DEVICE AND METHOD FOR HYBRID PRODUCTION OF SYNTHETIC DIHYDROGEN AND/OR SYNTHETIC METHAN

Abstract

The device (100) for hybrid production of synthetic dihydrogen and/or synthetic methane comprises: an inlet (105) for a synthesis gas stream preferably comprising at least CO and H.sub.2, a catalytic conversion reactor (110), the following alternative configurations: a first configuration in which the operating conditions of the reactor promote a Sabatier reaction, so as to produce an outlet gas comprising mainly methane, or a second configuration in which the operating conditions of the reactor promote a water gas shift reaction, so as to produce an outlet gas comprising mainly dihydrogen; an outlet (115) for synthetic dihydrogen and/or synthetic methane and a control system (120) comprising a means (121) for selecting a configuration for operating the reactor and a control means (122) according to the selected configuration, the reactor being configured to operate according to a command.

Claims

1. Device for the hybrid production of synthetic dihydrogen and/or synthetic methane, comprising: an inlet for a stream of synthetic gas (known as “syngas”), comprising at least CO; a catalytic conversion reactor, configured to operate according to one of the two following alternative configurations: a first configuration in which the operating conditions of the reactor promote a Sabatier reaction, so as to produce an outlet gas comprising mainly methane, or a second configuration in which the operating conditions of the reactor promote a water gas shift reaction, so as to produce an outlet gas comprising mainly dihydrogen; an outlet for a stream of synthetic dihydrogen and/or synthetic methane; and a control system comprising a selector for selecting a configuration for operating the reactor and a means for emitting a command representative of the selected configuration, the reactor being configured to operate according to a given configuration as a function of the command emitted by the emission means.

2. Device according to claim 1, wherein the conversion reactor comprises a catalytic bed comprising two separate catalysts, a first catalyst being configured to promote a Sabatier reaction at medium temperature, preferably between 250° C. and 350° C.; and a second catalyst being configured to promote a water gas shift reaction at high temperature, preferably higher than 350° C.

3. Device according to claim 1, wherein the conversion reactor comprises a catalytic bed comprising two separate catalysts, a first catalyst being configured to promote a Sabatier reaction at medium temperature, preferably between 250° C. and 350° C., and a second catalyst being configured to promote a water gas shift reaction at low temperature, preferably between 200° C. and 250° C.

4. Device according to claim 1, wherein the conversion reactor comprises a catalytic bed comprising a bifunctional catalyst, configured to promote a Sabatier reaction at medium temperature, preferably between 250° C. and 350° C., in the first configuration of the reactor; and to promote a water gas shift reaction at high temperature in the second configuration of the reactor, preferably higher than 350° C.

5. Device according to claim 1, wherein the conversion reactor comprises a catalytic bed comprising a bifunctional catalyst, configured to promote a Sabatier reaction at medium temperature, preferably between 250° C. and 350° C., in the first configuration of the reactor; and to promote a water gas shift reaction at low temperature in the second configuration of the reactor, preferably between 200° C. and 250° C.

6. Device according to claim 1, which comprises an injector injecting vapour into the stream of syngas and/or an injector injecting liquid water or vapour into the catalytic reactor, a quantity of water and/or vapour injected by at least one injector being realised as a function of the command emitted by the control system.

7. Device according to claim 6, which comprises, downstream from the conversion reactor, a water separator configured to supply the separated water to a water discharge or to an injector.

8. Device according to claim 1, which comprises a means for compressing syngas to a specified pressure, the outlet pressure of the compression means being determined as a function of the command emitted by the control system.

9. Device according to claim 1, which comprises a heat exchanger immersed in the conversion reactor, said heat exchanger being configured to cool or heat the reactor to a temperature determined as a function of the command emitted by the control system.

10. Device according to claim 1, which comprises a recirculator for recirculating at least part of the outlet gas towards the inlet for syngas, a quantity of recirculated gas being determined as a function of the command emitted by the control system.

11. Device according to claim 10 which comprises, downstream from the conversion reactor: a methane output selector connected to a recirculator for recirculating methane towards the inlet for syngas, and to a methane outlet; a dihydrogen output selector connected to a recirculator for recirculating dihydrogen towards the inlet for syngas, and to a dihydrogen outlet,  device wherein: when the command emitted corresponds to a configuration of the reactor to promote a water gas shift reaction, the dihydrogen output selector is configured to direct the dihydrogen towards the dihydrogen outlet and the methane output selector is configured to direct the methane towards the methane recirculator; and when the command emitted corresponds to a configuration of the reactor to promote a Sabatier reaction, the dihydrogen output selector is configured to direct the dihydrogen towards the dihydrogen recirculator, and the methane output selector is configured to direct the methane towards the methane outlet.

