Thermal power generation method

Abstract

To provide a thermal power generation method that can decrease the amount of carbon dioxide discharged therefrom, without requiring forcible injection of carbon dioxide present in exhaust of a thermal power station into the ground.SOLUTION: The thermal power generation method utilizing the combustion of an organic fuel and an inorganic fuel according to the present invention, with the inorganic fuel being an inorganic matter that can be combusted using oxidized carbon gas as combustion supporting gas, a hydrogenated inorganic matter with at least a portion thereof being hydrogenated, or a mixture of an inorganic matter and a hydrogenated inorganic matter, is characterized in that the inorganic fuel is combusted using oxidized carbon gas present in exhaust gas generated by the combustion of the organic fuel, as combustion supporting gas, and the carbon present in the oxidized carbon gas is solidified.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermal power generation method. [Background technology]

[0002] BACKGROUND ART Thermal power generation systems equipped with power generation boilers are generally known (see, for example, Non-Patent Document 1). However, thermal power generation systems that use so-called fossil fuels have the problem of emitting carbon dioxide, which is believed to be a cause of global warming.

[0003] Therefore, efforts are being made to reduce the atmospheric release of carbon dioxide even in thermal power generation systems that use fossil fuels.

[0004] For example, Non-Patent Document 2 introduces the CCS efforts being undertaken in Tomakomai City, Hokkaido, and specifically explains that carbon dioxide is separated and captured from the exhaust gases of thermal power plants, and that the captured carbon dioxide is then injected and stored deep underground beneath the seabed, approximately 3 to 4 km from the coast.

[0005] It is believed that carbon dioxide injected deep underground in this way will be stored stably for a long period of time, and will dissolve into salt water over a long period of time and become minerals in the gaps between rocks.

[0006] However, there are many constraints to achieving this type of storage, such as the need for a geological layer with gaps that allow carbon dioxide to be stored, and for the layer to be covered with a layer that does not allow carbon dioxide to pass through. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] “Promoting Regional Environmental Conservation: The Structure of Coal-Fired Power Plants and Various Environmental Conservation Measures,” [online], Okinawa Electric Power Co., Inc., [Retrieved June 30, 2022], Internet<URL:https: / / www.okiden.co.jp / environment / report2017 / sec6 / sec63.html> [Non-patent document 2] “CCS: CO2 Capture and Burial, Demonstration Tests Now Close to Realization (Part 1),” [online], November 27, 2020, Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry, [Retrieved June 16, 2022], Internet<URL:https: / / www.enecho.meti.go.jp / about / special / johoteikyo / ccs_tomakomai.html> Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a thermal power generation method that reduces carbon dioxide emissions and does not require the treatment of injecting carbon dioxide contained in exhaust gas from a thermal power plant underground. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention is realized by the following configuration. (1) The thermal power generation method of the present invention is a thermal power generation method that utilizes the combustion of an organic fuel and the combustion of an inorganic fuel, wherein the inorganic fuel is an inorganic substance that can be burned using carbon oxide gas as a combustion supporting gas, a hydrogenated inorganic substance in which at least a portion of the inorganic substance is hydrogenated, or a mixture of the inorganic substance and the hydrogenated inorganic substance, and the inorganic fuel is burned using carbon oxide gas in the exhaust gas generated by the combustion of the organic fuel as a combustion supporting gas, and the carbon in the carbon oxide gas is solidified.

[0010] (2) In the above configuration (1), the inorganic substance is lithium, magnesium, aluminum, or a mixture containing two or more of lithium, magnesium, and aluminum.

[0011] (3) In the above configuration (2), the inorganic substance is magnesium.

[0012] (4) In the configuration of (3) above, the organic fuel is a fossil fuel other than liquefied natural gas, the carbon dioxide gas used as the combustion supporting gas for the combustion of the inorganic fuel is carbon dioxide gas, and the carbon dioxide gas is recovered from the exhaust gas after passing through a denitration device, a dust collection device, and a desulfurization device through a carbon dioxide gas separation and recovery device.

