Heat utilization system and heat supply method

Abstract

To utilize heat generated in one among a methanation facility and an incineration facility effectively in the other among the methanation facility and the incineration facility.SOLUTION: A heat utilization system comprises: a methanation facility that generates methane from hydrogen and carbon dioxide; an incineration facility that has an incinerator; and a heat supply unit that supplies heat generated in one among the methanation facility and the incineration facility to the other among the methanation facility and the incineration facility.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a heat utilization system and a heat supply method. [Background technology]

[0002] Conventional efforts to reduce carbon dioxide emissions in incineration facilities have been made by separating and recycling fossil fuel-derived waste such as plastics, and generating electricity using heat generated by incinerating waste. In the recent trend toward decarbonization, decarbonization of incineration facilities is also desired, and separation, capture, and effective use of carbon dioxide in the exhaust gas generated by incineration of waste is required. Methanation, which reacts carbon dioxide with hydrogen to generate methane gas, has attracted attention as one of the technologies for effective use of carbon dioxide. Patent Document 1 discloses a methane production method and methane production facility that produces methane from carbon dioxide and hydrogen using a catalytic reaction. In Patent Document 1, reaction heat generated by a catalytic reaction is used to generate steam from cooling water, and the generated steam is used as thermal energy for separating carbon dioxide. Patent Document 2 discloses a system in which a methanation facility and a waste-to-energy device are installed side by side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-63206 A [Patent Document 2] JP 2020-45430 A Summary of the Invention [Problem to be solved by the invention]

[0004] Effective utilization of heat generated in a methanation facility in an incineration facility, or effective utilization of heat generated in an incineration facility in a methanation facility, has not been sufficiently considered in the past.

[0005] An object of the present invention is to provide a technique that enables heat generated in one of a methanation facility and an incineration facility to be effectively utilized in the other of the methanation facility and the incineration facility. [Means for solving the problem]

[0006] The present invention for solving the above problems provides a heat utilization system including a methanation facility that generates methane from hydrogen and carbon dioxide, an incineration facility having an incinerator, and a heat supply unit that supplies heat generated in one of the methanation facility and the incineration facility to the other of the methanation facility and the incineration facility. According to the heat utilization system, the heat generated in one of the methanation facility and the incineration facility is supplied to the other of the methanation facility and the incineration facility. This makes it possible to effectively utilize the heat generated in one of the methanation facility and the incineration facility in the other of the methanation facility and the incineration facility.

[0007] In the above heat utilization system, the methanation facility may have a reactor that produces the methane by reacting the hydrogen with the carbon dioxide, and a heat medium circulation line that circulates a heat medium for adjusting the temperature inside the reactor, and the heat supply unit may be a heat exchanger that exchanges heat between the heat medium flowing through the heat medium circulation line and the combustion air supplied to the incinerator. The reaction that produces methane by reacting hydrogen with carbon dioxide is an exothermic reaction. The heat medium flowing through the heat medium circulation line adjusts the temperature inside the reactor, thereby allowing the heat medium flowing through the heat medium circulation line to be exothermic. The temperature rises. Heat exchange is performed between the heat medium flowing through the heat medium circulation line and the combustion air supplied to the incinerator, and the heated combustion air is supplied to the incinerator. By exchanging heat between the heat medium flowing through the heat medium circulation line and the combustion air supplied to the incinerator and supplying the heat generated in the methanation facility to the incineration facility, it becomes possible to effectively utilize the heat generated in the methanation facility in the incineration facility.

[0008] In the above heat utilization system, the heat exchanger may be provided in a preheater that preheats the combustion air to be supplied to the incinerator. For example, when the combustion air is preheated with steam, a part of the steam generated in the boiler is consumed in the preheater. In the above heat utilization system, the heat exchanger provided in the preheater exchanges heat between the heat medium flowing in the heat medium circulation line and the combustion air to be supplied to the incinerator, so that the amount of steam consumed in the preheater can be reduced, and the amount of steam supplied for use in power generation can be increased.

[0009] In the above heat utilization system, the methanation facility has a reactor that reacts the hydrogen and the carbon dioxide to produce the methane, and a heat medium circulation line that circulates a heat medium for adjusting the temperature inside the reactor, and the heat supply unit may be a heat exchanger that performs heat exchange between the heat medium flowing through the heat medium circulation line and the exhaust gas discharged from the incinerator. The reaction that produces methane by reacting hydrogen and carbon dioxide is an exothermic reaction. The heat medium flowing through the heat medium circulation line adjusts the temperature inside the reactor, thereby increasing the temperature of the heat medium flowing through the heat medium circulation line. The exhaust gas discharged from the incinerator is heated by performing heat exchange between the heat medium flowing through the heat medium circulation line and the exhaust gas discharged from the incinerator. By performing heat exchange between the heat medium flowing through the heat medium circulation line and the exhaust gas discharged from the incinerator and supplying the heat generated in the methanation facility to the incineration facility, it becomes possible to effectively utilize the heat generated in the methanation facility in the incineration facility.

[0010] In the above heat utilization system, the heat exchanger may be provided in an exhaust gas heater that heats the exhaust gas discharged from the incinerator. For example, when the exhaust gas is heated by steam, a part of the steam generated in the boiler is consumed in the exhaust gas heater. In the above heat utilization system, the heat exchanger provided in the exhaust gas heater exchanges heat between the heat medium flowing in the heat medium circulation line and the exhaust gas discharged from the incinerator, so that the amount of steam consumed in the exhaust gas heater can be reduced, and the amount of steam supplied for use in power generation can be increased.

