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
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
  • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
  • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
  • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
  • C01B3/36—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using oxygen or mixtures containing oxygen as gasifying agents
• • 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
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2/00—Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon
  • C10G2/30—Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon from carbon monoxide with hydrogen
  • C10G2/32—Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon from carbon monoxide with hydrogen with the use of catalysts
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
  • C10K3/00—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide
  • C10K3/02—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide by catalytic treatment
  • C10K3/04—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide by catalytic treatment reducing the carbon monoxide content, e.g. water-gas shift [WGS]
• • 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
• • 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
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/02—Processes for making hydrogen or synthesis gas
  • C01B2203/0205—Processes for making hydrogen or synthesis gas containing a reforming step
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/02—Processes for making hydrogen or synthesis gas
  • C01B2203/025—Processes for making hydrogen or synthesis gas containing a partial oxidation step
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/06—Integration with other chemical processes
  • C01B2203/062—Hydrocarbon production, e.g. Fischer-Tropsch process
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/1603—Integration of gasification processes with another plant or parts within the plant with gas treatment
  • C10J2300/1618—Modification of synthesis gas composition, e.g. to meet some criteria
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/164—Integration of gasification processes with another plant or parts within the plant with conversion of synthesis gas
  • C10J2300/1656—Conversion of synthesis gas to chemicals
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/1684—Integration of gasification processes with another plant or parts within the plant with electrolysis of water
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
• • 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 subject of the invention is a chemical transformation process comprising a synthesis step taking, as input, reagents including at least dihydrogen and carbon monoxide and giving as output a synthetic compound such as a fuel, water and overhead gases.
• a particularly targeted application relates to the chemical transformation of combustible products such as coal, oil, biomass or natural gas, so as to form at the end of the synthesis step at least one synthetic compound consisting of a liquid fuel such as an alkane and / or an alkene.
• combustible products such as coal, oil, biomass or natural gas
• a synthesis step in a transformation process is a known and commonly used technique. It makes it possible to provide a desired synthetic compound from reactive products such as carbon monoxide and dihydrogen.
• a general problem consists in obtaining a determined and sufficient quantity of dihydrogen upstream of the synthesis reactor.
• This type of problem can arise in a process of chemical transformation of combustible products such as coal, oil, biomass or natural gas, so as to form, at the end of the synthesis step, water, overhead gases and especially at least one synthetic compound consisting of one or more fuel (s) liquid (s) such as an alkane and / or an alkene.
• combustible products such as coal, oil, biomass or natural gas
• the transformation process is based on two main stages: firstly, a step of gasification of the solid fuel and then, secondly, a step of synthesis of the liquid fuels from the gases obtained at the end of gasification. Additional steps of reagent preparation and co-product upgrading can complement the process.
• the reagents can undergo a specification between gasification and synthesis, while the top gases can be upgraded for example by means of a turbine.
• the solid fuel is injected, after a preparation step adapted to the type of fuel and the type of gasification, in a gasification reactor where the gasification step is carried out using a carrier gas (for example nitrous nitrogen N 2 or carbon dioxide C0 2 ) and oxidized using an oxidant such as oxygen 0 2 .
• a carrier gas for example nitrous nitrogen N 2 or carbon dioxide C0 2
• an oxidant such as oxygen 0 2 .
• the role of gasification is to generate a mixture of H 2 dihydrogen and CO carbon monoxide.
• These two compounds resulting from gasification are the main reagents taken into input by the synthesis reactor where the synthesis step is implemented.
• the following equation shows the main balance equations of the synthesis: n ⁇ CO + 2 H 2) + H 2 ⁇ C n H n + 2 + n H 2 0
• overhead gas n (CO + 2H 2 ) ⁇ C n H 2 n + n H 2 0
• inert compounds such as dinitrogen N 2 .
• the fuel itself is composed of a small proportion of nitrogen, released during gasification.
• the recovery of this purge is the implementation of a combustion step of the purged fraction of overhead gas (including a supply of air) which supplies the energy in the form of heat necessary for a reforming stage (including a water supply) applied to the recycled fraction of overhead gas. If the amount is too large, the recovery can be a combustion in a boiler to recover heat, or in a gas turbine to produce electricity (the latter case is shown in Figure 1). These two solutions have a low efficiency (significant entropic losses during combustion) and lead to the production of pollutants in the form of NO x nitrogen oxides.