[0013] (5) In the configuration of (3) above, the organic fuel is liquefied natural gas, the carbon dioxide gas used as the combustion supporting gas for burning the inorganic fuel is carbon dioxide gas, and the carbon dioxide gas is carbon dioxide gas recovered from the exhaust gas through a carbon dioxide gas separation and recovery device.

[0014] (6) In the configuration of (3) above, the solidified carbon is recovered as combustion ash together with oxides of the inorganic fuel generated by the combustion of the inorganic fuel, and the solidified carbon is separated from the combustion ash and used as a raw material for a carbon material.

[0015] (7) In the above configuration (6), the inorganic fuel is produced again using the oxide as a material and used in thermal power generation. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a thermal power generation method that does not require the treatment of injecting carbon dioxide contained in the exhaust gas from a thermal power plant underground, thereby reducing the amount of carbon dioxide emitted. [Brief explanation of the drawings]

[0017] [Figure 1]1 is a diagram for explaining a thermal power plant in which a thermal power generation method according to a first embodiment of the present invention is implemented. [Figure 2] FIG. 2 is a diagram for explaining a thermal power plant in which a thermal power generation method according to a second embodiment of the present invention is implemented. [Figure 3] FIG. 10 is a diagram for explaining a thermal power plant in which a thermal power generation method according to a fourth embodiment of the present invention is implemented. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. It should be noted that the same elements are denoted by the same reference numerals throughout the description of the embodiments.

[0019] (First embodiment) The thermal power generation method of the first embodiment according to the present invention is carried out in a thermal power plant, but since many of its components are similar to those of current thermal power plants, a description of the similarities may be omitted.

[0020] FIG. 1 is a diagram for explaining a thermal power plant in which the thermal power generation method of this embodiment is implemented. The thermal power plant includes a generator 1, a power generation boiler 2 that drives the generator 1, an organic fuel storage facility 3 that stores organic fuel to be supplied to the power generation boiler 2, and an inorganic fuel storage facility 4 that stores inorganic fuel to be supplied to the power generation boiler 2.

[0021] The power generation boiler 2 comprises a combustion chamber 21, a steam turbine 22 whose rotating shaft is connected to the generator 1 and is driven by steam produced in the combustion chamber 21, and piping 23 for supplying the steam to the steam turbine 22 and for supplying water that has been returned to a liquid state in a condenser (not shown) back to the combustion chamber 21.

[0022] The combustion chamber 21 comprises a first combustion chamber A which receives organic fuel from the organic fuel storage 3 and burns the organic fuel, and a second combustion chamber B which receives inorganic fuel from the inorganic fuel storage 4 and burns the inorganic fuel.

[0023] The power generation boiler 2 of this embodiment is a commonly known stoker-type boiler, and differs mainly in that its combustion chamber 21 is separated by a wall as shown by the dotted line into a first combustion chamber A and a second combustion chamber B.

[0024] The fuel supply mechanism that supplies fuel to the first combustion chamber A and the second combustion chamber B may be similar to that provided in a stoker-type boiler, and although not shown in the figure, in this embodiment, such a fuel supply mechanism is provided in the first combustion chamber A and the second combustion chamber B, respectively.

[0025] That is, a fuel supply mechanism for supplying organic fuel from the organic fuel storage 3 to the first combustion chamber A, and a fuel supply mechanism for supplying inorganic fuel from the inorganic fuel storage 4 to the second combustion chamber B are provided.

[0026] The piping 23 passes through the first combustion chamber A and the second combustion chamber B, and the heat of combustion of the organic fuel in the first combustion chamber A and the heat of combustion of the inorganic fuel in the second combustion chamber B are used to generate steam that drives the steam turbine 22.

[0027] Air is supplied to the first combustion chamber A, and the organic fuel is combusted with the oxygen in the air. For example, coal can be suitably used as an organic fuel, and carbon dioxide gas (CO2) is generated as a carbon oxide gas when burned. In addition, since air also contains nitrogen gas, nitrogen oxides (NOx) are also produced, and if the organic fuel is coal, sulfur components are also contained, so sulfur dioxide gas is also produced.