[0011] In the above heat utilization system, the methanation facility has a reactor that reacts the hydrogen and the carbon dioxide to produce the methane, and a heat medium circulation line that circulates a heat medium for adjusting the temperature in the reactor, and the heat supply unit may be a heat exchanger that performs heat exchange between the heat medium flowing through the heat medium circulation line and steam generated in a boiler of the incineration facility. For example, when the methanation facility is started, the heat medium is heated to increase the temperature in the reactor. The heat medium flowing through the heat medium circulation line is heated by performing heat exchange between the heat medium flowing through the heat medium circulation line and steam generated in the boiler of the incineration facility. By performing heat exchange between the heat medium flowing through the heat medium circulation line and steam generated in the boiler of the incineration facility and supplying the heat generated in the incineration facility to the methanation facility, it becomes possible to effectively utilize the heat generated in the incineration facility in the methanation facility.

[0012] In the heat utilization system, the incineration facility may have a recovery device that recovers the carbon dioxide from the exhaust gas discharged from the incinerator, and the carbon dioxide recovered by the recovery device may be supplied to the reactor together with the hydrogen. This makes it possible to reduce the amount of carbon dioxide emitted from the incineration facility.

[0013] The present invention also relates to a methanation facility for producing methane from hydrogen and carbon dioxide, and a combustion and an incineration facility having an incinerator, the heat supply method being configured to supply heat generated in one of the methanation facility and the incineration facility to the other of the methanation facility and the incineration facility. According to the heat supply method, the heat generated in one of the methanation facility and the incineration facility is supplied to the other of the methanation facility and the incineration facility. This makes it possible to effectively utilize the heat generated in one of the methanation facility and the incineration facility in the other of the methanation facility and the incineration facility. Effect of the Invention

[0014] Heat generated in one of the methanation facility and the incineration facility can be effectively utilized in the other of the methanation facility and the incineration facility. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a configuration diagram of a heat utilization system according to the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram of the methanation facility. [Diagram 3] FIG. 3 is a configuration diagram of a heat utilization system according to the second embodiment. [Figure 4] FIG. 4 is a configuration diagram of a heat utilization system according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present invention. The embodiment described below is an example of the present invention, and the technical scope of the present invention is not limited to the following aspect.

[0017] First Embodiment A first embodiment will be described with reference to FIG. 1 and FIG. 2. FIG. 1 is a configuration diagram of a heat utilization system according to the first embodiment. The heat utilization system shown in FIG. 1 includes a methanation facility 1, an incineration facility 2, and a heat exchanger 3 that supplies heat generated in one of the methanation facility 1 and the incineration facility 2 to the other of the methanation facility 1 and the incineration facility 2. The heat exchanger 3 is an example of a heat supply unit. In the example shown in FIG. 1, the heat exchanger 3 is provided in a preheater 10. The methanation facility 1 generates methane gas and water, which are product gases, by an exothermic reaction between gaseous hydrogen (H2) and carbon dioxide (CO2), which are raw material gases (reactant gases). The above exothermic reaction is expressed by the following chemical reaction formula. 4H2+CO2→CH4+2H2O (1)

[0018] The incineration facility 2 includes an incinerator 11, a dust collector 12, a blower 13, an exhaust gas treatment device 14, a recovery device 15, an exhaust gas heater 16, an induced draft fan 17, and a chimney 18. The incinerator 11, the dust collector 12, the blower 13, the exhaust gas treatment device 14, the recovery device 15, the exhaust gas heater 16, the induced draft fan 17, and the chimney 18 are connected by a flue of the incineration facility 2. The preheater 10 preheats the combustion air to be supplied to the incinerator 11. For example, the preheater 10 may be disposed in an air supply line (air supply pipe) for supplying the combustion air to the incinerator 11. The combustion air is primary air or secondary air. The combustion air may be outside air or may be air in a garbage pit of the incinerator 11. The garbage pit of the incinerator 11 is a garbage storage section that temporarily stores garbage brought in by a garbage truck. The combustion air may have a different ratio of oxygen and nitrogen within a range that does not interfere with combustion, or may contain other gas components such as carbon dioxide. In FIG. 1, an example in which the preheater 10 is disposed outside the incineration equipment 2 is shown, but the present invention is not limited to this example, and the preheater 10 may be disposed inside the incineration equipment 2. When the moisture content of the waste to be incinerated in the incinerator 11 is high, it is preferable to preheat the combustion air in order to completely combust the waste. For example, the combustion air is heated to a maximum of about 200°C and supplied to the incinerator 11. The collector 15 may be disposed outside the incineration equipment 2, or only a portion of the exhaust gas may be supplied to the collector 15.

[0019] In the incinerator 11, waste such as garbage is burned. The incinerator 11 has a boiler 19. The exhaust gas generated by the incineration of waste in the incinerator 11 is subjected to heat exchange in the boiler 19 and then sent to a dust collector 12 using a bag filter. The dust collector 12 removes dust such as dirt and dirt from the exhaust gas. A part of the exhaust gas from which the dust has been removed is sent to an exhaust gas treatment device 14. The exhaust gas treatment device 14 is, for example, a wet exhaust treatment device (scrubber). In addition, in order to control the combustion of the incinerator 11, a part of the exhaust gas discharged from the dust collector 12 is sent to the incinerator 11 by a blower 13. By returning a part of the exhaust gas to the incinerator 11, it is possible to prevent the incinerator 11 from becoming locally hot. The exhaust gas sent to the exhaust gas treatment device 14 is cooled in the exhaust gas treatment device 14, and impurities such as HCl and SOx in the exhaust gas are removed. The exhaust gas treatment device 14 sends the exhaust gas to a recovery device 15 .

