Waste incineration system

Abstract

This helps to prevent a decrease in the concentration of carbon dioxide emitted from incinerators. [Solution] The waste incineration system comprises a combustion chamber through which waste is burned while being transported by a grate; an inlet into which the waste is fed; a waste chute connected to the inlet through which the waste fed into the combustion chamber passes; a first valve having an inclined valve body, the valve body moving diagonally upward to close the passage of the waste chute and the valve body moving diagonally downward to open the passage of the waste chute; and a second valve provided downstream of the first valve, which opens and closes the passage of the waste chute.

Description

Technical Field

[0001] The present invention relates to a waste incineration system.

Background Art

[0002] There is, for example, a waste incineration system disclosed in Patent Document 1 as an invention related to oxygen combustion for increasing the concentration of carbon dioxide in exhaust gas by separating carbon dioxide from the exhaust gas generated in an incinerator for incinerating waste and supplying a mixed gas obtained by mixing oxygen with the separated carbon dioxide or the exhaust gas as an oxidant to the incinerator. In this waste incineration system, the cleaned exhaust gas is branched into two paths. One of the exhaust gases is separated from carbon dioxide by a separation device, and the separated carbon dioxide is mixed with oxygen and returned to the incinerator. The other branched exhaust gas is separated by liquefying the carbon dioxide contained in the exhaust gas by a liquefaction device. The exhaust gas sent to the liquefaction device has a higher concentration of carbon dioxide because the carbon dioxide separated from the exhaust gas is returned to the incinerator, so that carbon dioxide can be liquefied more efficiently as compared with the case where the mixed gas is not supplied to the incinerator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In stoker furnaces used for incinerating waste, harmful components are present in the gas generated inside the furnace. To prevent these harmful components from leaking out, the internal pressure is kept lower than the external pressure. However, in stoker furnaces, the waste inlet is open to the outside, allowing air to unintentionally flow into the low-pressure furnace. While the waste acts as a material seal between the inlet and the furnace, it is difficult to completely stop the airflow with waste. Oxygen from the air that unintentionally flows into the furnace is consumed in combustion along with oxygen in the mixed gas and oxygen supplied as an oxidizer. However, the amount of nitrogen remaining in the exhaust gas increases by the amount of nitrogen from the incoming air. Therefore, even if oxygen combustion is performed, it becomes difficult to sufficiently concentrate carbon dioxide in the exhaust gas. This may result in the inability to efficiently liquefy carbon dioxide from the exhaust gas.

[0005] The present invention has been made in view of the above, and aims to suppress the decrease in the concentration of carbon dioxide emitted from an incinerator. [Means for solving the problem]

[0006] A waste incineration system according to one aspect of the present invention comprises: a combustion chamber for burning waste while transporting it by a grate; an input port into which the waste is fed; a waste chute connected to the input port and forming a passage through which the waste fed into the combustion chamber passes; a first valve having an inclined valve body, the valve body moving diagonally upward to close the passage of the waste chute and the valve body moving diagonally downward to open the passage of the waste chute; and a second valve provided downstream of the first valve for opening and closing the passage of the waste chute.

[0007] Furthermore, in a waste incineration system according to one aspect of the present invention, the first valve has a horizontal plate-shaped first contact portion connected to the upper end of the inclined valve body and a horizontal plate-shaped second contact portion connected to the lower end of the inclined valve body, the waste chute has a first seal portion to which the upper surface of the first contact portion contacts and a second seal portion to which the upper surface of the second contact portion contacts, and when the valve body closes the waste chute, the first contact portion contacts the first seal portion and the second contact portion contacts the second seal portion to close the waste chute. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the decrease in the concentration of carbon dioxide emitted from the incinerator. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows the overall configuration of a waste incineration system according to an embodiment of the present invention. [Figure 2A] Figure 2A is a schematic diagram of a slide gate valve according to an embodiment. [Figure 2B] Figure 2B is a schematic diagram of a slide gate valve according to an embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the present invention is not limited to the embodiments described below. Furthermore, in the drawings, the same or corresponding elements are denoted by the same reference numerals as appropriate. It should also be noted that the drawings are schematic, and the dimensional relationships of each element may differ from those in reality.

[0011] Figure 1 shows the configuration of the waste incineration system SYS according to an embodiment of the present invention. The waste incineration system SYS comprises a waste incinerator 1 that employs a combustion technology called O2 / CO2 combustion, oxygen combustion, or oxygen-fuel combustion.