• a second solution provides for a production of dihydrogen by using an electrolysis of high temperature steam (known by the acronym "EVHT") by dissociating water from the following equation:
• the associated electrolysers use solid electrodes as the electrolyte.
• This so-called anionic solution separates the oxygen from the reagents (here, water) as shown in FIG. It also makes it possible to consume the heat generated in different areas of the transformation process to vaporize the water.
• the electrolysis of water allows more oxygen to produce the pure 0 2 used during the gasification step.
• the use of electrochemical solutions for producing dihydrogen and oxygen is proposed in the document US2008 / 0098654A1 which implements the recycling solution, but is also described for example in the document US2009 / 0235587A1 which has numerous options for use heat for the EVHT but does not provide a solution for upgrading the overhead gases.
• the object of the present invention is to provide a chemical transformation solution that overcomes the disadvantages listed above.
• an object of the invention is to improve the efficiency of the solution.
• Another object of the invention is to improve the recovery of the energy (contained in the material) of the overhead gases. Another object of the invention is to reduce or even eliminate the induced pollution.
• a first aspect of the invention relates to a chemical transformation process comprising a synthesis step taking as input reactants including at least dihydrogen and carbon monoxide and outputting a synthetic compound such as a fuel, water and overhead gases. He understands :
• it is a step of electrochemical production of dihydrogen by a conversion of the overhead gases recovered in the recovery step, electrochemically and in a manner creating the hydrogen.
• the process may comprise a step of transferring the dihydrogen formed in the step of producing dihydrogen to an input of a synthesis reactor implementing the synthesis step.
• a step of cracking the overhead gases from the synthesis step can advantageously be implemented.
• the step of producing dihydrogen may comprise an assisted electrolysis step, on the side of an anode of an electrochemical apparatus, by the overhead gases recovered in the recovery step.
• the method may comprise a step of collecting all or part of the water resulting from the synthesis step, the assisted electrolysis step using water recovered at the collection step.
• the electrolysis implemented at the assisted electrolysis step can be of anionic type and implement:
• the cracking step can then be applied to the gases recovered at the recovery stage, using a water vapor formed from the water recovered at the collection stage and / or a reused fraction of the total amount of water from the assisted electrolysis step.
• a step of collecting carbon dioxide produced during the combustion reaction at the anode can also be implemented.
• the process may also advantageously comprise a step of heat exchange between fluids chosen from the following list: overhead gases recovered during the recovery step, from the dihydrogen and / or water and / or carbon dioxide and / or nitrous from the assisted electrolysis step, the gases from the cracking step, the water recovered during the collection step, the carbon dioxide recovered during the collection step.
• the electrolysis implemented at the assisted electrolysis step may be of proton type and implement: an oxidation reaction on the anode side, from water and gases recovered at the recovery stage, producing carbon dioxide,
• Combustible products such as coal, petroleum, biomass or natural gas are in particular converted so as to form at the end of the synthesis step at least one synthetic compound consisting of a liquid fuel such as an alkane and / or an alkene.
• the process may comprise a gasification step, in a gasification reactor, taking at least at least said fuel products and leaving reagents including at least a portion of the dihydrogen and carbon monoxide used during the synthesis step.
• the method may also include a step of transferring carbon dioxide recovered in the carbon dioxide collection step to an inlet of the gasification reactor to form a carrier gas during the gasification step.
• a step of recycling the overhead gas fraction resulting from the synthesis step and not recovered during the head gas recovery step may be implemented, as well as a step of electrolysis of water, in particular of electrolysis type of steam at high temperature, using the water fraction from the synthesis step and not recovered during the water-collecting step.
• the process may comprise a dihydrogen transfer step produced during the step of electrolysis of water to an inlet of the synthesis reactor implementing the synthesis step and / or a step of transferring oxygen produced during the step electrolysis of water to an inlet of the gasification reactor implementing the gasification step to form an oxidizing compound during the gasification step.
• a second aspect of the invention relates to a chemical transformation plant, in particular for transforming fuels such as coal, oil, biomass or natural gas, into at least one synthetic compound, in particular a liquid fuel such as an alkane and / or an alkene, installation comprising the hardware and / or software elements that implement the transformation method described above.
• a third aspect of the invention relates to a computer program comprising a computer program code means adapted to performing the steps of the method, when the program is executed by a computer.
