Classifications

• • 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
  • C01B3/38—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 catalysts
  • C01B3/382—Multi-step processes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
  • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
  • B01J8/0492—Feeding reactive fluids
• • 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
  • C01B13/0229—Purification or separation processes
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  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B21/00—Nitrogen; Compounds thereof
  • C01B21/04—Purification or separation of nitrogen
  • C01B21/0405—Purification or separation processes
• • 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
• • 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
  • C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
  • C01B3/501—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by diffusion
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00017—Controlling the temperature
  • B01J2208/00106—Controlling the temperature by indirect heat exchange
  • B01J2208/00309—Controlling the temperature by indirect heat exchange with two or more reactions in heat exchange with each other, such as an endothermic reaction in heat exchange with an exothermic reaction
• • 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
  • C01B2203/0227—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step
  • C01B2203/0233—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step the reforming step being a steam 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
  • C01B2203/0205—Processes for making hydrogen or synthesis gas containing a reforming step
  • C01B2203/0227—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step
  • C01B2203/0244—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step the reforming step being an autothermal reforming step, e.g. secondary reforming processes
• • 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
  • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
  • C01B2203/0465—Composition of the impurity
  • C01B2203/0475—Composition of the impurity the impurity being carbon dioxide
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
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  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/08—Methods of heating or cooling
  • C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
  • C01B2203/0811—Methods of heating the process for making hydrogen or synthesis gas by combustion of fuel
• • 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
  • C01B2203/08—Methods of heating or cooling
  • C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
  • C01B2203/0811—Methods of heating the process for making hydrogen or synthesis gas by combustion of fuel
  • C01B2203/0822—Methods of heating the process for making hydrogen or synthesis gas by combustion of fuel the fuel containing hydrogen
• • 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
  • C01B2203/12—Feeding the process for making hydrogen or synthesis gas
  • C01B2203/1288—Evaporation of one or more of the different feed components
  • C01B2203/1294—Evaporation by heat exchange with hot process stream
• • 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
  • C01B2203/14—Details of the flowsheet
  • C01B2203/148—Details of the flowsheet involving a recycle stream to the feed of the process for making hydrogen or synthesis gas
• • 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
  • C01B2203/80—Aspect of integrated processes for the production of hydrogen or synthesis gas not covered by groups C01B2203/02 - C01B2203/1695
  • C01B2203/86—Carbon dioxide sequestration
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2210/00—Purification or separation of specific gases
  • C01B2210/0043—Impurity removed
  • C01B2210/0046—Nitrogen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
  • F28D21/0001—Recuperative heat exchangers
• • 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
• • 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
  • Y02P30/00—Technologies relating to oil refining and petrochemical industry

Definitions

• the present invention relates to a method and a device for producing hydrogen from a hydrocarbon with good energy efficiency and releasing very small or zero amounts of carbon dioxide and pollutants.
• hydrocarbon generally means any fossil or renewable fuel, including oxygenated bodies (alcohol, ester, etc.), gaseous, liquid or even pulverized solid (which can be handled as a fluid), provided that '' it forms only a small inert solid residue: ash content less than 1% by mass.
• This hydrogen can be produced from .two distinct sources: named by way downstream ⁇ ', i.e. by decomposition of water, heat to very high temperature electrically or by electrolysis, or by a route upstream named ⁇ 'by converting a hydrocarbon.
• Hydrogen being intended to then generate electricity in a fuel cell the path ⁇ electrolysis' may seem an aberration, at least in terms of overall energy efficiency. But if this electricity is from renewable sources (wind, solar, geothermal) or nuclear, there is no production of C02 or other pollutants in this production / consumption chain. Whether for fixed or mobile applications, hydrogen appears here as an energy vector, making it possible, through fuel cells, to produce clean electricity in places devoid of all or at certain times of nuclear or renewable energy.
• the conversion of a fossil or renewable hydrocarbon generates hydrogen but also C02, which can limit the advantage of using fuel cells.
• this route has the advantage of potentially high energy yields, thereby saving fossil fuel resources or biomass production for energy purposes.