[0028] This exhaust gas containing carbon dioxide gas, nitrogen oxides (NOx), sulfur dioxide gas, etc. is sent from the first combustion chamber A through an exhaust pipe (not shown) as indicated by the solid arrow to a denitrification device 5, where the nitrogen oxides (NOx) are rendered harmless. The denitration device 5 may be the same as that generally used in coal-fired power plants.

[0029] Then, the exhaust gas that has passed through the denitration device 5 is sent to the dust collector 6 through an exhaust pipe (not shown) as indicated by the solid arrow, where soot and the like contained in the exhaust gas are removed. The dust collector 6 may be the same as that generally used in coal-fired power plants.

[0030] Furthermore, the exhaust gas that has passed through the dust collector 6 is sent to a desulfurization device 7 through an exhaust pipe (not shown), as indicated by the solid arrow, where sulfur dioxide gas contained in the exhaust gas is removed. The desulfurization device 7 may be the same as that generally used in coal-fired power plants.

[0031] Then, the exhaust gas that has passed through the desulfurization device 7 is sent through an exhaust pipe (not shown) to a separation and recovery device 8 that separates and recovers carbon dioxide gas, as indicated by the solid arrow, and the carbon dioxide gas contained in the exhaust gas is recovered.

[0032] The carbon dioxide gas thus recovered by the separation and recovery device 8 is supplied to a storage tank 81 that stores carbon dioxide gas through a gas pipe (not shown), as indicated by the dotted arrow. A booster (not shown) is provided at the inlet of the storage tank 81 so that carbon dioxide gas is supplied to the storage tank 81 in a pressurized state, and some of the carbon dioxide gas is stored in a liquefied state inside the storage tank 81.

[0033] On the other hand, the exhaust gas from which carbon dioxide gas has been removed in the separation and recovery device 8 is sent to an exhaust fan 9 through an exhaust pipe (not shown) as indicated by the solid arrow, and then released into the atmosphere. The exhaust fan 9 also has a configuration that is generally provided in coal-fired power plants, and may be similar to that.

[0034] The storage tank 81 is connected to the second combustion chamber B through a gas pipe (not shown), as indicated by the dashed arrow, so that the carbon dioxide gas stored in the storage tank 81 can be supplied to the second combustion chamber B.

[0035] Specifically, carbon dioxide gas is supplied from the storage tank 81 so that the pressure inside the second combustion chamber B becomes slightly positive according to the output of a pressure measuring instrument (not shown) connected to the second combustion chamber B. For this pressure control, a flow control valve for controlling the flow rate of carbon dioxide gas is provided midway in the gas piping (not shown) from the storage tank 81 to the second combustion chamber B.

[0036] The second combustion chamber B is supplied with inorganic fuel that can be burned using carbon dioxide gas, specifically carbon dioxide gas, as a combustion supporting gas from the inorganic fuel storage tank 4, and combustion occurs using the supplied carbon dioxide gas as a combustion supporting gas.

[0037] Specifically, the inorganic fuel is an inorganic substance that can be burned using carbon oxide gas such as carbon dioxide gas (CO2) or carbon monoxide gas (CO) as a combustion supporting gas, a hydrogenated inorganic substance in which at least a portion of the inorganic substance is hydrogenated, or a mixture of an inorganic substance and a hydrogenated inorganic substance, and the inorganic substance is lithium (Li), magnesium (Mg), aluminum (Al), or a mixture containing two or more of lithium, magnesium, and aluminum.

[0038] When non-hydrogenated inorganic materials are used as inorganic fuel, they become flammable when in a fine powder form, and must therefore be treated as hazardous materials.

[0039] For this reason, when using a non-hydrogenated inorganic material as the inorganic fuel, it is desirable that the inorganic material have a particle size that does not fall under the category of a hazardous material.