• FIG. 1 is a view illustrating the known principle of converting fuel products into liquid fuels
• FIGS. 2b and 2c and 3 illustrate the known solution for recycling overhead gases
• FIGS. 2a and 2c, 4 and 5 illustrate the known solution for supplying dihydrogen obtained by electrolysis of water
• FIG. 6 represents the general principle of an exemplary transformation method according to the invention
• FIG. 7 represents the operating principle of a hydrogen pump used in FIG. 6, in its anionic operating version
• FIGS. 8 and 9 illustrate the principle of operation respectively anionic and protonic of assisted electrolysis implemented in FIG. 7.
• the invention relates, in general, to a chemical transformation process comprising a synthesis step 10 taking as input reactants including at least H 2 dihydrogen and carbon monoxide CO and giving mainly a synthetic compound such as fuel, but also water and overhead gases.
• the invention relates in particular to the synthesis of a fuel of a liquid nature.
• the invention can be extended to any method for which a dihydrogen addition is beneficial and having a co-production of poorly upgraded energy compounds comparable to the overhead gases described herein, with adaptations on a case by case basis. For example to extend it to gaseous fuels, a step Further separation of the gases leaving the synthesis into undesired compounds and desired gaseous fuels is required.
• the overhead gases essentially comprise:
• inert compounds such as dinitrogen N 2.
• the synthesis step 10 is carried out in a synthesis reactor.
• Biomass which is a compound consisting mainly of carbon, hydrogen and oxygen (up to 50% by mass of oxygen), is a fuel in itself.
• the chemical transformation process also comprises a gasification step 1 1 of the fuel products, carried out in a gasification reactor and intended to form the reagents supplied at the input of the synthesis step 10.
• the solid fuel products are injected at using a carrier gas (for example nitrous nitrogen N 2 or carbon dioxide C0 2 ), after a preparation step 12 adapted to the type of fuel and the type of gasification 1 1, in the gasification reactor and oxidized by an oxidant such as oxygen 0 2 .
• a carrier gas for example nitrous nitrogen N 2 or carbon dioxide C0 2
• the use of the carrier gas is superfluous, on the other hand the oxidation stage 1 1 by an oxidizer such as O 2 O 2 or H 2 O may also be called reforming.
• the gasification step 1 1 takes at least at least said combustible products and gives off reagents including at least a portion of the dihydrogen and carbon monoxide used during the synthesis step 10. In fact, additional dihydrogen can also be used.
• gasification 11 The role of gasification 11 is to generate a mixture of H 2 dihydrogen and carbon monoxide CO supplied to the synthesis reactor.
• the reagents may, beforehand, undergo a step of setting to the specifications 13 between the gasification 1 1 and the synthesis 10.
• the transformation process comprises a step of recovering all or part of the overhead gases from the synthesis step 10 and a step of producing dihydrogen, electrochemically, at a hydrogen pump. 14 whose operation will be detailed later, by a transformation of the overhead gas recovered in the recovery step.
• the transformation process may also include a known step of electrolysis of water 15, especially high temperature steam electrolysis type "EVHT", and / or a recycling step 16 of the eventual fraction of overhead gas from the synthesis step 10 and not recovered during the overhead gas recovery step.
• EVHT high temperature steam electrolysis type
• the principles of the conventional electrolysis step have been previously described with reference to Figures 4 and 5 and are incorporated herein.
• the principles of the recycling step 16 have also been previously described with reference to Figures 2 and 3 and are incorporated herein also.
• the overhead gases recovered at the recovery stage correspond concretely to the purged fraction of overhead gas used during the recycling step 16.
• the hydrogen formed in the hydrogen production step by the hydrogen pump 14 is transferred to an inlet of the synthesis reactor, in order to be added to the hydrogen already produced by the reactor.
• gasification step 1 so as to ensure that the stoichiometric ratio between the dihydrogen and the carbon monoxide input of the synthesis reactor is slightly greater than two.
• the amount of hydrogen possibly resulting from the water and / or recycling electrolysis steps 16 may also be added upstream of the synthesis step 10.
• the step of electrochemical production of hydrogen by the hydrogen pump 14 comprises a step of assisted electrolysis 18, on the side of an anode 19 of an electrochemical apparatus, by the overhead gas recovered at the recovery stage .
• an electrochemical apparatus in other applications, is known for example from WO200017418 whose teachings are incorporated herein. It may be aided electrolysis anionic type ( Figure 8) as described here or proton type ( Figure 9) whose respective principles will be detailed below.
