Heat management method in a combined process to produce methanol from water and co 2

Abstract

The present disclosure relates to a heat management method in a methanol-generating unit coupled to one or more solid oxide electrolyser cells (400) remarkable in that a water stream (23) is subjected to a transfer of thermal energy of an oxygen-containing effluent (13) exiting the one or more solid oxide electrolyser cells (400) so that an additional stream (25) of steam is generated and can transfer its own thermal energy to a separation unit that is downstream the methanol-generating unit.

Description

[0001] Heat management method in a combined process to produce methanol from water and CO2

[0002] Field of the disclosure

[0003] The present disclosure relates to a heat management method in a combined process to produce methanol from water and carbon dioxide. More specifically, the present disclosure relates to a heat management method in a methanol-generating unit.

[0004] Technical background

[0005] Methanol is widely used in different applications such as the synthesis of formaldehyde, which is then involved in the manufacture of plastic materials, paints, and textiles, for instance; the production of dimethyl ether, which may be used in aerosols or as an alternative fuel for diesel engines; the transesterification of triglycerides to produce biodiesel; or as a solvent or a fuel for engines.

[0006] Methanol is commercially produced from synthesis gas (syngas), namely a mixture of carbon oxides ( / .e., carbon monoxide (CO) and / or carbon dioxide (CO2)) and hydrogen (H2) that can be produced from a variety of carbonated sources.

[0007] CO and CO2 react with H2 according to the following equations:

[0008] (1) CO + 2H2CH3OH

[0009] (2) CO2+ 3H2CH3OH + H2O

[0010] (3) CO + H2O CO2+ H2wherein the third one corresponds to the water-gas shift (WGS) reaction.

[0011] When methanol is produced by a process involving the production of hydrogen by water electrolysis using green electricity over an alkaline electrolyser and its use to convert CO2in a CO2-to-methanol unit, the CO2-to-methanol pathway consumes 12.3 kWh / kgMeon.

[0012] This amount of energy spent on the generation of methanol can be considered as an impediment, since the current trends are rather focusing on processes that are ecological and / or energy-saving, with the ultimate goal of preserving the environment.

[0013] Such an approach implementing green policies has already been executed at some point. For example, the feeding of hydrogen and / or syngas using solid oxide electrolyser cells has succeeded in decreasing the amount of energy needed to perform the required reaction. A solid oxide electrolyser cell allows indeed to achieve the electrolysis of steam (SOEC) or the co-electrolysis of steam and CO2(co-SOEC) by using a solid oxide electrolyte to produce hydrogen gas or syngas respectively. The use of a high-temperature electrolyser allows using more heat energy than electrical energy. The energy is partially recovered on the SOEC / co- SOEC, as in US 2018 / 0287179, to pre-heat the steam from 125°C-180°C to the electrolysis temperature. The fact of being able to produce steam on the combined process leads reducing the heat energy to provide to the electrolyser and the distillation unit, increasing, therefore, the overall energy efficiency of the process. The solid oxide electrolyser cell usually operates at temperatures that allow high-temperature electrolysis to occur, typically between 500°C and 865°C. Thus, when combined with the water electrolysis, the CCh-to-methanol pathway consumes 11.59 kWh / kgMeon and when combined with co-electrolysis of CO2, the CCh-to- methanol pathway is consuming 10.48 kWh / kgMeOH.

[0014] However, there is still a need to reduce the energy consumption of a methanol-generating process in order to implement the ongoing green environmental policies.

[0015] Summary

[0016] According to a first aspect, the disclosure provides a heat management method in a methanolgenerating unit, said method is remarkable in that it comprises the following steps: a) providing a methanol-generating unit and a separation unit, wherein the separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein said separation unit comprises a temperature-regulating device, and wherein said methanol-generating unit comprises one or more reactors each comprising a cooling device; b) operating said one or more reactors under first operating conditions comprising at least regulating the thermal energy of said at least one reactor by adjusting the temperature of the cooling device with water; c) recovering from said cooling device, after said step of regulating the thermal energy, a first stream, said first stream comprising steam at a pressure P1; d) decreasing the pressure of said first stream so as to recover a second stream, said second stream comprising steam at a pressure P2, P2 being at least 0.31 MPa, and wherein P2 < P1 ; e) providing one or more solid oxide electrolyser cells; f) feeding said one or more solid oxide electrolyser cells with steam or with a mixture comprising steam and carbon dioxide; g) working said one or more solid oxide electrolyser cells under second operating conditions so as to generate at least one oxygen-containing effluent, said second operating conditions comprising at least electrical power and a temperature higher than 400°C; h) providing a water stream; i) transferring the thermal energy of the oxygen-containing effluent generated at step (g) to at least the water stream provided at step (h) so as to generate an additional stream of steam; j) operating said separation unit under third operating conditions comprising regulating the thermal energy of said separation unit by transferring the thermal energy of the additional stream of steam generated at step (i) and of at least the second stream recovered at step (d) to the temperature-regulating device of the separation unit.

[0017] Surprisingly, it has been found that the thermal energy of the oxygen-containing effluent exiting the solid oxide electrolyser cell can be used to run more efficiently the separation unit, reducing the production of steam to supply to such unit and subsequently decreasing the energy consumption with respect to the methanol production.

[0018] For example, the additional stream of steam generated at step (i) has a pressure ranging between 0.30 MPa and 3.10 MPa, preferably between 0.31 MPa and 3.00 MPa, preferably between 0.32 MPa and 2.00 MPa, more preferably between 0.33 MPa and 1.50 MPa, even more preferably between 0.34 MPa and 1.30 MPa, most preferably between 0.35 MPa and 1.10 MPa.

[0019] For example, the second stream recovered at step (d) has a pressure P2 ranging between 0.31 MPa and 3.11 MPa, preferably between 0.32 MPa and 3.10 MPa, preferably between 0.33 MPa and 2.00 MPa, more preferably between 0.34 MPa and 1.50 MPa, even more preferably between 0.35 MPa and 1.30 MPa, most preferably between 0.36 MPa and 1.10 MPa.

[0020] For example, the step (i) further comprises transferring the thermal energy of the oxygencontaining effluent generated at step (g) to the first stream recovered at step (c).

[0021] With preference, the step of transferring the thermal energy of the oxygen-containing effluent generated at step (g) to the first stream recovered at step (c) also generates an oxygen outflow and the method further comprises the step of transferring the thermal energy of said oxygen outflow to the water stream provided at step (h) so as to generate the additional stream of steam.

[0022] For example, the step of working the solid oxide electrolyser cell also generates either a hydrogen-rich effluent or a syngas effluent; and the method further comprises the step of transferring the thermal energy of either the hydrogen-rich effluent or the syngas effluent to said water stream before the step of transferring the thermal energy of the oxygen outflow to said water stream so as to generate the additional stream of steam.

[0023] Advantageously, the step of working the solid oxide electrolyser cell also generates either a hydrogen-rich effluent or a syngas effluent; the method further comprises the step of transferring the thermal energy of either the hydrogen-rich effluent or the syngas effluent to said water stream before the step of transferring the thermal energy of the oxygen-containing effluent to said water stream so as to generate the additional stream of steam.

[0024] Advantageously, the step of transferring the thermal energy of the oxygen-containing effluent generated at step (g) to the first stream recovered at step (c) also generates an oxygen outflow and the step (i) is the step of transferring the thermal energy of said oxygen outflow to the water stream provided at step (h) so as to generate the additional stream of steam, and when the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam, the step of working the solid oxide electrolyser cell also generates a hydrogen-rich effluent; and the method further comprises the step of transferring the thermal energy of the hydrogen-rich effluent to said water stream before the step of transferring the thermal energy of the oxygen outflow to said water stream so as to generate the additional stream of steam, and the step (j) is the step of transferring the thermal energy of the additional stream of steam generated at step (i) and of at least the second stream recovered at step (d) to the temperature-regulating device of the separation unit.

[0025] Advantageously, the step of transferring the thermal energy of the oxygen-containing effluent generated at step (g) to the first stream recovered at step (c) also generates an oxygen outflow and the step (i) is the step of transferring the thermal energy of said oxygen outflow to the water stream provided at step (h) so as to generate the additional stream of steam, and when the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam and carbon dioxide, the step of working the solid oxide electrolyser cell also generates a syngas effluent; and the method further comprises the step of transferring the thermal energy of the syngas effluent to said water stream before the step of transferring the thermal energy of the oxygen outflow to said water stream so as to generate the additional stream of steam; and the step (j) is the step of transferring the thermal energy of a first part of the additional stream of steam generated at step (i) and of at least the second stream recovered at step (d) to the temperature-regulating device of the separation unit. With preference, a second part of the additional stream of steam generated at step (i) is fed to the one or more solid oxide electrolyser cells.

[0026] Advantageously, the step (j) is the step of transferring the thermal energy of the additional stream of steam generated at step (i) and of at least the second stream recovered at step (d) to the temperature-regulating device of the separation unit; and when the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam, the step of working the one or more solid oxide electrolyser cells also generates a hydrogen-rich effluent; and the method further comprises the step of transferring the thermal energy of the hydrogen-rich effluent to said water stream before the step (i) of transferring the thermal energy of the oxygencontaining effluent generated at step (g) to said water stream provided at step (h) so as to generate the additional stream of steam.

[0027] Advantageously, when the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam and carbon dioxide, the step (j) is the step of transferring the thermal energy of a first part of the additional stream of steam generated at step (i) and of at least the second stream recovered at step (d) to the temperature-regulating device of the separation unit; and the step of working the one or more solid oxide electrolyser cells also generates a syngas effluent; and the method further comprises the step of transferring the thermal energy of the syngas effluent to said water stream before the step (i) of transferring the thermal energy of the oxygen-containing effluent generated at step (g) to said water stream provided at step (h) so as to generate the additional stream of steam. With preference, a second part of the additional stream of steam generated at step (i) is fed to the one or more solid oxide electrolyser cells.

