Overheating device

Abstract

The invention relates to a superheating device comprising a combustion chamber (10) comprising a fuel inlet, an oxidant inlet and a heat inlet for receiving heat at an average temperature (Tm) of between 150°C and 500°C, the combustion chamber being adapted to burn the fuel to heat and produce heat (Th) at a high temperature greater than 600°C. Application to the production of industrial installations requiring high temperature thermal energy. Figure 1

Description

Title of the invention: Superheating device Technical field of the invention

[0001] The technical field of the invention relates to industrial installations where heat above 600°C is necessary for the large-scale production of gaseous products, for example dihydrogen H2 or ammonia NH3. State of the art

[0002] Many industrial processes require the large-scale use of heat and fluids at high temperatures, above 600°C. Examples include the production of dihydrogen H2 by steam reforming of methane CH4, the main process used today for the production of dihydrogen, or the production of dihydrogen by electrolysis of water at high temperature, a process with a much more interesting yield than the electrolysis of water at low temperature using membrane devices, of the order of 80°C to 100°C. Also worth mentioning is the production of ammonia from dihydrogen and dinitrogen.

[0003] In such processes, heat is conventionally provided by the combustion of methane CH4 and more generally by the combustion of products derived from fossil resources. Such heating processes have the disadvantage of consuming non-renewable energy; they also have the disadvantage of producing CO2. Statement of the invention

[0004] The invention proposes a technical solution to overcome all or part of the drawbacks set out above.

[0005] For this purpose, the invention proposes a superheating device comprising a combustion chamber comprising a fuel inlet, an oxidizer inlet and a heat inlet for receiving heat at an average temperature (Tm) of between 150°C and 500°C, the combustion chamber being adapted to burn the fuel to heat and produce heat (Th) at a high temperature above 600°C.

[0006] The combustion reaction is initiated by the heat received by the combustion chamber. The invention thus proposes, from a heat source (i.e. thermal energy) at medium temperature, below 500°C, to produce heat at a higher temperature, above 600°C; coupled with a heat source at medium temperature, the device according to the invention thus forms a high-efficiency cogeneration assembly. The invention thus proposes a heat source at a temperature sufficient to implement high-efficiency industrial processes. temperature, from recovered energy or, more generally, from greener energy than the heating processes currently used in industry.

[0007] The invention also relates to an industrial installation comprising a superheating device as described above and a device for producing dihydrogen, one inlet of which is connected to the heat outlet of the superheating device and one outlet of which is connected to the fuel inlet of the superheating device. The high-temperature heat leaving the superheating device is thus used to produce dihydrogen, part of which is reintroduced as fuel into the combustion chamber to maintain the production of high-temperature heat. Presentation of the figures

[0008] The invention will be better understood, and other characteristics and advantages of the invention will appear in the light of the following description of an example of implementation of the invention. This example is given without limitation. The description is to be read in relation to the appended drawings in which: • [Fig.l] is a view of the essential device of the invention, • [Fig.2] is a view of an installation using the device of [Fig.l]

[0009] In the various figures, elements which are identical in their function or structure are referenced with the same references.

[0010] Conventionally, for physicists, heat is thermal energy. By convention, in the context of the invention, the word "heat" will be used to refer to a heat transfer fluid transporting thermal energy as a function of a temperature and a heat capacity of the heat transfer fluid, and the term "temperature of the heat" will be used to refer to the temperature of the heat transfer fluid transporting the associated thermal energy. The following concepts are also defined: an "average" temperature is a temperature between 150°C and 500°C, a "high" temperature is a temperature above 600°C. Detailed description

[0011] As stated previously, the invention relates to a superheating device 10 comprising a combustion chamber 11 comprising a fuel inlet, an oxidant inlet and a heat inlet for receiving heat at an average temperature Tm of between 150°C and 500°C, the combustion chamber being adapted to burn the fuel and the oxidant to heat and produce heat at a high temperature Th of greater than 600°C. The heat (or heat transfer fluid) may be water vapor or any other suitable heat transfer fluid.

