Plant and method for co-producing dihydrogen and cement clinker

Abstract

The invention relates to a plant for producing dihydrogen, referred to as plant. The plant comprises an electrolyser, arranged to produce dioxygen and dihydrogen from steam, referred to as hot steam, at a temperature higher than 150°C, or water, referred to as hot water, at a temperature lower than or equal to 90°C. The plant further comprises a clinker manufacturing unit. The plant further comprises a heat recovery unit arranged to produce the hot steam or the hot water from gaseous emissions, referred to as hot gases, at a temperature higher than 150°C, emitted by the clinker manufacturing unit.

Description

Installation and process for co-production of dihydrogen and cement clinker

[0001] The present invention belongs to the field of hydrogen production.

[0002] The invention relates to a plant for producing dihydrogen and a method for producing dihydrogen by electrolysis of water.

[0003] The invention also relates to the field of cement production and more specifically clinker. State of the art

[0004] The state of the art is known for the processes of producing dihydrogen, for example, by: gasification of coal, steam reforming of methane, electrolysis of water, by enzymatic fermentation, catalytic dissociation, or even pyrolysis.

[0005] Except for the specific case of enzymatic fermentation, state-of-the-art dihydrogen production processes are energy-intensive.

[0006] Furthermore, most state-of-the-art processes rely entirely on the use of fossil and / or organic raw materials.

[0007] Furthermore, the state-of-the-art dihydrogen manufacturing processes induce, for the most part, greenhouse gas emissions.

[0008] Clinker manufacturing processes are also known in the state of the art. Clinker, combined with additives, is used, in particular, for the manufacture of cement. Clinker is obtained by heat treatment, typically at temperatures of around 1450°C, of ​​raw cement. Raw cement is composed of a mixture of raw materials including limestone, clay and sand.

[0009] The clinker production process is also highly energy-intensive. It requires the consumption of a large quantity of fossil fuel to ensure the firing, and in particular the calcination, of the raw cement.

[0010] In addition, the clinker and cement manufacturing processes release a significant amount of greenhouse gases, particularly carbon dioxide.

[0011] An aim of the present invention is to remedy at least one of the drawbacks of methods for producing dihydrogen of the state of the art and / or methods for manufacturing clinker and / or cement of the state of the art.

[0012] Another aim of the invention is to propose a dihydrogen production facility: having low energy consumption, and / or having energy consumption lower than the energy consumption of dihydrogen production facilities and / or clinker manufacturing facilities of the state of the art, and / or having a limited and / or reduced environmental impact, and / or making it possible to limit and / or reduce the environmental impact of clinker manufacturing, and / or making it possible to limit the energy consumption of fossil and / or organic raw materials for clinker manufacturing, and / or making it possible to limit greenhouse gas emissions, and in particular carbon dioxide, emitted for clinker manufacturing.

[0013] To this end, the invention is proposed of a dihydrogen production plant, called the plant, comprising: an electrolyser, arranged to produce dioxygen and dihydrogen from: steam, called hot steam, at a temperature above 150°C, or water, called hot water, at a temperature below or equal to 90°C, a clinker manufacturing unit, a heat recovery unit arranged to produce, from gaseous discharges, called hot gases, at a temperature above 150°C, emitted by the clinker manufacturing unit: hot steam, or hot water.

[0014] The installation according to the invention can be defined as and / or is an installation for the co-production of dihydrogen and / or clinker and / or cement.

[0015] Preferably, the installation is part of and / or is included in a cement plant.

[0016] Preferably, the electrolyzer is a solid oxide electrolyzer, noted SOEC, for “solid oxide electrolyzer cell”.

[0017] Preferably, the heat recovery unit is arranged to produce hot water at a temperature: less than or equal to 90°C, and / or greater than or equal to 20°C.

[0018] Preferably, the heat recovery unit is arranged to produce hot steam or hot water from at least part of the waste heat generated by the clinker manufacturing unit.

[0019] Thus, by exploiting the fatal heat of the clinker manufacturing unit, the installation according to the invention makes it possible: to limit the energy consumption, in particular electricity, used for the production of dihydrogen and / or dioxygen, and / or to reduce the environmental impact associated with the production of dihydrogen and / or dioxygen.

[0020] Preferably, the heat recovery unit, called at least one heat exchanger of the heat recovery unit, comprises at least one heat exchanger arranged to extract heat from the hot gases emitted by the clinker manufacturing unit.

[0021] Preferably, the heat recovery unit further comprises:a hot steam production device arranged to produce the hot steam from the heat extracted from the hot gases, and / ora hot water production device arranged to produce the hot water from the heat extracted from the hot gases.

[0022] According to a first improvement, the hot steam production device preferably comprises at least one heat exchanger, called at least one exchanger of the hot steam production device.

[0023] Preferably, the at least one exchanger of the hot steam production device is chosen from a thermal preheater, an evaporator and a superheater.

[0024] According to a second improvement, the hot water production device preferably comprises at least one heat exchanger, called at least one exchanger of the hot water production device.

[0025] Preferably, the at least one exchanger of the hot water production device is chosen from a thermal preheater and a superheater.

[0026] The heat recovery unit may include the first and / or the second improvement. The first and second improvements may be combined.