12. Device according to claim 1, wherein the catalytic conversion reactor is an isothermal reactor.

13. Device according to claim 1, wherein the catalytic conversion reactor.

14. Device according to claim 1, wherein there is only one catalytic conversion reactor.

15. Method for the hybrid production of synthetic dihydrogen and/or synthetic methane, comprising: a step of selecting a configuration for operating a conversion reactor; a step of emitting a command representative of the selected configuration; a step of configuring the conversion reactor as a function of the command emitted according to one of the two following configurations: a first configuration in which the operating conditions of the reactor promote a Sabatier reaction, so as to produce an outlet gas comprising mainly methane, or a second configuration in which the operating conditions of the reactor promote a water gas shift reaction, so as to produce an outlet gas comprising mainly dihydrogen; a step of inputting a stream of synthetic gas, (known as “syngas”); a step of catalytic conversion reaction according to the selected configuration; and a step of outputting a stream of synthetic dihydrogen and/or synthetic methane.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0113] Other advantages, aims and particular features of the invention will become apparent from the non-limiting description that follows of at least one particular embodiment of the device and method that are the subjects of the present invention, with reference to drawings included in an appendix, wherein:

[0114] FIG. 1 represents, schematically, a particular embodiment of the device that is the subject of the present invention;

[0115] FIG. 2 represents, schematically and in the form of a logical diagram, a first particular series of steps of the method that is the subject of the present invention;

[0116] FIG. 3 represents, schematically and in the form of a logical diagram, a second particular series of steps of the method that is the subject of the present invention; and

[0117] FIG. 4 represents, schematically and in the form of a logical diagram, a third particular series of steps of the method that is the subject of the present invention.

DESCRIPTION OF THE EMBODIMENTS

[0118] The present description is given in a non-limiting way, in which each characteristic of an embodiment can be combined with any other characteristic of any other embodiment in an advantageous way.

[0119] Note that the figures are not to scale.

[0120] It is noted that the term “synthetic methane” refers, more generally, to synthetic natural gas, which can comprise other chemical species in addition to the methane produced.

[0121] Three ranges of temperature operating conditions are defined: [0122] the “low” temperatures are temperatures below 250° C. and above 200° C.; [0123] the “medium” temperatures are temperatures between 250° C. and 350° C.; and [0124] the “high” temperatures are temperatures above 350° C.

[0125] Two ranges of pressure operating conditions are also defined: [0126] the “low” pressures are pressures strictly below a predefined pressure limit, for example, atmospheric pressure, 2 bar or 3 bar; and [0127] the “high” pressures are pressures above the predefined pressure limit in bars.

[0128] FIG. 1, which is not to scale, shows a schematic view of an embodiment of the device 100 that is the subject of the present invention. The device 100 for the hybrid production of synthetic dihydrogen and/or synthetic methane comprises: [0129] an inlet 105 for a stream of synthetic gas, known as “syngas”, comprising at least CO and preferably at least H.sub.2; [0130] a catalytic conversion reactor 110, configured to operate according to one of the two following alternative configurations: [0131] a first configuration in which the operating conditions of the reactor promote a Sabatier reaction at medium temperature and high pressure, so as to produce an outlet gas comprising mainly methane, or [0132] a second configuration in which the operating conditions of the reactor promote a water gas shift reaction at high temperature, or a water gas shift reaction at low temperature, and at low pressure, so as to produce an outlet gas comprising mainly dihydrogen; [0133] an outlet 115 for a stream of synthetic dihydrogen and/or synthetic methane; and [0134] a control system 120 comprising a means 121 for selecting a configuration for operating the reactor and a means 122 for emitting a command representative of the selected configuration, the reactor being configured to operate according to a given configuration as a function of the command emitted by the emission means.

[0135] The inlet 105 for a stream of gas generally means any line allowing syngas to be conveyed towards a syngas inlet (unnumbered) of the conversion reactor 110. The precise nature of the inlet 105 depends on the operating conditions determined in terms of flow rate, in particular, and on the nature of the syngas to be transported.

[0136] In a particular embodiment, such as that shown in FIG. 1, the inlet 105 is fed with syngas by a gasifier 505 of waste, biomass and/or carbonaceous residue. It is noted that the term “gasifier” and “gasification reactor” are equivalent here.

[0137] Gasification corresponds to a thermal degradation of the biomass, waste or carbonaceous residue, which undergoes successively drying and then devolatilisation, or pyrolysis, of the organic matter to produce a carbonaceous residue (the “char”), a synthetic gas (known as “syngas”), and condensable compounds (tars). The carbonaceous residue can then be oxidised by the gasification agent (water vapour, air, oxygen, carbon dioxide) to produce a gas mainly composed of H.sub.2 and CO. Depending on its nature, this gasification agent may also react with the tars or the major constituent gases. Thus, in the case of water vapour (H.sub.2O), then a WGS (for “Water Gas Shift”) reaction also occurs in the gasification reactor 505.