[0012] The waste incinerator 1 is, for example, a stoker-type incinerator and is equipped with a combustion chamber 2, an inlet 3, and a waste chute 80. The inlet 3 is an inlet for introducing waste W, such as industrial waste or household waste, into the combustion chamber 2, and is located upstream of the flow of waste W in the waste incinerator 1, above the combustion chamber 2. The waste chute 80 is connected to the inlet 3. Below the inlet 3, an extruder 3a is positioned to push the introduced waste W into the waste chute 80. The waste W introduced into the inlet 3 is pushed into the waste chute 80 by the extruder 3a.

[0013] The waste chute 80 is a passage through which the waste W pushed out by the extruder 3a falls. The waste chute 80 is connected to the combustion chamber 2. Below the waste chute 80, a dust feeder 3b is positioned to push the waste W that has fallen through the waste chute 80 into the combustion chamber 2. The waste W that has fallen through the waste chute 80 is pushed into the combustion chamber 2 by the dust feeder 3b.

[0014] The waste chute 80 is equipped with a slide gate valve 81, a flap valve 82, a replacement gas supply passage 83, an exhaust passage 84, and a sensor 85. The slide gate valve 81, which is an example of the first valve according to the present invention, is installed above the flap valve 82. The slide gate valve 81 moves a plate-shaped valve body by a drive device (not shown). When the valve body of the slide gate valve 81 is moved outside the waste chute 80, it opens the waste chute 80 and allows the waste W to pass through, and when the valve body is moved inside the waste chute 80, it closes the passage of the waste chute 80 and blocks the passage of the waste W.

[0015] Figures 2A and 2B are schematic diagrams showing the configuration of the slide gate valve 81. The slide gate valve 81 has a valve body 81a, a first contact portion 81b, a second contact portion 81c, a first seal portion 81d, a second seal portion 81e, a first housing portion 81f, and a second housing portion 81g.

[0016] The valve body 81a is made of metal, is plate-shaped, and moves by a drive mechanism (not shown). The valve body 81a is inclined such that one end is higher than the other in the vertical direction. The angle between the valve body 81a and the horizontal is preferably less than 45 degrees. The valve body 81a has a first contact portion 81b at one end and a second contact portion 81c at the other end.

[0017] The first contact portion 81b is plate-shaped and horizontal, and is connected to the valve body 81a at one end of the valve body 81a. The second contact portion 81c is plate-shaped and horizontal, and is connected to the valve body 81a at the other end of the valve body 81a.

[0018] The first housing section 81f protrudes from the waste chute 80 toward the combustion chamber 2 and forms a space in which the first contact section 81b is housed. The second housing section 81g is formed protruding from the waste chute 80 toward the opposite side of the combustion chamber 2 and forms a space in which the second contact section 81c is housed when the valve body 81a moves into the waste chute 80. The vertical position of the second housing section 81g is lower than that of the first housing section 81f. The second housing section 81g is provided with an opening 81h through which the valve body 81a and the second contact section 81c pass.

[0019] The first sealing portion 81d is fixed to the upper surface of the first housing portion 81f within the first housing portion 81f. The first sealing portion 81d is plate-shaped and is made of, for example, heat-resistant silicone rubber. The second sealing portion 81e is fixed to the upper surface of the second housing portion 81g within the second housing portion 81g. The second sealing portion 81e is plate-shaped and is made of, for example, heat-resistant silicone rubber.

[0020] An example of the second valve according to the present invention, the flap valve 82, is provided below the slide gate valve 81. Regarding the flow of the waste W, when the inlet 3 side is the upstream and the discharge part 6 side is the downstream, it is located on the downstream side of the flap valve 82. The flap valve 82 rotates a plate-shaped valve body (not shown) installed in the waste chute 80 by a drive device (not shown). The flap valve 82 allows the waste W to pass through when the valve body opens the waste chute 80, and blocks the passage of the waste W when the valve body closes the waste chute 80.

[0021] The replacement gas supply machine 86 is a device that supplies replacement gas to the replacement gas supply path 83. The replacement gas supplied by the replacement gas supply machine 86 is, for example, carbon dioxide. The replacement gas supply path 83 and the exhaust path 84 are connected to the waste chute 80 between the slide gate valve 81 and the flap valve 82. The replacement gas supply path 83 is connected to the replacement gas supply machine 86 and is provided with a damper (not shown). The replacement gas supplied from the replacement gas supply machine 86 moves into the waste chute 80 through the replacement gas supply path 83. The exhaust path 84 is provided with a damper (not shown) and discharges the air between the slide gate valve 81 and the flap valve 82 outdoors.

[0022] The sensor 85 is a sensor that measures the concentration of the replacement gas, the oxygen concentration, and the pressure between the slide gate valve 81 and the flap valve 82 in the waste chute 80. The measurement result of the sensor 85 is output to the control unit 100.

