO while releasing 1/2 O 2 into the evaporator section (9) analogously to the H 2 O electrolysis.
• This is about the Collector (40) and the line (41) to the preheater (42) and from there to the methanation reactor (11).
• the conception of the treatment of the CH 4 -H 2 O mixture which emerges from the methanation reactor (11) remains unchanged compared to FIG. Analogous to FIG. 11, this device can be structurally simplified further, as shown in FIG. There, the distributor (38) is replaced by a CO 2 inlet chamber (43), which is used to supply gas to the electrolytic cell (39).
• the CO formed in the electrolytic cell (39) is then fed into the H 2 outlet chamber (36) and the H 2 – CO mixture is, as in Fig. 13, via the line (3) after preheating in the heat exchanger (16). supplied to the methanation reactor (11).
• Another way of improving the efficiency of methanation according to Eqs. (6) and (7) result from exploiting the unused potential for recovering electrical work in these thermal processes, as shown in FIG. 16 serves to explain the practical implementation.
• H 2 and CO 2 according to Eq. (6) or CO according to Eq. (7) flow into the methanation reactor (11). In both cases, additional H 2 is required compared to the requirement for CH 4 production alone, in order to be able to separate O 2 by condensation of CH 4 after oxidation with H 2 .
• the existing potential for delivering electrical work can be used by adding H 2 with the help of an H + -conducting fuel cell.
• H + ions then escape on the outer surface of the fuel cell and react with CO 2 or CO to form CH 4 and H 2 O.
• the construction principles derived above can be adapted to the corresponding devices.
• the electrolytic cells (24) are replaced by methanation reactors (11), the walls of which are formed from O 2- -conducting electrolytes, whereby the duct (37a) is formed with the cladding tube (25a), which is used to discharge the O 2 serves.
• the steam is supplied via the steam line (29) into the steam chamber (34).
• the CO 2 is supplied there via the line (12) after its preheating in the heat exchanger (17), the mixture of H 2 O and CO 2 is then passed into the methanation reactor (11).
• CO 2 and vaporous H 2 O can also be fed into the methanation reactor separately.
• the device according to FIG. 21 can be combined with an H 2 O electrolysis, as shown in FIG. 22 using Eq. (9) shows. All that is required is for the chambers (34, 36, 37) to be divided at the inlet and outlet with a partition (35a) and/or to be supplemented or replaced with the design of flow distributors (30) and collectors (31), (32). The corresponding division at the outlet leads to a chamber (36) for CH 4 and a chamber (36a) for H 2 .
• the construction of the electrolysis part corresponds to FIG.
• the H 2 formed is added to the CO 2 line (12) via line (3).
• the H 2 can also be admixed on the steam side in the line (29) or in the inlet chamber (34), with an optional H 2 withdrawal also being possible via the branch (3a).
• the amount of steam fed to the electrolysis (1, 24) and thus the H 2 production is regulated via a control device (29a).
• a control device 29a
• the methanation reactors (11) are supplied with CO and CO 2 , their ratio can also be regulated. If only a small amount of H 2 is required for methanation , the cladding tube (25 ) can be dispensed with, based on FIG.
• the geometric arrangement of the individual integrated methanation reactors (11) and the electrolysers (1) and (39) is decisively determined by their influence on the heat and substance concentrations as well as the heat and substance transport and, if necessary, optimized with installations for flow control.
• the further integration of the device of an integrated CH 4 generator (44) designed according to the above construction principles into a sustainable energy system is essential for the sustainability and CO 2 freedom of its operation.
• the reversible comparison process according to FIG. 1 represents the theoretical basis of the process management. Accordingly, the CH 4 produced is stored in existing gas storage tanks (45) and used in fuel cells (2) to generate electricity and heat.
• the resulting exhaust gas only contains CO 2 and H 2 O and the use of residual heat in a flue gas condenser (46) allows CO 2 and H 2 O to be separated.
• the resulting CO 2 is via a CO 2 line system (12) after compression in the CO 2 Compressor (47) supplied to the CO 2 store (48), which in turn supplies the CH 4 generator (44) again.
• it is expedient to cover the C n H m demand, general demand for hydrocarbon compounds, from industry and trade (49) from the gas storage facilities (45).

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• 2020
  • 2020-10-15 DE DE102020006326.8A patent/DE102020006326A1/de active Pending
• 2021
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