Incineration plant

Abstract

To provide an incineration plant capable of reducing emissions of carbon dioxide to outside and efficiently performing combustion of waste in an incinerator.SOLUTION: An incineration plant includes: an incinerator 1; a combustion air supply device AS1; a steam generator 60; an electrolytic methanation device 62 to which carbon dioxide and steam generated by the steam generator 60 are introduced and from which methane gas and oxygen-containing gas containing oxygen and steam are taken out; an oxygen-containing gas supply device GS1 that supplies oxygen-containing gas to the incinerator 1; a heat generation amount calculation device 91 that calculates a heat generation amount of waste; a mixing ratio calculation device 92 that calculates a mixing ratio of the combustion air and the oxygen-containing gas so that oxygen concentration of mixed gas of the combustion air and the oxygen-containing gas becomes target oxygen concentration corresponding to the heat generation amount of the waste; and a supply flow rate controller 93 that controls the combustion air supply device AS1 and the oxygen-containing gas supply device GS1 so that a supply flow rate of the combustion air and a supply flow rate of the oxygen-containing gas become the calculated mixing ratio.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to incineration plants for incinerating waste materials such as garbage. [Background technology]

[0002] In recent years, efforts have been made to reduce the amount of carbon dioxide emitted from incineration plants. Some incineration plants are equipped with equipment to generate methane using organic matter contained in waste before it is burned.

[0003] For example, Patent Document 1 describes that an incineration plant is equipped with a methane fermentation device, and that materials unsuitable for fermentation are removed from waste and used as raw material for the methane fermentation device. In the case of Patent Document 1, the biogas generated in the methane fermentation device is separated into methane and carbon dioxide. Furthermore, the separated carbon dioxide and hydrogen generated in a water electrolysis device are supplied to a methanation device, where methane and water are synthesized. In this way, by using the carbon dioxide contained in the biogas generated in the methane fermentation device as raw material for the methanation device, it is possible to reduce the amount of carbon dioxide emitted outside the plant. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6940713 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned Patent Document 1 describes that oxygen generated in a water electrolysis device may be mixed with the combustion air supplied to the inside of a waste incinerator to promote the combustion of waste, but does not describe a specific method for doing so, leaving room for improvement.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an incineration plant that can reduce carbon dioxide emissions to the outside and efficiently combust waste in the incinerator. [Means for solving the problem]

[0007] In order to achieve the above object, an incineration plant according to an embodiment of the present disclosure includes an incinerator for burning waste, a combustion air supplying device that takes in outside air and supplies it to the incinerator as combustion air and is capable of adjusting the flow rate of the supply, a steam generating device that generates steam, an electrolytic methanation device into which at least one of carbon dioxide separated and recovered from exhaust gas discharged from the incinerator and carbon dioxide separated and recovered from biogas produced by methane fermentation of waste not input to the incinerator and the steam generated by the steam generating device is introduced and electrolysis of the steam and a Sabatier reaction are caused to occur to extract methane gas and an oxygen-containing gas containing oxygen and water vapor, and a reaction system for extracting the oxygen-containing gas extracted by the electrolytic methanation device. the combustion air and the oxygen-containing gas supply device being capable of adjusting the flow rate of the supply; a calorific value calculation device calculating a calorific value of the waste to be combusted in the incinerator; a mixing ratio calculation device calculating a target oxygen concentration according to the calorific value of the waste calculated by the calorific value calculation device based on a predetermined relationship between the calorific value and a target oxygen concentration, and calculating a mixing ratio of the combustion air and the oxygen-containing gas such that the oxygen concentration of a gas obtained by mixing the combustion air and the oxygen-containing gas and supplied to the incinerator becomes the calculated target oxygen concentration; and a supply flow rate controller controlling the combustion air supply device and the oxygen-containing gas supply device such that the supply flow rates of the combustion air and the oxygen-containing gas become the mixing ratios calculated by the mixing ratio calculation device. Effect of the Invention

[0008] The present disclosure has the above-described configuration and has the effect of providing an incineration plant that can reduce carbon dioxide emissions to the outside and efficiently combust waste in the incinerator. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of an incineration plant according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an outline of the structure of a cell used in the electrolytic methanation device. [Diagram 3] FIG. 3 is a schematic diagram showing an example of an incineration plant according to the second embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an example of an incineration plant according to the third embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing an outline of an example of an incineration plant according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout the drawings, and duplicated descriptions thereof may be omitted. In addition, the drawings are schematic illustrations of the respective components for ease of understanding, and shapes, dimensional ratios, and the like may not be accurately depicted.

[0011] (First embodiment) FIG. 1 is a schematic diagram showing an example of an incineration plant according to a first embodiment.

[0012] The incineration plant 101 shown in FIG. 1 includes an incinerator 1, a boiler 2, a steam turbine generator 3, a crane 4 that supplies waste to the incinerator 1, an exhaust gas treatment system 8, an oxygen-containing gas generation and supply system 6 having an oxygen-containing gas supply device GS1, a combustion air supply device AS1, a control device 90, and a memory device 9M.

[0013] 〔crane〕 The crane 4 is, for example, an overhead crane with a bucket, and supplies waste to the incinerator 1. The crane 4 can, by automatic or manual operation, for example, hoist waste from a waste pit 17 and dump it into the hopper 13 of the incinerator 1. A weighing scale 5 is installed on the crane 4 to measure the weight of the lifted waste, and the weight of the waste dumped into the hopper 13 is measured by the weighing scale 5.