• the air is compressed before being introduced into the reforming process.
• air is also compressed to be introduced into the fuel cell.
• Air compressors represent auxiliaries consuming a significant part of the electrical energy produced by the fuel cell. To limit this consumption, the tendency is therefore to use low overpressures with respect to atmospheric pressure for the fuel cell as well as for the reforming process when it is directly coupled to a fuel cell.
• the invention relates to a method for producing hydrogen from a hydrocarbon with good energy efficiency and releasing very small or zero quantities of carbon dioxide and pollutants.
• the method comprises the step (a) of implementing a flow of oxygen (pure or almost pure) to (i) oxidize part of the hydrocarbons and (ii) provide the heat necessary to convert, by steam of water, at appropriate temperatures, almost all of the other part of the hydrocarbons into hydrogen, carbon monoxide and carbon dioxide.
• suitable temperatures is meant temperatures such as those used in the techniques described above.
• the method further comprises step (b) of preheating the hydrocarbons, the oxygen flow and the water to be vaporized.
• the hydrocarbons, the flow of oxygen, the water to be vaporized are hereinafter called the reactants.
• the mixture of hydrogen, carbon monoxide, carbon dioxide and excess water vapor is hereinafter called the products of conversion.
• the nitrogen being absent from the reactants, it does not dilute the conversion products and the subsequent stages of the process (b) to (f) are facilitated and the overall yield is increased.
• the method further comprises steps (c) of cooling (at least one) of the conversion products intended to recover a fraction of the thermal energy of the conversion products to preheat the reactants and at least partially condense the vapor d contained in conversion products.
• the method further comprises the following steps step (d) of upgrading the hydrogen: by extracting the hydrogen conversion products for the purpose of consuming it or in the perspective of storing it pending further consumption.
• Steps (a) to (d) are carried out at appropriate high pressures above 30 bars, to:
• the method according to the invention further comprises: - steps (e) of final conversion of carbon monoxide to carbon dioxide, where appropriate these steps are implemented during the recovery step of the hydrogen.
• the method according to the invention is implemented at a pressure sufficient to implement:
• the method according to the invention uses a membrane which is selectively permeable to hydrogen, in order to extract the hydrogen from the conversion products.
• the method further comprises the step of lowering the partial pressure of hydrogen downstream of the membrane by diluting the flow of permeated hydrogen in a flow of extraction gas, in particular a easily condensable gas. It results from the combination of technical features that the permeation of hydrogen is facilitated.
• the extraction of hydrogen by means of a permeable membrane is carried out at the same time as the step of final conversion of carbon monoxide into carbon dioxide. It results from the combination of technical features that the partial pressure of hydrogen, during the final conversion step, is lowered, which is favorable for the conversion of carbon monoxide to carbon dioxide.
• the method further comprises the step of regulating the final conversion temperature by adjusting the flow rate and / or the temperature of the flow of the extraction gas.
• the method is such that the preheating and cooling stages are coupled in a recovery exchanger so that the reactants and the conversion products circulate continuously in the recovery exchanger.
• the method according to the invention further comprises the step of relaxing the conversion products and / or final conversion products and / or hydrogen produced by compressing the air necessary for the operation of the fuel cell.
• the process according to the invention can also be coupled with a process for producing hydrogen generating a flow of oxygen, in particular by electrolysis. It results from the combination of technical features that we can thus:
• the method according to the invention can also be coupled with a method for producing nitrogen generating a flow of oxygen. It results from the combination of technical features that one can thus limit the cost of producing the oxygen consumed in the process according to the invention.
• the invention relates to a device for producing hydrogen from a hydrocarbon with good energy efficiency and by liberating very small or no quantities of carbon dioxide and of pollutants.
• the device comprises a reactor for converting (a) hydrocarbons by water vapor.
• the conversion reactor is supplied with pure or almost pure oxygen to (i) oxidize part of the hydrocarbons and (ii) provide the heat necessary to convert, into hydrogen, carbon monoxide and carbon dioxide, at appropriate temperatures, almost all of the other part of the oil.
