Recycled-heat facility for producing electricity comprising a heat engine

Abstract

Disclosed is a method for producing electricity that uses at least one heat engine, according to which at least part of the fuel for the heat engine is produced by a thermal dissociation process which is applied to a product resulting from the combustion of said fuel, and at least part of the heat released by the heat engine is used to carry out at least one endothermic reaction of said thermal dissociation process.

Description

DESCRIPTION TITLE: RECYCLED HEAT ELECTRICITY PRODUCTION INSTALLATION COMPRISING A HEAT ENGINE Technical field

[0001] The present invention relates to an electricity production installation comprising a heat engine and a chemical reactor capable of producing fuel for the heat engine using heat produced at least in part by the heat engine. Prior art

[0002] Thermophotovoltaic cells convert far-infrared electromagnetic radiation into electricity. However, the energy efficiency of these cells rarely exceeds 40% of the energy (Source: article published in the journal Nature on 14 / 4 / 2022: "Thermophotovoltaic efficiency of 40%").

[0003] Document JP 2005 306624 A describes the use of the heat produced by the combustion in a burner of the residual gases of a fuel cell, to provide thermal energy to chemical reactors where the stages of separation and concentration of products intended for the production of hydrogen take place, but does not recycle all the heat released by the fuel cell in which the dihydrogen reacts with the dioxygen, possibly using only the part of said heat transferred to the dioxygens and dihydrogens which have not reacted; and does not include a thermophotovoltaic cell associated with a burner.

[0004] US 2020 / 306624A and EP 1 851 816 A2 describe hydrocarbon reforming processes that enable the production of hydrogen.

[0005] Ullmnan's Encyclopaedia of Industrial Chemistry (ISBN 978-3-52-730673-2) describes, in its chapter "Hydrogen Production," various chemical processes for producing hydrogen, including processes for splitting water into hydrogen and oxygen.

[0006] The process described in patent application FR2311050 describes a process for producing electricity using a high-temperature fuel cell and heat pumps.

[0007] The process described in patent application FR3128064A1 describes a process for producing electricity using a liquid electrode electrochemical cell in which the heat released by the cell can be used for regenerating the fuel. Technical problem

[0008] In the context of the present invention, the term "heat engine" or, equivalently, "combustion engine" means a device transforming at least part of the energy released from the direct combustion of the fuel and the oxidant into mechanical or electrical work.

[0009] This therefore excludes fuel cells, in which the fuel and the oxidant do not react directly: they remain respectively on the anode and the cathode of the cell - the production of electricity then taking place by circulation of protons (H+) between these electrodes through an electrolyte which separates them, and by circulation of electrons in an electrical circuit connecting these electrodes together.

[0010] In other words, the fuel and the oxidizer are never in contact: they react through ionic exchanges.

[0011] Thermal engines are, for example, external combustion engines, internal combustion engines, or engines using thermo-photovoltaic cells, or a combination of at least two of these three processes.

[0012] None of the prior art methods described above describes a method or installation of a heat engine whose inputs are mixed with recycled combustion products or recycled products of products of the same nature as those of combustion, the energy from the recycling being derived from the heat and electricity produced within the installation. A fortiori, none of the prior art methods described above does not describe a process or installation of a heat engine whose inputs are of the same nature as recycled combustion products, or recycled products of products of the same nature as those of combustion, the energy from the recycling being derived from the heat and electricity produced within the installation.

[0013] However, apart from the problem of partial combustion of the fuel, the efficiency of a non-thermal energy production installation is significantly affected by its heat release.

[0014] In another version of the invention, the method aims to produce mechanical or electrical energy from low temperature thermal energy without transferring thermal energy to a colder medium. Brief description of the invention Process

[0015] The present invention relates to a method for producing electricity or mechanical work using a heat engine, said method making it possible to recover the heat released by the heat engine by a thermal dissociation process, applied to the product of the same chemical composition as that produced by the combustion of the fuel, at least part of the heat released by said engine being supplied to at least one of the endothermic reactions of said dissociation process; said dissociation process making it possible to produce fuel for the same engine.

[0016] In a preferred version of the installation, all the thermal energy required for the endothermic reactions of the dissociation process is provided by the heat from the heat engine.

[0017] An external fuel can be introduced into the installation to mix with the fuel from the chemical cycle reactors and be introduced into the heat engine.

[0018] Surprisingly, the overall efficiency of such a process is very satisfactory, whereas thermal engines are known to have relatively poor efficiency (typically around 35%).

[0019] A possible explanation for this good efficiency may be that a thermal dissociation process applied to a product of fuel combustion (this product may for example be water when the fuel is dihydrogen) has an energy efficiency close to 1, whereas other dissociation processes such as electrolysis have a significantly lower efficiency - typically of the order of 60%. Process with heat pump

[0020] Such an installation can also, by being combined with a heat pump, further reduce its quantity of fuel input, or even do without it, fuel being produced from the combustion products of the heat engine or products of the same chemical composition, thanks to the heat released by the heat engine and low temperature heat external to the installation, the temperature of which is raised by a heat pump supplied with electrical or mechanical work by the same installation. Water dissociation processes

[0021] The water splitting process can be, for example, one of the processes described in the book 'Comprehensive energy systems Vol 4' published in 2018 by Elsevier.