[0014] [Incinerator] The incinerator 1 is a stoker type incinerator that burns waste. The incinerator 1 is equipped with a hopper 13, a chute 14, a feeder 16, a combustion chamber 10, a stoker device 15, an incineration ash discharge chute 18, and wind boxes B1 to B4. The combustion chamber 10 has a main combustion chamber 11 for drying and burning the waste, and a re-burning chamber 12 for completely burning the combustion gas generated in the main combustion chamber 11.

[0015] A chute 14 is connected to the inlet of the main combustion chamber 11. A feeder 16 is provided at the lower end of the chute 14 to push the waste onto the drying stoker 15a. The amount of waste fed into the main combustion chamber 11 is adjusted by the feeding speed of the feeder 16.

[0016] A stoker device 15 that transports waste in a predetermined direction X is disposed at the bottom of the main combustion chamber 11. The stoker device 15 has a plurality of stokers. In this example, the stoker device 15 has three stokers: a drying stoker 15a, a combustion stoker 15b, and a post-combustion stoker 15c. Waste is transported in the order of the drying stoker 15a, the combustion stoker 15b, and the post-combustion stoker 15c. The stokers 15a, 15b, and 15c are, for example, configured by alternating fixed grates and movable grates in a stepped manner, and the waste is transported sequentially downstream by the reciprocating motion of the movable grates.

[0017] In this stoker device 15, the drying stoker 15a is assigned to a drying zone where waste is dried. The combustion stoker 15b is assigned to a combustion zone where the dried waste is burned, and the post-combustion stoker 15c is assigned to a post-combustion zone where the unburned waste in the combustion zone is burned. The incineration ash remaining after combustion is discharged to the outside through a discharge chute 18. The combustion gas generated in the main combustion chamber 11 is sent to the re-combustion chamber 12 that extends diagonally upward, where it is mixed and stirred with secondary air and completely combusted.

[0018] Wind boxes B1-B4 are provided below the stokers 15a, 15b, and 15c, and primary air is supplied to the wind boxes B1-B4. The primary air sent to each of the wind boxes B1-B4 is supplied to the main combustion chamber 11 through gaps such as air holes provided in the stokers 15a, 15b, and 15c. One or more wind boxes are provided for each of the stokers 15a, 15b, and 15c.

[0019] Secondary air is also supplied to the main combustion chamber 11. This secondary air flows from the main combustion chamber 11 to the reburning chamber 12, where it is mixed and agitated with the combustion gas generated in the main combustion chamber 11 as described above.

[0020] [Boiler] The boiler 2 recovers exhaust heat from the incinerator 1 to generate steam. The flue 20, 21, 22 connected to the reburning chamber 12 of the incinerator 1 are configured with the boiler 2 to recover thermal energy from the combustion gas flowing through the flue 20, 21, 22 to generate steam. The water pipe 23 connected to the boiler drum 24 is laid on the walls of the first flue 20 and the second flue 21. The boiler drum 24 is also connected to the superheater tube 26 of the superheater 25. The superheater tube 26 is installed in the third flue 22, and the steam passing through the superheater tube 26 recovers the heat of the exhaust gas passing through the third flue 22. In this boiler 2, the heat recovery water flowing through the water pipe 23 recovers the heat of the first flue 20 and the second flue 21 and returns to the boiler drum 24 in the form of saturated steam. The steam from the boiler drum 24 is sent to the superheater 25. In the superheater 25, the steam sent from the boiler drum 24 is further superheated to a high temperature while passing through the superheater tube 26, and is then sent to the steam turbine generator 3 and to the air preheater 43. The amount of steam sent from the superheater 25 to the steam turbine generator 3 and the air preheater 43 is an index of the amount of steam generated in the boiler 2, and is measured by a steam flow meter 27.

[0021] [Steam turbine generator] The steam turbine generator 3 generates electricity by utilizing the thermal energy recovered by the boiler 2. This steam turbine generator 3 includes a turbine 3a to which steam is supplied from a superheater 25, and a generator 3b connected to the turbine 3a. The steam that has been made high temperature and high pressure by the superheater 25 is sent to the turbine 3a of the steam turbine generator 3 and used for generating electricity.

[0022] [Exhaust gas treatment system] The exhaust gas treatment system 8 includes an exhaust passage 81 connected to an exhaust port provided in the third flue 22, an exhaust gas treatment device 82 such as a bag filter connected to the exhaust passage 81, and an exhaust passage 83 that guides the exhaust gas discharged from the exhaust gas treatment device 82 to a chimney 84. After soot is separated from the exhaust gas introduced into the exhaust gas treatment device 82, the exhaust gas is discharged to the exhaust passage 83 and released into the atmosphere from the chimney 84. In addition, a carbon dioxide separation and capture device 61 described later is connected to the exhaust passage 83. Note that a portion of the exhaust gas after passing through the exhaust gas treatment device 82 may be configured to be returned to the incinerator 1 as a recirculated gas.

[0023] [Combustion air supply device] The combustion air supply device AS1 takes in outside air and supplies it as combustion air into the combustion chamber 10 of the incinerator 1, and is capable of adjusting the flow rate of the air supplied. The combustion air includes primary air supplied to the wind boxes B1 to B4 and secondary air supplied from air supply ports 10a and 10b installed on the ceiling or the like of the combustion chamber 10. The air supply ports 10a and 10b are installed in the combustion chamber 10 and are supply ports that supply combustion air directly to the combustion chamber 10.