• the mixture formed by hydrogen, carbon monoxide, carbon dioxide and excess water vapor is hereinafter called the products of conversion.
• the device further comprises means for preheating (b) the hydrocarbons, the flow of oxygen and the water to be vaporized.
• the hydrocarbons, the flow of oxygen, the water to be vaporized are hereinafter called the reactants.
• the device further comprises: at least one heat exchanger (c) for (i) cooling the conversion products, for (ii) recovering a fraction of the thermal energy of the conversion products in order to preheat the reactants and for (iii) at least partially condensing the water vapor contained in the conversion products, - hydrogen upgrading equipment (d).
• the hydrogen upgrading equipment includes an extraction device for extracting the hydrogen from the conversion products with a view to consuming it in a hydrogen consuming device (for example in a fuel cell) or storing it in a tank pending further consumption.
• the conversion reactor, the preheating means, the heat exchanger and the upgrading equipment operate at appropriate high pressures greater than 30 bars, in order to: • intensify the heat exchanges, and / or
• the device according to the invention further comprises
• the pressure in the device is sufficient to implement:
• the extraction member comprises a membrane which is selectively permeable to hydrogen in order to extract the hydrogen from the conversion products.
• the extraction member also comprises a supply of extraction gas, in particular an easily condensable gas, located downstream of the membrane, lowering the partial pressure of hydrogen downstream of the membrane by diluting the permeated hydrogen flow. . It results from the combination of technical features that the permeation of hydrogen is facilitated.
• the extraction member with a permeable membrane is placed in the final conversion reactor. It results from the combination of technical features that the partial pressure of hydrogen during final conversion is lowered, which is favorable for the conversion of carbon monoxide to carbon dioxide.
• the device further comprises means for regulating the. final conversion temperature acting on the flow rate and / or the inlet temperature of the extraction gas.
• the device is such that the permeable membrane is composed of a plurality of tubes immersed in the extraction member. Each tube has the shape of a thermowell, the open end of which opens to the outside of the extraction member. The open end allows the extraction gas to be introduced into the tube.
• the device according to the invention is such that the preheating means and the cooling heat exchanger are coupled in a recovery exchanger so that the reactants and the conversion products circulate continuously in the recovery exchanger.
• the device according to the invention further comprises a product expansion member conversion and / or final conversion products and / or the hydrogen produced making it possible to compress the air necessary for the operation of the fuel cell.
• the device according to the invention can also be coupled with an apparatus for producing hydrogen generating a flow of oxygen, in particular by electrolyser. It results from the combination of technical features that we can thus:
• the device according to the invention can also be coupled with a nitrogen production apparatus generating a flow of oxygen. It results from the combination of technical features that one can thus limit the cost of producing the oxygen consumed in the process according to the invention. Other characteristics and advantages of the invention will appear on reading the description of alternative embodiments of the invention given by way of indicative and non-limiting example, and from the
• FIG. 1 which represents the variation of the fraction (fa) of hydrocarbon oxidized by pure oxygen as a function of the preheating temperature of the reactants in the case of diesel,
• FIG. 2 which represents the variation of the fraction (fa) of hydrocarbon oxidized by air as a function of the preheating temperature of the reactants in the case of diesel
• Figure 3 which represents, in the form of block diagrams, a variant of a unit for the production of pure hydrogen stored under pressure
• FIG. 4 which represents, in the form of block diagrams, another alternative embodiment of a unit for the production of pure hydrogen, intended to be used immediately in a fuel cell type PEMFC at low temperature and low pressure
• Figure 5 which shows, in the form of block diagrams, another alternative embodiment of a production of a mixture of hydrogen and carbon dioxide, intended for immediate use in a PEMFC type fuel cell at low temperature and medium pressure
• FIG. 6 which represents, in the form of block diagrams, another alternative embodiment of a unit for producing a mixture of hydrogen and carbon dioxide, intended for immediate use in a fuel cell of the SOFC type with high temperature and medium pressure,
• FIG. 7 which represents an alternative embodiment of a means for preheating the reactants and a heat exchanger for cooling the associated products to form a regenerative system, the regenerative system is coupled to a conversion reactor,
• FIG. 8 which represents another alternative embodiment of a means for preheating the reactants and a heat exchanger for cooling the associated products to constitute a recovery exchanger, the recovery system is coupled to a conversion reactor,
• Figure 9 which represents on a graph, the increase in the hydrogen permeation efficiency as a function of the ratio between the molar flow rate of the extraction gas downstream of the membrane and the molar flow rate of hydrogen to be extracted upstream of the membrane,
• FIGS. 10a and 10b which represent a reactor for converting CO into C02 equipped with a membrane permeable to hydrogen, supplied with water vapor from the downstream side,
• FIG. 11 which shows a reactor for converting CO into C02 equipped with a series of glove fingers plunging into the heart of the reactor and each supporting a membrane permeable to ydrogen.