[0020] The recovery unit 15 has an absorption tower 20 and a regeneration tower 21. In the absorption tower 20, carbon dioxide contained in the exhaust gas is absorbed in an aqueous solution of an amine compound (hereinafter, referred to as amine liquid). The recovery unit 15 sends the exhaust gas to an exhaust gas heater 16. The exhaust gas is heated by the exhaust gas heater 16, thereby suppressing condensation in the flue through which the exhaust gas flows and white smoke of the exhaust gas. After the exhaust gas is heated by the exhaust gas heater 16, the exhaust gas is denitrified by a catalytic denitrification device, and the exhaust gas is sent to an induced draft fan 17. The induced draft fan 17 discharges the exhaust gas outside the system (for example, to the atmosphere) through a chimney 18. The amine liquid that has absorbed carbon dioxide in the absorption tower 20 is heated in the regeneration tower 21, and carbon dioxide is separated from the amine liquid. The carbon dioxide separated from the amine liquid is mixed with hydrogen, and the raw material gas containing carbon dioxide and hydrogen is supplied to the methanation facility 1. As a method for recovering carbon dioxide, a method other than the amine method, such as a temperature swing adsorption method, may be adopted. The hydrogen supplied to the methanation facility 1 is not particularly limited. Hydrogen may be supplied to the methanation facility 1 from a hydrogen tank that stores hydrogen. In this case, hydrogen may be supplied to the methanation facility 1 through a hydrogen pipe connected to the hydrogen tank. Also, hydrogen generated by water electrolysis using surplus electricity from renewable energy may be supplied to the methanation facility 1. A portion of the exhaust gas does not need to be sent to the incinerator 11. Also, a catalytic denitration device may be included in the exhaust gas treatment device 14.

[0021] 1 shows an example in which a part of the exhaust gas discharged from the dust collector 12 is sent to the incinerator 11 via the blower 13, but the present invention is not limited to this example. A part of the exhaust gas discharged from the exhaust gas treatment device 14 may be sent to the incinerator 11 via the blower 13. Also, a part of the exhaust gas discharged from the exhaust gas heater 16 may be sent to the incinerator 11 via the blower 13.

[0022] 2 is a configuration diagram of the methanation facility 1. The methanation facility 1 includes a first-stage reactor (reaction tower) 101, a first-stage gas cooling heat exchanger 102, a second-stage reactor (reaction tower) 103, a second-stage gas cooling heat exchanger 104, a heater 105, a heat medium heat exchanger 106, gas-liquid separators 107 and 108, and a storage tank 109.

[0023] A raw material gas containing hydrogen and carbon dioxide is supplied to the reactor 101. The reactor 101 reacts hydrogen with carbon dioxide to produce methane. The reactor 101 also produces water by an exothermic reaction between hydrogen and carbon dioxide. The reactor 101 is connected to a gas cooling heat exchanger 102. Pipes, valves, and the like are provided on a path connecting the reactor 101 and the gas cooling heat exchanger 102. An economizer 111 is provided on a supply path of the raw material gas supplied to the reactor 101. In the economizer 111, heat exchange is performed between the raw material gas supplied to the reactor 101 and the discharge gas discharged from the reactor 101. The discharge gas is a product gas, an unreacted raw material gas, or a mixed gas of the product gas and the unreacted raw material gas.

[0024] The gas cooling heat exchanger 102 condenses the water (steam) generated in the reactor 101. The gas-cooling heat exchanger 102 and the gas-liquid separator 107 are connected. Pipes, valves, and the like are provided on the path connecting the gas-cooling heat exchanger 102 and the gas-liquid separator 107. The gas-liquid separator 107 separates the generated water (liquid) from the product gas, the unreacted raw material gas, or a mixed gas of the product gas and the unreacted raw material gas. The gas-cooling heat exchanger 102 and the gas-liquid separator 107 may be integrated, or the gas-liquid separator 107 may be a drain trap. Since the generated water condensed in the gas-cooling heat exchanger 102 or the gas-liquid separator 107 contains dissolved product gas and unreacted raw material gas, a degassing device may be provided.

[0025] The reactor 103 and the gas-liquid separator 107 are connected. A path connecting the reactor 103 and the gas-liquid separator 107 is provided with pipes, valves, and the like. An economizer 112 is provided in the path connecting the reactor 103 and the gas-liquid separator 107. In the economizer 112, heat exchange is performed between the delivery gas sent to the reactor 103 and the delivery gas sent from the reactor 103. The product gas and unreacted raw material gas generated in the reactor 101 are sent to the reactor 103 via the economizer 111, the gas cooling heat exchanger 102, the gas-liquid separator 107, and the economizer 112. The reactor 103 reacts hydrogen and carbon dioxide to generate methane. The reactor 103 also generates product water by an exothermic reaction between hydrogen and carbon dioxide. The methanation facility 1 can generate a high-concentration product gas by generating a product gas from the unreacted raw material gas in the reactor 103.