[0022] The dissociation process involves at least one endothermic reaction.

[0023] The dissociation process may be mixed, i.e. include at least one endothermic reaction and at least one redox reaction requiring an input of electricity; the electricity preferably being generated by the thermal engine of the installation.

[0024] The process of thermal dissociation of water is for example the iodine-sulfur cycle or a similar cycle using bromine instead of iodine.

[0025] The iodine sulfur cycle then uses the reactions: 120°C) H2SO4^ SO2+ H2O + 1 / 2O2(at 830°C) 2HI-> l2+ H2 (at 650 °C)

[0026] The bromine sulfur cycle then uses the reactions: Br2+ SO2+ 2 H2O -> 2 HBr +H2SO4 (at 650 °C) H2SO4^ SO2+ H2O + 1 / 2O2(at 830°) 2HBr-> Br2+ H2(at 1327 °C)

[0027] Each of the products of the thermal dissociation of water can then be used in part by the heat engine.

[0028] The iodine-sulfur cycle allows in a first endothermic reaction at for example 120°C between di-iodine, sulfur dioxide and water to produce hydrogen iodide and sulfuric acid (I2 + SO2 + 2 H2O — > 2 HI + H2SO4), the hydrogen iodide being recycled in a second endothermic reaction for example at 650°C into di-iodine and dihydrogen (2 HI -> I2 + H2) and the sulfuric acid into sulfur dioxide, water and dioxygen (H2SO4-> SO2 + H2O + 1 / 2O2) in a third endothermic reaction, for example at 830°C, the heat required for at least one of the three endothermic reactions coming from the heat engine, preferably via a thermal connection between the heat engine and the reactor(s) of the chemical reactions, and possibly via the combustion gases from the burner. The cycle used is then that described in Figure 1. Alternatively or in a complementary manner, the hydrogen iodide recycling reaction is carried out in a proton exchange electrolyte cell powered electrically by the electricity generated by the heat engine. Similarly, in the case of the bromine-sulfur cycle, hydrogen bromide can be dissociated into bromine and hydrogen using a proton exchange cell powered electrically by the electricity generated by the heat engine.

[0029] Alternatively, the thermal water splitting process can use an alkali metal in which water mixed with the alkali metal reacts to form a hydride of the alkali metal and oxygen (H2O + 2 Me -> 2MeH + 1 / 2O2) while the alkali metal hydride is transformed in another reactor into metal and dihydrogen (2MeH -> 2Me + H2). Alternatively, the dissociation of water can be done using Iron III Chloride and Iron II Chloride (H2O + Cl2->1 / 2 O2+ 2HCI at 973 °K, 2HCI + 2FeCI2-> H2+ 2FeCI3 at 873 °K, 2FeCI3->2FeCI2+ Cl2 at 723 °K).

[0030] Alternatively, the dissociation of water can be done using Vanadium Chloride and Vanadium Tetrachloride (H2O + CI2 -> 1 / z O2 + 2HCI at 883 °K, 2HCI + 2VCI2-> H2+ 2VCI3 at 298 °K, 2VCI3->VCI4+ VCI2 at 973 °K, 2VCI4->CI2+ 2VCI3 at 298 °K).

[0031] In yet another version, the process for thermal dissociation of water may use hydrocarbons, for example methane reacting in a first reactor with water to form dihydrogen and carbon monoxide (CI- +H2O -> CO + 3H2), carbon monoxide and part of the dihydrogen reacting in a second reactor to form methanol (CO+2H2 -> CH3OH), methanol reacting in a third reactor with arsenate to form arsenous anhydride and methane (CH3OH + As3O4-> CH4+ AS2O5), a fourth and a fifth reactor for forming arsenate and dioxygen from the arsenous anhydride ( 1 AS2O5 -> / 1 AS2O3 + / 1 O2 and / 1 / AS2O5 + AS2Û3-> AS2O4). Sulfur Iodine Cycle

[0032] In a preferred embodiment of the invention, the fuel of the installation is dihydrogen and the chemical production unit comprises at least one main compartment / main reactor allowing the chemical production of dihydrogen and diiodine from hydrogen iodide (HI), a first secondary compartment / first secondary reactor allowing the chemical production of dioxygen from sulfuric acid (H2SC), and / or at least one second secondary compartment / second secondary reactor which allows the reaction between diiodine, sulfur dioxide and water, which produces hydrogen iodide and sulfuric acid. This second secondary compartment therefore contains diatomic iodine, water and sulfur dioxide and possibly the products of this reaction, i.e. hydrogen iodide and sulfuric acid. At least one of the secondary reactors or the main reactor are thermally connected to the heat engine. The gases from the heat engine not recycled for fuel production are advantageously used to provide heat for the endothermic reactions, in order to reduce the temperature of said gases when they are discharged. Furthermore, the elements of the production unit are preferably thermally insulated from the outside in order to minimize thermal energy losses, for example using ceramic fibers and rock wool.The production unit further comprises means for introducing iodine produced in said main compartment / reactor into the second compartment / secondary reactor, means for introducing sulfuric acid produced in said second compartment / secondary reactor into said first compartment / secondary reactor and means for introducing oxygen produced in said first compartment / secondary reactor into said cell so that the latter serves as an oxidant. Hydrogen iodide can be separated from sulfuric acid for example by distillation or by liquid / liquid gravitational separation. Oxygen can be separated from the mixture resulting from the reaction at 830°C by condensation. Iodine, sulfur dioxide and hydrogen can be separated by condensation and gravitational separation.