• water factor (fe) is the ratio between the water flow rate actually made available by injection into the conversion reactor and the stoichiometric water flow rate required for complete conversion for the fraction d hydrocarbon to be converted according to the reaction:
• Such figures can be established for each fuel or mixture of fuels and are not specific to diesel. They are also not specific to the reforming process used (vapor reforming or partial oxidation, catalytic or not ).
• the temperature level to be used depends both on the hydrocarbon to be converted and on the presence or absence of catalyst. For example in the case of a reaction of the catalytic steam reforming type, a temperature of 200 to 250 ° C. is sufficient in the case of methanol. However if the fuel is methane temperatures from 800 to 950 ° C are required.
• the partial oxidation of petrol can be carried out at 800 ° C in the presence of catalyst and at 1200 ° C in the absence of catalyst.
• Non-catalytic conversion by water vapor requires 1200 ° C for all fuel and 1400 ° C to achieve complete conversion in less than a second, that is to say leaving hydrocarbon-free products even light such as methane , ethane or ethylene.
• a predetermined water factor and a chosen reagent preheating temperature, the fraction fa and the oxygen flow rate can be determined, as shown in FIG. 1.
• the three fluxes of reagent to contact in the conversion reactor are identified.
• the hydrogen conversion reaction being endothermic, however high the preheating temperature, it will in any case be necessary to oxidize a fraction of the hydrocarbon to compensate for the heat of conversion reaction.
• This minimum fraction to be burned can be determined according to the enthalpy of fuel formation and its composition.
• This particular value of fa is noted v. This value is characteristic of the fuel. It is equal to 0.2565 in the case of diesel.
• ⁇ (1 -fa) / (1-v)
• the oxygen and diesel flow rates to be used are then in the ratio of 1.27.
• a higher preheating temperature with exchangers made of ceramic material provides higher yields.
• FIG. 2 shows, in the case of diesel, the variation of the fraction (fa) of hydrocarbon oxidized by air as a function of the preheating temperature of the reactants.
• the reforming units for petrochemical sites commonly operate at high pressures of a few tens of bars.
• a partial oxidation unit or autothermal high pressure steam reforming is on the contrary harmful for the overall performance of the system because it is necessary to compress the air to be injected into the conversion reactor, which is costly in energy. It is therefore preferred to operate at a pressure close to atmospheric pressure.
• a hydrogen production unit according to the invention can be produced in different ways. Four alternative embodiments have been shown in Figures 3 to 6, by way of examples. We will now describe FIG. 3 which represents, in the form of block diagrams, an alternative embodiment of a unit for producing pure hydrogen stored under pressure.
• the production unit is composed of the following organs: - hydrocarbon tank: 2
• the production unit 1 is used to generate the ⁇ pure hydrogen. It is stored under high pressure (200 to 350 bar, or more) for later use.
• the pressure in the conversion reactors 4 of this unit is of the order of 50 to 60 bar. Downstream of the membrane 7, the pressure of the flow of extracted hydrogen is still significant (20 to 30 bars); the compression work to reach the storage pressure is then considerably reduced.