• the electrochemical apparatus which implements the electrolysis assisted at the anode 19 by the recovered overhead gases also comprises a cathode 20.
• Such assisted electrolysis consists in using the overhead gases at the level of the anode 19 in a manner to promote (by lowering the difference of electrical potentials) the electrolysis of the water addressed to the cathode 20 (or to the anode 19 in the case protonic), compared to a conventional electrolysis ( Figure 5) in which no overhead gas would be addressed to the anode 19.
• a step of collecting all or part of the water resulting from the synthesis step 10 can be carried out.
• This water thus collected is taken in input by the hydrogen pump 14 so that the assisted electrolysis step 18 can use water recovered at the collection step.
• the collected water may undergo a vaporization step 21 (also with a view to a possible cracking step 17 of the recovered overhead gas, detailed below).
• the electrolysis carried out at the assisted electrolysis step 18 implements:
• the dihydrogen produced during the assisted electrolysis step 18 is captured, which is represented by the reference 24.
• the amount of hydrogen captured 24 is equal to that produced, but can be less than to that outgoing at the cathode 20, because a part can be re-injected at the cathode 20.
• the carbon dioxide produced during the combustion reaction at the anode 19 can advantageously be collected during a collection step 23. This amount of carbon dioxide has the advantage of being diluted or not.
• the electrochemical apparatus which carries out the assisted electrolysis step 18 is therefore generally a combination of an electrolyzer for creating hydrogen and oxygen, and a fuel cell (thanks to the presence of the overhead gases at the reactor). anode 19) carrying out the combustion of the oxygen at the anode 19.
• a hydrolyzer and a fuel cell for respectively the production of hydrogen and the simultaneous recovery of the overhead gases is called a “hydrogen pump” because it makes it possible to separate the hydrogen element from the overhead gases and to obtain it in the form of pure dihydrogen, realizing what is called here an "assisted electrolysis".
• the electrolyser performs the electrolysis reaction in which the reduction reaction from water is carried out.
• the presence of overhead gas at the anode 19 makes it possible for the assembly to be also a fuel cell which implements at the anode 19 the combustion reaction described above and whose ideal reaction equation of Pure oxygen combustion (whether conventional or electrochemical) is presented below:
• any compound of the overhead gas satisfying c + ⁇ _ ⁇ > 0 can be used in this combustion reaction, in particular:
• the N 2 dinitrogen present in the recovered overhead gas can come from the dinitrogen used as carrier gas at the gasification stage 1 1 and from the fuel products themselves (for example 1% by mass on average for wood and coal). .
• the chemical reaction formula of the anionic hydrogen pump 14, which combines the reduction reaction and the combustion reaction, is as follows: ⁇ 2 0 ⁇ ⁇ 2 + - 0 2
• the electrolysis implemented at the assisted electrolysis step 18 implements:
• the carbon dioxide is undiluted at the purge combustion (carried out with pure dioxygen).
• the overhead gases recovered at the recovery stage can then be pressurized, so that the pressure of the hydrogen produced by the hydrogen pump 14 is equal to the pressure necessary for the implementation of the synthesis 10 (very variable between atmospheric pressure and approximately 90 bar).
• a cracking step 17 of the overhead gases from the synthesis step 10 can be carried out prior to the assisted electrolysis step 18.
• This cracking 17 of the overhead gases can be carried out before or after the possible pressurization described above. It can also be performed before or after the overhead gas recovery step.
• the advantage is not having to carry out additional cracking at the fraction of the overhead gases at which the recycling step 16 is applied.
• the cracking 17 is implemented after the recovery step, the advantage is that it is possible to use, for the realization of this cracking 17, the water resulting from the electrochemical production step of dihydrogen, at the outlet of the anode 19 and / or the cathode 20.
• Chemical Formula 17 cracking step is as follows: c n H "2 ⁇ + H 2 O ⁇ ⁇ ⁇ 1 ⁇ CH 4 + ⁇ ⁇ Co 2
• the cracking step makes it possible to convert the hydrocarbons of more than two carbon atoms into methane. In this case, they must previously be heated to the reaction temperature (about 400 to 600 ° C) and this is why the vaporization step 21 is performed, providing water vapor to be injected. This steam is injected excess, the molar ratio between water and carbon atoms being between 2 and 5.