[0026] The reactor 103 and the gas-cooling heat exchanger 104 are connected. A path connecting the reactor 103 and the gas-cooling heat exchanger 104 is provided with piping, valves, and the like. The gas-cooling heat exchanger 104 condenses the generated water (water vapor) generated in the reactor 103. The gas-cooling heat exchanger 104 and the gas-liquid separator 108 are connected. A path connecting the gas-cooling heat exchanger 104 and the gas-liquid separator 108 is provided with piping, valves, and the like. The gas-liquid separator 108 separates the generated water (liquid) from the product gas, the unreacted raw material gas, or a mixed gas of the product gas and the unreacted raw material gas. The gas-cooling heat exchanger 104 and the gas-liquid separator 108 may be integrated, or the gas-liquid separator 108 may be a drain trap. Since the product gas and unreacted raw material gas are dissolved in the water condensed in the gas-cooling heat exchanger 104 and the gas-liquid separator 108, a degassing device may be installed.

[0027] The product gas is sent from the gas-liquid separator 108 to the storage tank 109. The storage tank 109 stores the product gas. The gas-liquid separators 107 and 108 are provided with a drain valve 113 for draining the generated water. The drain valve 113 may be a valve that opens and closes using the buoyancy of a floating device such as a drain trap, or may be a valve that opens and closes an electromagnetic valve by electrically detecting the water level. The drain valve 113 drains the generated water from the gas-liquid separators 107 and 108.

[0028] The reactors 101 and 103 are filled with a catalyst in advance. The catalyst may be any catalyst that promotes reaction formula (1). The catalyst includes, for example, a stabilized zirconia support in which a stabilizing element is dissolved and which has a tetragonal and / or cubic crystal structure, and Ni supported on the stabilized zirconia support. The stabilizing element is, for example, at least one transition element selected from the group consisting of Mn, Fe, and Co.

[0029] As shown in Figs. 1 and 2, the methanation facility 1 has a heat medium circulation line 41 that circulates a heat medium for adjusting the temperature in the reactors 101 and 103. The heat medium is, for example, heat oil, water, or steam. The heat medium circulation line 41 has, for example, piping that connects the reactor 101, the reactor 103, and the heat exchanger 3 provided in the preheater 10, but may have other components. The reaction that produces methane gas is an exothermic reaction, and during operation of the methanation facility 1, in order to prevent the temperature in the reactors 101 and 103 from becoming excessively high, the heat medium circulation line 41 has, for example, piping that connects the reactor 101, the reactor 103, and the heat exchanger 3 provided in the preheater 10, A heat medium is circulated by a heat medium circulation line 41 in order to recover heat in the reactors 101 and 103. The heat medium flowing through the heat medium circulation line 41 circulates through the methanation facility 1 and the preheater 10. Specifically, the heat medium passes through the reactor 101, further through the reactor 103, and the heat exchanger 3, and then passes through the reactor 101 again.

[0030] The reactors 101 and 103 have a jacket structure, and the jacket portion (shell) allows the flow of a heat medium that exchanges heat with the heat generating portion in the reactor where the exothermic reaction occurs. The heater 105 and the jacket portion of the reactor 101 are connected by a pipe through which the heat medium flows. The jacket portion of the reactor 101 and the jacket portion of the reactor 103 are connected by a pipe through which the heat medium flows. The pipe through which the heat medium flows is provided with a valve or the like. The heater 105 is a heater that heats the heat medium. The heat medium heated by the heater 105 passes through the reactor 101 and then through the reactor 103. The heater 105 is mainly used when it is necessary to increase the temperature of the heat medium, such as when starting up the equipment. When it is not necessary to increase the temperature of the heat medium, the heater 105 may not heat the heat medium, or the heat medium may bypass the heater 105 and circulate through the heat medium circulation line 41.

[0031] As shown in FIG. 1 and FIG. 2, the heat medium that has passed through the reactor 103 passes through the heat exchanger 3. During operation of the methanation facility 1, the temperature of the heat medium that has passed through the reactor 103 is, for example, about 250°C. The heat exchanger 3 has an internal pipe through which the heat medium passes and an internal pipe through which the combustion air passes. In the heat exchanger 3, the internal pipe through which the heat medium passes and the internal pipe through which the combustion air passes may be arranged so that a part of the internal pipe through which the heat medium passes and a part of the internal pipe through which the combustion air passes are adjacent to each other. In the heat exchanger 3, heat exchange is performed between the heat medium passing through the heat exchanger 3 and the combustion air supplied to the incinerator 11 through the heat exchanger 3. Therefore, the heat exchanger 3 performs heat exchange between the heat medium flowing through the heat medium circulation line 41 and the combustion air supplied to the incinerator 11. The heat medium passing through the heat exchanger 3 is heated by the methanation facility 1. The heat medium passing through the reactor 101 is heated by heat exchange with the heat generating part in the reactor 101. The heat medium passing through the reactor 103 is heated by heat exchange with the heat generating portion in the reactor 103. In the heat exchanger 3, heat exchange is performed between the combustion air to be supplied to the incinerator 11 and the heated heat medium, whereby the combustion air is heated and the heated combustion air is supplied to the incinerator 11. By supplying the heated combustion air to the incinerator 11, high temperature air combustion is realized and the thermal efficiency of the incineration equipment 2 is improved. In addition, the heat medium flowing through the heat medium circulation line 41 may be used to heat hot water or steam in the incineration equipment 2.