[0024] The combustion air supply device AS1 has a blower 40, a combustion air supply line 50, a primary air supply line 51, and a secondary air supply line 52. The combustion air supply line 50 has an upstream end connected to the blower 40, a damper 30 serving as a flow rate regulator installed midway, and a downstream end branched into a primary air supply line 51 and a secondary air supply line 52. The primary air supply line 51 is a path for supplying combustion air to the wind boxes B1 to B4. A damper 45 serving as a flow rate regulator and an air preheater 43 are connected to the primary air supply line 51. The downstream side of the air preheater 43 of the primary air supply line 51 branches into branch lines 51a to 51d corresponding to the wind boxes B1 to B4, and dampers 46 to 49 serving as flow rate regulators are installed midway along the branch lines 51a to 51d. In addition, a bypass line 51e that bypasses the air preheater 43 and the damper 45 is connected to the primary air supply line 51, and a damper 44 serving as a flow rate regulator is installed midway along the bypass line 51e. The air preheater 43 is a heat exchanger that introduces a portion of the steam generated in the boiler 2 and heats the combustion air by heat exchange with the steam.

[0025] The secondary air supply line 52 is a path for supplying combustion air to the air supply ports 10a, 10b installed on the ceiling or the like of the combustion chamber 10. The secondary air supply line 52 is provided with a damper 53, which is a flow rate regulator, midway and is connected to the air supply ports 10a, 10b of the combustion chamber 10.

[0026] In this combustion air supply device AS1, outside air is taken in as combustion air by the blower 40 and sent to the combustion air supply line 50. The combustion air is supplied from the combustion air supply line 50 through the primary air supply line 51 and the secondary air supply line 52 into the combustion chamber 10. When the damper 44 is closed and the damper 45 is open, the combustion air supplied to the primary air supply line 51 is heated to a predetermined target temperature while passing through the air preheater 43, and is further supplied to the wind boxes B1 to B4 through the branch lines 51a to 51d. When it is not necessary to heat the combustion air, the damper 44 is opened and the damper 45 is closed, so that the combustion air is supplied to the wind boxes B1 to B4 through the bypass line 51e. The combustion air supplied to the wind boxes B1 to B4 is supplied to the combustion chamber 10 through gaps such as air insertion holes provided in the stokers 15a to 15c. The supply flow rate of the combustion air flowing through the branch lines 51a-51d can be increased by increasing the opening degree of the dampers 46-49, and the supply flow rate of the combustion air flowing through the branch lines 51a-51d can be decreased by decreasing the opening degree of the dampers 46-49. The supply flow rate of the combustion air flowing through the branch lines 51a-51d can be individually adjusted by controlling the opening degree of the dampers 46-49.

[0027] Moreover, the combustion air supplied to the secondary air supply line 52 is supplied into the combustion chamber 10 from the air supply ports 10a, 10b of the combustion chamber 10. By increasing the opening of the damper 53, the supply flow rate of the combustion air flowing through the secondary air supply line 52 can be increased, and by decreasing the opening of the damper 53, the supply flow rate of the combustion air flowing through the secondary air supply line 52 can be decreased.

[0028] An oxygen-containing gas supply line L1, through which an oxygen-containing gas described below is supplied, is connected to the combustion air supply line 50 downstream of the damper 30. Although only the combustion air taken in from the outside has been described above, a mixed gas obtained by mixing the combustion air made of the outside air and the oxygen-containing gas is supplied to the primary air supply line 51 and the secondary air supply line 52, and is further supplied into the combustion chamber 10.

[0029] [Oxygen-containing gas generation and supply system] The oxygen-containing gas generation and supply system 6 includes a water vapor generator 60, a carbon dioxide separation and capture device 61, an electrolytic methanation device 62, and an oxygen-containing gas supply device GS1. The oxygen-containing gas supply device GS1 includes a pump 63, a gas holder 64, a dehumidifier 65, a damper 70 which is a flow rate regulator, and an oxygen-containing gas supply line L1.

[0030] The water vapor generator 60 heats water to generate water vapor, and sends the generated water vapor to the electrolytic methanation device 62 .

[0031] The carbon dioxide separation and capture device 61 introduces the exhaust gas discharged from the exhaust gas treatment device 82 into the exhaust path 83, separates and captures carbon dioxide from the exhaust gas, and sends the separated and captured carbon dioxide to the electrolytic methanation device 62. The carbon dioxide separation and capture device 61 also discharges the exhaust gas from which carbon dioxide has been removed into the exhaust path 83. The carbon dioxide separation and capture device 61 may be any equipment capable of separating and capturing carbon dioxide from the exhaust gas, and may be any known equipment such as equipment using a solid absorbent material with an amine coated on its surface or equipment using an absorbing liquid containing an amine. Here, a portion of the exhaust gas discharged from the exhaust gas treatment device 82 is introduced into the carbon dioxide separation and capture device 61, but the device may be configured to introduce all of the exhaust gas discharged from the exhaust gas treatment device 82.

[0032] The electrolytic methanation device 62 receives the steam generated in the steam generator 60 and the carbon dioxide separated and captured in the carbon dioxide capture device 61, and generates methane, water (steam), and oxygen through electrolysis of the steam and the Sabatier reaction. Thus, the electrolytic methanation device 62 is a methane production device.

[0033] 2 is a diagram showing an outline of the structure of a cell used in the electrolytic methanation device 62. In the cell of the electrolytic methanation device 62, an electrolyte layer 622 is sandwiched between a positive electrode 621 and a negative electrode 623, and a catalyst layer 624 is formed on the outer surface of the negative electrode 623. Water vapor (H2O) is electrolyzed at the positive electrode 621 to produce oxygen (O2) and hydrogen ions (H + ) and hydrogen ions (H + ) moves through the electrolyte layer 622 to the negative electrode 623, and converts into hydrogen ions (H + The Sabatier reaction between argon and carbon dioxide (CO2) produces water vapor (H2O) and methane (CH4).