[0012] The superheating device can thus be seen as a device which produces heat, i.e. thermal energy, at high temperature. Ideally, the superheating device according to the invention is inserted into an installation industrial; it receives so-called "waste" heat from the implementation of an industrial process or a power generation unit and provides heat at a higher temperature to enable the implementation of another industrial process. In some applications, the difference between the high temperature and the average temperature may be small. However, some thermochemical industrial processes require a minimum temperature, in addition to a quantity of energy

[0013] The fuel is preferably gaseous dihydrogen H2 and the oxidant is a gas comprising gaseous dioxygen 02; the combustion chamber is arranged to carry out a combustion reaction of dihydrogen 2H2 + 02 —> H2O, a reaction known for its high exothermic capacities and calorific value. The heat from the combustion is used to heat and produce heat at high temperature. The combustion reaction is initiated by the heat received by the combustion chamber.

[0014] The oxidant may be air comprising approximately 21% of oxygen required for the combustion of hydrogen. The disadvantage is the undesired co-production of nitrogen oxides (commonly called NOx) linked to the presence of nitrogen in the air. Advantageously, the oxidant may be gaseous oxygen O2 to implement oxycombustion. By excluding nitrogen from the combustion, the flame temperature increases, which increases the temperature of the second heat transfer fluid and increases the efficiency of the device (in terms of the quantity of heat produced). Also, the quantity of fumes generated is limited and the production of nitrogen oxides is avoided.

[0015] The superheating device also comprises an adjustment means configured to control the operation of the combustion chamber. In particular, the adjustment means adjusts the fuel flow rate and the oxidant flow rate to optimize the combustion efficiency. The adjustment means takes into account the temperature and the quantity of heat entering the combustion chamber, and the temperature and the quantity of heat desired at the outlet of the combustion chamber. In particular, the adjustment means adjusts the fuel flow rate and the oxidant flow rate to achieve stoichiometric combustion by supplying, in the combustion chamber, one mole of O2 for two moles of H2.

[0016] The superheating device shown [Fig.l] also comprises an outlet exchanger 12 comprising a primary circuit, one inlet of which is connected to a heat outlet of the combustion chamber 11. The “cold” outlet of the primary circuit (not shown [Fig.l]) is connected in a conventional manner to an inlet of the combustion chamber. The exchanger 12 also comprises, in a conventional manner, a secondary circuit thermally coupled to the primary circuit to ensure the transfer of heat from the primary circuit to the secondary circuit; the secondary circuit comprises a heat outlet coupled to a heat inlet of a heat consuming device (not shown [Fig.l]) at high temperature Th and a “cold” inlet connected to an outlet of the heat consuming device. In a conventional manner, in the primary circuit as in the secondary circuit, the heat-energy is transported by a suitable heat transfer fluid.

[0017] As a variant (not shown), the outlet exchanger comprises only a secondary circuit placed at the outlet of the combustion chamber and whose heat outlet is coupled to a heat inlet of the high-temperature heat-consuming device.

[0018] Finally, the pure water produced in the combustion chamber in the form of steam can be condensed and reused in processes where demineralized water is necessary, such as for example the electrolysis of water for the purpose of producing dihydrogen.

[0019] The device according to the invention may also comprise a heat source 20 providing heat at the average temperature, and an inlet exchanger 30 comprising a primary circuit, one inlet of which is connected (solid arrow) to a heat outlet of the heat source and a secondary circuit, one outlet of which is connected (solid arrow) to a heat inlet of the combustion chamber to provide heat at average temperature Tm to the combustion chamber.

[0020] The heat source may be of any type, capable of heating a heat transfer fluid to an average temperature of 150°C to 500°C. For example, the heat source may be a waste heat recovery device from an industrial installation. The heat source may also be a fourth-generation nuclear reactor such as a lead-cooled fast neutron reactor (or LFR - Lead-cooled fast Reactor) or a sodium-cooled fast neutron reactor (or SFR - Sodium Fast Reactor). The device according to the invention is thus used in a cogeneration installation for reuse of the heat co-produced by the source which mainly produces another energy (for example electrical energy) or another product.