[0032] The jacket portion of the reactor 103 and the heat exchanger 3 are connected by a pipe through which the heat medium flows. The heat medium heat exchanger 106 in the methanation facility 1 cools the heat medium that has passed through the reactors 101, 103 and the heat exchanger 3. The heater 105 and the heat medium heat exchanger 106 are connected by a pipe through which the heat medium flows. The pipe connecting the heater 105 and the heat medium heat exchanger 106 is provided with a heat medium circulation pump 114 that sends the heat medium cooled by the heat medium heat exchanger 106 to the heater 105. In addition, the pipe through which the heat medium flows is provided with control valves 115 and 116. By opening and closing the control valves 115 and 116, the heat medium that has passed through the reactors 101, 103 and the heat exchanger 3 can be sent to the heater 105 via the heat medium heat exchanger 106, or sent to the heater 105 without passing through the heat medium heat exchanger 106. The arrangement of the heat medium heat exchanger 106, the heat medium circulating pump 114, and the control valves 115 and 115 may be changed so that the heat medium heated by the heater 105 passes through the heat exchanger 3 and the reactor 103, and then passes through the reactor 101.

[0033] The methanation facility 1 includes a cooling tower 117 and a cooling water circulation pump 118. The cooling tower 117 cools the cooling water that exchanges heat with the heat medium in the heat medium heat exchanger 106. For example, tap water supplied to the cooling tower 117 from outside the system may be used as the cooling water. The cooling water circulation pump 118 circulates the cooling water supplied to the cooling tower 117 between the heat medium heat exchanger 106 and the cooling tower 11 Cycle between 0 and 7.

[0034] The methanation facility 1 includes a cooling tower 119. The cooling tower 119 cools the cooling water (refrigerant) for condensing the generated water in the gas cooling heat exchangers 102 and 104. The gas cooling heat exchangers 102, 104 and the cooling tower 119 are connected by piping through which the cooling water flows. The cooling water cooled by the cooling tower 119 returns to the cooling tower 119 via the gas cooling heat exchangers 102 and 104. A chiller may be used instead of the cooling tower 119.

[0035] The heat utilization system shown in FIG. 1 includes a steam generator 31 and a condenser 32. In the heat utilization system according to the first embodiment, waste is incinerated in the incinerator 11, and steam generated in the boiler 19 is sent to the heat exchanger 3, the exhaust gas heater 16, and the steam generator 31. The temperature of the steam generated in the boiler 19 is, for example, 300 to 450°C. The heat exchanger 3 has an internal pipe through which the steam generated in the boiler 19 passes. In the heat exchanger 3, heat exchange is performed between the combustion air to be supplied to the incinerator 11 and the steam generated in the boiler 19, and the heated combustion air is supplied to the incinerator 11. The steam discharged from the heat exchanger 3 returns to the boiler 19. In the exhaust gas heater 16, the exhaust gas is heated by heat exchange between the steam generated in the boiler 19 and the exhaust gas. The steam discharged from the exhaust gas heater 16 returns to the boiler 19.

[0036] The steam generator 31 is a power generating unit driven by steam generated by the boiler 19. The steam generator 31 may be a turbine type generator or a screw type generator. The steam generator 31 generates electricity using steam supplied from the boiler 19. The electricity generated by the steam generator 31 can be used as in-process power for a control unit, heating equipment, compressor, etc. for operating the process. In addition, the electricity generated by the steam generator 31 may be used as in-process power, and surplus electricity may be supplied to any power source, etc. In addition, a power storage facility may be provided, and the electricity generated by the steam generator 31 may be stored in the power storage facility. The condenser 32 condenses the steam discharged from the steam generator 31. The condensate condensed by the condenser 32 returns to the boiler 19.

[0037] According to the heat utilization system according to the first embodiment, the combustion air to be supplied to the incinerator 11 is heated by heat exchange between the heat medium heated by the methanation facility 1 and the combustion air to be supplied to the incinerator 11. The amount of steam supplied to the preheater 10 can be reduced by heating the combustion air to be supplied to the incinerator 11 with the heat medium heated by the methanation facility 1 and the steam generated in the boiler 19. In the heat utilization system according to the first embodiment, the supply of steam to the preheater 10 may be stopped. The supply of steam to the preheater 10 can be omitted by heating the combustion air to be supplied to the incinerator 11 with the heat medium heated by the methanation facility 1. The amount of steam supplied to the exhaust gas heater 16 and the steam generator 31 is increased by reducing the amount of steam supplied to the preheater 10 or by omitting the supply of steam to the preheater 10. The amount of steam supplied to the steam generator 31 is increased by increasing the amount of steam supplied to the steam generator 31. The amount of steam supplied to the exhaust gas heater 16 may be kept constant, and the amount of steam supplied to the steam generator 31 may be increased. The amount of steam supplied to the steam generator 31 may be kept constant, and the amount of steam supplied to the exhaust gas heater 16 may be increased.

[0038] According to the heat utilization system of the first embodiment, heat exchange is performed between the heat medium flowing through the heat medium circulation line 41 and the combustion air supplied to the incinerator 11, and the heat generated in the methanation equipment 1 is supplied to the incineration equipment 2, making it possible to effectively utilize the heat generated in the methanation equipment 1 in the incineration equipment 2.

[0039] <Second embodiment> The second embodiment will be described with reference to Figures 2 and 3. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Fig. 3 is a configuration diagram of a heat utilization system according to a second embodiment. The heat utilization system shown in Fig. 3 includes a methanation facility 1, an incineration facility 2, and a heat exchanger 4 that supplies heat generated in one of the methanation facility 1 and the incineration facility 2 to the other of the methanation facility 1 and the incineration facility 2. The heat exchanger 4 is an example of a heat supply unit. In the example shown in Fig. 3, the heat exchanger 4 is provided in an exhaust gas heater 16. The configuration of the methanation facility 1 according to the second embodiment is similar to that of the first embodiment.