[0138] The pressure of the gasification reactor 505 has little effect on this reaction. In contrast, the equilibrium is strongly linked to the temperature of the reactor and to the “initial” composition of the reagents. The syngas obtained consists of a mixture of mostly non-condensable gases (H.sub.2, CO, CO.sub.2, CH.sub.4, C.sub.x), condensable compounds (tars), particles (char, coke, elutriated bed material), and inorganic gases (alkalis, heavy metals, H.sub.2S, HCl, NH.sub.3, etc.). After the elimination of impurities, the majority gases can be transformed into many energy carriers, including biomethane and biohydrogen. For the production of these two compounds, the H.sub.2/CO ratio in the syngas is a decisive factor. On output from the gasification reactor 505, this ratio does not generally exceed 2 but sometimes ratios higher than 6, under certain conversion conditions, can be obtained.

[0139] In a particular embodiment, such as that shown in FIG. 1, the device 100 comprises a means 510 for cooling products from the gasifier 505.

[0140] These embodiments make it possible to adapt the temperatures of the gas produced to the operation of the equipment of the device 100.

[0141] In a particular embodiment, such as that shown in FIG. 1, the device 100 comprises a means 515 for eliminating impurities from products from the gasifier 505. The elimination means 515 can be positioned upstream or downstream from the cooling means 510 if the device 100 comprises such a cooling means 510.

[0142] These embodiments make it possible to adapt the quality of the gas produced to the operation of the equipment of the device 100.

[0143] The precise nature of the elimination means 515 depends on the nature of the impurities to be eliminated. Such elimination means 515 are well known to the person skilled in the art. For example, such an elimination means 515 is a scrubber. Such a scrubber can utilise wet neutralisation, dry adsorption or neutralisation, depending on the use determined.

[0144] In some embodiments, the device 100 comprises a plurality of elimination means 515 in cascade incorporating a multitude of unitary operations or processes arranged in series or in parallel (absorption, physical and/or chemical adsorption on, for example, activated carbon, zeolite, ash, metals, etc.). In some variants, between two impurity elimination stages, the device 100 comprises a means (not shown) for cooling syngas and/or a syngas compressor (not shown).

[0145] In some embodiments, the device 100 comprises a means (not shown) for removing dust from the syngas. Such a dust removal means is, for example, is a venturi, multicyclone or filter type.

[0146] In a particular embodiment, such as that shown in FIG. 1, the device 100 comprises a means 145 for compressing syngas to a specified pressure, the outlet pressure of the compression means 145 being determined as a function of the command emitted by the control system 120.

[0147] This compression means 145 is, for example, a centrifugal, axial, vane, screw, lobe, piston or scroll type of compressor. This compression means 145 is configured, for example, to bring the syngas to a pressure between 1 and 80 bar, and preferably between 1 and 15 bar.

[0148] In a particular embodiment, not shown in FIG. 1, the device 100 comprises a means 146 for expanding syngas to a specified pressure, the outlet pressure of the expansion means being determined as a function of the command emitted by the control system 120.

[0149] This expansion means 146 can be any type known to the person skilled in the art and adapted to the use considered. In a particular embodiment, such as that shown in FIG. 1, the device 100 comprises, upstream from the inlet for syngas into the conversion reactor 110, a heat exchanger 535. This heat exchanger, which can be a plate or tube and shell exchanger or a series of heat exchangers (not shown), for example, is configured to heat or cool the syngas to a temperature compatible with the specific configuration of the conversion reactor 110.

[0150] Preferably, this exchanger 535 can make it possible to ensure a minimum inlet temperature for the reactor between 170° C. and 230° C., and preferably above 170° C. to prevent the formation of nickel tetracarbonyl (if a nickel-based reactor or catalyst) which is a poison in the gas produced.

[0151] The catalytic conversion reactor 110 is, preferably, an isothermal reactor. Preferably, this conversion reactor 110 is a wall-cooled isothermal reactor exchanger or a cascade of isothermal reactors. More preferably, this conversion reactor 110 is a fluidised-bed isothermal reactor. Preferably, this reactor 110 is a single fluidised-bed isothermal reactor. More preferably, this conversion reactor 110 is a dense or bubbling fluidised-bed isothermal reactor. The term “dense fluidised-bed isothermal reactor” refers to a reactor configured to operate according to a temperature between 200° C. and 600° C. and according to a pressure between 1 and 80 bar.

[0152] This reactor 110 is configured to operate according to two thermodynamic equilibrium configurations, or systems: [0153] a first configuration in which the operating conditions of the reactor promote a Sabatier reaction at medium temperature and high pressure, so as to produce an outlet gas comprising mainly methane, or [0154] a second configuration in which the operating conditions of the reactor promote a water gas shift reaction at high temperature, or a water gas shift reaction at low temperature, and at low pressure, so as to produce an outlet gas comprising mainly dihydrogen.

[0155] The choice of the temperature range of this second configuration will be a function of the catalytic bed 111 introduced into 110 to ensure the water-gas or WGS reaction. This configuration requires significant operating ranges in terms of pressure and temperature in particular.

[0156] It is noted that the invention is not limited to a single reactor, and this can implement a plurality of reactors, of identical or different types, in parallel or in series to obtain the reaction product envisaged.