[0040] For example, in the case of magnesium, if the particle size is 400 μm or more, it will not be classified as a hazardous material.

[0041] On the other hand, magnesium is a good inorganic material to be used for the inorganic fuel from the viewpoint of good combustibility in the second combustion chamber B, and when the inorganic fuel is magnesium, the combustion reaction shown in the following formula (1) occurs. 2Mg + CO2→ 2MgO + C + heat (1)

[0042] In the combustion reaction shown in equation (1), when solid magnesium (Mg) and carbon dioxide gas (CO2) undergo a combustion reaction, the inorganic fuel magnesium oxide, i.e., magnesium oxide (MgO), and solid carbon (C) are produced, and since the gas components are eliminated, a decompression reaction occurs, resulting in a decrease in the gas concentration. If the second combustion chamber B contains moisture, a small amount of magnesium hydroxide may be formed in addition to the oxide of magnesium, which is an inorganic fuel.

[0043] If the gas concentration becomes low and there is a shortage of combustion support gas, the combustion reaction cannot be sustained. Therefore, as explained above, carbon dioxide gas is supplied to the second combustion chamber B while measuring the pressure to maintain a positive pressure.

[0044] As mentioned above, the combustion reaction in the second combustion chamber B is a reduced pressure reaction, and a positive pressure environment is maintained by supplying carbon dioxide gas in excess of the amount required for the reaction. Therefore, it is preferable that the inner diameter of the exhaust pipe (not shown) that exhausts the exhaust gas from the second combustion chamber B be relatively small.

[0045] For example, by restricting the inner diameter to about 100 to 300 mmφ, it becomes easier to control the positive pressure inside the second combustion chamber B.

[0046] However, since the specific inner diameter of the exhaust pipe (not shown) needs to be matched to the internal volume of the second combustion chamber B, an inner diameter of 100 to 300 mmφ is not necessarily optimal.

[0047] For example, in clean rooms, the pressure is maintained at a positive level of 5 Pa or more to prevent outside air from entering the room. If the pressure is maintained at a positive level of 5 Pa or more, it is possible to prevent exhaust gas from flowing back into the second combustion chamber B through the exhaust pipe (not shown). Therefore, it is advisable to maintain the pressure at 5 Pa or more, which is more positive than atmospheric pressure.

[0048] The second combustion chamber B is provided with an exhaust pipe (not shown) connected to an exhaust pipe (not shown) that runs from the first combustion chamber A to the denitration device 5, as shown by the solid arrow, so that exhaust is taken out to prevent the internal pressure from becoming too high.

[0049] However, even if there is a slight negative pressure, it does not lead to a shortage of combustion supporting gas, so for example, the exhaust pressure immediately after leaving the first combustion chamber A (the exhaust pipe (not shown) near the first combustion chamber A before the exhaust pipe (not shown) from the second combustion chamber B joins) can be measured, and the pressure in the second combustion chamber B can be kept slightly higher than the measured pressure (for example, a pressure higher by 5 Pa or more). Even in this case, the pressure is controlled to be higher than that of the main exhaust, so that backflow of exhaust into the second combustion chamber B can be suppressed.

[0050] The carbon dioxide gas thus discharged from the second combustion chamber B reaches the separation and recovery device 8 in the flow explained above, and is stored in the storage tank 81 again.

[0051] As can be seen from the above explanation, the thermal power generation method of this embodiment is a thermal power generation method that utilizes the combustion of organic fuel and the combustion of inorganic fuel, in which inorganic fuel is burned using carbon oxide gases such as carbon dioxide gas in the exhaust gas generated by the combustion of the organic fuel as a combustion supporting gas, and as a result of this combustion reaction, the carbon in the carbon oxide gases is solidified, thereby suppressing the emission of carbon oxide gases such as carbon dioxide gas, which have an impact on global warming.