[0028] Advantageously, the step (b) of operating said at least one reactor generates a reactor effluent, and the method further comprises the step of transferring the thermal energy of said reactor effluent to said water stream so as to generate a third additional stream of steam, said third additional stream of steam being then fed to said one or more solid oxide electrolyser cells and / or the step of working said one or more solid oxide electrolyser cells also generates either a hydrogen-rich effluent or a syngas effluent; and the method further comprises the step of subjecting to a pressure increase step said hydrogen-rich effluent or said syngas effluent before directing them to the reactor, said pressure increase step generating heat, and that the method further comprises the step of transferring the heat generated by the pressure increase step to said water stream so as to generate a second additional stream of steam, said second additional stream of steam being then fed to said one or more solid oxide electrolyser cells.

[0029] Advantageously, the step (b) of operating said at least one reactor generates a reactor effluent, and the method further comprises the step of transferring the thermal energy of said reactor effluent to said water stream so as to generate a third additional stream of steam, said third additional stream of steam being then fed to said one or more solid oxide electrolyser cells and the step of working said one or more solid oxide electrolyser cells also generates either a hydrogen-rich effluent or a syngas effluent; and the method further comprises the step of subjecting to a pressure increase step said hydrogen-rich effluent or said syngas effluent before directing them to the reactor, said pressure increase step generating heat, and that the method further comprises the step of transferring the heat generated by the pressure increase step to said water stream so as to generate a second additional stream of steam, said second additional stream of steam being then fed to said one or more solid oxide electrolyser cells.

[0030] According to a second aspect, the disclosure provides an installation for producing methanol remarkable in that the installation comprises a methanol-generating unit and a separation unit, wherein said separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein the separation unit comprises a temperature-regulating device, and wherein the methanol-generating unit comprises one or more reactors, each reactor comprising a cooling device; at least one steam pressure-reducing device, the steam pressure-reducing device being placed downstream of said cooling device and upstream of said temperatureregulating device; a first line connecting fluidically the cooling device to the one or more steam pressurereducing devices; a second line connecting fluidically the one or more steam pressure-reducing devices to the temperature-regulating device, and wherein the one or more steam pressurereducing devices comprise at least one steam pressure regulator; one or more solid oxide electrolyser cells, each of said one or more solid oxide electrolyser cells comprising one oxygen-output line to direct an oxygen-containing effluent out of said solid oxide electrolyser cell; a water supply upstream of a heat exchanger, and a water line directing a water stream from said water supply to said heat exchanger; wherein each oxygen-output line is in connection with said heat exchanger so that the thermal energy of said oxygen-containing effluent is transferred to the water stream of the water supply to produce an additional stream of steam that is directed into an additional line connecting the heat exchanger to the temperature-regulating device so that the thermal energy of the additional stream of steam is transferred to the temperature-regulating device.

[0031] With preference, the heat management method as defined in accordance with the first aspect is carried out in said installation.

[0032] Advantageously, the installation further comprises a gas-liquid separator, said gas-liquid separator being placed on the second line downstream of and in fluidic connection with said at least one steam pressure-reducing device, said gas-liquid separator comprising an overhead fluidically connected to the temperature-regulating device.

[0033] For example, the one or more steam pressure regulators are one or more pressure control valves.

[0034] For example, the steam pressure-reducing device is at least one turbine or at least one Venturi scrubber, preferably at least one turbine.

[0035] According to a third aspect, the present disclosure also relates to the use, in an installation as defined in accordance with the second aspect, of the thermal energy of an oxygencontaining effluent exiting said one or more solid oxide electrolyser cells for heating a water stream to produce an additional stream of steam for providing thermal energy to a temperatureregulating device of the separation unit.

[0036] According to a fourth aspect, the disclosure provides a heat management method in a methanol-generating unit, said method is remarkable in that it comprises the following steps: a) providing a methanol-generating unit and a separation unit, wherein the separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein said separation unit comprises a temperature-regulating device, and wherein said methanol-generating unit comprises one or more reactors each reactor comprising a cooling device; b) operating said one or more reactors under first operating conditions comprising at least regulating the thermal energy of said at least one reactor by adjusting the temperature of the cooling device with water; c) recovering from said cooling device, after said step of regulating the thermal energy, a first stream, said first stream comprising steam at a pressure P1; d) decreasing the pressure of said first stream so as to recover a second stream, said second stream comprising steam at a pressure P2, P2 being at least 0.31 MPa, and wherein P2 < P1 ; e) providing one or more solid oxide electrolyser cells; f) feeding said one or more solid oxide electrolyser cells with steam or with a mixture comprising steam and carbon dioxide; g) working said one or more solid oxide electrolyser cells under second operating conditions so as to generate at least one oxygen-containing effluent, said second operating conditions comprising at least electrical power and a temperature higher than 400°C; k) transferring the thermal energy of said at least one oxygen-containing effluent to the first stream recovered at step (c); l) operating said separation unit under third operating conditions comprising regulating the thermal energy of said separation unit by transferring the thermal energy of the second stream recovered at step (d) to the temperature-regulating device of the separation unit.

[0037] Surprisingly, it has been found that the thermal energy of the oxygen-containing effluent exiting the solid oxide electrolyser cell can be used to preheat the stream of steam entering into a steam pressure-reducing device necessary to provide a stream of steam with the required pressure to run the separation unit, leading subsequently to a decrease of energy consumption with respect to the methanol production.

[0038] Advantageously, the heat management method further comprises a step (h) of providing a water stream, and the step (k) of transferring the thermal energy of said at least one oxygencontaining effluent to the first stream recovered at step (c) also generates an oxygen outflow, and the method further comprises the step of transferring the thermal energy of said oxygen outflow to the water stream provided at step (h) so as to generate an additional stream of steam, and the step carried out at step (I) of transferring the thermal energy of the second stream recovered at step (d) to the temperature-regulating device of the separation unit further comprises transferring the thermal energy of the additional stream of steam.

[0039] Advantageously, the heat management method further comprises a step (h) of providing a water stream, and the step (k) of transferring the thermal energy of said at least one oxygencontaining effluent to the first stream recovered at step (c) also generates an oxygen outflow, and the method further comprises the step of transferring the thermal energy of said oxygen outflow to the water stream provided at step (h) so as to generate an additional stream of steam, and the step carried out at step (I) of transferring the thermal energy of the second stream recovered at step (d) to the temperature-regulating device of the separation unit further comprises transferring the thermal energy of a first part of the additional stream of steam when the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam and carbon dioxide. With preference, a second part of the additional stream of steam is fed to the one or more solid oxide electrolyser cells.

[0040] Advantageously, the step (b) of operating said at least one reactor generates a reactor effluent, and the method further comprises the step of transferring the thermal energy of said reactor effluent to said water stream so as to generate a third additional stream of steam, said third additional stream of steam being then fed to said one or more solid oxide electrolyser cells and / or the step of working said one or more solid oxide electrolyser cells also generates either a hydrogen-rich effluent or a syngas effluent; and the method further comprises the step of subjecting to a pressure increase step said hydrogen-rich effluent or said syngas effluent before directing them to the reactor, said pressure increase step generating heat, and that the method further comprises the step of providing a water stream and the step of transferring the heat generated by the pressure increase step to said water stream so as to generate a second additional stream of steam, said second additional stream of steam being then fed to said one or more solid oxide electrolyser cells.

[0041] Advantageously, the step (b) of operating said at least one reactor generates a reactor effluent, and the method further comprises the step of transferring the thermal energy of said reactor effluent to said water stream so as to generate a third additional stream of steam, said third additional stream of steam being then fed to said one or more solid oxide electrolyser cells and the step of working said one or more solid oxide electrolyser cells also generates either a hydrogen-rich effluent or a syngas effluent; and the method further comprises the step of subjecting to a pressure increase step said hydrogen-rich effluent or said syngas effluent before directing them to the reactor, said pressure increase step generating heat, and that the method further comprises the step of providing a water stream and the step of transferring the heat generated by the pressure increase step to said water stream so as to generate a second additional stream of steam, said second additional stream of steam being then fed to said one or more solid oxide electrolyser cells.

[0042] According to a fifth aspect, the disclosure provides an installation for producing methanol remarkable in that the installation comprises a methanol-generating unit and a separation unit, wherein the separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein said separation unit comprises a temperature-regulating device, and wherein said methanol-generating unit comprises one or more reactors each reactor comprising a cooling device; at least one steam pressure-reducing device, the steam pressure-reducing device being placed downstream of said cooling device and upstream of said temperatureregulating device; a first line connecting fluidically the cooling device to the one or more steam pressurereducing devices so as to direct a first stream comprising steam at a pressure P1 from the cooling device to the one or more steam pressure-reducing devices; a second line connecting fluidically the one or more steam pressure-reducing devices to the temperature-regulating device, and wherein the one or more steam pressurereducing devices comprise at least one steam pressure regulator; one or more solid oxide electrolyser cells, each of said one or more solid oxide electrolyser cells comprising one oxygen-output line to direct an oxygen-containing effluent out of said solid oxide electrolyser cell; a third heat exchanger placed on the first line, between the cooling device and the one or more steam pressure-reducing devices; wherein the oxygen-output line is in connection with said third heat exchanger so that the thermal energy of said oxygen-containing effluent is transferred to the first stream comprising steam at a pressure P1.

[0043] With preference, the heat management method as defined in accordance with the fourth aspect is carried out in said installation, namely in the installation as defined in the fifth aspect.

[0044] Advantageously, the installation further comprises a gas-liquid separator, said gas-liquid separator being placed on the second line downstream of and in fluidic connection with said at least one steam pressure-reducing device, said gas-liquid separator comprising an overhead fluidically connected to the temperature-regulating device.

[0045] For example, the one or more steam pressure regulators are one or more pressure control valves.

[0046] For example, the steam pressure-reducing device is at least one turbine or at least one Venturi scrubber, preferably at least one turbine.

[0047] According to a sixth aspect, the present disclosure also relates to the use, in an installation as defined in accordance with the fifth aspect, of the thermal energy of an oxygen-containing effluent exiting said one or more solid oxide electrolyser cells for heating a first stream entering a steam pressure-reducing device to produce a second stream for providing thermal energy to a temperature-regulating device of the separation unit.