[0027] Preferably, the at least one exchanger of the hot steam production device and / or, respectively, the at least one exchanger of the hot water production device is arranged to produce or supply additional heat, preferably in addition to the heat extracted from the hot gases by the at least one heat exchanger of the heat recovery unit, for the production of hot steam and / or, respectively, hot water.

[0028] The at least one exchanger of the hot steam production device and / or the at least one exchanger of the hot water production device may be defined as being arranged to supplement or supplement the heat coming from the at least one heat exchanger of the heat recovery unit.

[0029] Preferably, the clinker manufacturing unit comprises:a preheating unit arranged to preheat raw material, called cement raw material, for the manufacture of clinker, and / ora rotary kiln for firing the preheated cement raw material, and

[0030] Preferably, the preheating unit is arranged upstream, relative to the path or flow of the cement raw material in the clinker manufacturing unit, of the rotary kiln.

[0031] Clinker can be defined as the raw cement, preferably preheated, baked or clinkerized or heat-treated, and, in particular, calcined.

[0032] It can be understood as raw cement firing, heat treatment or raw cement clinkerization.

[0033] Preferably, the clinker manufacturing unit further comprises a unit for cooling the manufactured clinker.

[0034] Preferably, the cooling unit is arranged downstream, relative to the path or flow of the cement raw material in the clinker manufacturing unit, the preheating unit and the rotary kiln.

[0035] Preferably, the heat recovery unit is arranged to extract: heat from hot gases, called fumes, resulting from the manufacture of the clinker, and / or heat from hot gases, called reheated gases, resulting from the cooling of the manufactured clinker.

[0036] Preferably, the fumes correspond to the gases used to cook and preheat the cement raw material. Preferably, the fumes correspond to the gases circulated in the rotary kiln and then in the preheating unit. Preferably, the fumes correspond to the gases that were in contact with the cement raw material during its manufacture. Preferably, the fumes correspond to the hot gases leaving, or recovered at the outlet of, the preheating unit.

[0037] Preferably, the reheated gases correspond to the gases resulting from the cooling of the manufactured clinker, or having been used to cool the manufactured clinker. Preferably, the reheated gases correspond to the hot gases having circulated in the clinker cooling unit. Preferably, the reheated gases correspond to cooling gases leaving, or recovered at the outlet, of the cooling unit.

[0038] Preferably:at least one heat exchanger of the heat recovery unit, preferably one or more heat exchangers among the at least one heat exchanger of the heat recovery unit, is arranged to extract heat from the flue gases, and / orat least one heat exchanger of the heat recovery unit, preferably one or more heat exchangers among the at least one heat exchanger of the heat recovery unit, is arranged to extract heat from the reheated gases.

[0039] Preferably, the heat recovery unit comprises at least two heat exchangers, more preferably two heat exchangers.

[0040] Preferably, the heat recovery unit comprises: a heat exchanger, called the first heat exchanger, arranged to extract heat from the fumes, and / or a heat exchanger, called the second heat exchanger, arranged to extract heat from the reheated gases.

[0041] Preferably, the heat recovery unit comprises: several heat exchangers, called the first group of heat exchangers, arranged to extract heat from the fumes, and / or several heat exchangers, called the second group of heat exchangers, arranged to extract heat from the reheated gases.

[0042] Preferably, the installation further comprises a means for producing heating gas. Preferably, the means for producing heating gas is arranged to inject said heating gas into the rotary furnace. Preferably, the means for producing heating gas is arranged to produce, at least in part, the heating gas from dihydrogen produced by the electrolyser.

[0043] Preferably, the installation is arranged to supply, at least in part, the heating gas production means with the dihydrogen produced by the electrolyser.

[0044] Preferably, the installation is arranged so that the heating gases circulate through the rotary kiln, to bake the cement raw material, and then through the preheating unit, to preheat the cement raw material.

[0045] Preferably, the fumes correspond to the heating gases having circulated in the rotary kiln and then in the preheating unit, or, in other words, the heating gases after having circulated in the rotary kiln and then in the preheating unit constitute the fumes.

[0046] Preferably, the installation and / or the electrolyser is arranged to supply the heating gas production means with dihydrogen produced by the electrolyser.

[0047] Preferably, supplying the heating gas production means with dihydrogen makes it possible to: reduce the environmental impact of clinker production, and / or limit the energy consumption of fossil and / or organic raw materials for clinker production.

[0048] Preferably, the installation further comprises a dihydrogen purification unit, called HPU, arranged to purify the dihydrogen produced by the electrolyser. Preferably, the heating gas production means is arranged to produce, at least in part, the heating gases from the purified dihydrogen coming from the HPU.

[0049] Preferably, the installation is arranged to supply, at least in part, the heating gas production means with the dihydrogen purified by the HPU.

[0050] Preferably, the installation and / or the electrolyser and / or the HPU is arranged to supply the heating gas production means with dihydrogen purified by the HPU.

[0051] Preferably, the heating gas production means is arranged to produce, at least in part, the heating gases from oxygen produced by the electrolyser.

[0052] Preferably, the installation is arranged to supply, at least in part, the heating gas production means with the oxygen produced by the electrolyser.

[0053] Preferably, the installation and / or the electrolyser is arranged to supply the heating gas production means with oxygen produced by the electrolyser.