[0034] As a result, the following reaction occurs in the electrolytic methanation device 62: CO2+4H2O→CH4+2H2O+2O2 The electrolytic methanation device 62 is provided with one or more cells as shown in FIG. 2. The electrolytic methanation device 62 is provided with a first gas outlet from which methane gas containing generated water vapor is taken out, and a second gas outlet from which oxygen-containing gas in which generated oxygen and excess water vapor that has been introduced and not electrolyzed are mixed is taken out. The oxygen-containing gas taken out from the second gas outlet has a temperature of about 180 to 300°C, which is a higher temperature gas than the outside air taken in from the blower 40. The second gas outlet is connected to a pump 63 by a pipe. In addition, the methane gas taken out from the first gas outlet can be used as fuel, etc.

[0035] The oxygen-containing gas taken out from the second gas outlet of the electrolytic methanation device 62 is sent to the oxygen-containing gas supply device GS1, compressed to a predetermined pressure by the pump 63 of the oxygen-containing gas supply device GS1, and temporarily stored in the gas holder 64. The oxygen-containing gas supply line L1 has an upstream end connected to the gas holder 64 and a downstream end connected to the combustion air supply line 50, and a dehumidifier 65 and a damper 70, which is a flow regulator, are connected in the middle. By increasing the opening of the damper 70, the supply flow rate of the oxygen-containing gas flowing through the oxygen-containing gas supply line L1 can be increased, and by decreasing the opening of the damper 70, the supply flow rate of the oxygen-containing gas flowing through the oxygen-containing gas supply line L1 can be decreased. The oxygen-containing gas stored in the gas holder 64 is dehumidified by the dehumidifier 65 through the oxygen-containing gas supply line L1 and sent to the combustion air supply line 50, mixed with the combustion air, and sent to the incinerator 1 together with the combustion air.

[0036] As described above, the oxygen-containing gas extracted by the electrolytic methanation device 62 is temporarily stored in the gas holder 64, so that the oxygen-containing gas can be stably supplied to the oxygen-containing gas supply line L1. The dehumidifier 65 may be installed upstream of the gas holder 64. Also, a configuration without the dehumidifier 65 is possible.

[0037] The control device 90 is configured to include, for example, a CPU and a memory, and the CPU executes a control program stored in the memory to perform various calculations and control the operation of each component of the incineration plant 101. That is, the control device 90 controls the incinerator 1, the boiler 2, the steam turbine generator 3, the crane 4, the exhaust gas treatment device 82, and the like. The control device 90 is also configured to be able to communicate with the weighing scale 5, and acquires the weight of the waste put into the hopper 13 by the crane 4 from the weighing scale 5. The control device 90 also acquires the amount of steam measured from the steam flowmeter 27. The control device 90 also includes functions as a calorific value calculation device 91, a mixture ratio calculation device 92, and a supply flow rate controller 93. The control device 90 may be configured as a single control device that performs centralized control, or may be configured as a plurality of control devices that cooperate with each other to perform distributed control.

[0038] The memory 9M stores information necessary for the control device 90 to function as the heat generation amount calculation device 91, the mixture ratio calculation device 92, etc. The memory 9M may be included in the control device 90.

[0039] It should be noted that the functions of the control device 90 disclosed herein can be performed using circuits or processing circuits including general purpose processors, special purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, or combinations thereof configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this specification, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed in this specification or other known hardware that is programmed or configured to perform the recited functions. If the hardware is a processor that is considered a type of circuit, the circuit, unit, or means is a combination of hardware and software, and the software is used to configure the hardware or processor.

[0040] During the operation of this incineration plant 101, combustion air consisting of outside air taken in by the blower 40 and oxygen-containing gas stored in the gas holder 64 are supplied to the combustion chamber 10. In addition, waste appropriately fed into the hopper 13 by the crane 4 is temporarily stored in the chute 14, and is pushed out from the inlet of the main combustion chamber 11 onto the drying stoker 15a by the feeder 16. As the waste passes over the drying stoker 15a, it is dried by the primary air containing oxygen-containing gas and the radiant heat of the main combustion chamber 11, and is burned on the combustion stoker 15b, and the remaining unburned waste is burned while being transported by the post-combustion stoker 15c. The main ash remaining after combustion is discharged from the discharge chute 18 and supplied to the incineration ash treatment facility. The combustion gas generated in the main combustion chamber 11 is mixed with the secondary air containing oxygen-containing gas blown out to the inlet of the re-combustion chamber 12, and is completely burned in the re-combustion chamber 12.

[0041] Then, the exhaust gas discharged from the boiler 2 after the combustion gas passes through the flue gas ducts 20, 21, 22 is separated from soot in the exhaust gas treatment device 82, and then released into the atmosphere from the chimney 84. Carbon dioxide separated and recovered from the exhaust gas in the carbon dioxide separation and capture device 61 is introduced into the electrolytic methanation device 62. Steam generated in the steam generator 60 is introduced into the electrolytic methanation device 62, and methane gas and an oxygen-containing gas are extracted. The oxygen-containing gas is compressed by the pump 63 and temporarily stored in the gas holder 64. Steam generated in the boiler 2 is sent to the steam turbine generator 3 and also to the air preheater 43.

[0042] Next, a case where the control device 90 functions as the calorific value calculation device 91, the mixture ratio calculation device 92, and the supply flow rate controller 93 while the incineration plant 101 is in operation will be described.

[0043] The calorific value calculation device 91 calculates the calorific value of the waste at a predetermined timing. At this time, the calorific value calculation device 91 calculates the calorific value of the waste using a predetermined calorific value calculation formula with variables such as the input weight of the waste obtained from the weight meter 5 and the amount of steam obtained from the steam flow meter 27. The calorific value calculation formula is stored in advance in, for example, the memory 9M. The calorific value of the waste may be calculated by other known calculation methods. In addition, when the boiler 2 is not provided, there is also a method of calculating the calorific value based on the gas temperature of the combustion gas generated in the incinerator 1.