[0157] To be able to achieve the two reactions according to the two configurations in question, the reactor 110 utilises a catalytic bed 111. Such a catalytic bed 111 can be formed of: [0158] either a mixture of two separate catalysts, 112 and 113, each configured to promote one of the two configurations, wherein each catalyst can utilise different metals for example; [0159] or a single bifunctional catalyst 114 configured to promote, based on other reaction parameters (temperature or pressure for example), one or other of the configurations.

[0160] In the case of separate catalysts: [0161] the catalyst promoting the Sabatier reaction can be based on Ni/Al.sub.2O.sub.3, Ni/Pr/Al.sub.2O.sub.3, Ruthenium, for example; and [0162] the catalyst promoting the WGS reaction can be based, for example, on CuO/ZnO/Al.sub.2O.sub.3, ZnO, Cr.sub.2O.sub.3, KOH/Pt/Al.sub.2O.sub.3, Pt-CeOx/Al.sub.2O.sub.3, CuO/Al.sub.2O.sub.3, for conversions at low temperature, for example around 200° C., or Fe.sub.2O.sub.3/Cr.sub.2O.sub.3, Au—Fe.sub.2O.sub.3, Au—CeO.sub.2, Au—TiO.sub.2, Ru—ZrO.sub.2, Rh—CeO.sub.2, Pt—CeO.sub.2 or Pd—CeO.sub.2, for conversions at high temperature, for example around 450° C.

[0163] In the first configuration, the objective of the reactor 110 is to maximise the production of synthetic methane (CH.sub.4). The syngas can be converted into biomethane by the catalytic methanation reaction of the CO, also called the “Sabatier reaction”. This reaction, which has rapid kinetics at the temperatures utilised, are characterised by very high exothermicity.

[0164] To maximise the production of CH.sub.4, the H.sub.2 and CO should have a stoichiometric ratio of about 3:1. This ratio can be obtained by performing an additional WGS reaction positioned upstream from 110.

[0165] In some variants (not shown), the device 100 comprises a dedicated WGS reactor comprising specific catalysts. Such a specific catalyst is, for example, based on Cu—Zn—Al.sub.2O.sub.3, Fe.sub.2O.sub.3/Cr.sub.2O.sub.3. In other preferred variants, such as that shown in FIG. 1, the additional WGS reaction is performed directly in the same conversion reactor 110.

[0166] Regardless of the variant chosen, a supply of water (vapour or liquid) is therefore necessary.

[0167] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises an injector 125 injecting vapour into the stream of syngas and/or an injector 130 injecting liquid water or vapour into the catalytic reactor, a quantity of water and/or vapour injected by at least one injector being realised as a function of the command emitted by the control system 120. The injector 125 can be positioned upstream or downstream from a possible recirculation, 155 or 160, described below.

[0168] The injector 125 for injecting vapour is, for example, a branch in the inlet line 105 associated to a production means (not shown) to bring the water to a temperature corresponding to the vapour state at the operating conditions of the inlet 105 for syngas.

[0169] The injector 130 for injecting water into the conversion reactor 110 is, for example, a branch feeding liquid water or vapour into the conversion reactor 110. This branch can be fed with external water or with recycled water in the device 100.

[0170] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises, downstream from the conversion reactor 110, a water separator 135 configured to supply the separated water to a water discharge 140 or to an injector, 125 and/or 130, after its vapour phase transformation, for example through a heat exchanger (not shown). The separator 135 can be of condenser type, for example. The water separator 135 is configured to dehydrate the stream produced on output from the conversion reactor 110, by cooling, for example, to a temperature corresponding to a temperature below or equal to the dew point temperature of the water at the operating conditions of the device 100.

[0171] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises, upstream from the water separator 135, at least one heat exchanger 540. At least one heat exchanger 540, of type plate or tube and shell exchanger for example, is configured to cool the products from the conversion reactor 110 to a temperature corresponding to a temperature above or equal to the dew point temperature of the water at the operating conditions of the device 100.

[0172] Inside the conversion reactor 110, the CO.sub.2 also present in the syngas can also produce CH.sub.4 by methanation reaction of the CO.sub.2 if the hydrogen is in sur-stoichiometry for CO methanation.

[0173] In the second configuration, the objective of the reactor 110, or of the plurality of reactors 110, is to maximise the production of synthetic hydrogen. To this end, the WGS reaction can be specifically implemented in the single conversion reactor 110 or in a plurality of conversion reactors 110. For this, a greater quantity of water is injected than the quantity mentioned in the case of methanation, so as to maximise the production of hydrogen.

[0174] Regardless of the configuration, the products from the conversion reactor 110 comprise water in excess or in products, carbon dioxide, hydrogen and methane in proportions that vary according to the configuration implemented.

[0175] The outlet 115 for a stream of synthetic dihydrogen and/or synthetic methane means any line allowing the products from the conversion reactor 110 to be carried away from the conversion reactor 110.