[0052] On the other hand, not only in stoker-type boilers, but also in other combustion chambers, combustion ash and the like accumulates, so a recovery mechanism is provided to recover the combustion ash. Although not shown in the figure, in this embodiment, combustion ash recovery mechanisms of a similar configuration are provided in the first combustion chamber A and the second combustion chamber B, and the combustion ash recovered from the first combustion chamber A is stored in the first combustion ash storage section, and the combustion ash recovered from the second combustion chamber B is stored in the second combustion ash storage section.

[0053] The soot and the like collected by the dust collector 6 may be sent to a first combustion ash storage section that stores the combustion ash collected from the first combustion chamber A.

[0054] The combustion ash stored in the first combustion ash storage area is almost the same as the combustion ash produced by general coal-fired power plants, so it can be used as an admixture for concrete, etc.

[0055] On the other hand, the combustion ash stored in the second combustion ash storage section, i.e., the combustion ash obtained by recovering solidified carbon together with oxides of inorganic fuel, consists of magnesium oxide and carbon in this embodiment and contains almost no other impurities.

[0056] Therefore, the carbon obtained by separating the solidified carbon from the combustion ash can be used as a raw material for carbon materials that require high purity.

[0057] Specifically, when combustion ash consisting of magnesium oxide and carbon is placed in a hydrochloric acid solution, the magnesium oxide reacts with the hydrochloric acid to become magnesium chloride, which dissolves in the solution, while the carbon does not react with hydrochloric acid and therefore does not dissolve in the solution and remains solid. Like magnesium oxide, magnesium hydroxide becomes magnesium chloride and dissolves in aqueous solution.

[0058] Therefore, by filtering this aqueous solution through a filter, the carbon powder can be recovered. In order to obtain a high purity, the recovered carbon powder is preferably washed with pure water or the like.

[0059] On the other hand, magnesium chloride is dissolved in the filtrate, so if this magnesium chloride is recovered and subjected to molten salt electrolysis, magnesium can be produced.

[0060] Specifically, when the water in the collected filtrate is evaporated, magnesium chloride hexahydrate precipitates as crystals, which are then collected.

[0061] Then, in order to remove moisture from the crystals, the magnesium chloride hexahydrate is heated to a temperature of about 300°C to 600°C while hydrogen chloride gas is blown over it. In addition, the temperature is preferably set to 400°C to 550°C in terms of the reaction rate of the dehydration reaction and suppression of the production of magnesium oxide.

[0062] If you simply heat magnesium chloride hydrate to remove the water, it turns into magnesium oxide.

[0063] However, if heating is carried out while hydrogen chloride gas is blown over the material, the reaction leading to magnesium oxide is inhibited, and the dehydration reaction proceeds, resulting in anhydrous magnesium chloride.

[0064] The anhydrous magnesium chloride produced in this way can be heated to around 700°C, molten, and electrolyzed to produce magnesium.

[0065] Therefore, it is possible to use magnesium oxide, which is an oxide of inorganic fuel in the combustion ash, as a material to produce magnesium, which can be used as inorganic fuel again, and if the produced inorganic fuel is used in the thermal power generation described above, it becomes a resource-circulating thermal power generation method.

[0066] In terms of resource recycling, it is preferable that the oxides of inorganic fuel contained in the combustion ash are of a single type, since this saves the effort of separation.

[0067] Therefore, it is preferable that the inorganic fuel consists of only one inorganic substance, or is a mixture of inorganic hydrides.

[0068] For example, if the inorganic substance is magnesium, it is better to use magnesium hydride as the inorganic hydride to be mixed.

[0069] On the other hand, the molten salt electrolysis method described above uses only electricity as energy, and therefore can be carried out using the electricity of wind turbines and the like that cannot be connected to a grid, and can suppress the generation of carbon dioxide gases, which have an impact on global warming, including the overall resource circulation.

[0070] In the above, coal has been used as an example of an organic fuel, but similarly, any fuel that can be burned in a stoker-type boiler and generates carbon oxide gas (carbon monoxide gas, carbon dioxide gas, etc.) that acts as a combustion-supporting gas for inorganic fuels during combustion can be used.