[0048] Whichever the aspect selected, one or more of the following features are preferably true:

[0049] For example, the first operating conditions of step (b) comprise providing a carbon oxides feedstock to said at least one reactor, providing a stream of hydrogen and mixing together the carbon oxides feedstock and the stream of hydrogen within said at least one reactor so as to produce a methanol effluent.

[0050] With preference, the carbon oxides of the carbon oxides feedstock provided to said at least one reactor are selected from CO2 and / or CO. With preference, the first operating conditions of step (b) comprise providing a carbon oxides feedstock to said at least one reactor, providing a hydrogen-rich effluent generated by working said one or more solid oxide electrolyser cells as a stream of hydrogen and mixing together the carbon oxides feedstock and the stream of hydrogen within said at least one reactor so as to produce a methanol effluent.

[0051] Alternatively, the first operating conditions of step (b) preferably comprise providing a syngas effluent generated by working said one or more solid oxide electrolyser cells so as to produce a methanol effluent.

[0052] For example, the first stream is at a temperature T 1 comprised between 200°C and 325°C, or between 205°C and 300°C, preferably between 210°C and 295°C, more preferably between 215°C and 290°C, even more preferably between 220°C and 285°C.

[0053] For example, the pressure P1 of the first stream is comprised between 1.5 MPa and 12.0 MPa, preferably between 2.2 MPa and 7.0 MPa. The pressure P1 of the first stream is measured at dew point.

[0054] For example, the pressure P1 of the first steam corresponds to the pressure of water used in step (b).

[0055] For example, the pressure P2 of the second stream is ranging between 0.31 MPa and 1.30 MPa, preferably between 0.32 MPa and 1.29 MPa, preferably between 0.33 MPa and 1.28 MPa, more preferably between 0.34 MPa and 1.27 MPa, even more preferably between 0.35 MPa and 1.26 MPa, most preferably between 0.36 MPa and 1.25 MPa.

[0056] Advantageously, the second stream comprising steam at a pressure P2 further comprises one condensate; and the method further comprises the step of separating the steam from said condensate so as to recover a third stream, said third stream comprising steam at a pressure P3, wherein P3 is equal or inferior to P2.

[0057] With preference, the step of regulating the thermal energy carried out in step (j) and / or in step (I) further comprises transferring the thermal energy of the third stream to the temperatureregulating device of the separation unit.

[0058] For example, the pressure P3 of the third stream is ranging between 0.30 MPa and 1.29 MPa, preferably between 0.31 MPa and 1.28 MPa, preferably between 0.32 MPa and 1.27 MPa, more preferably between 0.33 MPa and 1.26 MPa, even more preferably between 0.34 MPa and 1 .25 MPa, most preferably between 0.35 MPa and 1 .24 MPa. The pressure P3 of the third stream is measured at dew point.

[0059] When the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam, the method advantageously further comprises the step of providing a complementary stream of steam to the second stream.

[0060] When the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam, the method advantageously further comprises the step of providing a complementary stream of steam to the third stream.

[0061] For example, said complementary stream of steam is at a pressure ranging between 0.30 MPa and 1 .29 MPa, preferably between 0.31 MPa and 1 .28 MPa, preferably between 0.32 MPa and 1.27 MPa, more preferably between 0.33 MPa and 1.26 MPa, even more preferably between 0.34 MPa and 1.25 MPa, most preferably between 0.35 MPa and 1.24 MPa.

[0062] When the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam and carbon dioxide, the step of regulating the thermal energy carried out in step (j) is the step of transferring the thermal energy of a first part of the additional stream of steam generated at step (i) and of at least the second stream recovered at step (d) to the temperature-regulating device of the separation unit.

[0063] With preference, a second part of the additional stream of steam generated at step (i) is fed to the one or more solid oxide electrolyser cells.

[0064] When the step (f) is the step of feeding said one or more solid oxide electrolyser cells with steam and carbon dioxide, the step of feeding said one or more solid oxide electrolyser cells advantageously further comprises feeding said one or more solid oxide electrolyser cells with hydrogen, syngas, methane, hydrocarbons or any mixture thereof. For example, hydrocarbons are alkanes.

[0065] For example, the first operating conditions of step (b) comprises providing a carbon oxide feedstock to said at least one reactor, providing the hydrogen-rich effluent or the syngas effluent generated by working said one or more solid oxide electrolyser cells as a stream of hydrogen and mixing together the carbon oxides feedstock and the stream of hydrogen within said at least one reactor so as to produce a methanol effluent.

[0066] For example, the step (d) of decreasing the pressure of said first stream further produces electrical energy; and said method further comprises the step of supplying said electrical energy to said solid oxide electrolyser cell so as to run said solid oxide electrolyser cell. For example, the methanol-generating unit provided at step (a) comprises one or more compressors, and the step (d) of decreasing the pressure of said first stream further produces electrical energy and / or shaft work; and the method further comprises the step of supplying said electrical energy and / or shaft work to said one or more compressors so as to run the one or more compressors comprised within the methanol-generating unit.

[0067] Description of the figures

[0068] Figure 1a: Installation comprising a methanol-generating unit upstream of a separation unit along with a solid oxide electrolyser cell working in electrolysis mode (SOEC).

[0069] Figure 1b: Installation comprising a methanol-generating unit upstream of a separation unit along with a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC).

[0070] Figure 2a: Installation comprising a methanol-generating unit upstream of a separation unit. Steam at medium pressure ( / .e., above 0.32 MPa) is directed from a steam pressure-reducing device to the separation unit. A solid oxide electrolyser cell working in electrolysis mode (SOEC) is shown.

[0071] Figure 2b: Installation comprising a methanol-generating unit upstream of a separation unit. Steam at medium pressure ( / .e., above 0.32 MPa) is directed from a steam pressure-reducing device to the separation unit. A solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC) is shown.

[0072] Figure 3a: Installation according to the present disclosure comprising a methanol-generating unit upstream of a separation unit, wherein production of additional steam thanks to the oxygen-containing effluent exiting the solid oxide electrolyser cell working in electrolysis mode (SOEC) is carried out and directed to the separation unit.

[0073] Figure 3b: Installation according to the present disclosure comprising a methanol-generating unit upstream of a separation unit, wherein production of additional steam thanks to the oxygen-containing effluent exiting the solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC) is carried out and directed to the separation unit.

[0074] Figure 4a: Installation comprising a methanol-generating unit upstream of a separation unit, wherein a stream of steam entering a steam pressure-reducing device is pre-heated thanks to the oxygen-containing effluent exiting a solid oxide electrolyser cell working in electrolysis mode (SOEC). Figure 4b: Installation comprising a methanol-generating unit upstream of a separation unit, wherein a stream of steam entering a steam pressure-reducing device is pre-heated thanks to the oxygen-containing effluent exiting a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC).

[0075] Figure 5a: Installation according to the present disclosure wherein in addition of pre-heating the stream of steam entering a steam pressure-reducing device, the oxygen-containing effluent exiting a solid oxide electrolyser cell working in electrolysis mode (SOEC) generates an oxygen outflow which transfers its thermal energy to steam directed to the separation unit.

[0076] Figure 5b: Installation according to the present disclosure wherein in addition of pre-heating the stream of steam entering a steam pressure-reducing device, the oxygen-containing effluent exiting a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC) generates an oxygen outflow which transfers its thermal energy to steam directed to the separation unit.

[0077] Figure 6a: Installation according to the present disclosure wherein in addition of pre-heating the stream of steam entering a steam pressure-reducing device, the oxygen-containing effluent exiting a solid oxide electrolyser cell working in electrolysis mode (SOEC) generates an oxygen outflow which transfers its thermal energy, along with the thermal energy of the hydrogen-rich effluent, to steam directed to the separation unit.

[0078] Figure 6b: Installation according to the present disclosure wherein in addition of pre-heating the stream of steam entering a steam pressure-reducing device, the oxygen-containing effluent exiting a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC) generates an oxygen outflow which transfers its thermal energy, along with the thermal energy of the syngas effluent, to steam directed to the separation unit.

[0079] Figure 7a: Installation according to the present disclosure comprising a methanol-generating unit upstream of a separation unit, wherein production of additional steam thanks to the oxygen-containing effluent and the hydrogen-rich effluent exiting the solid oxide electrolyser cell working in electrolysis mode (SOEC) is carried out and directed to the separation unit.

[0080] Figure 7b: Installation according to the present disclosure comprising a methanol-generating unit upstream of a separation unit, wherein production of additional steam thanks to the oxygen-containing effluent and the syngas effluent exiting the solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC) is carried out and directed to the separation unit.

[0081] Figure 8a: Installation according to the present disclosure comprising a methanol-generating unit upstream of a separation unit. Steam at medium pressure ( / .e., above 0.32 MPa) is directed from a steam pressure-reducing device to the separation unit. A compressor is upstream to the reactor of the methanol-generating unit and generates heat upon pressure increase of the hydrogen-rich effluent, said heat serving to produce steam fed to a solid oxide electrolyser cell working in electrolysis mode (SOEC).

[0082] Figure 8b: Installation according to the present disclosure comprising a methanol-generating unit upstream of a separation unit. Steam at medium pressure ( / .e., above 0.32 MPa) is directed from a steam pressure-reducing device to the separation unit. A compressor is upstream to the reactor of the methanol-generating unit and generates heat upon pressure increase of the syngas effluent, said heat serving to produce steam fed to a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC).

[0083] Detailed description

[0084] For the purpose of the disclosure, the following definitions are given.

[0085] The terms "comprising", "comprises" and "comprised of' as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms "comprising", "comprises" and "comprised of" also include the term “consisting of”.

[0086] The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g., 1 to 5 includes 1 , 2, 3, 4, 5 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of endpoints also includes the recited endpoint values themselves (e.g., from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

[0087] The reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The particular features, structures, characteristics or embodiments may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the disclosure and form different embodiments, as would be understood by those in the art. The unit “kilowatt hours per kilogram of methanol” (kWh / kgMeon) is the reference unit used to measure or indicate the density of energy contained or storable in methanol.