[0054] Preferably, supplying the heating gas production means with oxygen makes it possible to: reduce the environmental impact of clinker production, and / or limit the energy consumption of fossil and / or organic raw materials for clinker production.

[0055] Preferably, the installation further comprises a dioxygen purification unit, called OPU, arranged to purify the dioxygen produced by the electrolyser; said heating gas production means being arranged to produce, at least in part, the heating gases from the purified dioxygen coming from the OPU.

[0056] Preferably, the installation is arranged to supply, at least in part, the heating gas production means with the oxygen purified by the OPU.

[0057] Preferably, the installation and / or the electrolyser and / or the OPU is arranged to supply the heating gas production means with oxygen purified by the OPU.

[0058] Preferably, the installation further comprises a unit for capturing carbon dioxide (CO2) contained in the fumes, having circulated in the heat recovery unit, to produce CO2 or CO2-enriched gas.

[0059] Preferably, the CO2 capture unit is arranged downstream, relative to the path or route of the fumes in the heat recovery unit and / or in the clinker manufacturing unit and relative to the path or route, of the heat recovery unit.

[0060] Preferably, the installation further comprises a CO2 conversion unit arranged to produce gaseous hydrocarbons (such as methanol, methane, or kerosene) from dihydrogen produced by the electrolyser and from CO2 produced by the CO2 capture unit.

[0061] Preferably, the installation and / or the electrolyser is arranged to supply the CO2 conversion unit with dihydrogen produced by the electrolyser.

[0062] Preferably, the CO2 capture installation and / or unit is arranged to supply the CO2 conversion unit with CO2 or CO2-enriched gas.

[0063] Preferably, the supply of the CO2 to dihydrogen conversion unit makes it possible: to limit the energy consumption of fossil and / or organic raw materials for the manufacture of clinker, and / or to limit the greenhouse gas emissions, and in particular carbon dioxide, emitted for the manufacture of clinker.

[0064] According to the invention, a cement plant is also proposed comprising the installation for co-production of dihydrogen and / or clinker according to the invention.

[0065] According to the invention, a process for producing dihydrogen is also proposed. The process for producing dihydrogen, called the process, comprises the steps of:recovering heat, by means of the heat recovery unit, from gaseous waste, or hot gases, emitted by the clinker manufacturing unit,producing, from the recovered heat:hot steam, at a temperature greater than or equal to 150°C, orhot water, at a temperature less than or equal to 90°C,producing dihydrogen and dioxygen, by means of the electrolyser, from the hot steam.

[0066] Preferably, the method further comprises the step of manufacturing clinker using the clinker manufacturing unit.

[0067] The process can be defined as a process for the co-production of clinker and dihydrogen and / or dioxygen.

[0068] Preferably, the production method according to the invention is implemented by the dihydrogen and / or clinker and / or cement production plant according to the invention.

[0069] Preferably, the hydrogen production plant according to the invention is suitable, more preferably is particularly suitable, more preferably is designed and particularly advantageously is specially designed, for implementing the hydrogen production method according to the invention.

[0070] Thus, any characteristic of the installation according to the invention can be directly transposed to the method according to the invention and vice versa. Brief description of the FIGURES

[0071] The invention will be better understood upon reading the following description, given solely as a non-limiting example and with reference to the appended drawings in which: is a schematic representation of a non-limiting example of an embodiment of a hydrogen production installation according to the invention, FIGURES 2 to 4 are schematic representations of non-limiting examples of advantageous improvements to the embodiment of the production installation illustrated in the.

[0072] It is understood that the embodiments which will be described below are in no way limiting. In particular, it is possible to imagine variants of the invention comprising only a selection of characteristics described below isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art. This selection includes at least one preferably functional characteristic without structural details, or with only part of the structural details if it is this part which is only sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art.

[0073] In particular, all the variants and embodiments described can be combined with each other if there is no technical obstacle to this combination.

[0074] In the figures and in the rest of the description, the elements common to several figures retain the same reference. Detailed description of the FIGURES

[0075] Hydrogen can be produced by water electrolysis. This process of producing hydrogen is carried out using water and electricity. The state of the art includes alkaline electrolysis, proton exchange membranes, and solid oxide electrolyzers.

[0076] This is a schematic representation of a non-limiting exemplary embodiment of a hydrogen production installation 1 according to the invention.

[0077] The hydrogen production facility 1, referred to as facility 1 in the remainder of this description, comprises a clinker manufacturing unit 6, referred to as CMU 6 in the remainder of this description.

[0078] According to a first non-limiting embodiment, the installation 1 further comprises a heat recovery unit 7, called HRU 7 in the remainder of this description, arranged to produce hot steam 5, at a temperature greater than or equal to 150°C, from gaseous discharges 8, 9, called hot gases 8, 9, at a temperature greater than 150°C, emitted by the CMU 6.

[0079] The installation 1 further comprises an electrolyser 2, arranged to produce dioxygen 3 and dihydrogen 4 from the hot steam 5 produced by the HRU 7. According to the embodiment presented, the electrolyser 2 is a high-temperature electrolyser. By way of non-limiting example, the electrolyser is a solid oxide electrolyser 2, called SOEC 2.