[0033] Alternatively or in a complementary manner, the hydrogen iodide dissociation reaction is carried out by supplying electricity to a proton exchange fuel cell through which the hydrogen dissociated from the iodide passes, for example at a temperature of 120°C, the voltage across the electrode preferably being greater than 0.04 V, for example 0.1 V.

[0034] The cycles of the hydrogen / oxygen production reactions are not limited according to the invention. They may be, for example, one of the water dissociation processes described above.

[0035] The heat engine of the invention is connected to a main source of fuel and to a main source of oxidant. The supply of fuel and oxidant provided from outside the installation is a complementary supply. If the engine thermal engine provides mechanical work, this can be partly or entirely converted into electricity by a dynamo or an alternator; conversely, if the thermal engine provides electrical work, for example produced by a thermo photovoltaic cell, this can be partly or entirely converted into mechanical work by an electric motor.

[0036] The installation according to one of its implementations therefore makes it possible to produce, at the same time, electricity, dihydrogen and dioxygen, which are used as fuel in the burner within said installation. The heat continuously generated by the hydrogen burner during its operation is used for the production of electricity thanks to the thermo-photovoltaic cell, and dihydrogen and / or dioxygen during endothermic reactions and a remainder of heat, if it exists, can still be used possibly for the production of electricity by a turbine or for heating, for example.

[0037] According to a variant which can be combined with each of the aforementioned embodiments, the heat engine is thermally connected only to said first reactor / secondary compartment, the main reactor being thermally connected to the first secondary reactor and the second secondary reactor to the main reactor.

[0038] According to another variant, the heat engine is thermally connected to the three reactors.

[0039] The endothermic chemical reaction 2HI— > I2 + H2, can take place in the gas phase at 650 °C. The main compartment therefore contains hydrogen iodide and possibly the reaction products (namely dihydrogen and diiodine).

[0040] The first compartment / secondary reactor allows the reaction between two sulfuric acid molecules to produce dioxygen (this compartment / reactor therefore contains at least sulfuric acid and possibly the products of the reaction, i.e. sulfur dioxide, water and dioxygen). The second compartment / secondary reactor allows the reaction between diiodine, sulfur oxide and water, which produces hydrogen iodide and sulfuric acid. This second The secondary compartment / reactor therefore contains diatomic iodine, water and sulfur dioxide and possibly the products of this reaction, i.e. hydrogen iodide and sulfuric acid.

[0041] Indeed, the publication entitled "Sulfur-iodine Thermochemical Cycle" by P. Pickard, published on May 17, 2006 in the journal Sandia National Labs, describes a series of reactions allowing for environmentally friendly production of dihydrogen. The aforementioned Sulfur-Iodine cycle allows, using high heat, to produce hydrogen. The reaction 2 HI -> h + H2 operates at 650 °C. The two endothermic reactions: 2 H2SO4— 2 SO2 + 2 H2O + O2 and I2 + SO2 + 2 H2O — > 2 HI +H2SO4 are preferably carried out, respectively at 830 °C and 120 °C.

[0042] The reaction I2 + SO2 + 2 H2O — > 2 HI +H2SO4 is preferably carried out at temperatures and pressures such that all the compounds are liquid except HI which is gaseous, for example 120°C under 45atm.

[0043] The reaction 2 HI -> I2 + H2 is preferably carried out at temperatures and pressures such that all the compounds are gaseous except iodine which is liquid, for example 650°C under 10 atm or 650°C under 45 atm.

[0044] This makes it easier to extract the products of the reactions.

[0045] Throughout the present application, the expression "reactor allowing the reaction between A and B" encompasses a reactor containing the reactants A and B and possibly the products and by-products of this reaction. Other fuels

[0046] The fuel used in the heat engine is not limited according to the invention. It may also be, for example, methanol, the carbon dioxide resulting from its combustion being separated from the water, for example by cooling and pressurizing, for example, at 60°C under 1 atmosphere so that the water becomes liquid while the carbon dioxide remains gaseous; the water being, for example, regenerated into dihydrogen by one of the processes described above for dissociating the water, then the dihydrogen reacting in a reactor separated with carbon dioxide to form methanol according to the reaction: CO2 + 3 H2 -> CH3OH + H2O.

[0047] The fuel can also be gasoline, for example Octane CsHis or heptane C7H16 or a mixture of the two. The water and carbon dioxide resulting from their combustion allow methanol to be generated by the process described above, which is then mixed with the gasoline supplied to the installation to fuel the burner.