[0088] The value “0 barg” (relative pressure) corresponds to a difference of pressure with respect to the atmospheric pressure. Therefore, 0 barg = 1 atm = 101325 Pa (absolute pressure, namely the pressure measured with respect to the vacuum) or 0.101325 MPa, rounded to 0.1 MPa.

[0089] The consumption gain in the methanol production have been simulated using the software ProSimPlus.

[0090] The installations represented at figures 1a and 1 b schematize a methanol-generating unit which is upstream of a separation unit and in fluidic connection with it. The methanolgenerating unit comprises at least one reactor 100, which is for example in fluidic connection with the separation unit. Indeed, there is a fluidic connection between the reactor 100 and the separation unit, in particular with the distillation column 200. This line conveys the reactor effluent 150 from the reactor 100 to the separation unit. Each reactor comprises a cooling device. The separation unit, such as one or more distillation columns 200, preferably three distillations columns that can be arranged in series, comprises a temperature-regulating device 250. The installations further comprise at least one steam pressure-reducing device, for example a turbine 300. The one or more steam pressure-reducing devices are placed downstream of the cooling device and upstream of the temperature-regulating device. The methanol-generating unit and the separation unit are in combination with one or more solid oxide electrolyser cells 400 which work either in electrolysis mode (figure 1a) or in coelectrolysis mode (figure 1 b). The steam pressure-reducing device comprises at least one steam pressure regulator, which can be one or more pressure control valves (PCV) which are used to reduce the pressure of first stream 3 exiting the cooling device. Upon the pressure reduction of the first stream 3, the steam pressure-reducing device produces electricity and / or shaft work, as schematized by the arrow 9. The second stream 5 exiting the steam pressurereducing device can be therefore used to regulate the thermal energy of the separation unit. The condensate that is the liquid formed when the pressure of a condensable gas is reduced due to (partial) condensation of the gas itself, and that is present into the first stream 3, is optionally removed through a gas / liquid separation column 500, so that a third stream 7 is recovered and a stream 8 comprising the condensate is also recovered. The third stream 7 can also be used to regulate the thermal energy of the separation unit. A complementary stream of steam 11 can be supplemented to the second stream 5 and / or to the third stream 7, preferably the complementary stream of steam 11 is supplemented to the third stream 7. In the installation represented at figure 2a, namely when the second stream 5 exiting the turbine is at a pressure P2 of 0.5 MPa and when one solid oxide electrolyser cell 400 working in electrolysis mode (SOEC) is coupled to the methanol-generating unit and to the separation unit, the process of methanol production is consuming 10.98 kWh / kgMeOH.

[0091] In the installation represented at figure 2b, namely when the second stream 5 exiting the turbine is at a pressure P2 of 0.5 MPa and when one solid oxide electrolyser cell 400 working in co-electrolysis mode (co-SOEC) is coupled to the methanol-generating unit and to the separation unit, the process of methanol production is consuming 10.26 kWh / kgMeOH.

[0092] Production of additional steam thanks to the oxygen-containing effluent exiting the solid oxide electrolyser cell and transfer of its thermal energy to the separation unit

[0093] As represented at figure 3a or 3b, the present disclosure provides a heat management method in a methanol-generating unit, said method is remarkable in that it comprises the following steps: a) providing a methanol-generating unit and a separation unit, wherein the separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein said separation unit comprises a temperature-regulating device 250, and wherein said methanol-generating unit comprises one or more reactors 100 each comprising a cooling device; b) operating said at least one reactor 100 under first operating conditions, said first operating conditions comprising at least regulating the thermal energy of said at least one reactor 100; wherein the step of regulating the thermal energy comprises adjusting the temperature of the cooling device with water 1 ; c) recovering from said cooling device, after said step of regulating the thermal energy, a first stream 3, said first stream 3 comprising steam at a pressure P1 ; d) decreasing the pressure of said first stream 3 so as to recover a second stream 5, said second stream 5 comprising steam at a pressure P2, P2 being at least 0.31 MPa, and wherein P2 < P1 ; e) providing one or more solid oxide electrolyser cells 400; f) feeding said one or more solid oxide electrolyser cells with steam 12 or with a mixture comprising steam 12 and carbon dioxide 17; g) working said one or more solid oxide electrolyser cells under second operating conditions so as to generate at least one oxygen-containing effluent 13, said second operating conditions comprising at least electrical power and a temperature higher than 400°C; h) providing a water stream 23; i) transferring the thermal energy of the oxygen-containing effluent 13 generated at step (g) to at least the water stream 23 provided at step (h) so as to generate an additional stream 25 of steam; j) operating said separation unit under third operating conditions, said third operating conditions comprising regulating the thermal energy of said separation unit; wherein the step of regulating the thermal energy comprises transferring the thermal energy of the additional stream 25 of steam generated at step (i) and of at least the second stream 5 recovered at step (d) to the temperature-regulating device 250 of the separation unit.

[0094] The heat management method described above is advantageously carried out in an installation for producing methanol remarkable in that the installation comprises a methanol-generating unit and a separation unit, wherein said separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein the separation unit comprises a temperature-regulating device 250, and wherein the methanol-generating unit comprises one or more reactors 100, each reactor 100 comprising a cooling device; at least one steam pressure-reducing device, the steam pressure-reducing device being placed downstream of said cooling device and upstream of said temperatureregulating device 250; a first line connecting fluidically the cooling device to the one or more steam pressurereducing devices; a second line connecting fluidically the one or more steam pressure-reducing devices to the temperature-regulating device 250, and wherein the one or more steam pressure-reducing devices comprise at least one steam pressure regulator; one or more solid oxide electrolyser cells 400, each of said one or more solid oxide electrolyser cells 400 comprising one oxygen-output line to direct an oxygen-containing effluent 13 out of said solid oxide electrolyser cell 400; a water supply upstream of a heat exchanger, and a water line directing a water stream 23 from said water supply to said heat exchanger; wherein each oxygen-output line is in connection with said heat exchanger so that the thermal energy of said oxygen-containing effluent 13 is transferred to the water stream 23 of the water supply to produce an additional stream 25 of steam that is directed into an additional line connecting the heat exchanger to the temperature-regulating device 250 so that the thermal energy of the additional stream 25 of steam is transferred to the temperature-regulating device 250. For example, the one or more steam pressure regulators are one or more pressure control valves.

[0095] For example, the steam pressure-reducing device is at least one turbine or at least one Venturi scrubber, preferably at least one turbine.

[0096] The thermal energy of the oxygen-containing effluent 13 exiting the one or more solid oxide electrolyser cells 400 can thus be used to feed the separation unit, leading subsequently to a decrease of energy consumption with respect to the methanol production.

[0097] In an installation comprising a methanol-generating unit, a separation unit downstream of said methanol-generating unit and wherein the methanol-generating unit is coupled to one or more solid oxide electrolyser cells 400 and the separation unit comprising a temperature-regulating device 250, the present disclosure is therefore related to the use of the thermal energy of an oxygen-containing effluent 13 exiting said one or more solid oxide electrolyser cells 400 for heating a water stream 23 to produce an additional stream 25 of steam for providing at least part of the thermal energy to the temperature-regulating device 250 in order to enhance the methanol production process.

[0098] For example, the first operating conditions of step (b) comprise providing a carbon oxides feedstock to said at least one reactor, providing a stream of hydrogen and mixing together the carbon oxides feedstock and the stream of hydrogen within said at least one reactor so as to produce a methanol effluent. Alternatively, the first operating conditions of step (b) comprise providing a syngas effluent 19 generated by working said one or more solid oxide electrolyser cells 400 so as to produce a methanol effluent. With preference, the carbon oxides of the carbon oxides feedstock provided to said at least one reactor are selected from CO2 and / or CO. With preference, the pressure of the stream of hydrogen in the first operating conditions used in step (b) is ranging between 0.1 MPa and 12.0 MPa, preferably between 0.5 MPa, and 9.5 MPa, more preferably between 1.0 MPa and 9.0 MPa; even more preferably between 1.5 MPa and 8.5 MPa, most preferably between 2.0 MPa and 8.0 MPa. With preference, the pressure of the carbon oxides feedstock in the first operating conditions used in step (b) is at the same pressure as the stream of hydrogen, namely is ranging between 0.1 MPa and 12.0 MPa, preferably between 0.5 MPa, and 9.5 MPa, more preferably between 1.0 MPa and 9.0 MPa; even more preferably between 1.5 MPa and 8.5 MPa, most preferably between 2.0 MPa and 8.0 MPa. If a syngas effluent is used, its pressure is also similar, namely ranging between 0.1 MPa and 12.0 MPa, preferably between 0.5 MPa, and 9.5 MPa, more preferably between 1.0 MPa and 9.0 MPa; even more preferably between 1.5 MPa and 8.5 MPa, most preferably between 2.0 MPa and 8.0 MPa.

[0099] For example, the first operating conditions of step (b) comprise a temperature ranging between 200°C and 320°C, preferably between 220°C and 275°C.

[0100] For example, the first operating conditions of step (b) comprise a start-of-run outlet reactor temperature ranging between 200°C and 320°C, preferably between 220°C and 275°C.

[0101] For example, the water 1 used in step (b) for adjusting the temperature of the cooling device has a pressure ranging between 1.5 MPa and 12.0 MPa, or between 2.2 MPa and 7.0 MPa.

[0102] For example, the water 1 used in step (b) for adjusting the temperature of the cooling device has a temperature ranging between 100°C and 200°C, or between 120°C and 150°C.

[0103] The one or more solid oxide electrolyser cells 400 have each an anode and a cathode and comprise a solid oxide electrolyte between the anode and the cathode. The anode, the cathode and the solid oxide electrolyte are each composed of one or more ceramic materials. The temperature at which said one or more solid oxide electrolyser cells are working under electrical power can be higher than 425°C, preferably higher than 450°C, more preferably higher than 475°C, even more preferably higher than 500°C. For example, the temperature at which said one or more solid oxide electrolyser cells are working under electrical power is ranging between 400°C and 1000°C, or between 450°C and 900°C, preferably between 500°C and 890°C, more preferably between 550°C and 880°C, even more preferably between 600°C and 870°C, most preferably between 700°C and 860°C.