[0080] The hot steam 5 is therefore produced from fatal heat coming from the CMU 6. The hot steam 5 produced by or leaving the HRU 7 feeds the SOEC 2 with, optionally, a gas sweep 28 such as air.

[0081] Thus, the invention makes it possible, by means of the HRU 7, to recover, at least in part, the fatal heat coming from the CMU 6 to produce hot steam 5 which will then be used to produce dihydrogen 4 and dioxygen 3. Advantageously, the invention makes it possible to co-produce both dihydrogen 4, dioxygen 3, or gas enriched in dioxygen 3, and clinker 14.

[0082] The invention makes it possible to limit the energy consumption, in particular electricity, used for the production of dihydrogen and / or dioxygen by exploiting the fatal heat coming from the CMU 6.

[0083] The invention also makes it possible to reduce the environmental impact associated with the production of dihydrogen and / or dioxygen by exploiting the fatal heat coming from CMU 6.

[0084] As known to those skilled in the art, the SOEC 2 comprises a reaction zone where the electrolysis of water leads to the production of dioxygen 3 and dihydrogen 4. In practice, the reaction zone is in the form of unit cells for the electrolysis of solid oxides composed of an anode, an electrolyte and a cathode.

[0085] The oxygen 3 stream is formed on the anode side and can be transported by the optional gas sweep 28. The hydrogen 3 stream is formed at the cathode and leaves the electrolysis cell with any unreacted water.

[0086] The SOEC 2 further comprises a set of elements or devices (additional or auxiliary) ensuring the integration of useful heat and the transport of fluids. The set of elements or devices (additional or auxiliary) may comprise, by way of non-limiting examples, a feed / effluent heat exchanger, a heat pump, a compressor and / or an ejector.

[0087] It is known from the state of the art that the production of clinker is carried out by heat treatment, typically at a temperature close to 1450°C, of ​​raw cement.

[0088] According to the embodiment illustrated in the, the CMU 6 comprises a preheating unit 601 (or preheating tower 601), denoted PHT 601, arranged to preheat the cement raw material 13 and a rotary kiln 602 for firing the preheated cement raw material 13. The heat treatment of the cement raw material 13 comprises the preheating and firing of the cement raw material 13. Thus, the heat treatment begins in the PHT 601 and continues and ends in the rotary kiln 602.

[0089] Preferably but not limited to, the PHT 601 may be a preheating tower 601. For example, the PHT 601 may be a cyclone preheating tower.

[0090] The installation 1 comprises a heating gas production means 17, denoted HGP 17, arranged to inject heating gases 16 into the rotary kiln 602. The HGP 17 is arranged to produce the heating gases 16 from carbonaceous fuels, such as methane or coal. The heating gases 16 have the effect of cooking and preheating the raw cement 13 in the CMU 6.

[0091] The HGP 17 is located downstream, relative to the path or route of the cement raw material 13 in the CMU 6, the PHT 601 and the rotary kiln 602. Thus, the heating gases having their highest temperature come into contact with the cement raw material 13 in the rotary kiln 602 and then come into contact, at a lower temperature, with the cement raw material 13 in the PHT 601.

[0092] Preferably, the HGP 17 is arranged to produce the heating gases 16, at least in part, advantageously only in part, more preferably sporadically, from carbon fuels supplying the installation 1 and / or the HGP 17. In other words, the installation 1 and / or the HGP 17 is supplied, at least in part, advantageously only in part, more preferably sporadically, with external fuels, i.e. not coming from the installation 1.

[0093] The installation 1, and / or the rotary kiln 602 and / or the PHT 601, is arranged to allow the circulation of the heating gases 16 in the rotary kiln 602 then the PHT 601.

[0094] According to the embodiment illustrated in the, the CMU 6 further comprises a cooling unit 603, denoted CC, for the manufactured clinker 14.

[0095] Once produced, the clinker 14 is cooled in the CC 603 using air 15. The air 15 used to cool the clinker 14 leaves the CC 603 in the form of hot gases 8, called reheated gas 8, at a temperature between 150 and 1300°C.

[0096] The installation 1 and / or the HGP 17 may be arranged so that a fraction, preferably all, of this reheated gas 8 is reinjected into the HGP 17. This recycling of the reheated gas makes it possible to reduce the energy consumption and the environmental impact of the production of dihydrogen. In the processes of the state of the art, this excess heat contained in the reheated gas 8, typically having a temperature of between 150 and 400°C, is released in the form of residual gas.

[0097] The heating gases 16 and the cement raw material 13 exchange heat countercurrently with the cement raw material 13 throughout the rotary kiln 602 and the PHT 601. The heating gases 16 leaving the PHT 601 are denoted fumes 9. The fumes 9 leave the PHT 601 at a temperature between 150 and 400°C.

[0098] The fumes 9 at the outlet of the PHT 601 and the reheated gases 8 at the outlet of the CC may contain solid materials such as, by way of non-limiting examples, minerals, unreacted raw materials, unreacted solid fuels, in a range between 10 mg / Nm 3 and 20 g / Nm 3 , where mg / Nm 3 and g / Nm 3 are respectively milligrams per normal cubic meter and grams per normal cubic meter.

[0099] According to the embodiment illustrated in the, the HRU 7 is arranged to extract heat from the reheated gases 8, resulting from the cooling of the manufactured clinker 14.