[0048] Even if the fuel is other than dihydrogen, in particular if it is methanol or gasoline, the installation can produce a second fuel, for example dihydrogen from water, coming from the exhaust gases of the burner or from an external source, said other fuel produced being injected together with the fuel into the burner, for example by another nozzle. Chemical reactors

[0049] The means of introduction into chemical reactors can be simple pipes possibly equipped with nozzles preceded by compressors. Heat exchangers are advantageously used to simultaneously lower the temperature of certain chemical products and increase the temperature of others in order to bring the temperatures of these chemical products to the operating temperatures of the chemical reactor which consumes them. In addition, a heat engine can be used to produce mechanical or electrical energy when lowering the temperature of certain chemical compounds brought to a reactor operating at a lower temperature, and conversely, a heat pump consuming mechanical or electrical work can be used to increase the temperature of a compound brought to a reactor operating at a higher temperature.Finally, heat from combustion gases or the heat engine can be used to heat products entering a chemical reactor or supplying heat to a reactor where an endothermic reaction occurs. In the case of the sulfur-iodine cycle, the phase of the iodine and sulfuric acid during their reintroduction is not limiting according to the invention. They can be liquid or gaseous, independently of each other. depending on the temperature and pressure conditions in the separators which equip the outlets of the reactor compartments. Thermal connections

[0050] The installation includes chemical reactors, heat exchangers, heat sources, heat pumps and Sterling engines thermally connected to each other, either directly by contact or by a heat transfer fluid circuit; the Sterling engines allow the temperature of a heat flow to be lowered while producing mechanical work. Thermal engines

[0051] Preferably, at least one heat engine (also called a "combustion engine") chosen from the group comprising internal combustion engines, external combustion engines, Sterling engines, Rankine cycle engines, steam turbines, gas turbines, thermo-photovoltaic cells and combinations thereof is used for the method and installation according to the invention.

[0052] A heat engine directly reacts a fuel and an oxidant to produce mechanical or electrical work and combustion gases. The mechanical work produced can be converted, in whole or in part, into electricity, for example by a dynamo, a rotary alternator or a linear alternator.

[0053] The heat engine is preferably an external combustion engine, for example comprising a steam turbine, a Sterling engine or a Rankine cycle. Alternatively, the heat engine is an internal combustion engine, for example an internal combustion engine. Alternatively, the burner of the external combustion engine comprises a thermo-photovoltaic cell. Steam turbines

[0054] A steam turbine converts thermal energy into mechanical energy and lower-temperature thermal energy. A burner provides thermal energy to the steam turbine. A heat turbine is preferably used. combined, using the heat released by said steam turbine to provide heat to one of the endothermic reactions. Several steam turbines can be used, sourcing their heat from the same burner but providing heat of different temperatures to different endothermic reaction reactors. The bodywork or various elements of the bodywork can be cooled by heat transfer fluids providing heat to endothermic chemical reaction reactors or to heat pumps allowing their temperature to be raised, making it possible to use said heat for at least one of said endothermic chemical reactions. For example, any turbine described in the book by Lucien Vivier entitled "Steam and Gas Turbines" published by Albin Michel can be used. Sterling Engine

[0055] The fuel can be burned in a burner supplying one or more Sterling engines cooled by at least one of the endothermic reactions. The Sterling engine can be for example Alpha, Beta or Gamma. Said Sterling engine can then supply mechanical work to an alternator or a dynamo producing electric current. Several Sterling engines can be used providing heat of different temperatures to different endothermic reaction reactors. The body or various elements of the body can be cooled by heat transfer fluids supplying heat to endothermic chemical reaction reactors or to heat pumps allowing the rise of their temperature allowing the use of said heat for at least one of said endothermic chemical reactions. Rankine cycle The heat released by the burner or by a gas turbine or by a Sterling engine can power an engine operating according to the Rankine cycle and cooled by at least one of the endothermic reactions to a temperature allowing the liquefaction of the gas used. An auxiliary heat pump can also be used to cool the gas used by the Rankine cycle to liquefy it and provide heat at a higher temperature to an endothermic reaction. For example, a heat pump can be used to cool steam used for a Rankine cycle at less than 100°C while supplying heat at 120°C to the reaction producing hydrogen iodide and acid. Alternatively, the operating pressure of the Rankine cycle in its liquid phase can be adjusted so that the gas liquefies there at a temperature close to the temperature of one of the endothermic reactions, for example 120°C. Gas turbines

[0056] The gas turbine is used to burn fuel and accelerate compressed gas heated by the combustion of said burned gas towards blades which are used to compress said compressed gas, and to provide mechanical work. The gas turbine can also be used to supply heat to a steam turbine, as described in the book by Lucien Vivier cited above. The heat of the gas leaving the gas turbine is preferably used to provide heat to at least one of the endothermic reactions which cools it, the gas then preferably being recycled to be supplied upstream of the compressor of said turbine. The compressed gas can be water vapor, in particular if the fuel is dihydrogen. Part of the gas can be taken in order to recycle it in the fuel generation cycle, in particular if it is dihydrogen.Several gas turbines can be used, providing heat of different temperatures to different endothermic reaction reactors. The body or various elements of the body can be cooled by heat transfer fluids providing heat to endothermic chemical reaction reactors or to heat pumps or to Sterling engines allowing the raising or lowering of their temperature to use said heat for at least one of said endothermic chemical reactions. For example, any gas turbine described in the book by Lucien Vivier entitled "Steam and Gas Turbines" published by Albin Michel can be used. Internal combustion engine