[0104] For example, the one or more solid oxide electrolyser cells 400 are operated at a current density that is ranging between 0.2 A / cm2and 5 A / cm2, preferably between 0.4 A / cm2and 4.8 A / cm2. For example, the one or more solid oxide electrolyser cells are operated at an electrical potential ranging between 0.2 V / cell and 2.0 V / cell, preferably between 0.4 V / cell and 1.8 V / cell.

[0105] For example, the first stream 3 is at a temperature T1 comprised between 200°C and 325°C, or between 200°C and 300°C, preferably between 205°C and 295°C, more preferably between 210°C and 290°C, even more preferably between 215°C and 285°C, most preferably between 220°C and 280°C, even most preferably between 225°C and 275°C. For example, the pressure P1 of the first stream 3 is comprised between 1.5 MPa and 12.0 MPa, preferably between 2.2 MPa and 7.0 MPa. The pressure P1 of the first stream is measured at dew point.

[0106] For example, the second stream 5 recovered at step (d) has a pressure P2 ranging between 0.31 MPa and 1.30 MPa, preferably between 0.32 MPa and 1.29 MPa, preferably between 0.33 MPa and 1.28 MPa, more preferably between 0.34 MPa and 1.27 MPa, even more preferably between 0.35 MPa and 1.26 MPa, most preferably between 0.36 MPa and 1.25 MPa.

[0107] For example, the pressure P3 of the third stream 7 is ranging between 0.30 MPa and 1.29 MPa, preferably between 0.31 MPa and 1.28 MPa, preferably between 0.32 MPa and 1.27 MPa, more preferably between 0.33 MPa and 1.26 MPa, even more preferably between 0.34 MPa and 1.25 MPa, most preferably between 0.35 MPa and 1.24 MPa. The pressure P3 of the third stream is measured at dew point.

[0108] The pressure P1 of the first stream and / or the pressure P3 of the third stream is measured at dew point. The pressure P2 of the second stream is not measured at dew point because it is related to a steam that is at the exit of the steam pressure-reducing device and which subsequently comprises a condensate.

[0109] For example, the at least one oxygen-containing effluent 13 generated at step (g) is at a temperature Toxeffluent ranging between 300°C and 400°C, preferably between 305°C and 395°C, more preferably between 310°C and 390°C.

[0110] For example, the additional stream 25 of steam generated at step (i) has a pressure ranging between 0.30 MPa and 1.29 MPa, preferably between 0.31 MPa and 1.28 MPa, preferably between 0.32 MPa and 1.27 MPa, more preferably between 0.33 MPa and 1.26 MPa, even more preferably between 0.34 MPa and 1.25 MPa, most preferably between 0.35 MPa and 1 .24 MPa. It corresponds to the pressure P3 of the third stream 7.

[0111] It is preferred when the step (f) is the step of feeding the one or more solid oxide electrolyser cells 400 with steam 12 only, namely when the one or more solid oxide electrolyser cells 400 work in the electrolysis mode (SOEC), that the method further comprises the step of providing a complementary stream 11 of steam to at least the second stream 5 recovered at step (d).

[0112] It is also preferred when the step (f) is the step of feeding the one or more solid oxide electrolyser cells 400 with steam 12 and carbon dioxide 17, namely when the one or more solid oxide electrolyser cells 400 work in the co-electrolysis mode (co-SOEC), that the step of regulating the thermal energy carried out in step (j) is the step of transferring the thermal energy of a first part 27 of the additional stream of steam generated at step (i) and of at least the second stream 5 recovered at step (d) to the temperature-regulating device 250 of the separation unit. With preference, a second part 29 of the additional stream of steam generated at step (i) is fed to the one or more solid oxide electrolyser cells 400.

[0113] As the second stream 5 comprising steam at a pressure P2 recovered at step (d) further comprises one condensate; the method can advantageously comprise the step of separating the steam from said condensate so as to recover a third stream 7; said third stream 7 comprising steam at a pressure P3, wherein P3 is equal or inferior to P2. A stream 8 comprising a condensate is also recovered. Thus, advantageously, the installation further comprises a gas-liquid separator 500, said gas-liquid separator 500 being placed on the second line downstream of and in fluidic connection with said at least one steam pressure-reducing device, said gas-liquid separator 500 comprising an overhead fluidically connected to the temperatureregulating device 250.

[0114] Subsequently, the step of regulating the thermal energy carried out in step (j) further comprises transferring the thermal energy of the third stream 7 to the temperature-regulating device 250 of the separation unit, in addition of transferring the thermal energy of the additional stream 25 of steam generated at step (i) when the one or more solid oxide electrolyser cells are working in the electrolysis mode (SOEC), or in addition of transferring the thermal energy of a first part 27 of the additional stream of steam generated at step (i) when the one or more solid oxide electrolyser cells are working in the co-electrolysis mode (co-SOEC).

[0115] For example, the step (d) of decreasing the pressure of said first stream 3 further produces electrical energy; and said method further comprises the step of supplying said electrical energy to said one or more solid oxide electrolyser cells so as to run said one or more solid oxide electrolyser cells.

[0116] For example, the methanol-generating unit provided at step (a) comprises one or more compressors, and the step (d) of decreasing the pressure of said first stream 3 further produces electrical energy and / or shaft work; and the method further comprises the step of supplying said electrical energy and / or shaft work to said one or more compressors so as to run the one or more compressors comprised within the methanol-generating unit.

[0117] In the installation represented at figure 3a, namely when in addition of the third stream 7 comprising steam at a pressure P3 and of a complementary stream 11 of steam, an additional stream 25 of steam thanks to the thermal energy of the oxygen-containing effluent 13 exiting the one or more solid oxide electrolyser cells 400 working in electrolysis mode (SOEC) is directed to the separation unit to transfer its thermal energy to the temperature-regulating device 250, the process of methanol production is consuming at most 10.75 kWh / kgMeon, preferably at most 10.80 kWh / kgMeOH.

[0118] In the installation represented at figure 3b, namely when an additional stream 25 of steam produced thanks to the thermal energy of the oxygen-containing effluent 13 exiting the one or more solid oxide electrolyser cells 400 working in co-electrolysis mode (co-SOEC) is directed to the separation unit to transfer its thermal energy to the temperature-regulating device 250, the process of methanol production is consuming at most 10.05 kWh / kgMeOH, preferably at most 10.00 kWh / kgMeOH.

[0119] In essence, the present disclosure relates to a heat management method in a methanolgenerating unit coupled to one or more solid oxide electrolyser cells 400 remarkable in that a water stream 23 is subjected to a transfer of thermal energy of an oxygen-containing effluent 13 exiting the one or more solid oxide electrolyser cells 400 so that an additional stream 25 of steam is generated and can transfer its own thermal energy to a separation unit that is downstream the methanol-generating unit.

[0120] Use of the oxygen-containing effluent to pre-heat the stream of steam entering the pressure-reducing device

[0121] As represented at figure 4a or 4b, the disclosure also provides a heat management method in a methanol-generating unit, said method is remarkable in that it comprises the following steps: a) providing a methanol-generating unit and a separation unit, wherein the separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein said separation unit comprises a temperature-regulating device 250 and wherein said methanol-generating unit comprises one or more reactors 100 each comprising a cooling device; b) operating said at least one reactor 100 under first operating conditions comprising at least regulating the thermal energy of said at least one reactor 100 by adjusting the temperature of the cooling device with water 1 ; c) recovering from said cooling device, after said step of regulating the thermal energy, a first stream 3, said first stream 3 comprising steam at a pressure P1; d) decreasing the pressure of said first stream 3 so as to recover a second stream 5, said second stream 5 comprising steam at a pressure P2, P2 being at least 0.31 MPa, and wherein P2 < P1 ; e) providing one or more solid oxide electrolyser cells 400; f) feeding said one or more solid oxide electrolyser cells 400 with steam 12 or with a mixture comprising steam 12 and carbon dioxide 17; g) working said one or more solid oxide electrolyser cells 400 under second operating conditions so as to generate at least one oxygen-containing effluent 13, said second operating conditions comprising at least electrical power and a temperature higher than 400°C; k) transferring the thermal energy of said at least one oxygen-containing effluent 13 to the first stream 3 recovered at step (c); l) operating said separation unit under third operating conditions comprising regulating the thermal energy of said separation unit by transferring the thermal energy of the second stream 5 recovered at step (d) to the temperature-regulating device 250 of the separation unit.

[0122] The heat management described above is advantageously carried out in an installation for producing methanol remarkable in that the installation comprises a methanol-generating unit and a separation unit, wherein the separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein said separation unit comprises a temperature-regulating device 250, and wherein said methanol-generating unit comprises one or more reactors 100, each reactor 100 comprising a cooling device; at least one steam pressure-reducing device, the steam pressure-reducing device being placed downstream of said cooling device and upstream of said temperatureregulating device 250; a first line connecting fluidically the cooling device to the one or more steam pressurereducing devices so as to direct a first stream 3 comprising steam at a pressure P1 from the cooling device to the one or more steam pressure-reducing devices; a second line connecting fluidically the one or more steam pressure-reducing devices to the temperature-regulating device 250, and wherein the one or more steam pressure-reducing devices comprise at least one steam pressure regulator; one or more solid oxide electrolyser cells 400, each of said one or more solid oxide electrolyser cells 400 comprising one oxygen-output line to direct an oxygen-containing effluent 13 out of said solid oxide electrolyser cell 400; a third heat exchanger placed on the first line, between the cooling device and the one or more steam pressure-reducing devices; wherein the oxygen-output line is in connection with said third heat exchanger so that the thermal energy of said oxygen-containing effluent 13 is transferred to the first stream 3 comprising steam at a pressure P1.

[0123] For example, the one or more steam pressure regulators are one or more pressure control valves.

[0124] For example, the steam pressure-reducing device is at least one turbine or at least one Venturi scrubber, preferably at least one turbine.

[0125] The thermal energy of the oxygen-containing effluent 13 exiting the one or more solid oxide electrolyser cells 400 can be used to preheat the stream of steam entering into a steam pressure-reducing device necessary to provide the second stream 5, which comprises steam at pressure P2, to run the separation unit, leading subsequently to a decrease of energy consumption with respect to the methanol production.