[0176] The products passing through the outlet 115 are preferably adjusted to the specifications of use downstream from the conversion reactor 110 as described below.

[0177] These specifications correspond, for example, in the case of synthetic methane that can be injected into the natural gas networks, to: [0178] a higher heating value between 9.5 and 12.8 kWh/Nm.sup.3; [0179] a Wobbe index between 12.01 and 15.70 kWh/Nm.sup.3; [0180] a relative density between 0.555 and 0.7; [0181] a CO.sub.2 content of less than 2.5%; and [0182] a dihydrogen content of less than 6%, or less than 2%, depending on the use.

[0183] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises a separator 520 for separating carbon dioxide from the stream on output from the conversion reactor 110.

[0184] This separator 520 is, for example, a device configured to perform the adsorption (physical or chemical) or pressure swing adsorption, membrane permeation or cryogenics of the carbon dioxide of the stream, and direct it towards a discharge or a recovery system 530 for carbon dioxide.

[0185] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises at least one recirculator, 155 and/or 160, for recirculating at least part of the outlet gas towards the inlet 105 for syngas, a quantity of recirculated gas being determined as a function of the command emitted by the control system 120.

[0186] The term “recirculator”, 155 and 160, refers to a line transporting a stream of gas towards the inlet 105 for syngas. This stream of gas can be a stream of hydrogen 160 or synthetic methane 155, as a function of the command emitted by the control system 120. For example, if the control system 120 has configured the device 100 for producing hydrogen, the residual methane is recirculated by the “recirculator” 155, whereas if the control system 120 has configured the device 100 for producing methane, it is the dihydrogen which is recirculated by the “recirculator” 160. Alternatively, the product whose production is maximised by the configuration of the device 100 can also be recirculated so as to keep the flow rate passing through the conversion reactor 110 constant.

[0187] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises, downstream from the conversion reactor 110: [0188] a methane output selector 165 connected to a recirculator 155 for recirculating methane towards the inlet 105 for syngas, and to a methane outlet 170; [0189] a dihydrogen output selector 175 connected to a recirculator 160 for recirculating dihydrogen towards the inlet 105 for syngas, and to a dihydrogen outlet 180, [0190] device wherein: [0191] when the command emitted corresponds to a configuration of the reactor to promote a water gas shift reaction, the dihydrogen output selector is configured to direct the dihydrogen mainly towards the dihydrogen outlet and the methane output selector is configured to direct the methane mainly towards the methane recirculator; and [0192] when the command emitted corresponds to a configuration of the reactor to promote a Sabatier reaction, the dihydrogen output selector is configured to direct the dihydrogen mainly towards the dihydrogen recirculator, and the methane output selector is configured to mainly direct the methane towards the methane outlet.

[0193] For clarity, “mainly” means a proportion higher than 50%.

[0194] Preferably, the amount of dihydrogen and/or the amount of methane recirculated are adjusted to produce a mixture of dihydrogen and methane in the proportions given.

[0195] The recirculation of residual methane and residual hydrogen, 155 and 160, can inject the residual gas downstream from the compression means 145, for example during the use of a membrane separation in 525. The H.sub.2 is thus obtained in the permeate, therefore at low pressure. In the second configuration, H.sub.2 is taken up by a recovery system 180 downstream. In the case of the first configuration, the low-pressure permeate H.sub.2 is fed upstream from 145 at a lower pressure than the operating pressure of 110.

[0196] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises, upstream from the dihydrogen output selector 175, a dihydrogen separator 525.

[0197] Such a dihydrogen separator 525 is, for example, a device for performing a membrane permeation, pressure swing adsorption and/or and electrical compressor and/or electrochemical compression.

[0198] On output from this hydrogen separation: [0199] in the case of biomethane production: the small quantity of hydrogen present in the gas on output from the syngas conversion reactor is mainly separated from the biomethane, which can therefore be used in the transportation or distribution grids, or in a mobility station; all or part of the small quantity of hydrogen separated can be recirculated towards the stream 105 feeding the syngas catalytic conversion reactor 110; and [0200] in the case of biohydrogen production: the large quantity of hydrogen present in the gas on output from the syngas conversion reactor is separated from the rest of the gas, thus producing a biohydrogen with sufficient purity to be used in an industrial network or in a mobility station; the rest of the gas can be recirculated in full or in part towards the stream 105 feeding the syngas catalytic conversion reactor 110.

[0201] In a particular embodiment, such as that shown in FIG. 1, the device 100 comprises a means 545 for compressing products from the conversion reactor 110 to a specified pressure, this pressure corresponding to a nominal pressure of use for said products or to an operating pressure of the conversion reactor 110 with a view to the recirculation of a portion of the reaction products.

[0202] This compression means 545 is, for example, a centrifugal, axial, vane, screw, lobe or scroll type of compressor. On output from this compression means, the reaction products preferably have a pressure of between 4 and 80 bar.

[0203] The means, 135, 520 and 525, 545, can be reversed.