[0057] Fuel can be burned in an internal combustion engine. Said internal combustion engine can then supply mechanical work to an alternator or a dynamo producing electric current. The exhaust gases of the internal combustion engine preferably contribute to at least one of the endothermic reactions. The bodywork or various Bodywork elements can be cooled by heat transfer fluids supplying heat to endothermic chemical reaction reactors or to heat pumps allowing their temperature to be raised. Engine using thermo-photovoltaic cells

[0058] An engine comprising thermo-photovoltaic cells comprises a burner in which the combustion of the fuel releases infrared radiation, part of the energy of which is captured by thermo-photovoltaic cells to be converted into electrical energy, part is reflected and another part is absorbed by the base of the thermo-photovoltaic cell which is maintained at a given operating temperature. Burner with a thermo-photovoltaic cell

[0059] The burner is for example cylindrical supplied with fuel by a nozzle and with oxidant by another nozzle. The oxidant is for example air. Preferably and to limit the production of nitrogen oxides and simplify the recycling of gases from combustion, the oxidant is oxygen-enriched air, or better, oxygen, for example from chemical reactors or extracted from the air by the pressure swing absorption method which uses zeolites, as described in patent application FR2100229. The burner is however not necessarily cylindrical: it can be of other shapes, for example rectangular, comprising thermophotovoltaic cells on one or more of its faces.Or hyperbolic or parabolic, the flame being located at the focus of the hyperbola or parabola coated with an infrared-reflecting material and which concentrates the radiative flux towards the thermo-photovoltaic cell and / or the thermal connections with the chemical reactors. Thermal reflectors can be made of aluminum or stainless steel.

[0060] The burner is covered on at least part of its faces with thermo-photovoltaic cells. Thermal connectors are preferably located behind the thermo-photovoltaic cells and on the walls of the burner not covered with cells. thermo-photovoltaic cells to extract the heat produced in the burner not absorbed by the thermo-photovoltaic cells and not evacuated by the exhaust gases. The thermal connectors located behind the thermo-photovoltaic cells make it possible to maintain the temperature below a predetermined temperature, while evacuating the heat. Thermal connectors can be located on the walls of the burner not covered with thermo-photovoltaic cells to capture the heat, particularly at higher temperatures than those located behind the thermo-photovoltaic cells, said heat being able to be used to power a heat engine such as a steam turbine or a Sterling engine, provide heat to a heat pump or even directly supply heat to a chemical reactor where an endothermic reaction occurs.

[0061] The burner exhaust gases containing a significant portion of the combustion energy are directed to heat conductors connected to the thermochemical cycles regenerating the fuel in order to transmit their thermal energy and be cooled. Thermophotovoltaic cell

[0062] The thermo-photovoltaic cell is arranged to produce electricity from thermal radiation from the heat produced by the burner, for example a thermo-photovoltaic cell as described in the article: "Thermophotovoltaic efficiency of 40%" cited above, making it possible to convert 40% of the energy of a flame and being optimized for flame temperatures between 1900°C and 2400°C, or a cell optimized to produce electricity from heat at temperatures below 1300°C as described in the report entitled "World record demonstration of > 30% thermophotovoltaic conversion efficiency" from the 47th IEEE Photovoltaic Specialists Conference, PVSC 2020 in Calgary, Canada. Fuel

[0063] The fuel is preferably dihydrogen. Alternatively, the fuel is other, for example methanol, octane, heptane or a mixture thereof.

[0064] If the fuel is hydrogen, it can be regenerated, partly by a process of water dissociation. Heat pumps

[0065] The installation is advantageously coupled to a heat pump powered by electricity or mechanical work by the heat engine to raise the temperature of the heat extracted from outside the installation and allow it to be supplied to at least one of the endothermic reactions necessary for the production of the fuel.

[0066] In a preferred version of the invention, no external fuel is supplied to the installation, all the fuel being produced by the chemical reactions allowing the production of said fuel. The heat released by the heat engine preferably feeds as a priority the reactions requiring the highest temperatures while the one or a series of heat pumps feeds heat to the other reactions or provides additional heat energy to the reactions fed with heat by the burner.

[0067] The gas used by the heat pump(s) is, for example, mercury in gaseous state, water vapour or chlorine; these three gases have boiling and critical temperatures of 356°C, 1476°C, 100°C, 376°C, -35°C and 144°C respectively, thus making it possible to raise, using electricity to drive the compressors, a cold heat of, for example, 10°C up to 1400°C.

[0068] A high-temperature lubricant can be used to facilitate the sliding of the heat pump piston or some of its joints. For example, you can use high-temperature grease marketed by Jelt, which can be used at temperatures between -180°C and 2000°C.