[0126] As the second stream 5 comprising steam at a pressure P2 recovered at step (d) further comprises one condensate; the method can advantageously comprise the step of separating the steam from said condensate so as to recover a third stream 7; said third stream 7 comprising steam at a pressure P3, wherein P3 is equal or inferior to P2. A stream 8 comprising a condensate is also recovered. Thus, advantageously, the installation further comprises a gas-liquid separator 500, said gas-liquid separator 500 being placed on the second line downstream of and in fluidic connection with said at least one steam pressure-reducing device, said gas-liquid separator 500 comprising an overhead fluidically connected to the temperatureregulating device 250.

[0127] Subsequently, the step of regulating the thermal energy of the separation unit carried out at step (I) is the step of transferring the thermal energy of the third stream 7 to the temperatureregulating device 250 of the separation unit.

[0128] In the installation represented at figure 4a, namely when the thermal energy of the oxygencontaining effluent 13 exiting the one or more solid oxide electrolyser cells working in electrolysis mode (SOEC) is transferred to the first stream 3 entering the steam-pressure reducing device, the process of methanol production is consuming at most 11.05 kWh / kgMeOH, preferably at most 11.00 kWh / kgMeOH. In the installation represented at figure 4b, namely when the thermal energy of the oxygencontaining effluent 13 exiting the one or more solid oxide electrolyser cells working in coelectrolysis mode (co-SOEC) is transferred to the first stream 3 entering the steam-pressure reducing device, the process of methanol production is consuming at most 10.30 kWh / kgMeon, preferably at most 10.25 kWh / kgMeon.

[0129] Production of additional steam thanks to the oxygen outflow and transfer of its thermal energy to the separation unit

[0130] As represented at figure 5a or 5b, the use of the oxygen-containing effluent 13 exiting the one or more solid oxide electrolyser cells 400 to preheat the first stream 3 entering the steam pressure-reducing device can also be applied to the configuration into which an additional stream 25 of steam is generated.

[0131] Indeed, the step of transferring the thermal energy of the oxygen-containing effluent 13 generated at step (g) to the first stream 3 recovered at step (c) also generates an oxygen outflow 21 and the method further comprises the step of transferring the thermal energy of said oxygen outflow 21 to the water stream 23 provided at step (h) so as to generate the additional stream 25 of steam.

[0132] Therefore, the heat management method can advantageously further comprise a step (h) of providing a water stream 23, and the step (k) of transferring the thermal energy of said at least one oxygen-containing effluent 13 to the first stream 3 recovered at step (c) also generates an oxygen outflow 21 , and the method further comprises the step of transferring the thermal energy of said oxygen outflow 21 to the water stream 23 provided at step (h) so as to generate an additional stream 25 of steam, and the step carried out at step (I) of transferring the thermal energy of the second stream 23 recovered at step (d) to the temperature-regulating device 250 of the separation unit further comprises transferring the thermal energy of the additional stream 25 of steam.

[0133] Thus, the installation can further comprise a water supply upstream of a fourth heat exchanger, and a water line directing a water stream 23 from said water supply to said fourth heat exchanger; and wherein the installation further comprises a third line connecting the third heat exchanger to the fourth heat exchanger to direct an oxygen outflow 21 from said third heat exchanger to said fourth heat exchanger, so that the thermal energy of the oxygen outflow 21 is transferred to the water stream 23 directed into the water line to produce an additional stream 25 of steam that is directed into an additional line connecting the fourth heat exchanger to the temperature-regulating device 250.

[0134] For example, the oxygen outflow 21 is at a temperature T02 outflow ranging between 260°C and 360°C, preferably between 265°C and 355°C, more preferably between 270°C and 350°C.

[0135] It is preferred that when the step (f) is the step of feeding the one or more solid oxide electrolyser cells 400 with steam 12 only, namely when the one or more solid oxide electrolyser cells 400 work in the electrolysis mode (SOEC), the method further comprises the step of providing a complementary stream 11 of steam to at least the second stream 5 recovered at step (d). Upon removal of the condensate through for example the gas / liquid separation column 500, a third stream 7 comprising steam at pressure P3 being equal or inferior to P2 is recovered, and the method can further comprise the step of providing the complementary stream 11 of steam to said third stream 7.

[0136] In the installation represented at figure 5a, namely wherein the stream entering the steam pressure-regulating device has been preheated thanks to the thermal energy of the oxygencontaining effluent 13 exiting the one or more solid oxide electrolysis cells 400 working in electrolysis mode (SOEC) and wherein an additional stream 25 of stream is produced and directed to the separation unit along with the third stream 3 comprising steam at a pressure P3 of 0.5 MPa and a complementary stream 11 of steam at a pressure of 0.5 MPa, the process of methanol production is consuming at most 10.85 kWh / kgMeOH, preferably at most 10.80 kWh / kgMeoH.

[0137] When the step (f) is the step of feeding the one or more solid oxide electrolyser cells 400 with steam 12 and carbon dioxide 17, namely when the one or more solid oxide electrolyser cells 400 are working in co-electrolysis mode (co-SOEC), the heat management method can advantageously further comprise a step (h) of providing a water stream 23 and the step (k) of transferring the thermal energy of said at least one oxygen-containing effluent 13 to the first stream 3 recovered at step (c) also generates an oxygen outflow 21. Therefore, the method further comprises the step of transferring the thermal energy of said oxygen outflow 21 to the water stream 23 provided at step (h) so as to generate an additional stream 25 of steam, and the step carried out at step (I) of transferring the thermal energy of the second stream 5 recovered at step (d) to the temperature-regulating device 250 of the separation unit can further comprise transferring the thermal energy of a first part 27 of the additional stream of steam. With preference, a second part 29 of the additional stream of steam is fed to the one or more solid oxide electrolyser cells 400 working in co-electrolysis mode (co-SOEC).

[0138] In the installation represented at figure 5b, namely wherein the stream entering the steam pressure-regulating device has been preheated thanks to the thermal energy of the oxygencontaining effluent 13 exiting the one or more solid oxide electrolysis cells 400 working in coelectrolysis mode (co-SOEC) and wherein an additional stream 25 of stream is produced, the process of methanol production is consuming at most 10.10 kWh / kgMeon, preferably at most 10.05 kWh / kgMeOH.

[0139] Production of additional steam thanks to both the hydrogen-rich effluent / syngas effluent and the oxygen outflow before transferring its thermal energy to the separation unit

[0140] As the step of working the one or more solid oxide electrolyser cells 400 in electrolysis mode (SOEC) also generates a hydrogen-rich effluent 15; the method can advantageously further comprise the step of transferring the thermal energy of said hydrogen-rich effluent 15 to the water stream 23 before the step of transferring the thermal energy of the oxygen outflow 21 to said water stream 23 so as to generate the additional stream 25 of steam, as represented at figure 6a.

[0141] For example, the hydrogen-rich effluent comprises at least 50 vol.% of hydrogen based on the total volume of said effluent; preferably at least 60 vol.%, more preferably at least 70 vol.%, even more preferably at least 80 vol.%, most preferably at least 90 vol.%, even most preferably at least 99 vol.%.

[0142] Thus, each of said one or more solid oxide electrolyser cells further comprises one hydrogenoutput line to direct a hydrogen-rich effluent 15 or a syngas effluent 19 out of said solid oxide electrolyser cell 400 and the installation further comprises a fifth heat exchanger placed on the water line upstream of the fourth heat exchanger, the hydrogen-output line can be connected to said fifth heat exchanger so that the thermal energy of the hydrogen-rich effluent 15 or the syngas effluent 19 is transferred to the water stream 23 directed into the water line upstream of the fourth heat exchanger. Then, the thermal energy of the oxygen outflow 21 is transferred to the water stream 23 to produce an additional stream 25 of steam that is directed into an additional line connecting the fourth heat exchanger to the temperature-regulating device 250. This is implemented by the installation represented at figure 6a, into which the process of methanol production is consuming at most 10.80 kWh / kgMeon, preferably at most 10.75 kWh / kgMeoH.

[0143] Similarly, when the step (f) is the step of feeding the one or more solid oxide electrolyser cells with steam 12 and carbon dioxide 17, the step of working the one or more solid oxide electrolyser cells 400 in co-electrolysis mode (co-SOEC) also generates a syngas effluent 19; the method can advantageously further comprise the step of transferring the thermal energy of said syngas effluent 19 to the water stream 23 before the step of transferring the thermal energy of the oxygen outflow 21 to said water stream 23 so as to generate the additional stream 25 of steam, as represented at figure 6b. In this case, the step (j) can be the step of transferring a first part 27 of the additional stream of steam and of at least the second steam 5 recovered at step (d) to the temperature-regulating device 250 of the separation unit. An excess of steam, namely the second part 29 of the additional stream of steam can thus be used to feed the one or more solid oxide electrolyser cells 400.

[0144] For example, the syngas effluent comprises carbon monoxide, hydrogen, carbon dioxide and optionally methane. With preference, the syngas effluent comprises between 15 vol. % and 40 vol.% of carbon monoxide (CO), between 25 vol.% and 35 vol.% of hydrogen (H2), between 2 vol.% and 15 vol.% of carbon dioxide (CO2), and between 0 vol.% and 5 vol.% of methane (CH4) all based on the total volume of said effluent. Indeed, For example, the syngas effluent comprises between 15 vol.% and 40 vol.% of carbon monoxide (CO) based on the total volume of said effluent. For example, the syngas effluent comprises between 25 vol.% and 35 vol.% of hydrogen (H2) based on the total volume of said effluent. For example, the syngas effluent comprises between 2 vol.% and 15 vol.% of carbon dioxide (CO2) based on the total volume of said effluent. For example, the syngas effluent comprises between 0 vol.% and 5 vol.% of methane (CH4) based on the total volume of said effluent.

[0145] This is implemented by the installation represented at figure 6b, into which the process of methanol production is consuming at most 10.05 kWh / kgMeoH, preferably at most 10.00 kWh / kgMeoH.