• FIG. 4 represents, in the form of block diagrams, another alternative embodiment of a unit for producing pure hydrogen, intended to be used immediately in a fuel cell of the PEMFC type at low temperature and low pressure.
• the production unit otherwise known as device 1, is made up of the following organs:
• the production unit 1 produces pure hydrogen which is immediately recovered in another system, for example a fuel cell 17 of the PEMFC (Proton Exchange Membrane Fuel Cell) type operating at relatively low temperature (60 to 120 ° C) and low pressure (between 1 to 5 bars).
• the production unit is identical to that of FIG. 3 downstream of the membrane 7 where the pressure of the flow of extracted hydrogen is still significant (20 to 30 bars) and its high temperature (350 ° C).
• a turbocharger 18, 19 the expansion of the hydrogen downstream of the membrane 7 supplies the compression energy of the air supplying the cell 17, which usually requires an expensive auxiliary for the overall efficiency of the process.
• FIG. 5 represents, in the form of block diagrams, another alternative embodiment of a unit for producing a mixture of hydrogen and carbon dioxide, intended for immediate use in a fuel cell.
• PEMFC type fuel at low temperature and medium pressure.
• the production unit otherwise known as device 1, is made up of the following organs:
• the production unit 1 produces hydrogen for immediate use and in mixture with C02 in a fuel cell 17 at relatively low temperature and medium pressure.
• the production unit 1 does not include a membrane 7 for permeating hydrogen, but an additional cooling 6b of the products during the final conversion of CO to C02.
• the hydrogen production unit 1 operates under a high pressure level (30 to 60 bars).
• the energy recovered during the expansion 18, 19 of the H2 / C02 mixture makes it possible to compress the air admitted into the fuel cell 17.
• the recoverable energy is important since the mass and volume flow rate of the H2 + C02 mixture to be expanded is higher than in the case of the production unit shown in FIG. 4. It is possible to operate the cell 17 at a higher pressure (5 or 7 bar absolute rather than 1 bar), which is favorable for the recovery of the water at the outlet of cell 17 for supplying the conversion reactor 4, which is also favorable for the compactness of the equipment.
• FIG. 6 represents, in the form of block diagrams, another alternative embodiment of a unit for producing a mixture of hydrogen and carbon dioxide, intended for immediate use in a fuel cell SOFC type at high temperature and medium pressure.
• the production unit is composed of the following organs: - hydrocarbon tank: 2
• Production unit 1 produces hydrogen in mixture with CO and C02 for use in a fuel cell type SOFC (Solid Oxide Fuel Cell) operating at high temperature (600 to 900 ° C) and relatively medium pressure ( between 1 to 7 bars).
• SOFC Solid Oxide Fuel Cell
• the production unit 1 also does not have a membrane 8 for hydrogen permeation, nor even a final conversion 11 of CO to C02 since the CO can be upgraded by SOFC .
• the hydrogen production unit 1 operates under a high pressure level (30 to 60 bars). The energy recovered during expansion 18, of the H2 / CO / C02 mixture makes it possible to compress the air 19 admitted into the fuel cell 17.
• Figure 7 shows an alternative embodiment of a means for preheating the reactants 5 and a heat exchanger for cooling the 6 associated products to constitute a regenerative system.
• the means for preheating the reactants previously referenced 5 is referenced 22 and the cooling heat exchanger previously referenced 6 is referenced 23.
• the heat is stored in the elements made of ceramic material placed in the means for preheating the reactants 22 and in the cooling heat exchanger 23.
• the means for preheating the reactants 22 and the heat exchanger of cooling 23 are arranged on either side of the conversion reactor 4.
• the flows are alternated periodically.
• the cold reagents enter the means for preheating the reactants 22, the ceramic elements of which are hot, heat up on contact and cool it while the hot products enter the relatively cold cooling heat exchanger 23, cool down on contact ceramic elements and heat them.
• the flows are reversed by means of the valves 21 and the roles of the means for preheating the reactants 22 and the heat exchanger of cooling 23 are reversed.