[0069] According to the inventor's calculations, the share of electrical energy produced by the thermo-photovoltaic cell dedicated to powering the heat pumps is only 40% of the electrical energy produced by the thermo-photovoltaic cell, if it has an efficiency of 40% and 29% if the efficiency of the cell is 30%, using a Sulphur-Iodine cycle. Tanks

[0070] Tanks for storing the fuel produced within the installation are advantageously added to it when said installation includes a heat pump sourcing heat from outside the installation as described above.These tanks then make it possible to modulate the electrical power supplied by the installation, either by reducing the quantity of fuel supplied to the burner compared to a so-called normal regime, and therefore by storing the excess fuel produced by the chemical reactors, or by reducing the use of the heat pump by using the fuel stored in said tanks compared to said normal regime, thus making it possible to provide users of the installation with a greater proportion of the electricity supplied by the heat engine; the normal regime then referring to the operational regime in which the fuel is supplied to the burner with the same flow rate as its production, that is to say without being either stored in reserve or drawn from a reserve.

[0071] Heat pumps used to raise the temperatures of the heat transferred to chemical reactors are preferably reversible, allowing them to be transformed into a Sterling engine in order to adapt the installation to the quantity of fuel produced and possibly generate electricity with the heat sometimes intended for chemical reactors. The installation

[0072] The present invention also relates to an electricity production installation making it possible to implement the electricity production method described above.

[0073] The installation includes: - at least one thermal engine capable of burning fuel, - a heat pump, - a chemical reactor / chemical production unit thermally connected to the burner and the heat pump and allowing the chemical production of a fuel from the product of the reaction taking place in the burner, or from chemical compounds of the same composition as them contained in said reaction products of the burner, via at least one endothermic chemical reaction which takes place at a temperature lower than or equal to said operating temperature of the burner, and - means for introducing into said heat engine the fuel produced by the chemical reactor. Uses

[0074] The installation of the invention can produce both dihydrogen and dioxygen which can be used in other devices, while cooling the external environment in which it pumps heat.

[0075] The installation of the invention can operate with a reduced supply of dihydrogen and / or external oxygen, or even without external supply if a heat pump is used. It is therefore particularly ecological and proves to be economically advantageous.

[0076] The installation of the invention can be used to produce electric current or mechanical work, for example for industrial or domestic use, or combined with one or more electric motors to move vehicles. Figures

[0077] The present invention, its characteristics and the various advantages it provides will appear better on reading the following description, presented as an illustrative and non-limiting example, and which refers to the appended figures 1 to 5. The dynamos and alternators converting mechanical work into electricity, and conversely the electric motors driving the heat pumps are not shown in the figures.

[0078] [Fig. 1] describes an embodiment of the invention using any heat engine.

[0079] [Fig. 2] represents a schematic view of an embodiment of the invention using a gas turbine.

[0080] [Fig. 3] shows a detail of a heat engine using an internal combustion engine.

[0081] [Fig. 4] shows a detail of a heat engine using a steam turbine.

[0082] [Fig. 5] shows a detail of a heat engine using a thermo-photovoltaic cell.

[0083] [Fig. 6] shows a schematic view of a particular embodiment of the present invention comprising a Sterling engine.

[0084] We now refer to Figure 1.

[0085] Figure 1 describes an embodiment of the invention using any heat engine.

[0086] A heat engine 101 produces electricity 102, heat 103 and water 104 by consuming dihydrogen 105 and oxygen 106 coming respectively from a dihydrogen inlet 107 and a chemical reactor 110 operating at a temperature of 650°C, and from a dioxygen inlet 108 and a chemical reactor 109 operating at a temperature of 830°C. A portion of the electricity generated by the heat engine 101 is directed to the outside of the device 113 while another portion powers a group of heat pumps and Sterling motors 112 receiving heat 103 from the heat engine 101, from a group of heat exchangers 114 and from the exterior E to provide the reactors 109, 110 and 111 with heat at temperatures of 830°C, 650°C and 120°C respectively. Each of said reactors absorbs the heat thus supplied to it, these reactors being the site of endothermic chemical reactions.The group of heat exchangers 114 groups together heat exchangers making it possible to lower and raise the temperature of the gases and liquids exchanged between the three chemical reactors 109, 110, 111; said gases and liquids. passing through the heat exchanger group. The excess heat is supplied to the Sterling 112 heat pump and motor group.

[0087] Figure 2 shows a schematic view of an embodiment of the invention using a gas turbine. The gas turbine 201 receives dihydrogen 210 as combustion gas.

[0088] The gas turbine contains water vapor as a carrier gas, which is heated by the combustion of dihydrogen 210 with dioxygen 211, the combustion product of which joins said carrier gas. A large portion of the water vapor is recycled by a recycling circuit 202 to be used again as carrier gas.

[0089] A portion 203 of the water from the gas turbine 201 is taken and added in an equimolar mixture to sulfur dioxide 204, this mixture being led to a reactor 205 operating at 120°C.

[0090] In this reactor 205 an endothermic chemical reaction takes place producing hydrogen iodide and sulfuric acid, which are extracted separately from the reactor 205 by a separator SI to be conducted respectively into a reactor 207 operating at 650°C, and into a reactor 208 operating at 830°C.

[0091] From reactor 207 operating at 650°C, diiodine 209 is extracted and separated by a separator S2 and led to reactor 205 operating at 120°C, and dihydrogen 210 is led to gas turbine 201 to be burned there.