[0146] Production of additional steam thanks to both the oxygen-containing effluent and the hydrogen-rich effluent / syngas effluent exiting the solid oxide electrolyser cell and transfer of its thermal energy to the separation unit As represented at figure 7a, the thermal energy of the hydrogen-rich effluent 15 produced by one or more solid oxide electrolyte cells 400 working in electrolysis mode (SOEC) can be transferred to the water stream 23 before the step of transferring the thermal energy of the oxygen-containing effluent to said water stream 23, so as to generate the additional stream 25 of steam that is then directed to the temperature-regulating device 250 of the separation unit so that the additional stream 25 of steam can transfer its own thermal energy for improving the efficacy of the separation unit.

[0147] Therefore, the step (j) is the step of transferring the thermal energy of the additional stream 25 of steam generated at step (i) and of at least the second stream 5 recovered at step (d) to the temperature-regulating device 250 of the separation unit; and when the step (f) is the step of feeding the one or more solid oxide electrolyser cells 400 with steam 12, the step of working the one or more solid oxide electrolyser cells 400 also generates a hydrogen-rich effluent 15; and the method further comprises the step of transferring the thermal energy of the hydrogenrich effluent 15 to said water stream 23 before the step (i) of transferring the thermal energy of the oxygen-containing effluent 13 generated at step (g) to said water stream 23 provided at step (h) so as to generate the additional stream 25 of steam.

[0148] Thus, each of said one or more solid oxide electrolyser cells 400 further comprises one hydrogen-output line to direct a hydrogen-rich effluent 15 or a syngas effluent 19 out of said solid oxide electrolyser cell 400 and as the heat exchanger can be a first heat exchanger, the installation can further comprise a second heat exchanger placed on the water line upstream of the first heat exchanger, wherein the hydrogen-output line is connected to the second heat exchanger so that the thermal energy of the hydrogen-rich effluent 15 or the syngas effluent 19 is transferred to the water stream 23 directed into the water line upstream of the first heat exchanger. Then, the thermal energy of said oxygen-containing effluent 13 is transferred to the water stream 23 to produce an additional stream 25 of steam that is directed into an additional line connecting the first heat exchanger to the temperature-regulating device 250 so that the thermal energy of the additional stream 25 of steam is transferred to the temperatureregulating device 250.

[0149] This is implemented by the installation represented at figure 7a, into which the process of methanol production is consuming at most 10.80 kWh / kgMeOH, preferably at most 10.75 kWh / kgMeoH.

[0150] Similarly, as represented at figure 7b, the thermal energy of the syngas effluent 19 produced by one or more solid oxide electrolyte cells 400 working in co-electrolysis mode (co-SOEC) can be transferred to the water stream 23 before the step of transferring the thermal energy of the oxygen-containing effluent to said water stream 23, so as to generated the additional stream 25 of steam that is then directed to the temperature-regulating device 250 of the separation unit so that the additional stream 25 of steam can transfer its own thermal energy for improving the efficacy of the separation unit. In this case, the step (j) can be the step of transferring a first part 27 of the additional stream of steam and of at least the second steam 5 recovered at step (d) to the temperature-regulating device 250 of the separation unit.

[0151] This is implemented by the installation represented at figure 7b, into which the process of methanol production is consuming at most 10.05 kWh / kgMeOH, preferably at most 10.00 kWh / kgMeoH.

[0152] Use of heat generated by one or more compressors upstream of the reactor

[0153] As represented at figures 8a and 8b, one or more compressors 700 are placed upstream of the reactor 100 of the methanol-generating unit, namely upstream of the reactor inlet, so that the hydrogen-rich effluent 15 or the syngas effluent 19 exiting the one or more solid oxide electrolyser cells 400 is directed into said one or more compressors 700 before being fed to the reactor 100. Under electrolysis mode (SOEC), a carbon oxides feedstock 16 is also directed into said one or more compressors 700, before being fed to the reactor 100. The step of pressure increase of the hydrogen-rich effluent 15 or the syngas effluent 19 that is performed within said one or more compressors 700 also generates heat. Then, a water stream 23 is provided, and there is a step of transferring the heat generated by said one or more compressors 700 to said water stream 23, so that a second additional stream of steam 39 is generated and then fed to the one or more solid oxide electrolyser cells 400.

[0154] With preference, the step of pressure increase of the hydrogen-rich effluent 15 comprises increasing the pressure to a range comprised between 0.32 MPa and 12.0 MPa, preferably between 0.5 MPa, and 9.5 MPa, more preferably between 1.0 MPa and 9.0 MPa; even more preferably between 1.5 MPa and 8.5 MPa, most preferably between 2.0 MPa and 8.0 MPa. With preference, the step of pressure increase of the carbon oxides feedstock 16 comprises increasing the pressure at the same pressure as the pressure of the hydrogen-rich effluent 15, namely to a range comprised between 0.32 MPa and 12.0 MPa, preferably between 0.5 MPa, and 9.5 MPa, more preferably between 1.0 MPa and 9.0 MPa; even more preferably between 1.5 MPa and 8.5 MPa, most preferably between 2.0 MPa and 8.0 MPa. In the case of co-electrolysis (co-SOEC), the step of pressure increase of the syngas effluent 19 comprises increasing the pressure to a range comprised between 0.32 MPa and 12.0 MPa, preferably between 0.5 MPa, and 9.5 MPa, more preferably between 1.0 MPa and 9.0 MPa; even more preferably between 1.5 MPa and 8.5 MPa, most preferably between 2.0 MPa and 8.0 MPa.

[0155] For example, the second additional stream of steam 39 is at a pressure ranging between 0.38 MPa and 1.10 MPa, preferably between 0.39 MPa and 1.00 MPa, more preferably between 0.40 MPa and 0.90 MPa. For example, the second additional stream of steam 39 is at a temperature ranging between 142°C and 184°C, preferably between 143°C and 180°C, more preferably between 144°C and 175°C.

[0156] On these figures, a line connecting the reactor 100 to the separation unit, in particular to the distillation column 200, has been represented. This line conveys the reactor effluent 150 from the reactor 100 to the separation unit.

[0157] In the installation represented at figure 8a, namely when a third stream 7 comprising steam at pressure P3 and a complementary stream 11 of steam are directed to the separation unit to transfer its thermal energy to the temperature-regulating device 250, and when the one or more solid oxide electrolyser cells 400 working in electrolysis mode (SOEC) are notably coupled to the reactor 100 of the methanol-generating unit via one or more compressors 700, the process of methanol production is consuming at most 11 .00 kWh / kgMeOH, preferably at most 10.95 kWh / kgMeoH.

[0158] In the installation represented at figure 8b, namely when a third stream 7 comprising steam at pressure P3 and a complementary stream 11 of steam are directed to the separation unit to transfer its thermal energy to the temperature-regulating device 250, and when the one or more solid oxide electrolyser cells 400 working in co-electrolysis mode (co-SOEC) are notably coupled to the reactor 100 of the methanol-generating unit via one or more compressors 700, the process of methanol production is consuming at most 10.35 kWh / kgMeoH, preferably at most 10.30 kWh / kgMeoH.

[0159] Examples

[0160] The advantages of the present disclosure are illustrated by the following examples. However, it is understood that the disclosure is no means limited to the specific examples.

[0161] Table 1 indicates the results of the simulation of the energy consumption in relation with the methanol production in accordance with the different heat management methods that have been described in case where a solid oxide electrolyser cell working into electrolysis mode (SOEC) is combined with the methanol-generating unit. The energy consumption which is saved (5) is given with respect to a method wherein only the second stream 5 exiting the turbine at a pressure P2 of 0.5 MPa is directed to the separation unit to transfer its thermal energy to the temperature-regulating device 250, in the case where the methanol-generating unit is combined with a solid oxide electrolyser cell working in electrolysis mode (SOEC) (figure 2a).

[0162] Table 1 : Results of simulation implying a heat management method comprising a solid oxide electrolyser cell working in electrolysis mode (SOEC)

[0163] As indicated, one of the best configurations in term of energy consumption ( / .e., figure 6a) is in the case where a step of transferring the thermal energy of the oxygen-containing effluent 13, exiting the one or more solid oxide electrolyser cells working in electrolysis mode (SOEC), to the first stream 3 recovered at step (c) is carried out so as to generate an oxygen outflow 21 followed by a step of providing a water stream 23. Then a step of transferring the thermal energy of the hydrogen-rich effluent 15 to the water stream 23 is carried out before a step of transferring the thermal energy of the oxygen outflow 21 , so as to generate an additional stream 25. The pressure of the first stream 3 is reduced so that a second stream 5 is recovered. Finally, the step of regulating the thermal energy carried out in step (j) further comprises transferring the thermal energy of the additional stream 25 and of at least the second stream 5 to the temperature-regulating device 250 of the separation unit.

[0164] A similar result in term of energy consumption ( / .e., figure 7a) is achieved in the case where a step of transferring the thermal energy of the hydrogen-rich effluent 15 to a water stream 23 before a step of transferring the thermal energy of the oxygen-containing effluent 13 to said water stream 23, so that an additional stream 25 of steam is generated. Then, the step of regulating the thermal energy carried out in step (j) is the step of transferring the thermal energy of the additional stream 25 of steam and at least the second stream 5 to the temperatureregulating device 250 of the separation unit.

[0165] Table 2 indicates the results of the simulation of the energy consumption in relation with the methanol production in accordance with the different heat management methods that have been described in case where a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC) is combined with the methanol-generating unit. The energy consumption which is saved (5) is given with respect to a method wherein only the second stream 5 exiting the turbine at a pressure P2 of 0.5 MPa is directed to the separation unit to transfer its thermal energy to the temperature-regulating device 250, in the case where the methanol-generating unit is combined with a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC) (figure 2b).