• the water resulting from the synthesis step 10 collected at the collection stage and / or at least a reused part of the water coming from the anode 19 and or the cathode 20 at the end of the assisted electrolysis step 18 may be used.
• the cracking step 17 is then applied to the gases recovered at the recovery stage, using the steam formed in the vaporization step 21 from the water recovered at the stage of collection and / or the recycled fraction of the total amount of water resulting from the assisted electrolysis step 18.
• the cracking reaction is almost athermic and at the outlet, the overhead gases are a mixture of hydrogen dihydrogen H 2 , H 2 O water, CH 4 methane, CO carbon monoxide, C0 2 carbon dioxide and N 2 dinitrogen.
• a heat exchange step 22 can be performed between fluids chosen from the following list:
• the overhead gases from the cracking step 17 must indeed be brought to a reaction temperature of between about 600 ° C. and 1 ° C. 100 ° C according to the electrolysis technology. This rise in temperature can be achieved by recovering the heat from the gases leaving the assisted electrolysis 18 with the aid of a suitable heat exchanger performing the heat exchange step 22. This heat recovery can also be carried out for the heating of the overhead gases and / or the water used for the cracking step 17.
• the cathode 20 of the electrochemical apparatus performing the assisted electrolysis 18 must also be supplied with steam. water, especially the steam from the vaporization step 21, previously brought to a pressure close to that of the overhead gases.
• this steam Before injection at the cathode 20 of the electrochemical apparatus performing assisted electrolysis 18, this steam must be brought to a reaction temperature of between about 600 ° C. and 1100 ° C., depending on the electrolysis technology. This rise in temperature can be achieved by recovering the heat from the gases leaving the assisted electrolysis using a heat exchanger performing the heat exchange step 22.
• the overhead gases are oxidized, for anionic operation, carbon dioxide C0 2 and water H 2 0.
• the dinitrogen N 2 is inert.
• the water in the form of steam from the heat exchanger 22 is reduced to H 2 dihydrogen. Some of the water is not converted, however. Part of this dihydrogen can be returned directly or indirectly to the cathode 20 at the heat exchanger so that the water is not pure at the inlet of the the electrochemical apparatus (in fact, up to 20% of hydrogen is required in the incoming water at the cathode 20).
• the outgoing currents of the assisted electrolysis 18 have undergone a pressure drop of less than a few bars in the heat exchangers and the electrochemical apparatus.
• the outgoing currents of the electrochemical apparatus will be 10 to 50 ° C warmer than the incoming currents, making them usable for heating the incoming currents in the electrochemical apparatus. They are then cooled to a temperature of between 100 and 300 ° C. They can optionally be cooled to a lower temperature, for example between 10 and 50 ° C in order to separate the water by condensation (respectively according to references 25 and 26 for the flow of hydrogen and for the flow of the carbon dioxide mixture and dinitrogen). Pure dihydrogen is further preferable for carrying out the synthesis step to avoid dilution of the reagents.
• the separation 25, 26 of the water allows its reuse in the vaporization stage 21.
• the energy contained in the overhead gases is transferred directly and therefore effectively to the hydrogen produced by the hydrogen pump 14 described above.
• the dihydrogen is thus separated from inert diluents (such as dinitrogen) which tend to limit the feasibility of recycling 16, and is obtained pure (after condensation 25, 26 of the water) and therefore does not have to undergo separation additional.
• the carbon dioxide obtained with assisted electrolysis 18 is not or only slightly diluted with additional dinitrogen, making it more easily catchable 23.
• the chemical transformation process may advantageously comprise a step of transfer of the carbon dioxide C0 2 recovered 23 during the collection stage, to an inlet of the gasification reactor to form a carrier gas during the gasification stage 1 1.
• the optional step of electrolysis of water may advantageously use the fraction of water resulting from the synthesis step 10 and not recovered during the water-collecting step, as illustrated in FIG. limit the overall cost of operation.
• the chemical transformation process may comprise a step of transfer of dihydrogen H 2 produced during the step of electrolysis of water to an inlet of the synthesis reactor implementing the synthesis step 10 and / or oxygen transfer step 27 produced during the step of electrolysis of water to an inlet of the gasification reactor implementing the gasification step 1 1 to form an oxidizing compound during the gasification step 1 1.
• the invention also relates to the chemical transformation plant as such, in particular for converting fuels such as coal, oil, biomass or natural gas, into at least one synthetic compound, in particular a liquid fuel. such as an alkane and / or an alkene, this installation comprising for this the hardware and / or software elements that implement the previously described transformation method.