[0040] The methanation facility 1 has a heat medium circulation line 42 that circulates a heat medium for adjusting the temperature in the reactors 101 and 103. The heat medium is, for example, heat oil, water, or steam. The heat medium circulation line 42 has, for example, a pipe that connects the reactor 101, the reactor 103, and the heat exchanger 4 provided in the exhaust gas heater 16, but may have other components. The reaction that produces methane gas is an exothermic reaction, and during operation of the methanation facility 1, the heat medium is circulated by the heat medium circulation line 42 to recover heat in the reactors 101 and 103 so that the temperature in the reactors 101 and 103 does not become excessively high. The heat medium flowing through the heat medium circulation line 42 circulates through the methanation facility 1 and the exhaust gas heater 16. Specifically, the heat medium passes through the reactor 101, further through the reactor 103, passes through the heat exchanger 4, and then passes through the reactor 101 again.

[0041] The incineration facility 2 includes an incinerator 11, a dust collector 12, a blower 13, an exhaust gas treatment device 14, a recovery device 15, an exhaust gas heater 16, an induced draft fan 17, and a chimney 18. FIG. 3 shows an example in which the preheater 10 is disposed inside the incineration facility 2, but the present invention is not limited to this example, and the preheater 10 may be disposed outside the incineration facility 2. FIG. 3 shows an example in which a part of the exhaust gas discharged from the dust collector 12 is sent to the incinerator 11 via the blower 13, but the present invention is not limited to this example. A part of the exhaust gas discharged from the exhaust gas treatment device 14 may be sent to the incinerator 11 via the blower 13. Also, a part of the exhaust gas discharged from the exhaust gas heater 16 may be sent to the incinerator 11 via the blower 13. A part of the exhaust gas does not need to be sent to the incinerator 11.

[0042] In the heat utilization system according to the second embodiment, waste is incinerated in the incinerator 11, and steam generated in the boiler 19 is sent to the preheater 10 and the steam generator 31. The temperature of the steam generated in the boiler 19 is, for example, 300 to 450°C. The steam generated in the boiler 19 is not sent to the exhaust gas heater 16. As shown in Figs. 2 and 3, the heat medium that has passed through the reactor 103 passes through the heat exchanger 4. During operation of the methanation facility 1, the temperature of the heat medium that has passed through the reactor 103 is, for example, about 250°C. The heat exchanger 4 has an internal pipe through which the heat medium passes and an internal pipe through which the exhaust gas passes. In the heat exchanger 4, the internal pipe through which the heat medium passes and the internal pipe through which the exhaust gas passes may be arranged so that a part of the internal pipe through which the heat medium passes and a part of the internal pipe through which the exhaust gas passes are adjacent to each other. In the heat exchanger 4, heat exchange is performed between the heat medium passing through the heat exchanger 4 and the exhaust gas passing through the heat exchanger 4. Therefore, the heat exchanger 4 exchanges heat between the heat medium flowing through the heat medium circulation line 42 and the exhaust gas discharged from the incinerator 11. The heat medium flowing through the heat medium circulation line 42 may also be used to heat hot water or steam in the incineration facility 2.

[0043] The preheater 10 has an internal pipe through which the steam generated in the boiler 19 passes, and an internal pipe through which the combustion air passes. In the preheater 10, the internal pipe through which the heat medium passes and the internal pipe through which the combustion air passes may be arranged so that a part of the internal pipe through which the steam passes and a part of the internal pipe through which the combustion air passes are adjacent to each other. The steam discharged from the preheater 10 returns to the boiler 19.

[0044] The heat medium passing through the heat exchanger 4 is heated by the methanation equipment 1. The heat medium passing through the reactor 101 is heated by heat exchange with the heat generating part in the reactor 101. The heat medium passing through the reactor 103 is heated by heat exchange with the heat generating part in the reactor 103. In the heat exchanger 4, heat exchange is performed between the exhaust gas passing through the heat exchanger 4 and the heated heat medium, and the exhaust gas sent to the induced draft fan 17 is heated. The exhaust gas is heated by the exhaust gas heater 16, so that condensation in the flue through which the exhaust gas flows and white smoke of the exhaust gas are suppressed. In addition, when denitrifying the exhaust gas, it is necessary to heat the exhaust gas to a temperature suitable for denitrification (for example, 170°C). By performing heat exchange between the heat medium heated by the methanation equipment 1 and the exhaust gas, it is possible to heat the exhaust gas to a temperature suitable for denitrification. In FIG. 3, an example is shown in which all the exhaust gas that has passed through the exhaust gas treatment device 14 flows into the recovery device 15, but this example is not limited to this example. A part of the exhaust gas discharged from the exhaust gas treatment device 14 may be sent to the recovery device 15. In that case, the exhaust gas heater 16 may heat the exhaust gas that has not been sent to the recovery device 15, or may heat the exhaust gas that has passed through the recovery device 15. Alternatively, the exhaust gas heater 16 may heat both the exhaust gas that is not sent to the recovery device 15 and the exhaust gas that has passed through the recovery device 15. Also, heat exchange may be performed between the exhaust gas to be sent to the recovery device 15 and the exhaust gas that has passed through the recovery device 15. In this case, the exhaust gas heater 16 may heat the exhaust gas after heat exchange between the exhaust gas to be sent to the recovery device 15 and the exhaust gas that has passed through the recovery device 15.