[0204] In some particular embodiments, such as that shown in FIG. 1, the device 100 comprises a heat exchanger 150 immersed in the conversion reactor, said heat exchanger being configured to cool or heat the reactor 110 to a temperature determined as a function of the command emitted by the control system 120.

[0205] Such a heat exchanger 150 is, for example, formed of horizontal, vertical or inclined tubes, or a plate heat exchanger or wall-cooling of the reactor 110 or of the multiplicity of reactors 110.

[0206] The control system 120 is, for example, an electronic calculation circuit configured to: [0207] receive a manual or automatic configuration selection via the selection means 121;

[0208] and [0209] emit a configuration command via the emission means 122.

[0210] The selection means 121 is, for example, a mechanical, electrical or electronic interface allowing a configuration to be selected from the two configurations available.

[0211] The emission means 122 is, for example, an electronic control circuit, configured to adapt operating variables of the device 100 to correspond to the configurations available.

[0212] These operating variables are at least one of the following: [0213] the pressure of the conversion reactor 110 adjusted by the means 145 or 146 and/or by a pressure regulating valve (not shown) positioned downstream from 110: the pressure is a variable that considerably boosts the methanation reaction. Thus, for the production of biomethane the pressure of the reactor is high, preferably higher than atmospheric pressure and even more preferably higher than 3 bar, while it is lower (preferably less than 3 bar, and even more preferably less than 2 bar, and even more preferably close to atmospheric pressure) for the production of biohydrogen by Water-Gas Shift; [0214] the temperature of the conversion reactor 110 adjusted by the systems 150 and/or 535 or the injection of water 130: the two reactions (methanation and Water-Gas Shift) are exothermic, thus boosted by the low temperatures. However, the Water-Gas Shift catalyst in the reactor 110 is active at a low or high temperature. Therefore, the temperature of the reactor is preferably between 250° C. and 350° C. for the production of biomethane, and preferably between 200° C. and 250° C., or above or equal to 350° C., for the production of biohydrogen based on the WGS catalytic function contained in the catalyst bed 111; [0215] the flow rate of the vapour added to the syngas or the water vapour content of the syngas: the vapour flow rate affects the thermodynamic equilibrium, and therefore the production of biomethane or biohydrogen. For the production of biomethane, the fraction by volume of vapour in the syngas conversion reactor 110 is preferably between 0 and 30% vol and preferably between 10 and 30% vol, versus 20 to 80% vol and preferably between 30 and 50% vol for the production of biohydrogen. It is noted that the fraction by volume of vapour comprises the vapour on input to the syngas conversion reactor 110 and, when the reactor 110 is cooled by injecting cooling water 130, the injected water that vaporises on contact with the hot catalyst bed 111.

[0216] This high content of water vapour added or contained in the syngas in the case of the production of biohydrogen makes it possible to discourage the methanation reaction at the expense of the water-gas reaction; [0217] the gas fraction recirculated: in biomethane or biohydrogen production mode, the device 100 generates a residual gas. In the case of biomethane production, the hydrogen separated from the biomethane can be recycled towards the inlet 105 of the conversion reactor 110 in order to be transformed into biomethane by methanation or recovered as a small-scale biohydrogen production. In the case of biohydrogen production, the residual gas (comprised mainly of CH.sub.4 and CO) can be recycled towards the inlet 105 of the syngas conversion reactor 110 in order to increase the biohydrogen yield. The gas fractions recirculated 155 and/or 160 towards the inlet 105 of the syngas conversion reactor 110 can vary from 0 to 100% according to the operating modes.

[0218] To maximise the production of hydrogen, specific operating conditions must be implemented: [0219] an increase in the temperature equal to or above 350° C. promotes the production of biohydrogen if the catalyst bed 111 contains a WGS catalyst having a high-temperature WGS catalytic function; [0220] a decrease in the temperature equal to or below 250° C. does not allow the methanation reaction to take place and promotes the production of biohydrogen if the catalyst bed 111 contains a WGS catalyst having a low-temperature WGS catalytic function; [0221] the production of biohydrogen increases significantly when the vapour content of the syngas rises; [0222] a decrease in the pressure of the catalytic conversion reactor 110 reduces the production of biomethane and boosts the production of biohydrogen; [0223] the production of biohydrogen increases when the recirculation of the residual methane increases.

[0224] Based on the effects described above, and taking into account the energy impact of the settings for the different parameters mentioned above, the “nominal” conditions of the process for high-temperature Water-Gas Shift biohydrogen production can be, for example, the following:

TABLE-US-00001 TABLE 1 Pressure of the reactor 110 1.2 bar Temperature of the reactor 110 450 ° C. Vapour content of the syngas 50 % mol Rate of Recirculation 165 80 % Rate of Recirculation 175 0 %

[0225] Note that the rate of recirculation 165 corresponds to the ratio between the stream in the recirculator 155 and the sum of the streams in the recirculator 155 and on output 170. Note that the rate of recirculation 175 corresponds to the ratio between the stream in the recirculator 160 and the sum of the streams in the recirculator 160 and on output 180.