[0044] The mixing ratio calculation device 92 calculates the mixing ratio of the combustion air and the oxygen-containing gas supplied to the combustion chamber 10 of the incinerator 1 so as to reach the target oxygen concentration according to the calorific value of the waste calculated by the calorific value calculation device 91. Here, a relational expression between the calorific value of the waste and the target oxygen concentration when a good combustion state is obtained in the incinerator 1 is stored in advance in the memory 9M. This relational expression includes a relationship that, for example, the higher the calorific value, the easier the waste is to burn, and therefore the higher the calorific value, the lower the oxygen concentration. Based on this relational expression, the target oxygen concentration according to the calorific value of the waste calculated by the calorific value calculation device 91 is calculated, and the mixing ratio of the combustion air and the oxygen-containing gas is calculated so that the oxygen concentration of the mixed gas of the combustion air and the oxygen-containing gas supplied to the combustion chamber 10 reaches the target oxygen concentration. At this time, the oxygen concentration of the outside air, which is the combustion air, is set to a predetermined value A, and the oxygen concentration of the oxygen-containing gas supplied from the gas holder 64 is set to a predetermined value B, so that the mixing ratio can be calculated. In other words, the mixing ratio is the ratio of the supply flow rates of the combustion air and the oxygen-containing gas.

[0045] The supply flow rate controller 93 controls the combustion air supplying device AS1 and the oxygen-containing gas supplying device GS1 so that the ratio between the flow rate of the combustion air supplied by the combustion air supplying device AS1 and the flow rate of the oxygen-containing gas supplied by the oxygen-containing gas supplying device GS1 becomes the mixture ratio calculated by the mixture ratio calculation device 92. Specifically, the opening degree of the dampers 30, 70 is controlled so that the ratio between the flow rate of the combustion air passing through the damper 30 of the combustion air supplying line 50 and the flow rate of the oxygen-containing gas passing through the damper 70 of the oxygen-containing gas supplying line L1 becomes the mixture ratio. At this time, the total flow rate of the combustion air and the oxygen-containing gas may be set to a predetermined flow rate. The supply flow rate controller 93 may control all dampers 30, 44 to 49, 53, 70 provided in the combustion air supplying device AS1 and the oxygen-containing gas supplying device GS1.

[0046] According to this embodiment, carbon dioxide separated and captured by the carbon dioxide separation and capture device 61 from the exhaust gas discharged from the incinerator 1, and water vapor generated by the water vapor generator 60 are introduced into the electrolytic methanation device 62. Then, methane gas and an oxygen-containing gas containing oxygen and water vapor are extracted from the electrolytic methanation device 62. This makes it possible to reduce the amount of carbon dioxide discharged to the outside. In addition, the calorific value calculation device 91 calculates the calorific value of the waste, and the mixture ratio calculation device 92 calculates the mixture ratio of the combustion air and the oxygen-containing gas supplied to the incinerator 1 so that the oxygen concentration of the mixed gas of the combustion air and the oxygen-containing gas supplied to the incinerator 1 becomes a target oxygen concentration according to the calculated calorific value. Then, the supply flow rate controller 93 controls the supply flow rate of the combustion air by the combustion air supply device AS1 and the supply flow rate of the oxygen-containing gas by the oxygen-containing gas supply device GS1 so that the calculated mixture ratio is obtained, thereby making it possible to efficiently combust the waste in the incinerator 1. In addition, the oxygen-containing gas extracted as a by-product from the electrolytic methanation device 62 that generates methane gas can be effectively utilized.

[0047] In this embodiment, oxygen-containing gas is supplied to the combustion air supply line 50 on the upstream side of the primary air supply line 51. Therefore, oxygen-containing gas is supplied to the primary air supply line 51 upstream of the air preheater 43. The oxygen-containing gas is hotter than the outside air taken in as combustion air by the combustion air supply device AS1, and the air preheater 43 is supplied with a mixed gas hotter than the outside air, which is a mixture of the combustion air and the high-temperature oxygen-containing gas. In the air preheater 43, the amount of steam introduced from the boiler 2 is controlled so that the temperature of the supplied mixed gas becomes a target temperature. Since the mixed gas supplied to the air preheater 43 is hotter than the outside air, the amount of steam introduced from the boiler 2 to the air preheater 43 can be reduced compared to the case where only the outside air is taken in to the air preheater 43. This increases the amount of steam introduced to the steam turbine generator 3, increasing the amount of power generation, and improving the power generation efficiency of the entire incineration plant.

[0048] Second embodiment Fig. 3 is a schematic diagram showing an example of an incineration plant according to the second embodiment. The incineration plant 102 shown in Fig. 3 is different from the incineration plant 101 shown in Fig. 1 in that the configurations of the combustion air supply device AS2 and the oxygen-containing gas supply device GS2 are partially changed.

[0049] The combustion air supplying device AS2 is equipped with two blowers 41, 42 that take in outside air and send it out as combustion air. That is, it is equipped with the blower 41 that sends out combustion air to the primary air supplying line 51, and the blower 42 that sends out combustion air to the secondary air supplying line 52. The primary air supplying line 51 is provided with a damper 31 that adjusts the supply flow rate of the combustion air supplied from the blower 41, and the secondary air supplying line 52 is provided with a damper 32 that adjusts the supply flow rate of the combustion air supplied from the blower 42. Other parts are the same as those of the combustion air supplying device AS1 shown in FIG. 1.