[0045] According to the heat utilization system of the second embodiment, heat exchange is performed between the exhaust gas passing through the heat exchanger 4 and the heat medium heated by the methanation facility 1, so that the exhaust gas is heated in the exhaust gas heater 16. Therefore, it is possible to omit the supply of steam to the exhaust gas heater 16. By omitting the supply of steam to the exhaust gas heater 16, the amount of steam supplied to the preheater 10 and the steam generator 31 is increased. The amount of steam supplied to the preheater 10 may be constant, and the amount of steam supplied to the steam generator 31 may be increased. The amount of steam supplied to the steam generator 31 may be constant, and the amount of steam supplied to the preheater 10 may be increased. In the heat utilization system of the second embodiment, steam may be supplied to the exhaust gas heater 16. In this case, heat exchange is performed between the exhaust gas passing through the heat exchanger 4 and the heat medium heated by the methanation facility 1, so that the exhaust gas is heated in the exhaust gas heater 16, and therefore the amount of steam supplied to the exhaust gas heater 16 can be reduced. As a result, the amount of steam supplied to the steam generator 31 increases, and therefore it is possible to increase the amount of power generated by the steam generator 31.

[0046] According to the heat utilization system of the second embodiment, heat is exchanged between the heat medium flowing through the heat medium circulation line 42 and the exhaust gas discharged from the incinerator 11, and the heat generated in the methanation equipment 1 is supplied to the incineration equipment 2, making it possible to effectively utilize the heat generated in the methanation equipment 1 in the incineration equipment 2.

[0047] <Third embodiment> A third embodiment will be described with reference to FIG. 2 and FIG. 4. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. FIG. 4 is a configuration diagram of a heat utilization system according to a third embodiment. The heat utilization system shown in FIG. 4 includes a methanation facility 1, an incineration facility 2, and a heat exchanger 5 that supplies heat generated in one of the methanation facility 1 and the incineration facility 2 to the other of the methanation facility 1 and the incineration facility 2. The heat exchanger 5 is an example of a heat supply unit. In FIG. 4, an example in which the heat exchanger 5 is disposed outside the methanation facility 1 is shown, but this is not limited to this example, and the heat exchanger 5 may be disposed inside the methanation facility 1. When the heat exchanger 5 is disposed inside the methanation facility 1 shown in FIG. 2, the heat exchanger 5 may be disposed adjacent to the heater 105, or the heat exchanger 5 may be disposed instead of the heater 105.

[0048] The methanation facility 1 has a heat medium circulation line 43 that circulates a heat medium for adjusting the temperature in the reactors 101 and 103. The heat medium is, for example, heat oil, water, or steam. The heat medium circulation line 43 has, for example, a pipe connecting the reactor 101, the reactor 103, and the heat exchanger 5, but may have other components. The reaction that produces methane gas is an exothermic reaction, and when the temperature in the reactors 101 and 103 exceeds 100° C. during operation of the methanation facility 1, the heat medium circulation line 43 circulates a heat medium for adjusting the temperature in the reactors 101 and 103. To prevent the temperature from becoming too high, a heat medium is circulated through a heat medium circulation line 43 to recover heat in the reactors 101 and 103. The heat medium flowing through the heat medium circulation line 42 circulates through the methanation facility 1 and the heat exchanger 5. Specifically, the heat medium passes through the reactor 101, further through the reactor 103, and through the heat exchanger 5, and then passes through the reactor 101 again.

[0049] The incineration facility 2 includes an incinerator 11, a dust collector 12, a blower 13, an exhaust gas treatment device 14, a recovery device 15, an exhaust gas heater 16, an induced draft fan 17, and a chimney 18. FIG. 4 shows an example in which the preheater 10 is disposed inside the incineration facility 2, but the present invention is not limited to this example, and the preheater 10 may be disposed outside the incineration facility 2. FIG. 4 shows an example in which a part of the exhaust gas discharged from the dust collector 12 is sent to the incinerator 11 via the blower 13, but the present invention is not limited to this example. A part of the exhaust gas discharged from the exhaust gas treatment device 14 may be sent to the incinerator 11 via the blower 13. Also, a part of the exhaust gas discharged from the exhaust gas heater 16 may be sent to the incinerator 11 via the blower 13.

[0050] In the heat utilization system according to the third embodiment, waste is incinerated in the incinerator 11, and steam generated in the boiler 19 is sent to the heat exchanger 5, the preheater 10, the exhaust gas heater 16, and the steam generator 31. The temperature of the steam generated in the boiler 19 is, for example, 300 to 450°C. As shown in Figs. 2 and 4, the heat medium that has passed through the reactor 103 passes through the heat exchanger 5. The heat exchanger 5 has an internal pipe through which the heat medium passes and an internal pipe through which the steam generated in the boiler 19 passes. In the heat exchanger 5, the internal pipe through which the heat medium passes and the internal pipe through which the steam passes may be arranged so that a part of the internal pipe through which the heat medium passes and a part of the internal pipe through which the steam passes are adjacent to each other. In the heat exchanger 5, heat exchange is performed between the heat medium passing through the heat exchanger 5 and the steam passing through the heat exchanger 5. Therefore, the heat exchanger 5 exchanges heat between the heat medium flowing through the heat medium circulation line 43 and the steam generated in the boiler 19. The steam discharged from the heat exchanger 5 returns to the boiler 19 .

[0051] The preheater 10 has an internal pipe through which the steam generated in the boiler 19 passes, and an internal pipe through which the combustion air passes. In the preheater 10, the internal pipe through which the heat medium passes and the internal pipe through which the combustion air passes may be arranged so that a part of the internal pipe through which the steam passes and a part of the internal pipe through which the combustion air passes are adjacent to each other. The steam discharged from the preheater 10 returns to the boiler 19.