[0100] The HRU 7 is alternatively, preferably also, arranged to extract heat from hot gases 9, called fumes 9, resulting from the firing of the raw cement 13.

[0101] There is nothing to prevent the HRU 7 from being arranged to extract heat only from the reheated gases 8 or only from the fumes 9. However, in order to effectively limit energy consumption and further reduce the environmental impact associated with the production of dihydrogen 4 and / or dioxygen 3, the HRU 7 is preferably arranged to extract heat from the reheated gases 8 and from the fumes 9.

[0102] According to the embodiment illustrated in the, the HRU 7 comprises at least one heat exchanger 10, 11, called heat exchanger 10, 11 of the HRU 7. The at least one heat exchanger 10, 11 of the HUR 7 is arranged to extract heat from the hot gases 8, 9. The person skilled in the art knows heat exchangers (or thermal exchangers) and will be able to choose the type of exchanger adapted according to his needs and the specific case. For information, the exchanger 10, 11 may be a heat exchanger of the economizer-recuperator type, for example following a tube and fin, tube and shell or plate exchanger technology.

[0103] The HRU 7 further comprises a hot steam production device 18. The steam production device 18 is arranged to produce the hot steam 5 from the heat extracted from the hot gases 8, 9. A person skilled in the art knows steam production devices and will be able to choose the type of steam production device suitable according to his needs and the specific case.

[0104] Preferably, the steam production device 18 comprises at least one heat exchanger, for example a single exchanger, preferably several heat exchangers, called exchangers of the steam production device 18. Preferably, the at least one heat exchanger of the steam production device 18 is chosen, for information purposes, from: a thermal preheater, an evaporator, and a superheater, for example using a shell and tube exchanger technology, or a plate exchanger technology.

[0105] The at least one heat exchanger of the steam generating device 18 is arranged to produce, or supply to the steam generating device 18, additional heat supplementing or adding to the heat produced or extracted, from the hot gases 8, 9, by the at least one heat exchanger 10, 11 of the HRU 7.

[0106] By way of non-limiting example, the at least one exchanger of the steam production device 18 is arranged to provide additional heat to the steam production device 18 from an energy source other than the hot gases 8, 9. The energy source, other than the hot gases 8, 9, may come from the installation 1, for example dihydrogen 4 or dioxygen 3 produced by the installation 1. The energy source, other than the hot gases 8, 9, may be an energy source external to the installation 1, for example energy from a gas or electricity supply network or from external fuels.

[0107] The HRU 7 comprises at least one heat exchanger 10, advantageously several heat exchangers 10, called exchanger(s) 10 of the HRU 7, arranged to extract heat from the fumes 9.

[0108] The HRU7 alternatively comprises, preferably also, at least one heat exchanger 11, advantageously several heat exchangers 11, called exchanger(s) 11 of the HRU 7, arranged to extract heat from the heated gases 8.

[0109] As described above, there is nothing to prevent the HRU 7 from comprising a single heat exchanger 11 arranged to extract heat from the reheated gases 8 or a single heat exchanger 10 arranged to extract heat from the fumes 9. However, in order to effectively reduce energy consumption and further reduce the environmental impact associated with the production of dihydrogen and / or dioxygen, the HRU 7 preferably comprises at least one heat exchanger 11 arranged to extract heat from the reheated gases 8 and at least one heat exchanger 10 arranged to extract heat from the fumes 9.

[0110] The HRU 7 comprises a network 25 arranged to allow the circulation of a heat transfer fluid (such as for example water or oil) between the at least one heat exchanger 10, 11, and the steam production device 18.

[0111] The heat transferred to the water to produce the hot steam 5 is obtained by using the intermediate heat transfer fluid circulating in the network 25, such as, for example, water or thermal oil, or directly in a device (not shown) allowing heat transfer between the flows 9, 8 and the water.

[0112] By way of non-limiting examples, the installation 1 may comprise a water treatment unit. The water treatment unit is arranged to treat and purify water supplying the installation 1, i.e. water coming from the outside battery limits, or "OSBL" for "outside the battery limits", and / or water coming from the SOEC 2, in particular water vapor, coming from the SOEC 2, which would not have reacted in the SOEC 2 during the electrolysis step. The water treatment unit is further arranged so that the treated water has a conductivity and a content of ions and particles suitable for supplying the HRU 7, or the network 25. The HRU 7, or the network 25, may therefore be supplied, in whole or in part, with treated water coming from the water treatment unit.

[0113] The HRU 7, preferably the steam production device 18, is arranged to produce the hot steam 5 from, in addition, the treated water and / or, possibly, using electricity which may come from the network and / or from an accumulator.

[0114] In the state of the art, the heating gases used for the thermal treatment of raw cement are exclusively produced by the combustion of carbon fuels, such as methane or coal, with air.

[0115] With reference to the, there is illustrated an improvement, called first improvement, of the installation 1 according to the embodiment presented on the. The HGP 17 is arranged to produce, at least in part, the heating gases 16 from dihydrogen 4 produced by the SOEC 2. The dihydrogen 4 feeds the HGP 17 as fuel. The dihydrogen 4 can feed the HGP 17 in addition, it can for example be mixed with a carbon fuel, for example methane or coal, or as a substitute for such a carbon fuel.