[0050] 1 to the combustion air supplying apparatus AS2, the oxygen-containing gas supplying apparatus GS2 has an oxygen-containing gas supplying line L1 branched into two gas supplying lines L11 and L12. One gas supplying line L11 is connected to the primary air supplying line 51 downstream of the damper 31, and the other gas supplying line L12 is connected to the secondary air supplying line 52 downstream of the damper 32. The gas supplying lines L11 and L12 are provided with dampers 71 and 72, respectively, for adjusting the supply flow rate of the oxygen-containing gas.

[0051] In the case of the second embodiment, the actual mixture ratio of the combustion air and the oxygen-containing gas is the ratio between the total flow rate of the combustion air passing through the two dampers 31, 32 and the total flow rate of the oxygen-containing gas passing through the two dampers 71, 72. Therefore, the supply flow rate controller 93 controls the openings of the dampers 31, 32 and the dampers 71, 72 so that the ratio between the total flow rate of the combustion air passing through the two dampers 31, 32 and the total flow rate of the oxygen-containing gas passing through the two dampers 71, 72 becomes the mixture ratio calculated by the mixture ratio calculation device 92. In the second embodiment, the same effects as in the first embodiment can be obtained.

[0052] Third embodiment Fig. 4 is a schematic diagram showing an example of an incineration plant according to the third embodiment. The incineration plant 103 shown in Fig. 4 is different from the incineration plant 101 shown in Fig. 1 in that the configurations of the combustion air supply device AS3 and the oxygen-containing gas supply device GS3 are partially changed.

[0053] The combustion air supplying device AS3 does not have the damper 30 in FIG. 1, and other parts are the same as the combustion air supplying device AS1 shown in FIG. 1. In the oxygen-containing gas supplying device GS3, the oxygen-containing gas supplying line L1 is branched into two gas supplying lines L11 and L12. One of the gas supplying lines L11 is branched into four gas supplying branching lines La to Ld, and the gas supplying branching lines La to Ld are connected to the downstream side of the dampers 46 to 49 of the branching lines 51a to 51d of the primary air supplying line. Each of the gas supplying branching lines La to Ld is provided with a damper 66 to 69 for adjusting the supply flow rate of the oxygen-containing gas. By controlling the opening degree of the dampers 66 to 69, the supply flow rate of the oxygen-containing gas supplied from the gas supplying branching lines La to Ld to the branching lines 51a to 51d can be individually adjusted.

[0054] In the case of the third embodiment, the actual mixture ratio of the combustion air and the oxygen-containing gas is the ratio between the total flow rate of the combustion air passing through the dampers 44, 45, 53 and the total flow rate of the oxygen-containing gas passing through the five dampers 66-69, 72. Therefore, the supply flow rate controller 93 controls the opening degree of the dampers 44, 45, 53 and the dampers 66-69, 72 so that the ratio between the total flow rate of the combustion air passing through the dampers 44, 45, 53 and the total flow rate of the oxygen-containing gas passing through the dampers 66-69, 72 becomes the mixture ratio calculated by the mixture ratio calculation device 92. In the third embodiment, the same effects as in the first embodiment can be obtained.

[0055] In the third embodiment, the ratio of the combustion air and the oxygen-containing gas supplied to each of the wind boxes B1-B4 can be adjusted by controlling the opening of the dampers 46-49 and the dampers 66-69. Thus, the oxygen concentration of the mixed gas supplied to the combustion chamber 10 from the wind boxes B1-B4 through the stokers 15a-15c can be adjusted for each of the drying zones, combustion zones, and post-combustion zones to which the stokers 15a-15c are assigned.

[0056] (Fourth embodiment) Fig. 5 is a schematic diagram showing an example of an incineration plant according to the fourth embodiment. The incineration plant 104 shown in Fig. 5 is different from the incineration plant 103 shown in Fig. 4 in that the configurations of the combustion air supply device AS4 and the oxygen-containing gas supply device GS4 are partially changed.

[0057] The combustion air supplying device AS4 is equipped with two fans 41 and 42 that take in outside air and send it out as combustion air. That is, it is equipped with the fan 41 that sends out combustion air to the primary air supplying line 51, and the fan 42 that sends out combustion air to the secondary air supplying line 52. The secondary air supplying line 52 is provided with a damper 32 that adjusts the supply flow rate of the combustion air supplied from the fan 42. Other parts are the same as the combustion air supplying device AS3 shown in FIG.

[0058] In the oxygen-containing gas supplying apparatus GS4, the oxygen-containing gas supplying line L1 is branched into two gas supplying lines L11 and L12, similar to the oxygen-containing gas supplying line L1 shown in Fig. 4. One of the gas supplying lines L11 is branched into four gas supplying branching lines La-Ld, similar to the gas supplying line L11 shown in Fig. 4, and the gas supplying branching lines La-Ld are connected to the downstream side of the dampers 46-49 of the branching lines 51a-51d of the primary air supplying line. The other gas supplying line L12 is connected to the secondary air supplying line 52 downstream of the damper 32. The rest of the configuration is the same as the oxygen-containing gas supplying apparatus GS3 shown in Fig. 4.

[0059] In the case of the fourth embodiment, the actual mixture ratio of the combustion air and the oxygen-containing gas is the ratio between the total flow rate of the combustion air passing through the dampers 32, 44, 45 and the total flow rate of the oxygen-containing gas passing through the five dampers 66-69, 72. Therefore, the supply flow rate controller 93 controls the opening degree of the dampers 32, 44, 45 and the dampers 66-69, 72 so that the ratio between the total flow rate of the combustion air passing through the dampers 32, 44, 45 and the total flow rate of the oxygen-containing gas passing through the dampers 66-69, 72 becomes the mixture ratio calculated by the mixture ratio calculation device 92. In the fourth embodiment, the same effect as in the third embodiment can be obtained.