[0021] The inlet exchanger 30 and the heat transfer fluids used to transport the heat in the primary circuit and in the secondary circuit of the exchanger 30 are chosen in particular as a function of the heat source 20, the quantities of heat to be transferred, the temperature Tm of the heat to be transferred. The exchanger is for example a spiral exchanger optimized for the transfer of heat between the primary circuit and the secondary circuit at the average temperature between 150 and 500°C. In the case where the heat source is a lead-cooled reactor, the heat transfer fluid used in the primary will be lead and the heat transfer fluid used in the secondary circuit will be for example water.

[0022] The superheating device according to the invention can be used in any industrial installation requiring heat (energy) at a high temperature.

[0023] A first application envisaged is the production of an installation comprising a superheating device 10 as described above and a dihydrogen production device 40 of which a heat inlet is connected (solid arrow) to the heat outlet of the superheating device 10 to receive the high temperature heat Th and of which an outlet is connected (dotted arrow) to the fuel inlet of the superheating device. The high temperature heat leaving the superheating device is thus used to produce dihydrogen, a portion of which is thus reintroduced as fuel into the combustion chamber to maintain the production of high temperature heat.For example, 6 to 13 kg of dihydrogen reintroduced into the superheating device can make it possible to obtain, from an incoming heat of between 150 and 500°C, an outgoing heat at 850°C, while avoiding the cracking of water, a phenomenon which appears for water vapor at 850°C (in the case where the heat is in the form of water vapor).

[0024] Similarly, if the hydrogen production process implemented generates oxygen as a co-produced gas, the oxygen can be reintroduced into the combustion chamber. The complete installation is thus autonomous in hydrogen and possibly also in oxygen for the production of heat, while producing, massively, hydrogen.

[0025] Ideally, the dihydrogen production device 40 is configured to implement a process for producing dihydrogen at a temperature above 600°C; for example, a process of the reforming type, pyrolysis of a product derived from petroleum (methane, ethanol, etc.). These processes are currently the most used for producing dihydrogen; the invention makes it possible to make them more virtuous by using heat from the combustion of dihydrogen rather than heat from the combustion of petroleum products as is currently the case.

[0026] Alternatively, the dihydrogen production device can implement a high-temperature water electrolysis process, in particular using solid oxides (or SOEC - Solid Oxide Electroliser Cell), which has an interesting yield, in terms of transforming heat into chemical energy H2.

[0027] Other applications of the invention may be envisaged. For example, a superheating device may be coupled to an NH3 ammonia production plant. Since ammonia is produced essentially from dihydrogen H2 and dinitrogen, part of the dihydrogen produced or introduced into the plant may be reinjected into the combustion chamber.

Claims

Claims

1. A superheating device (10) comprising a combustion chamber (11) comprising a fuel inlet, an oxidizer inlet and a heat inlet for receiving heat at an average temperature (Tm) between 150°C and 500°C, the combustion chamber being adapted to burn the fuel to heat and produce heat (Th) at a high temperature above 600°C.

2. Device according to claim 1 wherein the fuel is gaseous dihydrogen (H2), wherein the oxidant is a gas comprising gaseous dioxygen (02) and wherein the combustion chamber is arranged to carry out a combustion reaction of dihydrogen 2H2 + 02 —> H2O.

3. Device according to claim 2 in which the oxidant is gaseous dioxygen (02).

4. A device according to claim 3 comprising adjustment means configured to adjust an oxidant flow rate and a fuel flow rate to achieve stoichiometric combustion.

5. Device according to one of the preceding claims also comprising an outlet heat exchanger (12) comprising a primary circuit, one inlet of which is connected to a heat outlet of the combustion chamber (10).

6. Device according to one of the preceding claims, also comprising a heat source (20) providing heat at the average temperature, and a heat inlet exchanger comprising a primary circuit of which a hot inlet is connected to an outlet of the heat source and a secondary circuit of which a hot outlet is connected to a heat inlet of the combustion chamber.

7. Industrial installation comprising a superheating device (10) according to one of the preceding claims and a dihydrogen production device (40) of which one inlet is connected to the heat outlet of the superheating device and one outlet of which is connected to the fuel inlet of the superheating device.

8. Installation according to the preceding claim, in which the device for producing dihydrogen is configured to implement a method for producing dihydrogen at a temperature above 600°C, such as a reforming process or a pyrolysis process for a petroleum product or a high-temperature water electrolysis process.

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