[0071] Therefore, for example, wood chips may be used as organic fuel, and since wood chips are made from wood that is renewable in nature, they are positioned as a carbon-neutral, sustainable fuel.

[0072] Therefore, when wood chips are used as organic fuel, the carbon dioxide gas (carbon dioxide gas, etc.) generated by its combustion is decomposed by the combustion of inorganic fuel, resulting in a thermal power generation method that does not emit carbon dioxide gas, making this a carbon-negative power generation method.

[0073] (Second embodiment) FIG. 2 is a diagram for explaining a thermal power plant in which a thermal power generation method according to a second embodiment of the present invention is implemented. The thermal power plant of this embodiment is also substantially similar to the thermal power plant of the first embodiment, and therefore, a description of the same parts may be omitted.

[0074] The thermal power generation method of this embodiment is different in that it uses a hydrogenated inorganic substance in which at least a part of an inorganic fuel is hydrogenated. For example, as a specific example, there is low-purity magnesium hydride having a magnesium hydride layer in which at least the surface is hydrogenated.

[0075] In this case, the combustion reaction in the second combustion chamber B includes, in addition to the combustion reaction of magnesium (see formula (1)) in which the combustion-supporting gas described in the first embodiment is carbon dioxide gas (carbon dioxide gas), the combustion reaction of the magnesium hydride part is added.

[0076] And the combustion reaction of magnesium hydride (MgH2) starts from the reaction shown in the following formula (2) in which magnesium hydride is decomposed into magnesium and hydrogen gas (H2) by heat, and the magnesium generated thereby causes the combustion reaction shown in formula (1) first. MgH2 - heat → Mg + H2 ················ (2)

[0077] In this case, the hydrogen gas generated by the decomposition of magnesium hydride is not consumed in the second combustion chamber B, but is discharged outside the second combustion chamber B together with the exhaust gas discharged from the second combustion chamber B.

[0078] Therefore, in this embodiment, as shown by the solid-line arrow, the exhaust gas is first supplied to a hydrogen recovery device H that recovers hydrogen gas through an exhaust pipe (not shown), and the hydrogen gas is recovered there.

[0079] Then, the recovered hydrogen gas is supplied to a fuel cell F through a gas pipe (not shown) as shown by the two-dot chain line arrow, and power generation is performed.

[0080] Note that the recovered hydrogen gas may be once stored in a hydrogen gas tank that stores hydrogen gas and then sent from the hydrogen gas tank to the fuel cell F.

[0081] For example, the electric power generated by this fuel cell F is used as the electric power required for the operation of a thermal power plant that implements this thermal power generation method. Therefore, all of the power generated by the generator 1 can be used for power transmission.

[0082] Although the above description has been given in the case where the inorganic fuel is at least partially hydrogenated magnesium, the same applies when a mixture of magnesium and at least partially hydrogenated magnesium, that is, a mixture of an inorganic material and a hydrogenated inorganic material, is used as the inorganic fuel.

[0083] (Third embodiment) In the first and second embodiments, the case of a stoker-type boiler has been described, but the present invention may also be applied to a thermal power generation method using a power generation boiler in the form of a pulverized coal combustion boiler, for example.

[0084] In this case, the first combustion chamber A may be provided with a general pulverized coal burner for burning pulverized coal.

[0085] In addition, the second combustion chamber B may have a stoker-type structure, but it is also possible to provide a powder combustion burner with a structure similar to that of a pulverized coal burner, and use inorganic fuel that has been pulverized into a powder suitable for combustion in the powder combustion burner.

[0086] In this case, combustible inorganic materials tend to become flammable as they are further pulverized, so it is preferable to use hydrogenated inorganic materials having at least a hydrogenated layer on the surface.

[0087] In this way, the hydrogenated film suppresses the reaction between the inorganic substance and oxygen in the atmosphere and also protects it from ignition.