[0060] In the fourth embodiment, as in the third embodiment, the ratio of the combustion air and the oxygen-containing gas supplied to each of the wind boxes B1-B4 can be adjusted by controlling the opening of the dampers 46-49 and the dampers 66-69. Thus, the oxygen concentration of the mixed gas supplied to the combustion chamber 10 from the wind boxes B1-B4 through the stokers 15a-15c can be adjusted for each of the drying zones, combustion zones, and post-combustion zones to which the stokers 15a-15c are assigned.

[0061] In the above first to fourth embodiments, the oxygen-containing gas is supplied to both the primary air supply line 51, 51a to 51d and the secondary air supply line 52, but the oxygen-containing gas may be supplied to only one of the primary air supply line 51, 51a to 51d and the secondary air supply line 52.

[0062] In the first to fourth embodiments, the carbon dioxide separated and recovered from the exhaust gas of the incinerator 1 is introduced into the electrolytic methanation device 62, but this is not limited thereto. For example, when the incineration plants 101 to 104 are provided with a methane fermentation device that performs methane fermentation on waste that is not input to the incinerator 1, a carbon dioxide separation and capture device that separates and captures carbon dioxide from the biogas generated by the methane fermentation device may be installed, and the carbon dioxide separated and captured by this carbon dioxide separation and capture device may be introduced into the electrolytic methanation device 62. Therefore, at least one of the carbon dioxide separated and captured from the exhaust gas discharged from the incinerator 1 and the carbon dioxide separated and captured from the biogas generated by methane fermentation of the waste that is not input to the incinerator 1 may be configured to be introduced into the electrolytic methanation device 62.

[0063] From the above description, many improvements and other embodiments of the present disclosure will be apparent to those skilled in the art. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present disclosure.

[0064] Summary of the Disclosure The incineration plant according to the first aspect of the present disclosure includes an incinerator for burning waste, a combustion air supplying device that takes in outside air and supplies it to the incinerator as combustion air and is capable of adjusting the flow rate of the supply, a steam generating device that generates steam, an electrolytic methanation device that introduces at least one of carbon dioxide separated and recovered from exhaust gas discharged from the incinerator and carbon dioxide separated and recovered from biogas generated by methane fermentation of waste that has not been input to the incinerator, and the steam generated by the steam generating device, and causes electrolysis of the steam and a Sabatier reaction to extract methane gas and an oxygen-containing gas containing oxygen and water vapor, and a gas supplying device that supplies the oxygen-containing gas extracted by the electrolytic methanation device to the incinerator. the incinerator is provided with an oxygen-containing gas supply device that supplies an oxygen-containing gas to the incinerator and is capable of adjusting the flow rate of the gas supplied; a heat generation amount calculation device that calculates a heat generation amount of the waste to be combusted in the incinerator; a mixing ratio calculation device that calculates a target oxygen concentration according to the heat generation amount of the waste calculated by the heat generation amount calculation device based on a predetermined relationship between the heat generation amount and a target oxygen concentration, and calculates a mixing ratio of the combustion air and the oxygen-containing gas so that the oxygen concentration of a gas obtained by mixing the combustion air and the oxygen-containing gas and supplied to the incinerator becomes the calculated target oxygen concentration; and a supply flow rate controller that controls the combustion air supply device and the oxygen-containing gas supply device so that the supply flow rates of the combustion air and the oxygen-containing gas become the mixing ratios calculated by the mixing ratio calculation device.

[0065] According to this configuration, at least one of carbon dioxide separated and recovered from the exhaust gas of the incinerator and carbon dioxide separated and recovered from the biogas generated by methane fermentation of waste not fed into the incinerator, and water vapor are introduced into the electrolytic methanation device. Then, methane gas and an oxygen-containing gas containing oxygen and water vapor are extracted from the electrolytic methanation device. This makes it possible to reduce the amount of carbon dioxide discharged to the outside. In addition, the calorific value of the waste is calculated, a target oxygen concentration according to the calorific value is calculated, and a mixture ratio of the combustion air and the oxygen-containing gas is calculated so that the oxygen concentration of a gas obtained by mixing the combustion air and the oxygen-containing gas becomes the calculated target oxygen concentration. Then, the flow rate of the combustion air supplied by the combustion air supply device and the flow rate of the oxygen-containing gas supplied by the oxygen-containing gas supply device are controlled so as to obtain the calculated mixture ratio, thereby making it possible to efficiently burn the waste in the incinerator.

[0066] An incineration plant according to a second aspect of the present disclosure is an incineration plant according to the first aspect, wherein the incinerator has a combustion chamber for burning waste, a plurality of stokers installed below the combustion chamber and arranged in the direction of transport of waste, and a plurality of wind boxes installed below the plurality of stokers, the combustion air supply device has a primary air supply line that supplies the combustion air to the wind box, and a secondary air supply line that supplies the combustion air to an air supply port installed in the combustion chamber, and the oxygen-containing gas supply device supplies the oxygen-containing gas to at least one of the primary air supply line and the secondary air supply line.

[0067] According to this configuration, the incinerator is a stoker-type incinerator, and by supplying oxygen-containing gas to at least one of the primary air supply line and the secondary air supply line, the oxygen-containing gas can be mixed with the combustion air and supplied to the combustion chamber.

[0068] An incineration plant according to a third aspect of the present disclosure is the incineration plant according to the second aspect, further comprising a boiler for recovering exhaust heat from the incinerator, and a steam turbine generator for generating electricity using steam generated in the boiler, the combustion air supply device further having an air preheater disposed midway along the primary air supply line for introducing steam generated in the boiler and heating the combustion air to a target temperature by heat exchange with the steam, and the oxygen-containing gas supply device supplies the oxygen-containing gas to the primary air supply line upstream of the air preheater.