[0092] From reactor 208 operating at 830°C are extracted and separated by a separator S3 dioxygen 211 conducted to the gas turbine 201, and the mixture of sulfur dioxide and water 204 conducted to reactor 205 operating at 120°C.

[0093] Heat exchangers, not shown, adjust the temperatures of the chemical compounds exchanged between the three chemical reactors 205, 207, 208 and the three separators S1, S2, S3 of products from these chemical reactors.

[0094] The temperatures of the dihydrogen 210 and dioxygen 211 are preferably unadjusted, these being intended to be burned in the gas turbine 201.

[0095] A first heat pump PI extracts heat from the outside E, for example at 20°C to conduct it at 120°C to reactor 205 operating at 120°C, and to a second heat pump P2 which conducts heat to reactor 207 operating at 650°C and to a third heat pump P3 which in turn conducts heat to reactor 208 operating at 830°C.

[0096] Excess heat from the heat exchanger system is preferably supplied to one of the chemical reactors, preferably to reactor 207 operating at 650°C.

[0097] Excess heat from the heat exchanger system is also advantageously supplied to the third heat pump P3.

[0098] The mechanical work provided by the gas turbine 201 can be used to supply energy to the heat pumps PI, P2, P3, the excess being supplied to the user of the installation.

[0099] An alternator can advantageously convert the work provided by the gas turbine 201 not supplied to the heat pumps into electricity. Alternatively, all the mechanical work produced by the turbine is converted into electricity which can then be at least partly used to supply energy to the heat pumps PI to P3.

[0100] According to the inventor's calculations, by using a gas turbine 201 with an efficiency of 50% and heat pumps operating with coefficients of performance (COP) equal to 85% of the maximum theoretical heat pump coefficient of performance, i.e. corresponding to the Carnot cycle coefficient of performance, the system can operate autonomously, collecting only external heat and supplying the outside with electricity 29% of the chemical energy generated by the system consisting of the three chemical reactors 205, 207, 208 and the separators S1, S2, S3.

[0101] This also represents 59% of the mechanical work provided by the 201 gas turbine.

[0102] The gas turbine 201 has two cooling circuits, one at 830°C supplying heat to the reactor 208 operating at 830°C and the other at 650°C supplying heat to the reactor 207 operating at 650°C as well as the third heat pump P3.

[0103] Alternatively, no external heat is supplied by the installation, but dihydrogen and dioxygen are supplied, in addition to those supplied by the system comprising the three chemical reactors 205, 207, 208 and the separators SI, S2, S3.

[0104] The first heat pump PI is then no longer required, and the operation of the heat pump P2 is reversed to operate as a Sterling engine providing heat at a temperature of 120°C, from the heat supplied at 650°C by the 650°C cooling system of the gas turbine 201, and from electricity.

[0105] According to the inventor's calculations, the proportion of regenerated fuel in the fuel consumed by the gas turbine is then 53% and the proportion of conversion into mechanical or electrical energy of the energy contained in the dihydrogen is close to 100%.

[0106] The gas turbine 201 may include, instead of or in addition to its 650°C cooling system, one or more cooling systems at other temperatures, for example 400°C or 200°C. Additional heat pumps are then installed to raise the temperature of the heat extracted from the gas turbine to 650°C.

[0107] The heat engine can also be an internal combustion engine 301 (see figure 3), for example cooled to 150°C and whose exhaust gases 302 are used to supply heat to the chemical reactors 110, 109 operating at 650°C and 830°C, the combustion product at 120°C being directly supplied to the reactor 111 operating at 120°C.

[0108] The exhaust gases 302 resulting from the combustion of the fuel are then cooled according to figure 3: they successively heat the reactors 109, 110, 111 operating at 830°C, 650°C and 120°C, passing through exchangers E7, E8.

[0109] The heat 304 emitted by the combustion engine 301 can also be used to heat the chemical reactors, and the mechanical work 306 provided by the engine can be partly recovered by the user of the installation.

[0110] According to the inventor's calculations, using a 301 internal combustion engine with an efficiency of 25%, 35% of the combustion energy is released by the exhaust gases and the rest by cooling the engine to 150°C.

[0111] 6% of the combustion energy is exportable by the installation, pumping the heat outside at 20°C and requiring no fuel.

[0112] If the engine is cooled to 450°C, this efficiency is 14%.

[0113] The heat engine may also include a burner 401a and a steam turbine 401b (see figure 4).

[0114] The exhaust gases 402 resulting from the combustion are then cooled according to figure 4: they successively heat the reactors 109, 110, 111 operating at 830°C, 650°C and 120°C by passing through exchangers E7, E8.

[0115] The heat 404a generated by the burner 401a operates the steam turbine 401b, which emits heat 404b, 404c at 120°C and 650°C respectively, contributing to the heating of the reactors 111 and 110 operating at these temperatures.

[0116] The mechanical work 406 provided by the steam turbine 401b can be partly recovered by the user of the installation.

[0117] The heat engine may also include a burner 501a and at least one thermo-photovoltaic cell 501b (see figure 5).

[0118] The heat engine also includes three heat pumps 507, 508, 509 which may be part of the heat pump group 112 and two cooling mechanisms 511, 515 of the heat from the base of the thermo-photovoltaic cell 501b to 120°C and 650°C respectively: It may require a supply of mechanical work.