[0116] Still with reference to the first improvement of the installation 1 illustrated in the, the installation 1 comprises a dihydrogen purification unit 19, called HPU 19. The HPU 19 is arranged to purify the dihydrogen 4 produced by the SOEC 2. The dihydrogen 4 produced by the SOEC 2 feeds the HPU 19. The HGP 17 is arranged to produce, at least in part, the heating gases (16) from, in addition, the purified dihydrogen 401 coming from the HPU 19. The purified dihydrogen 401 feeds, in whole or in part, the HGP 17. In other words, the purified dihydrogen 401 feeds the HGP 17 in addition, it can for example be mixed with carbon fuel, or as a substitute for such carbon fuel.

[0117] In addition to being arranged to purify the dihydrogen produced by the SOEC 2, the HPU 19 can also be arranged to compress the purified dihydrogen 401. The compression makes it possible to achieve a suitable pressure both for the purification process and for the storage, in a suitable gas storage tank 26, of the dihydrogen 4. If the storage pressure of the dihydrogen 4 is higher than the purification pressure, several compression stages can be provided.

[0118] The first improvement of installation 1 allows to reduce energy and / or raw material consumption, in particular the consumption of HGP 17, for the production of clinker.

[0119] The first improvement of Facility 1 also reduces the environmental impact, including greenhouse gas emissions, for clinker manufacturing.

[0120] With reference to the, there is illustrated an improvement, called second improvement, of the installation 1 according to the embodiment presented on the. The HGP 17 is arranged to produce, at least in part, the heating gases 16 from dioxygen 3, or a gas enriched in dioxygen 3, produced by the SOEC 2. The dioxygen 3, or the gas enriched in dioxygen 3, feeds the HGP 17 as an oxidant. The dioxygen 3, or the gas enriched in dioxygen 3 can feed the HGP 17 in addition, it can for example be mixed with the oxidant, preferably air according to the embodiment, or as a substitute for the oxidant.

[0121] Still with reference to the second improvement of the installation 1 illustrated in the, the installation 1 comprises a dioxygen purification unit 20, called OPU 20. The OPU 20 is arranged to purify the dioxygen 3, or the gas enriched in dioxygen 3, produced by the SOEC 2. The dioxygen 3, or the gas enriched in dioxygen 3, produced by the SOEC 2 feeds the OPU 20. The HGP 17 is arranged to produce, at least in part, the heating gases 16 from the purified dioxygen 301 coming from the OPU 20. The purified dioxygen 301 feeds, in whole or in part, the HGP 17. In other words, the purified dioxygen 301 feeds the HGP 17 in addition, it can for example be mixed with the oxidant, or in substitution for the oxidant.

[0122] Thus, according to the second improvement, the higher the oxygen content of the oxidant, the more the heating efficiency is improved.

[0123] The second improvement of installation 1 allows to reduce energy and / or raw material consumption, in particular the consumption of HGP 17, for the production of clinker.

[0124] The second improvement of Facility 1 also reduces the environmental impact, including greenhouse gas emissions, for clinker manufacturing.

[0125] In the state of the art, the combustion of carbon fuels, in particular fossil fuels, for the production of heat required for the thermal treatment of cement raw material, results in the direct and significant emission of carbon dioxide (CO2).

[0126] One of the main chemical reactions responsible for direct CO2 emissions during clinker production is the decarbonation of calcium carbonate to produce calcium oxide.

[0127] With reference to the, there is illustrated an improvement, called third improvement, of the installation 1 according to the embodiment presented on the. The installation 1 further comprises a CO221 capture unit, called CTU 21, contained in the fumes 9, having circulated in the HRU 7, to produce CO222 or gas 22 enriched in CO2.

[0128] The third improvement of installation 1 therefore makes it possible to limit the environmental impact, including direct greenhouse gas emissions, for the manufacture of clinker 14 by also limiting the quantity of CO2 contained in the gases released into the atmosphere.

[0129] CO2 capture can be based on one or a combination of the following processes or technologies: adsorption, absorption, membrane filtration or distillation. The main energy requirement of CTU 21 concerns the regeneration step, during which pure CO2 is released and the solvent or sorbent is regenerated. The energy required to implement this step can be extracted at the outlet of HRU 7 after generating water vapor for SOEC 2.

[0130] Preferably but not limitingly, the installation 1 may comprise, preferably upstream of the CTU 21, a smoke treatment device 9, such as a suitable particle filtration system (for example an electrostatic precipitator), to remove particles and / or dust from the smoke 9.

[0131] Preferably but not limitingly, the installation 1 may comprise, preferably upstream of the CTU 21, a smoke treatment device 9 arranged to eliminate sulfur oxides (SO x ), nitrogen oxides (NO x ) and acid gases.

[0132] Still with reference to the third improvement of the installation 1 illustrated in the, the installation 1 further comprises a CO223 conversion unit, denoted CCU 23, arranged to produce gaseous hydrocarbons 24 from dihydrogen 4 produced by the SOEC 2 and from CO222, or from the gas 22 enriched in CO2, produced by the CTU 21.