[0069] According to this configuration, oxygen-containing gas is supplied to the primary air supply line upstream of the air preheater. The oxygen-containing gas is hotter than the outside air taken in as combustion air by the combustion air supply device, and a mixture of the combustion air and the high-temperature oxygen-containing gas passes through the air preheater, so the amount of steam introduced from the boiler to heat the air to a target temperature in the air preheater can be reduced. This increases the amount of steam introduced to the steam turbine generator, thereby increasing the amount of power generation.

[0070] An incineration plant according to a fourth aspect of the present disclosure is the incineration plant according to the second aspect, wherein the primary air supply line supplies the combustion air to each of the plurality of wind boxes and has a plurality of branch lines capable of adjusting the supply flow rate of the combustion air, and the oxygen-containing gas supply device supplies the oxygen-containing gas to the plurality of branch lines and is capable of individually adjusting the supply flow rate of the oxygen-containing gas supplied to the branch lines.

[0071] According to this configuration, the ratio of the combustion air and the oxygen-containing gas supplied to each wind box can be adjusted, and therefore the oxygen concentration of the mixed gas supplied from the wind box to the combustion chamber via the stoker can be adjusted, for example, for each stoker.

[0072] An incineration plant according to a fifth aspect of the present disclosure is an incineration plant according to any one of the first to fourth aspects, wherein the oxygen-containing gas supply device has a gas holder that stores the oxygen-containing gas extracted by the electrolytic methanation device in a compressed state at a predetermined pressure, and supplies the oxygen-containing gas stored in the gas holder.

[0073] According to this configuration, the oxygen-containing gas supply device can stably supply the oxygen-containing gas by temporarily storing the oxygen-containing gas extracted by the electrolytic methanation device in the gas holder. [Explanation of symbols]

[0074] 1 Incinerator 2. Boiler 3. Steam turbine generator 10 Combustion chamber 10a, 10b Air supply port 15a, 15b, 15c Stalker 43 Air preheater 51 Primary air supply line 51a, 51b, 51c, 51d Branch lines 52 Secondary air supply line 60 Steam Generator 62 Electrolytic methanation equipment 64 Gas Holder 91 Calorific value calculation device 92 Mixture ratio calculation device 93 Supply flow controller 101~104 Incineration plant AS1~AS4 Combustion air supply device GS1~GS4 Oxygen-containing gas supply equipment B1~B4 Wind box

Claims

1. an incinerator for burning waste; A combustion air supply device that takes in outside air and supplies it to the incinerator as combustion air and is capable of adjusting the flow rate of the air supplied; A water vapor generator for generating water vapor; an electrolytic methanation device into which at least one of carbon dioxide separated and recovered from the exhaust gas discharged from the incinerator and carbon dioxide separated and recovered from biogas generated by methane fermentation of waste not input to the incinerator and water vapor generated in the water vapor generator is introduced, and electrolysis of the water vapor and a Sabatier reaction are caused to occur, thereby extracting methane gas and an oxygen-containing gas containing oxygen and water vapor; An oxygen-containing gas supply device capable of supplying the oxygen-containing gas extracted by the electrolytic methanation device to the incinerator and adjusting the flow rate of the gas supplied; A calorific value calculation device for calculating the calorific value of the waste burned in the incinerator; a mixing ratio calculation device that calculates a target oxygen concentration according to the calorific value of the waste calculated by the calorific value calculation device based on a predetermined relationship between the calorific value and a target oxygen concentration, and calculates a mixing ratio of the combustion air and the oxygen-containing gas so that the oxygen concentration of a gas obtained by mixing the combustion air and the oxygen-containing gas supplied to the incinerator becomes the calculated target oxygen concentration; a supply flow rate controller that controls the combustion air supply device and the oxygen-containing gas supply device so that the supply flow rate of the combustion air and the supply flow rate of the oxygen-containing gas become equal to the mixture ratio calculated by the mixture ratio calculation device; An incineration plant equipped with

2. The incinerator comprises: a combustion chamber for burning waste; A plurality of stokers are installed below the combustion chamber, transport the waste, and are arranged in the transport direction; A plurality of wind boxes installed below the plurality of stokers, The combustion air supply device includes: a primary air supply line that supplies the combustion air to the wind box; a secondary air supply line that supplies the combustion air to an air supply port provided in the combustion chamber; The oxygen-containing gas supply device is supplying the oxygen-containing gas to at least one of the primary air supply line and the secondary air supply line; 2. Incineration plant according to claim 1.

3. A boiler for recovering exhaust heat from the incinerator; a steam turbine generator that generates electricity using steam generated in the boiler; and Further equipped with The combustion air supply device includes: The present invention further includes an air preheater that is disposed in the primary air supply line, introduces steam generated in the boiler, and heats the combustion air to a target temperature by heat exchange with the steam. The oxygen-containing gas supply device is supplying the oxygen-containing gas to the primary air supply line upstream of the air preheater; 3. An incineration plant according to claim 2.

4. The primary air supply line includes: a plurality of branch lines that supply the combustion air to each of the plurality of wind boxes and are capable of adjusting the supply flow rate of the combustion air; The oxygen-containing gas supply device is The oxygen-containing gas is supplied to a plurality of the branch lines, and the supply flow rates of the oxygen-containing gas supplied to the branch lines are individually adjustable.

3. An incineration plant according to claim 2.

5. The oxygen-containing gas supply device is A gas holder is provided for storing the oxygen-containing gas extracted by the electrolytic methanation apparatus in a compressed state at a predetermined pressure, and the oxygen-containing gas stored in the gas holder is supplied. The incineration plant according to any one of claims 1 to 4.

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