• the reactants feed the cooling heat exchanger 23, which has become hot enough to be the means for preheating the reactants 22, then pass through the conversion reactor 4 in the opposite direction.
• the conversion products leave the conversion reactor 4 to the means for preheating the reactants 22.
• the latter has become cold enough to be the cooling heat exchanger.
• the ceramic elements have the advantage of being able to be used at very high temperatures.
• FIG. 8 represents an alternative embodiment of a means for preheating the reactants 5 and a heat exchanger for cooling the associated products 6 to form a recovery system 24.
• the means for preheating the reactants 5 and the heat exchanger for cooling the products 6 form two sides of the same equipment and the heat is transferred from one to the other through the watertight surface which separates them.
• This configuration has the advantage of continuous operation and does not require a system of control valves and flow reversals.
• the thermal inertia is also much lower. Hydrocarbons, oxygen and water or steam enter the recovery system 24 where they heat up by cooling the hot products of the conversion. They are then injected into the conversion reactor 4, opposite to the recovery system 24 via supply circuits 25. The hot conversion products then enter the recovery system 24.
• the gas after extraction of the hydrogen or its recovery by the fuel cell, the gas may still contain a low residual hydrogen content. It is the same for CO after its conversion to C02 or its recovery by the SOFC type battery.
• the gas is then subjected to a post combustion 12 of these residues which transforms them into H20 and C02.
• the gas under a high pressure (50 or 60 bars in the case of the variant embodiments of FIGS. 3 or 4) or a medium pressure (5 to 7 bars in the case of the variant embodiments of FIGS. 5 or 6), then does not comprise more than water vapor and carbon dioxide (with weak traces of CO, H2 if the post combustion is not complete and nitrogen if the oxygen used is not pure).
• the C02 can then be stored in dense liquid form. Pressures as low as 30 bar are acceptable for condensing C02: a refrigerant must therefore be used at negative temperatures such as -20 ° C to reach significant C02 condensation rates, depending on the amount of residual impurities in the gas.
• the flow of C02 generated can be stored under a pressure of 7 bars or possibly re-compressed to be condensed.
• Figures 3 and 4 show two alternative embodiments comprising two successive steps.
• One is to convert CO to C02 by the catalytic reaction of gas to water: CO + H20 - »C02 + H2.
• the other is to extract the hydrogen formed using a membrane 7.
• the use of oxygen instead of air promotes extraction by membrane 7 since the partial pressure of the hydrogen, not diluted in nitrogen, is higher.
• it is advantageous to be able to combine several functions in the same equipment.
• Any gas inert to hydrogen and the membrane such as nitrogen, argon, water vapor, ammonia ... can be used to lower the partial pressure of hydrogen downstream the membrane and thus more easily extract hydrogen.
• an easily condensable extraction gas such as water vapor or ammonia: a step of cooling and condensing the carrier gas / hydrogen mixture will make it possible to separate them and recover pure hydrogen.
• FIGS. 10a and 10b two alternative embodiments according to the invention of a reactor for the final conversion of CO to C02 11 comprising a membrane permeable 7 to hydrogen making it possible to extract the hydrogen.
• a reactor for the final conversion of CO to C02 11 comprising a membrane permeable 7 to hydrogen making it possible to extract the hydrogen.
• the hydrogen is extracted at the center of the final conversion reactor 11.
• the membrane tube 26 is placed along the axis of the enclosure 27 and is supplied with extraction water vapor.
• the conversion catalyst is placed in the annular enclosure around the membrane tube 26 and is traversed by the gases to be converted overall against the current of the extraction water vapor.
• the hydrogen is extracted at the periphery of the final conversion reactor 11.
• the hydrogen extraction water vapor circulates at the periphery of the final conversion reactor 11.
• the conversion catalyst is placed in the center.
• FIG. 11 another alternative embodiment according to the invention of a reactor for the final conversion of CO into C02 11 equipped with a series of glove fingers plunging into the heart of the reactor and supporting each a membrane permeable to hydrogen making it possible to extract the hydrogen.