[0119] The burner 501a produces heat 510 and 514, exhaust gases 502 and infrared radiation partly absorbed by the thermo-photovoltaic cell 501b which produces electricity 513, and the base of which is cooled, for example to 60°C, producing a heat flow 514.

[0120] The exhaust gases are cooled by a heat transfer liquid in a first heat exchanger E8 at 830°C then in a second heat exchanger E7 at 650°C before being introduced in the form of water vapor at 505 into the chemical reactor 111 operating at 120°C.

[0121] The burner body is cooled to 830°C and its heat 510 is removed to the chemical reactor 109 operating at 830°C.

[0122] The heat 514 from the base of the thermo-photovoltaic cell 501b is evacuated by the first heat pump 507 which provides heat at 120°C to direct part of the heat thus created towards the chemical reactor 111 operating at 120°C, while the excess heat has its temperature increased by the second heat pump 508 up to 650°C, making it possible to supply heat on the one hand to the reactor 110 operating at 650°C and on the other hand to the third heat pump 509 producing heat at 830°C making it possible to supply heat to the reactor 109 operating at 830°C.

[0123] In an alternative version, the base of the thermo-photovoltaic cell 501b is cooled to a heat between 120°C and 650°C, for example 600°C.

[0124] In this case, the first heat pump 507 is then unnecessary. In addition, the heat from the heat exchanger at 600°C is directed to the reactor operating at 120°C using a Sterling engine which generates electricity.

[0125] In an alternative version, the base of the thermo-photovoltaic cell is cooled to a heat between 650°C and 830°C, for example 750°C.

[0126] Heat pumps 507, 508 raising the temperature of the base of the thermo-photovoltaic cell to 120°C and then from 120°C to 650°C are then useless.

[0127] Figure 6 indicates a variant in which the water vapor resulting from the combustion which takes place in the heat engine 601 (which may be in accordance with any of the heat engines described above), passes successively into a first exchanger E1 making it possible to lower the temperature to 650°C, the excess heat making it possible to operate a first Sterling STI engine in order to generate mechanical work which can be recovered by the user, then into a second exchanger E2 making it possible to lower the temperature to 120°C, the excess heat making it possible to operate a second Sterling ST2 engine in order to generate mechanical work which can be recovered by the user.

Claims

CLAIMS 1. Method for producing electricity using at least one heat engine (201; 301a, 301b; 401a, 401b; 501) capable of producing electricity, in which at least part of the fuel of the heat engine is produced by a thermal dissociation method which is applied to a product resulting from the combustion of said fuel, and at least part of the heat released by the heat engine is used to implement at least one endothermic reaction of said thermal dissociation method.

2. A method according to claim 1, wherein dihydrogen is used as fuel, and the following series of iodine-sulfur cycle reactions are applied to the water resulting from the combustion of the dihydrogen to dissociate the water: l2+ SO2+ 2 H2O -> 2 HI +H2SO4 3. A method according to claim 1, wherein dihydrogen is used as fuel, and the following series of bromine-sulfur cycle reactions are applied to the water resulting from the combustion of the dihydrogen to dissociate the water: Br2+ SO2+ 2 H2O 2 HBr +H2SO4 H2SO4— SO2+ H2O + 1 / 2O2 2HBr^ Br2+ H2 4. Method according to any one of the preceding claims, in which at least one heat engine (201; 301a, 301b; 401a, 401b; 501) is used, chosen from the group comprising internal combustion engines (201), external combustion engines, Sterling engines, Rankine cycle engines, steam turbines (301a, 301b), gas turbines, thermo-photovoltaic cells (401b) and combinations thereof.

5. Method according to any one of the preceding claims, in which heat produced by at least one heat pump (PI, P2, P3; 407, 408, 409) is used to supplement the heat inputs required for said thermal dissociation process.

6. Method according to any one of the preceding claims, in which all of the fuel of the heat engine is produced by said thermal dissociation process.

7. Installation for implementing a method according to any one of the preceding claims, comprising: a heat engine (201; 301a, 301b; 401a, 401b; 501) powered by said fuel; a production unit (S1, S2, S3) of at least a portion of said fuel by thermal dissociation of said product; means for thermally connecting said engine to said production unit.

8. Installation according to claim 7 for implementing a method according to claim 4, in which said heat engine (201; 301a, 301b; 401a, 401b; 501) is selected from the group comprising internal combustion engines (201), external combustion engines, Sterling engines, Rankine cycle engines, steam turbines (301a, 301b), gas turbines, thermo-photovoltaic cells (401b) and combinations thereof.

9. Installation according to one of claims 7 or 8 for implementing a method according to one of claims 2 or 3, comprising at least: a main compartment / main reactor allowing the production of dihydrogen from iodide / hydrogen bromide, a first secondary compartment / first secondary reactor allowing the reaction between two sulfuric acid molecules to produce in particular dioxygen, and a second secondary compartment / second secondary reactor allowing the reaction between diiodine / dibromine, sulfur oxide and water to produce sulfuric acid and hydrogen iodide / bromide.

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