[0133] Dihydrogen 4 and CO2, from CTU 21, are used as reactants in CCU 23. The conversion of CO2 by CCU 23 could, for example, comprise one or the combination of the following reactions such as, for example, the reversed water gas reaction, the synthesis of oxygenated carbon compounds, preferably of compounds comprising a single carbon atom, (for example methanol, formaldehyde or formic acid), methanation (for the synthesis of methane), Fischer-Tropsch reactions (for obtaining hydrocarbons).

[0134] The combination of the third improvement with the second improvement of installation 1 makes it possible: to limit the environmental impact, including direct greenhouse gas emissions, for the manufacture of clinker 14 and for the manufacture of dihydrogen 4, to reduce the energy consumption and / or raw materials for the production of hydrogen 4 and for the manufacture of clinker 14.

[0135] Indeed, the use of purified oxygen 301, or gas enriched in oxygen 301, promotes oxycombustion and therefore the production of fumes 9 comprising a high CO2 content. In addition, oxycombustion allows the release of gases having a small quantity of nitrogen oxides. Thus, the high concentration of CO2 has the effect of promoting the conversion of CO2 into carbon compounds (in particular into fuel) which can be recovered and used directly on the installation 1. Oxycombustion also makes it possible to reduce the quantity of gaseous discharges with a high environmental impact.

[0136] The first, second, and third upgrades of Facility 1 can be combined with each other. However, there is no requirement to combine the upgrades, and each upgrade can be considered individually.

[0137] According to a second embodiment, the HRU 7 is arranged to produce hot water 5, at a temperature less than or equal to 90°C, from gaseous discharges 8, 9, called hot gases 8, 9, at a temperature greater than 150°C, emitted by the CMU 6.

[0138] The second embodiment is not exclusive of the first embodiment. The first and second embodiments may be combined or implemented jointly or alternatively. In other words, the HRU 7 may be arranged to produce hot steam 5 and / or hot water 5.

[0139] Only the HRU 7 shows differences between the first and second embodiments.

[0140] According to the second embodiment, the HRU 7 comprises, in addition to or as a substitute for the hot steam production device 18 according to the first embodiment, a hot water production device 18. The hot water production device 18 is arranged to produce hot water 5 from the heat extracted from the hot gases 8, 9. A person skilled in the art knows hot water production devices and will be able to choose the type of steam production device suitable according to his needs and the specific case.

[0141] Preferably, the hot water production device 18 comprises at least one heat exchanger, for example a single exchanger, preferably several heat exchangers, called exchangers of the hot water production device 18. Preferably, the at least one heat exchanger of the hot water production device 18 is chosen, for information purposes, from: a thermal preheater and a superheater, for example using a shell and tube exchanger technology, or a plate exchanger technology.

[0142] The at least one heat exchanger of the hot water production device 18 is arranged to produce, or supply to the hot water production device 18, additional heat supplementing or adding to the heat produced or extracted, from the hot gases 8, 9, by the at least one heat exchanger 10, 11 of the HRU 7.

[0143] By way of non-limiting example, the at least one exchanger of the hot water production device 18 is arranged to provide additional heat to the hot water production device 18 from an energy source other than the hot gases 8, 9. The energy source, other than the hot gases 8, 9, may come from the installation 1, for example dihydrogen 4 or dioxygen 3 produced by the installation 1. The energy source, other than the hot gases 8, 9, may be an energy source external to the installation 1, for example energy from a gas or electricity supply network or from external fuels.

[0144] The invention does not aim to achieve all of the objectives described in the application. The invention aims to achieve at least one of the objectives presented in the application, and, in particular, at least one of the objectives relating to the embodiment illustrated in the.

[0145] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

[0146] Thus, in variants of the previously described embodiments that can be combined with each other: the CMU 6 can be included in or be part of a cement plant, and / or cement is obtained from the clinker 6 and additives, and / or according to the first embodiment, the HRU 7 is arranged to produce hot steam 5, at a temperature greater than or equal to 150°C, according to the second embodiment, the HRU 7 is arranged to produce hot water 5, at a temperature less than or equal to 90°C, according to the second embodiment, the HRU 7 is arranged to produce hot water 5, at a temperature greater than or equal to 20°C, the installation 1 comprises means for flowing hot gases 8, 9 from the CMU 6 to the HRU 7, and / or the water treatment unit is arranged to treat and purify, in addition,water streams recovered from the OPU 20 and / or water streams recovered from the HPU 19 such that the treated water reaches a conductivity and ion and particle content suitable for supplying the HRU 7, and / orby way of non-limiting examples, the HRU 7 may further comprise an economizer, one or more particle filters, a fan, a water heating system, for example electric, a water deaerator, a water vaporizer, a superheater, a heat storage device, a heat pump and / or an electricity storage means, for example one or more accumulators, and / orthe installation 1 may comprise a tank 26 and be arranged to store the purified dihydrogen 401 coming from the HPU 19, and / orthe installation 1 may comprise a tank 27 and be arranged to store the purified dihydrogen 301 coming from the OPU 20, and / or the installation 1 may comprise, in addition to or as an alternative to the OPU 20, an air separation unit, denoted ASU,and / orthe oxygen 3, or the oxygen 3-enriched gas, may be mixed with air and fed to the ASU to produce purified oxygen, and / orthe ASU and the OPU 20 allow the separation or removal of impurities such as, but not limited to, water, nitrogen, argon, carbon monoxide and nitrogen dioxide, and / orthe ASU and the OPU 20 may be arranged to purify the oxygen 3, or the oxygen 3-enriched gas, based on one of the following processes or technologies: adsorption, absorption, membrane separation, distillation or conversion.,