• the membrane surface to be installed will lead to too large a diameter and length if the configuration shown in FIGS. 10a or 10b is kept.
• the amount of catalyst to be used would lead to an excessively thick crown. Therefore, the compositions and temperatures in each section would not be homogeneous. It is preferable to fractionate the thicknesses of catalyst using numerous membrane tubes 26, in the form of glove fingers. The tubes 26, of smaller diameter and length, plunge to the heart of the conversion reactor 11, from the outer wall.
• Reactors such as those described with reference to FIGS. 10a, 10b and 11 make it possible not to dissociate the stages of final conversion C0 / C02 and extraction of hydrogen. They are carried out in the same enclosure. It is thus possible to decrease the partial pressure of hydrogen during the final conversion C0 / C02 and therefore to shift the equilibrium towards the formation of C02 and H2: the conversion reaction is accelerated. A smaller amount of catalyst or a smaller enclosure can be used for equivalent performance.
• This configuration is possible because the conversion of CO to C02 and the extraction by a membrane permeable to hydrogen are carried out at the same temperature level: of the order of 250 and 400 ° C.
• the reaction of gas to water is exothermic and heat must be extracted to keep the gas within the optimum operating temperature range of the catalyst.
• the flow of extraction water vapor can advantageously be used to cool the CO to CO 2 conversion enclosure.
• the flow of steam of extraction water can be used to provide heat to this conversion reactor.
• the - or the tube (s) supporting the permeation membrane 26 and through which the extraction water vapor passes can advantageously act as a heat exchanger and avoid the use of equipment specific to this exchange function of heat.
• the temperature of the conversion enclosure can thus be regulated by variation in flow rate and temperature of the flow of extraction water vapor.
• Nitrogen can be produced by distillation of air under cryogenic conditions. The production of one kg of nitrogen is accompanied by the production of 0.30 kg of oxygen.
• This liquid oxygen can be recovered on site for the production of hydrogen by the process according to the invention described with reference to Figures 3 to 6. It can also be transported to be recovered on another site using the process according to the invention described with reference to Figures 3 to 6. With the oxygen produced, and for a yield energy consumption of the hydrogen production process from 80 to 90%, the diesel consumption is respectively equal to 0.21 kg / kg of nitrogen and to 0.26 kg / kg of nitrogen for a quantity of C02 captured respectively equal at 0.67 kg per kg of nitrogen and at 0.82 kg per kg of nitrogen.
• the amount of hydrogen generated is respectively 0.054 kg H2 per kg of nitrogen produced and 0.073 kg H2 per kg of nitrogen produced, representing a chemical energy of 7.7 to 10 MJ and an electrical energy of 1.1 at 1.45 kWh after use in a fuel cell.
• Hydrogen can also be produced by electrolysis of water.
• the production of one kg of electrolytic hydrogen is accompanied by the production of 8 kg of oxygen.
• the electrolysers operate at medium pressure: from a few bars to a few tens of bars.
• the oxygen produced can be recovered according to any of the variant embodiments shown in FIGS. 3 to 6.
• the variant embodiment represented in FIG. 3 however has the advantage of valuing the oxygen on site to produce hydrogen. Thanks to the process according to the invention, a flow of chemical hydrogen supplements the electrolytic hydrogen, while contributing to the capture of C02, as well as to the amortization of all the conditioning utilities of the hydrogen produced. .
• the leverage is important since with 8 kg of oxygen produced, and for an energy efficiency of chemical process of hydrogen production of 80 to 90%, the consumption of diesel is respectively equal to 5.75 to 6.9 kg / kg of electrolytic hydrogen for a quantity of CO 2 captured respectively equal to 18.1 kg per kg of electrolytic hydrogen and to 21.8 kg per kg of electrolytic hydrogen.
• the amount of hydrogen generated is respectively 1.45 kg of chemical hydrogen per kg of electrolytic hydrogen and 1.96 kg of chemical hydrogen per kg of electrolytic hydrogen.

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