[0166] Table 2: Results of simulation implying a heat management method comprising a solid oxide electrolyser cell working in co-electrolysis mode (co-SOEC)

[0167] As indicated, one of the best configurations in term of energy consumption ( / .e., figure 6b) is in the case where a step of transferring the thermal energy of the oxygen-containing effluent 13, exiting the one or more solid oxide electrolyser cells working in co-electrolysis mode (co- SOEC), to the first stream 3 recovered at step (c) is carried out so as to generate an oxygen outflow 21 followed by a step of providing a water stream 23. Then a step of transferring the thermal energy of the hydrogen-rich effluent 15 to the water stream 23 is carried out before a step of transferring the thermal energy of the oxygen outflow 21 , so as to generate an additional stream 25. The pressure of the first stream 3 is reduced so that a second stream 5 is recovered. Finally, the step of regulating the thermal energy carried out in step (j) further comprises transferring the thermal energy of the additional stream 25 and of at least the second stream 5 to the temperature-regulating device 250 of the separation unit. A similar result in term of energy consumption ( / .e., figure 7b) is achieved in the case where a step of transferring the thermal energy of the syngas effluent 19 to a water stream 23 before a step of transferring the thermal energy of the oxygen-containing effluent 13 to said water stream 23, so that an additional stream 25 of steam is generated. Then, the step of regulating the thermal energy carried out in step (j) is the step of transferring the thermal energy of the additional stream 25 of steam and at least the second stream 5 to the temperature-regulating device 250 of the separation unit.

Claims

Claims1. A heat management method in a methanol-generating unit, said method is characterized in that it comprises the following steps: a) providing a methanol-generating unit and a separation unit, wherein the separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein said separation unit comprises a temperature-regulating device (250), and wherein said methanol-generating unit comprises one or more reactors (100) each comprising a cooling device; b) operating said at least one reactor (100) under first operating conditions comprising at least regulating the thermal energy of said at least one reactor (100) by adjusting the temperature of the cooling device with water (1); c) recovering from said cooling device, after said step of regulating the thermal energy, a first stream (3), said first stream (3) comprising steam at a pressure P1; d) decreasing the pressure of said first stream (3) so as to recover a second stream (5), said second stream (5) comprising steam at a pressure P2, P2 being at least 0.31 MPa, and wherein P2 < P1 ; e) providing one or more solid oxide electrolyser cells (400); f) feeding said one or more solid oxide electrolyser cells (400) with steam (12) or with a mixture comprising steam (12) and carbon dioxide (17); g) working said one or more solid oxide electrolyser cells (400) under second operating conditions so as to generate at least one oxygen-containing effluent (13), said second operating conditions comprising at least electrical power and a temperature higher than 400°C; h) providing a water stream (23); i) transferring the thermal energy of the oxygen-containing effluent (13) generated at step (g) to at least the water stream (23) provided at step (h) so as to generate an additional stream (25) of steam; j) operating said separation unit under third operating conditions comprising regulating the thermal energy of said separation unit by transferring the thermal energy of the additional stream (25) of steam generated at step (i) and of at least the second stream (5) recovered at step (d) to the temperature-regulating device2. The heat management method according to claim 1 , characterized in that the pressure P2 of the second stream is ranging between 0.31 MPa and 1.30 MPa, and / or in that the first stream (3) is at a temperature T 1 comprised between 200°C and 325°C.

3. The heat management method according to claim 1 or 2, characterized in that the second stream (5) comprising steam at a pressure P2 further comprises one condensate; and in that the method further comprises the step of separating the steam from said condensate so as to recover a third stream (7); said third stream (7) comprising steam at a pressure P3, wherein P3 is equal or inferior to P2; with preference, the step of regulating the thermal energy carried out in step (j) further comprises transferring the thermal energy of the third stream (7) to the temperatureregulating device (250) of the separation unit.

4. The heat management method according to claim 3, characterized in that when the step (f) is the step of feeding the one or more solid oxide electrolyser cells (400) with steam (12), the method further comprises the step of providing a complementary stream (11) of steam to the third stream (7).

5. The heat management method according to any one of claims 1 to 4, characterized in that step (i) further comprises transferring the thermal energy of the oxygen-containing effluent (13) generated at step (g) to the first stream (3) recovered at step (c).

6. The heat management method according to claim 5, characterized in that the step of transferring the thermal energy of the oxygen-containing effluent (13) generated at step (g) to the first stream (3) recovered at step (c) also generates an oxygen outflow (21) and the method further comprises the step of transferring the thermal energy of said oxygen outflow (21) to the water stream (13) provided at step (h) so as to generate the additional stream (25) of steam; with preference, the step of working the one or more solid oxide electrolyser cells (400) also generates either a hydrogen-rich effluent (15) or a syngas effluent (19); and the method further comprises the step of transferring the thermal energy of either the hydrogen-rich effluent (15) or the syngas effluent (19) to said water stream (23) before the step of transferring the thermal energy of the oxygen outflow (21) to said water stream (23) so as to generate the additional stream (25) of steam.

7. The heat management method according to any one of claims 1 to 6, characterized in that the step (b) of operating said at least one reactor (100) generates a reactor effluent (150), and wherein the method further comprises the step of transferring the thermal energy of said reactor effluent (150) to said water stream (23) so as to generate a third additional stream of steam (41), said third additional stream of steam (41) being then fed to said one or more solid oxide electrolyser cells (400) and / or in that the step of working said one or more solid oxide electrolyser cells (400) also generates either a hydrogen-rich effluent (15) or a syngas effluent (19); and the method further comprises the step of subjecting to a pressure increase step said hydrogen-rich effluent (15) or said syngas effluent (19) before directing them to the reactor (100), said pressure increase step generating heat, and that the method further comprises the step of transferring the heat generated by the pressure increase step to said water stream (23) so as to generate a second additional stream of steam (39), said second additional stream of steam (39) being then fed to said one or more solid oxide electrolyser cells (400).

8. The heat management method according to any one of claims 1 to 7, characterized in that the step of working the one or more solid oxide electrolyser cells (400) also generates either a hydrogen-rich effluent (15) or a syngas effluent (19); in that the method further comprises the step of transferring the thermal energy of either the hydrogen-rich effluent (15) or the syngas effluent (19) to said water stream (23) before the step of transferring the thermal energy of the oxygen-containing effluent (13) to said water stream (23) so as to generate the additional stream (25) of steam.

9. The heat management method according to any one of claims 1 to 8, characterized in that the step (d) of decreasing the pressure of said first stream (3) further produces electrical energy; and in that said method further comprises the step of supplying said electrical energy to said one or more solid oxide electrolyser cells (400) so as to run said one or more solid oxide electrolyser cells (400) and / or in that the methanolgenerating unit provided at step (a) comprises one or more compressors, and the step (d) of decreasing the pressure of said first stream (3) further produces electrical energy and / or shaft work; and the method further comprises the step of supplying said electrical energy and / or shaft work to said one or more compressors so as to run the one or more compressors comprised within the methanol-generating unit.

10. The heat management method according to any one of claims 1 to 9, characterized in that the first operating conditions of step (b) comprise providing a carbon oxides feedstock to said at least one reactor (100), providing a stream of hydrogen and mixing together the carbon oxides feedstock and the stream of hydrogen within said at least one reactor (100) so as to produce a methanol effluent; with preference, the first operating conditions of step (b) comprise providing a carbon oxides feedstock to said at least one reactor (100), providing a hydrogen-rich effluent (15) generated by working said one or more solid oxide electrolyser cells (400) as a stream of hydrogen and mixing together the carbon oxides feedstock and the stream of hydrogen within said at least one reactor (100) so as to produce a methanol effluent, or the first operating conditions of step (b) comprise providing a syngas effluent (19) generated by working said one or more solid oxide electrolyser cells (400) so as to produce a methanol effluent.

11. The heat management method according to any one of claims 1 to 10, characterized in that when the step (f) is the step of feeding the one or more solid oxide electrolyser cells (400) with steam (12) and carbon dioxide (17), the step of regulating the thermal energy carried out in step (j) is the step of transferring the thermal energy of a first part (27) of the additional stream of steam generated at step (i) and of at least the second stream (5) recovered at step (d) to the temperature-regulating device (250) of the separation unit; with preference, a second part (29) of the additional stream of steam generated at step (i) is fed to the one or more solid oxide electrolyser cells (400).

12. An installation for producing methanol, remarkable in that the installation comprises a methanol-generating unit and a separation unit, wherein said separation unit is placed downstream of the methanol-generating unit and is in fluidic connection with it, wherein the separation unit comprises a temperature-regulating device (250), and wherein the methanol-generating unit comprises one or more reactors (100), each reactor (100) comprising a cooling device; at least one steam pressure-reducing device, the steam pressure-reducing device being placed downstream of said cooling device and upstream of said temperatureregulating device (250); a first line connecting fluidically the cooling device to the one or more steam pressurereducing devices; a second line connecting fluidically the one or more steam pressure-reducing devices to the temperature-regulating device (250), and wherein the one or more steam pressure-reducing devices comprise at least one steam pressure regulator;one or more solid oxide electrolyser cells (400), each of said one or more solid oxide electrolyser cells (400) comprising one oxygen-output line to direct an oxygencontaining effluent (13) out of said solid oxide electrolyser cell (400); a water supply upstream of a heat exchanger, and a water line directing water from said water supply to said heat exchanger; wherein each oxygen-output line is in connection with said heat exchanger so that the thermal energy of said oxygen-containing effluent (13) is transferred to the water stream (23) of the water supply to produce an additional stream (25) of steam that is directed into an additional line connecting the heat exchanger and the temperature-regulating device (250) so that the thermal energy of the additional stream (25) of steam is transferred to the temperature-regulating device (250); with preference, the heat management method as defined in accordance with any one of claims 1 to 11 is carried out in said installation.

13. The installation of claim 12, characterized in that the one or more steam pressure regulators are one or more pressure control valves; and / or in that one steam pressurereducing device is at least one turbine (300).

14. The installation of claim 12 or 13, characterized in that it further comprises a gas-liquid separator (500), said gas-liquid separator (500) being placed on the second line downstream of and in fluidic connection with said at least one steam-pressure reducing device, said gas-liquid separator comprising an overhead fluidically connected to the temperature-regulating device (250).

15. Use, in an installation according to any one of the claims 12 to 14, of the thermal energy of an oxygen-containing effluent (13) exiting one or more solid oxide electrolyser cells (400) for heating a water stream (23) to produce an additional stream (25) of steam for providing thermal energy to a temperature-regulating device (250) of the separation unit.

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