[0226] Under these operating conditions, the composition of the various key streams of the process is as follows:

TABLE-US-00002 TABLE 2 Stream - Stream - Stream - Stream - Methanation Catalytic Biohydrogen Residual reactor reactor recoverable gas output Parameters input output 170 process 180 Pressure 1.40 1.20 10.00 10.00 (BarA) Temperature 400.00 450.00 240.80 240.80 (° C.) Molar flow rate 20.64 19.97 3.26 — (kmol/h) CO.sub.2 content 10.13% 17.43% 0.00% 0.00% (% mol) H.sub.2O content 36.87% 32.23% 0.00% 0.00% (% mol) CO content 9.00% 1.24% 0.00% 0.00% (% mol) CH.sub.4 content 27.63% 31.91% 0.00% 0.00% (% mol) H.sub.2 content 15.28% 17.19% >99.99% 0.00% (% mol) C.sub.2H.sub.4 content 1.10% 0.00% 0.00% 0.00% (% mol)

[0227] Based on the effects described above, and taking into account the energy impact of the settings for the different parameters mentioned above, the “nominal” conditions of the process for low-temperature Water-Gas Shift biohydrogen production can be, for example, the following:

TABLE-US-00003 TABLE 3 Pressure of the reactor 1.2 bar Temperature of the reactor 200 ° C. Vapour content of the syngas 50 % mol Rate of Recirculation 165 90 % Rate of Recirculation 175 0 %

[0228] Under these operating conditions, the composition of the various key streams of the process is as follows:

TABLE-US-00004 TABLE 4 Stream - Stream - Stream - Stream - Methanation Catalytic Biohydrogen Residual reactor reactor recoverable gas output Parameters input output 170 process 180 Pressure 1.30 1.10 10.00 10.00 (BarA) Temperature 200.00 200.00 250.45 250.45 (° C.) Molar flow rate 22.12 22.41 5.22 — (kmol/h) CO.sub.2 content 9.52% 17.65% 0.00% 0.00% (% mol) H.sub.2O content 34.57% 25.03% 0.00% 0.00% (% mol) CO content 7.56% 0.07% 0.00% 0.00% (% mol) CH.sub.4 content 27.26% 26.91% 0.00% 0.00% (% mol) H.sub.2 content 14.75% 24.51% >99.99% 0.00% (% mol) C.sub.2H.sub.4 content 6.33% 5.83% 0.00% 0.00% (% mol)

[0229] With regard to biomethane: [0230] an average temperature of between 250° C. and 350° C. promotes the production of biomethane—preferably a reaction below 350° C., and preferably below 320° C. and more preferably below 300° C., and preferably above or equal to 250° C. is implemented in methanation mode in order to limit the production of biohydrogen; below 250° C. the methanation reaction is limited by the kinetics, because the reactions are unable to start or are too slow; [0231] as with the temperature, a lower water vapour content in the syngas feeding the catalytic conversion reactor promotes the production of biomethane; [0232] a higher pressure of the catalytic conversion reactor promotes the production of biomethane in the process chain proposed; [0233] the recirculation of the hydrogen stream towards the syngas feeding the catalytic conversion reactor 110 has no significant impact on the production of biomethane—this is because the quantity of residual hydrogen present in the stream on output from the catalytic conversion reactor in methanation mode is very low due to its consumption by the methanation reaction.

[0234] Based on the effects described above, and taking into account the energy impact of the settings for the different parameters mentioned above, the “nominal” conditions of the process for producing biomethane by methanation are, for example, the following:

TABLE-US-00005 TABLE 5 Pressure of the reactor 4.7 bar Temperature of the reactor 300 ° C. Vapour content of the syngas 20 % mol Rate of Recirculation 165 0 % Rate of Recirculation 175 100 %

[0235] Under these operating conditions, the composition of the various key streams of the process is as follows:

TABLE-US-00006 TABLE 6 Stream - Stream - Stream - Stream - Methanation Catalytic Biohydrogen Residual reactor reactor recoverable gas output Parameters input output 170 process 180 Pressure 4.90 4.70 10.00 10.00 (BarA) Temperature 250.00 300.00 77.78 77.78 (° C.) Molar flow rate 9.49 7.16 — 1.66 (kmol/h) CO.sub.2 content 21.45% 36.86% 0.00% 2.43% (% mol) H.sub.2O content 19.86% 32.64% 0.00% 0.23% (% mol) CO content 17.47% 0.03% 0.00% 0.09% (% mol) CH.sub.4 content 6.35% 29.47% 0.00% 97.08% (% mol) H.sub.2 content 32.49% 1.00% 0.00% 0.16% (% mol) C.sub.2H.sub.4 content 2.38% 0.00% 0.00% 0.00% (% mol)