Claims

Hydrogen production plant (1), said plant, comprising:an electrolyser (2), arranged to produce dioxygen (3) and dihydrogen (4) from:steam (5), called hot steam, at a temperature above 150°C, orwater (5), called hot water, at a temperature less than or equal to 90°C,a clinker manufacturing unit (6),a heat recovery unit (7) arranged to produce, from gaseous discharges (8, 9), called hot gases, at a temperature above 150°C, emitted by the clinker manufacturing unit (6):hot steam, orhot water,said heat recovery unit comprises:at least one heat exchanger (10, 11), called at least one heat exchanger of the heat recovery unit, said at least one heat exchanger of the heat recovery unit being arranged to extract heat from the hot gases (8, 9) issued by the clinker manufacturing unit (6),anda hot steam production device (18) arranged to produce the hot steam (5) from the heat extracted from the hot gases (8, 9), and / ora hot water production device (18) arranged to produce the hot water (5) from the heat extracted from the hot gases (8, 9)., Installation (1) according to the preceding claim, in which the hot steam production device (18) comprises at least one heat exchanger, called at least one exchanger of the hot steam production device, among a thermal preheater, an evaporator and a superheater. Installation (1) according to claim 1 or 2, in which the hot water production device (18) comprises at least one heat exchanger, said at least one exchanger of the hot water production device, among a thermal preheater and a superheater. Installation (1) according to any one of the preceding claims, in which the clinker manufacturing unit (6) comprises: a preheating unit (601) arranged to preheat raw material (13), called cement raw material, for the manufacture of clinker (14), a rotary kiln (602) for firing the preheated cement raw material, Installation (1) according to the preceding claim, in which the heat recovery unit (7) is arranged to extract heat from hot gases (9), called fumes (9), resulting from the manufacture of the clinker (14). Installation (1) according to the preceding claim, in which at least one exchanger (10) of the heat recovery unit (7) is arranged to extract heat from the fumes (9). Installation (1) according to any one of the preceding claims, in which the clinker manufacturing unit (6) further comprises a cooling unit (603) for the manufactured clinker (14). Installation (1) according to the preceding claim, in which the heat recovery unit (7) is arranged to extract heat from hot gases (8), called reheated gases (8), resulting from the cooling of the manufactured clinker (14). Installation (1) according to the preceding claim, in which at least one heat exchanger (11) of the heat recovery unit (7) is arranged to extract heat from the heated gases (8). Installation (1) according to claim 4, or according to any one of claims 5 to 9 taken in combination with claim 4, further comprising a heating gas production means (17); said heating gas production means being arranged to produce, at least in part, said heating gases (16) from dihydrogen (4) produced by the electrolyser (2). Installation (1) according to the preceding claim, further comprising a dihydrogen purification unit (19), called HPU, arranged to purify the dihydrogen (4) produced by the electrolyser (2); the heating gas production means (17) being arranged to produce, at least in part, the heating gases (16) from the purified dihydrogen (401) coming from the HPU. Installation (1) according to claim 4, or according to any one of claims 5 to 9 taken in combination with claim 4, further comprising a heating gas production means (17); said heating gas production means being arranged to produce, at least in part, the heating gases (16) from oxygen (3) produced by the electrolyser (2). Installation (1) according to the preceding claim, further comprising a dioxygen purification unit (20), called OPU, arranged to purify the dioxygen (3) produced by the electrolyser (2); said heating gas production means (17) being arranged to produce, at least in part, the heating gases (16) from the purified dioxygen (301) coming from the OPU. Installation (1) according to claim 5, or according to any one of claims 6 to 13 taken in combination with claim 5, further comprising a unit for capturing carbon dioxide (CO2) (21) contained in the fumes (9), having circulated in the heat recovery unit (7), to produce CO2 (22) or gas (22) enriched in CO2. Installation (1) according to the preceding claim, further comprising a CO2 conversion unit (23) arranged to produce gaseous hydrocarbons (24) from dihydrogen (4) produced by the electrolyser (2) and from CO2 (22) produced by the CO2 capture unit (21). A method for producing dihydrogen, comprising the steps of:recovering heat, by means of a heat recovery unit (7), from gaseous discharges (8, 9), called hot gases, emitted by a clinker manufacturing unit (6),producing, from the recovered heat:steam (5), called hot steam, at a temperature above 150°C, orwater (5), called hot water, at a temperature less than or equal to 90°C,producing dihydrogen (4) and dioxygen (3), by means of an electrolyser, from the hot steam,extracting the heat from the hot gases (8, 9) emitted by the clinker manufacturing unit (6) by at least one heat exchanger (10, 11) of the heat recovery unit, andproducing hot steam (5) from the heat extracted from the hot gases (8, 9), by a hot steam production device (18), and / or production of hot water (5) from the heat extracted from the hot gases (8, 9),by a hot steam production device (18)., A method according to the preceding claim, further comprising the step of manufacturing clinker (14) by means of a clinker manufacturing unit (6).

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