• the hydrogen pump 14 then supplies 0.31 kg / s (15 mol / s) of dihydrogen to the cathode 20.
• the current leaving the anode 19 is in turn constituted as follows:
• the carbon dioxide represents 83% by weight and 75% in terms of the flow outgoing.
• This high value allows easy capture.
• the reuse of water allows to limit its consumption by the hydrogen pump 14 to 1, 34 kg / s (75 mol / s), or 49 mol% of the production of dihydrogen by the heat pump.
• the electricity consumption of assisted electrolysis 18 is 3.27 MW, ie 10.5 MJ per kilogram of electrochemically produced dihydrogen.
• the total production of dihydrogen, combining that obtained by the water electrolysis step and that obtained by the step of assisted electrolysis 18 by the overhead gases, is 2.25 kg / sec. mol / s), for 244 MW required for the reactions, that is to say 108 MJ per kilogram of dihydrogen on average.
• simple electrolysis of water requires 124 MJ per kilogram of dihydrogen obtained.
• the solution proposed here assisted electrolysis 18 can reduce the power consumption of 12%. This performance is partially offset by a greater need for high temperature heat provided by natural gas.
• the gains in secondary energy (corresponding to the energy consumed by the process and measured at the input of the process) then become of the order of 1, 5%.
• the configuration studied is particularly unfavorable to assisted electrolysis 18 because simple electrolysis makes it possible to exactly supply the quantity of oxygen required for gasification 11 (assisted electrolysis 18 then creates a need for electricity for the production of dioxygen ) and the heat supplied by the purge is of the same order as the need for the reforming of the recycling step 16 (the assisted electrolysis 18 then creates a need for natural gas to bring the heat to this reaction).
• the yields are obtained by dividing the energy contained in the fuels at the output of the process by the energy consumed at the process inlet: (wattage in MW) Hydrogen pump and EVHT EVHT only
• the conventional recycling step 16 is not realized.
• the hydrogen pump 14 then supplies 0.84 kg / s (415 mol / s) of dihydrogen to the cathode 20.
• the current leaving the anode 19 is in turn constituted as follows:
• the cooling of the whole of the hydrogen produced on the one hand by the simple electrolysis of water and on the other hand by the electrolysis assisted by the overhead gases by the hydrogen pump 14 makes it possible to heat the gases of The head from the cracking step 17 from 535 ° C to 770 ° C, vaporize the water for the cracking step 17 and bring it to 500 ° C.
• the hydrogen is thus cooled to 160 ° C. Cooling the outlet of the anode 19 allows the steam to overheat from 240 to 770 ° C and to heat the liquid water for the electrolyses 15 and 18 to 210 ° C.
• the carbon dioxide After condensation of the water, the carbon dioxide represents 38% by weight and 28% with respect to the flow leaving the anode 19. This value is much lower than previously for the case 1, given the quantities of dinitrogen injected.
• the reuse of the water makes it possible to limit its consumption by the hydrogen pump 14 to 1. 81 kg / s (101 mol / s), ie 24 mol% of the hydrogen production by the hydrogen pump.
• the electricity consumption of assisted electrolysis 18 is 7.14 MW, or 8.5 MJ per kilogram of hydrogen produced from electrochemically by transformation of the overhead gases.
• the total production of dihydrogen, combining that obtained by the water electrolysis step and that obtained by the step of assisted electrolysis 18 by the overhead gases, is 1.29 kg / s (638 mol / l). s), for 63 MW required for the reactions, ie 49 MJ per kilogram of hydrogen.
• simple electrolysis of water requires 124 MJ per kilogram of dihydrogen obtained.
• the solution proposed here assisted electrolysis 18 reduces power consumption by 32%, despite a greater need for oxygen, obtained by separation of air. Secondary energy gains are 6.7%.
• the configuration studied is particularly favorable to assisted electrolysis because the amount of inert compound injected into the process is such that all the overhead gases resulting from the synthesis must be purged (the recovery of these overhead gases electrochemically by the hydrogen pump 14 is more efficient than a recovery by combustion followed by a production of electricity).
• the yields are obtained by dividing the energy contained in the fuels at the output of the process by the energy consumed at the process inlet:
• the carbon dioxide produced is undiluted on purge combustion (performed in the presence of pure oxygen).

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