[0236] As can be understood, the aim of the present invention is to convert the syngas, for example from biomass/waste/residue, into biomethane or biohydrogen in a flexible way by simply modifying certain operating conditions while keeping the same equipment, the same process chain and the same catalyst bed 111. A hybrid fluidised-bed catalytic conversion reactor for syngas utilising a mixture of catalysts, a single low-yield catalyst or a bifunctional catalyst, makes it possible to carry out these conversions by operating: [0237] at a medium temperature, between 250° C. and 350° C.: [0238] high pressure, preferably higher than atmospheric pressure, and preferably higher than 2 bar and more preferably higher than 3 bar, and preferably lower than 80 bar and more preferably lower than 20 bar, and [0239] low water vapour content, preferably between 0 and 30% vol and more preferably between 10 and 30% vol, for the production of biomethane, [0240] at a high temperature, preferably above 350° C.: [0241] low pressure, preferably between 1 and 2 bar, and [0242] high water content, preferably between 30% vol and 80% vol, for the production of biohydrogen if the catalyst bed 111 contains a so-called “high-temperature” WGS catalyst, [0243] or at a low temperature, preferably between 200° C. and 250° C.: [0244] low pressure, preferably between 1 and 2 bar, and [0245] high water content, preferably between 30% vol and 80% vol, for the production of biohydrogen if the catalyst bed 111 contains a so-called “low-temperature” WGS catalyst.

[0246] Alternatively, a plurality of reactors can be utilised in series or in parallel. Whereas an excess of vapour is conventionally used for limiting the methanation reaction during the conversion of syngas into biohydrogen by the Water-Gas Shift reaction, the present invention allows the methanation reaction to be limited by controlling the pressure, temperature, water vapour content, and also the methane content in the syngas conversion reactor. In effect, by recirculating more or less of the stream of residual gas rich in CH.sub.4 towards the syngas conversion reactor in WGS mode, the thermodynamic equilibrium and the reaction kinetics driving the biomethane production are discouraged, which further limits the methanation reaction.

[0247] FIG. 2 shows, schematically, an embodiment of the method 200 that is the subject of the present invention. This method 200 for the hybrid production of synthetic dihydrogen and/or synthetic methane comprises: [0248] a step 205 of selecting a configuration for operating a conversion reactor; [0249] a step 210 of emitting a command representative of the selected configuration; [0250] a step 215 of configuring the conversion reactor as a function of the command emitted according to one of the two following configurations: [0251] a first configuration in which the operating conditions of the reactor promote a Sabatier reaction, so as to produce an outlet gas comprising mainly methane, or [0252] a second configuration in which the operating conditions of the reactor promote a water gas shift reaction, so as to produce an outlet gas comprising mainly dihydrogen; [0253] a step 220 of inputting a stream of synthetic gas, (known as “syngas”); [0254] a step 225 of catalytic conversion reaction according to the selected configuration; and [0255] a step 230 of outputting a stream of synthetic dihydrogen and/or synthetic methane.

[0256] Performance of the steps of: [0257] selection 205; [0258] emission 210; [0259] inputting 220 a stream of syngas; [0260] reaction 225; and [0261] output 230  is described with reference to FIG. 1 and in particular respectively: [0262] the selection means 121; [0263] the emission means 122; [0264] the inlet 105 for a stream of syngas; [0265] the reaction reactor 110; and [0266] the outlet 115 for reaction products.

[0267] The configuration step 215 is carried out with all the operational adjustments described with reference to FIG. 1 concerning the configuration for the production of synthetic dihydrogen or biomethane.

[0268] FIG. 3 shows, schematically, a particular embodiment of the method 300 that is the subject of the present invention when the method 200 is in the methane production configuration. In this embodiment, the method 300 comprises: [0269] a step 315 of converting a stream of syngas by utilising a conversion reactor 110, which can include a step (unnumbered) of supplying water directly into the reactor 110 or into the inlet stream (unnumbered); [0270] a first 320, second 325 and third 330 separation steps, each of these separation steps, 320, 325 and 330, being of a distinct type from amongst: [0271] a separation of water; [0272] a separation of CO.sub.2; and [0273] a separation of dihydrogen; [0274] optionally, a step (unnumbered) of recirculating residual methane on output from the third separation step 330; and [0275] a step 335 of supplying dihydrogen for a dedicated use or storage.

[0276] FIG. 4 shows, schematically, an embodiment of the method 400 that is the subject of the present invention when the method 200 is in the dihydrogen production configuration. In this embodiment, the method 400 comprises: [0277] a step 315 of converting a stream of syngas by utilising a conversion reactor 110, which can include a step (unnumbered) of supplying water directly into the reactor 110 and/or into the inlet stream (unnumbered); [0278] a first 320, second 325 and third 330 separation steps, each of these separation steps, 320, 325 and 330, being of a distinct type from amongst: [0279] a separation of water; [0280] a separation of CO.sub.2; and [0281] a separation of dihydrogen; [0282] optionally, a step (unnumbered) of recirculating residual dihydrogen on output from the third separation step 330; and [0283] a step 405 of supplying methane for a dedicated use or storage.