[0052] When the methanation facility 1 is started (when operation starts), the temperature of the heat medium flowing through the heat medium circulation line 43 is low. When the methanation facility 1 is started, the heat medium flowing through the heat medium circulation line 43 is heated with steam generated in the boiler 19, and then the heat medium is supplied to the methanation facility 1. The heated and temperature-raised heat medium passes through the reactor 101, thereby raising the temperature of the reactor 101. As a result, the catalyst in the reactor 101 is heated to the reaction start temperature. The heat medium that passed through the reactor 101 is sent to the jacket portion of the reactor 103 and passes through the reactor 103. The heated and temperature-raised heat medium passes through the reactor 103, thereby raising the temperature of the reactor 103. As a result, the catalyst in the reactor 103 is heated to the reaction start temperature.

[0053] According to the heat utilization system of the third embodiment, heat exchange is performed between the heat medium flowing through the heat medium circulation line 43 and the steam generated in the boiler 19, and the heated heat medium passes through the reactors 101 and 103. Therefore, when the heat medium is heated by the heater 105 at the start of the methanation facility 1, it is possible to reduce the amount of power supplied to the heater 105 (power consumption for the heater). Even when the heater 105 is operated to maintain the temperature of the heat medium when the methanation facility 1 is temporarily stopped or the operating load of the methanation facility 1 is reduced, the amount of power supplied to the heater 105 can be reduced. In addition, when it is not necessary to heat the heat medium by the heater 105, it is possible to omit the installation of the heater 105, and there is no need to supply power to the heater 105 or maintain the heater 105.

[0054] According to the heat utilization system of the third embodiment, the heat medium flowing through the heat medium circulation line 43 and the incineration By exchanging heat with the steam generated in the boiler 19 of the equipment 2 and supplying the heat generated in the incineration equipment 2 to the methanation equipment 1, it is possible to effectively utilize the heat generated in the incineration equipment 2 in the methanation equipment 1.

[0055] In addition, each of the processes and steps described above may be regarded as a heat supply method in a heat utilization system, a control method for a heat utilization system, etc. Each of the processes and steps described above in the methanation facility 1 may be regarded as a method for generating a product gas in the methanation facility 1, or a method for operating the methanation facility 1, etc. Each of the processes and steps described above in the incineration facility 2 may be regarded as an incineration method in the incineration facility 2, or a method for operating the incineration facility 2, etc. Each of the processes and steps may be regarded as a control system, a generation system, or an operation system having at least a part of each of the processes or functions described above. Note that each of the above means and processes can be combined with each other as much as possible to constitute the present invention. Each of the above embodiments can be combined with each other.

[0056] In the first to third embodiments, the incineration equipment 2 has been described as having a boiler 19, but in the case where heat generated in the methanation equipment 1 is supplied to the incineration equipment 2, the incineration equipment 2 may not have a boiler 19, for example, may be a water injection furnace. [Explanation of symbols]

[0057] 1··Methanation equipment; 2··Incineration equipment; 3, 4, 5··Heat exchanger; 10··Preheater; 11··Incinerator; 12··Dust collector; 13··Blower; 14··Exhaust gas treatment equipment; 15··Recovery equipment; 16··Exhaust gas heater; 17··Induced draft fan; 18··Chimney; 19··Boiler; 20··Absorption tower; 21··Regeneration tower; 31··Steam generator; 32··Condenser; 41, 42, 43··Media circulation line; 101, 103··Reactor

Claims

1. a methanation facility for producing methane from hydrogen and carbon dioxide; An incineration facility having an incinerator; A heat supply unit that supplies heat generated in one of the methanation facility and the incineration facility to the other of the methanation facility and the incineration facility; A heat utilization system comprising:

2. The methanation facility has a reactor that reacts the hydrogen and the carbon dioxide to produce the methane, and a heat medium circulation line that circulates a heat medium to adjust the temperature in the reactor, The heat supply unit is a heat exchanger that performs heat exchange between the heat medium flowing through the heat medium circulation line and the combustion air supplied to the incinerator. The heat utilization system according to claim 1 .

3. The heat exchanger is provided in a preheater that preheats the combustion air to be supplied to the incinerator. The heat utilization system according to claim 2 .

4. The methanation facility has a reactor that reacts the hydrogen and the carbon dioxide to produce the methane, and a heat medium circulation line that circulates a heat medium to adjust the temperature in the reactor, The heat supply unit is a heat exchanger that performs heat exchange between the heat medium flowing through the heat medium circulation line and the exhaust gas discharged from the incinerator. The heat utilization system according to claim 1 .

5. The heat exchanger is provided in an exhaust gas heater that heats the exhaust gas discharged from the incinerator. The heat utilization system according to claim 4.

6. The methanation facility has a reactor that reacts the hydrogen and the carbon dioxide to produce the methane, and a heat medium circulation line that circulates a heat medium to adjust the temperature in the reactor, The heat supply unit is a heat exchanger that performs heat exchange between the heat medium flowing through the heat medium circulation line and steam generated in a boiler of the incineration equipment. The heat utilization system according to claim 1 .

7. The incineration facility has a recovery device that recovers the carbon dioxide from the exhaust gas discharged from the incinerator, The carbon dioxide recovered by the recovery vessel is supplied to the reactor together with the hydrogen. The heat utilization system according to any one of claims 2 to 6.

8. a methanation facility for producing methane from hydrogen and carbon dioxide; An incineration facility having an incinerator; A heat supply method for a heat utilization system comprising: Heat generated in one of the methanation facility and the incineration facility is supplied to the other of the methanation facility and the incineration facility; Heat supply method.

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