[0088] Since this hydrogenated film is for protection purposes, it does not need to be a highly pure inorganic hydrogenated material, but rather a low purity inorganic hydrogenated material of 30 mass % or less will suffice.

[0089] In this way, by limiting the hydrogenation rate to a low-purity hydrogenated inorganic material, the hydrogenation treatment time for treating the inorganic material in a hydrogen atmosphere can be significantly reduced, and production efficiency can be improved.

[0090] On the other hand, instead of the pulverized coal burner, the burner provided in the first combustion chamber A may be a burner for burning liquid fuel, and the organic fuel may be a petroleum-based liquid fuel (for example, heavy oil, light oil, etc.).

[0091] In this way, even if the organic fuel is a petroleum-based liquid fuel, it contains sulfur components and also generates soot, so the treatment of the exhaust gas discharged from the first combustion chamber A can be done in the same way as in the first embodiment.

[0092] That is, the carbon dioxide gas may be recovered by a separation and recovery device that recovers the carbon dioxide gas from the exhaust gas that has passed through a denitration device, a dust collector, and a desulfurization device.

[0093] (Fourth embodiment) The organic fuel is not limited to those described above (that is, fossil fuels other than liquefied natural gas), but may also be liquefied natural gas.

[0094] In this case, a gas combustion burner may be provided in the first combustion chamber A, but in the case of thermal power generation that burns gas, it is better to use a gas turbine in consideration of power generation efficiency and the like.

[0095] Therefore, as a fourth embodiment, a case where the organic fuel is liquefied natural gas and a gas turbine is used will be described.

[0096] Furthermore, liquefied natural gas is produced through a process of refining natural gas obtained from oil and gas fields, and does not contain any sulfur components, so no sulfur dioxide gas is produced, and neither is sulfur dioxide gas produced when inorganic fuels are burned.

[0097] Therefore, when a gas combustion burner for burning liquefied natural gas is provided in the first combustion chamber A mentioned above, the desulfurization device described above may be omitted.

[0098] FIG. 3 is a diagram for explaining a thermal power plant in which the thermal power generation method of this embodiment is implemented. The thermal power plant in which the thermal power generation method of this embodiment is implemented is similar in many respects to the thermal power plant described with reference to Figure 1, and therefore, a description of the similar points may be omitted.

[0099] As shown in FIG. 3, in this embodiment, a gas turbine G that is powered by the combustion of liquefied natural gas is added to drive the generator 1.

[0100] The liquefied natural gas, which is the organic fuel in this embodiment, is sent to the gas turbine G, rather than being sent from the organic fuel storage 3 to the combustion chamber 21 of the power generation boiler 2, in order to be burned in the gas turbine G.

[0101] The organic fuel storage 3 is a tank for storing liquefied gas, since it stores liquefied natural gas.

[0102] The exhaust gas containing carbon dioxide gas remaining after the liquefied natural gas is burned in the gas turbine G is sent through an exhaust pipe (not shown) to a denitration device 5 as shown by the solid arrow, and then to a dust collector 6, where the carbon dioxide gas is recovered in a separation and recovery device 8 that separates and recovers the carbon dioxide gas, and then released into the atmosphere via an exhaust fan 9.

[0103] On the other hand, the carbon dioxide gas recovered by the separation and recovery device 8 is supplied to the combustion chamber 21 of the power-generating boiler 2 via a storage tank 81.

[0104] In this embodiment, the liquefied natural gas, which is an organic fuel, is combusted in the gas turbine G, and does not need to be combusted in the combustion chamber 21 of the power-generating boiler 2.

[0105] Therefore, unlike the first embodiment, the combustion chamber 21 is not divided into a first combustion chamber and a second combustion chamber, and the combustion chamber 21 is used only for burning inorganic fuel.

[0106] Then, as indicated by the solid arrow, the exhaust gas from the combustion chamber 21 passes through an exhaust pipe (not shown) and merges with an exhaust pipe (not shown) between the gas turbine G and the denitration device 5.

[0107] In this embodiment, the exhaust gas containing fine powder that needs to be collected by the dust collector 6 is exhaust gas discharged from the combustion chamber 21, so the dust collector 6 is provided in the exhaust pipe (not shown) between the gas turbine G and the denitration device 5 until it joins the exhaust pipe (not shown), and the exhaust gas discharged from the gas turbine G may pass through the denitration device 5 without passing through the dust collector 6, and then be sent to the separation and recovery device 8 that separates and recovers carbon dioxide gas.

[0108] In addition, some gas turbines that use liquefied natural gas as fuel can suppress the generation of nitrogen oxides (NOx) to below environmental standards if the combustion temperature can be maintained high, and some use a combustion-supporting gas with an increased oxygen concentration to suppress the generation of nitrogen oxides (NOx).In such cases, the denitrification device 5 may be omitted.

[0109] Furthermore, when the inorganic fuel contains hydrogenated inorganic matter, a hydrogen recovery device H and a fuel cell F may be provided, as described with reference to FIG. 2, and when a large amount of hydrogen is recovered, the fuel cell F may be replaced with a hydrogen gas turbine for power generation.

[0110] The thermal power generation method of the present invention has been described above through specific embodiments, but the present invention is not limited to the specific embodiments, and appropriate modifications and improvements are also included in the technical scope of the present invention, which will be clear to those skilled in the art from the description of the claims. [Explanation of symbols]

[0111] 1. Generator 2. Power generation boilers 21 Combustion chamber 22 Steam turbine 23 Piping 3 Organic Fuel Storage 4 Inorganic Fuel Storage 5 Denitration equipment 6 Dust collector 7 Desulfurization equipment 8 Separation and collection device 81 Storage Tank 9 Exhaust fan F fuel cell H Hydrogen recovery equipment

Claims

1. A thermal power generation method utilizing the combustion of organic fuel and the combustion of inorganic fuel, the inorganic fuel is a hydrogenated inorganic material in which at least a part of an inorganic material combustible with carbon dioxide gas as a combustion-supporting gas is hydrogenated, the inorganic fuel is burned using carbon oxide gas in the exhaust gas generated by the combustion of the organic fuel as a combustion-supporting gas, and carbon in the carbon oxide gas is solidified; The hydrogenation rate of the hydrogenated inorganic material is 30% by mass or less. Thermal power generation method.

2. The thermal power generation method according to claim 1 , wherein the inorganic substance is lithium, magnesium, aluminum, or a mixture containing two or more of lithium, magnesium, and aluminum.

3. The thermal power generation method according to claim 2 , wherein the inorganic substance is magnesium.

4. the organic fuel is a fossil fuel other than liquefied natural gas, the carbon oxide gas used as the combustion supporting gas for the combustion of the inorganic fuel is carbon dioxide gas; 4. The thermal power generation method according to claim 3, wherein the carbon dioxide gas is recovered from the exhaust gas after passing through a denitration device, a dust collector, and a desulfurization device, through a carbon dioxide gas separation and recovery device.

5. the organic fuel is liquefied natural gas; the carbon oxide gas used as the combustion supporting gas for the combustion of the inorganic fuel is carbon dioxide gas; The thermal power generation method according to claim 3 , wherein the carbon dioxide gas is recovered from the exhaust gas through a carbon dioxide gas separation and recovery device.

6. 4. The thermal power generation method according to claim 3, wherein the solidified carbon together with oxides of the inorganic fuel generated by combustion of the inorganic fuel is recovered as combustion ash, the solidified carbon is separated from the combustion ash, and the solidified carbon is used as a raw material for a carbon material.

7. The thermal power generation method according to claim 6, wherein the inorganic fuel is produced again using the oxide as a material and used for thermal power generation.

8. adjusting the flow rate of the carbon dioxide gas supplied to the combustion chamber in order to maintain a positive pressure in the combustion chamber in which the inorganic fuel is burned; The thermal power generation method according to claim 1 .

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