[0023] A grate 5 is provided at the bottom of the combustion chamber 2 for burning the waste W while it is being moved. The grate 5 consists of a drying grate 5a, a combustion grate 5b, and a post-combustion grate 5c. The grates 5 are arranged in the order of drying grate 5a, combustion grate 5b, and post-combustion grate 5c from the dust feeder 3b side in the direction of movement of the waste W. In the drying grate 5a, the waste W is mainly dried and its moisture evaporated. In the combustion grate 5b, the waste W is mainly thermally decomposed and partially oxidized. In addition, in the combustion grate 5b, the pyrolysis gas containing carbon monoxide and hydrocarbons generated by thermal decomposition, as well as some of the fixed carbon, are burned. In the post-combustion grate 5c, post-combustion is performed to completely burn the unburned portion of the remaining waste W, mainly fixed carbon. As a result of this post-combustion, a layer of incinerated ash is formed in the post-combustion grate 5c after complete combustion. This incinerated ash is discharged to the outside of the combustion chamber 2 from a discharge section 6 located downstream of the waste flow W from the post-combustion grate 5c.

[0024] The upper downstream side of the combustion chamber 2, along the flow direction of the waste W, is connected to the boiler 4. The area near the inlet of the boiler 4 constitutes a secondary combustion chamber 11 for burning unburned gas in the gas discharged from the combustion chamber 2. The secondary combustion chamber 11 is equipped with an injection nozzle 40 connected to a supply line 31e through which secondary combustion gas flows. The secondary combustion gas that has flowed through the supply line 31e is injected into the secondary combustion chamber 11 from the injection nozzle 40. In the secondary combustion chamber 11, the unburned portion of the combustion gas generated in the combustion chamber 2 undergoes secondary combustion, and the sensible heat of the exhaust gas after secondary combustion is recovered by the boiler 4.

[0025] The boiler 4, which recovers heat from the sensible heat of the exhaust gas, has two bends 12 and 13 that bend the flow path of the exhaust gas. These bends 12 and 13 form a first radiating chamber 14, a second radiating chamber 15, and a convection heat transfer chamber 16, starting from the upstream side along the direction of the exhaust gas flow. The first radiating chamber 14, through which the exhaust gas from the waste incinerator 1 flows, has a secondary combustion chamber 11 in its upstream section along the direction of the exhaust gas flow. The first radiating chamber 14 and the second radiating chamber 15 are continuous via the bend 12, and the lower part of the second radiating chamber 15 and the lower part of the convection heat transfer chamber 16 are continuous via the bend 13. The upper end of the convection heat transfer chamber 16 is connected to a dust removal device 23, which consists of a bag filter and the like, via a flue 21.

[0026] The boiler 4 has an inner wall made of refractory material. The first radiating chamber 14 and the second radiating chamber 15 of the boiler 4 are provided with heat transfer tubes (not shown) densely arranged on the outside of the refractory wall forming the inner wall, which are pipes through which steam flows. The heat transfer tubes, which are located on the outside of the refractory wall and through which water flows, become radiant heat transfer surfaces that receive radiant heat from the exhaust gas and generate steam, and function as evaporators.

[0027] The convection heat transfer chamber 16 has heat transfer tubes (not shown) arranged in a flag shape at the uppermost part of the flow direction of the exhaust gas. By cooling the exhaust gas flowing into the convection heat transfer chamber 16 with the heat transfer tubes, gaseous or mist-like dust components solidify and are separated from the exhaust gas as dust. The convection heat transfer chamber 16 also includes three superheaters 16A and an economizer 16B, arranged from the upstream side along the flow direction of the exhaust gas. Each superheater 16A has a group of heat transfer tubes arranged in multiple stages in the height direction, with multiple heat transfer tubes arranged horizontally, and the group of heat transfer tubes functions as a convection heat transfer surface. The superheater 16A further superheats the steam generated in the first radiating chamber 14 and the second radiating chamber 15 through heat exchange with the exhaust gas to produce high-temperature, high-pressure superheated steam.

[0028] The economizer 16B is located downstream of the superheater 16A in the direction of exhaust gas flow, and is equipped with heat transfer tubes (not shown). The steam generated in the boiler 4 and used to drive the steam turbine (not shown) is condensed in a condenser (not shown) and flows through the heat transfer tubes of the economizer 16B. The condensate flowing through the heat transfer tubes of the economizer 16B is heated by the residual heat in the exhaust gas after the steam has been superheated by the superheater 16A, and the heated water is supplied to the heat transfer tubes of the first radiating chamber 14 and the second radiating chamber 15, which function as evaporators. The economizer 16B may be installed outside the boiler 4 downstream of the boiler 4 in the direction of exhaust gas flow, rather than inside the convection heat transfer chamber 16, or both an economizer inside the boiler 4 and an economizer outside the boiler 4 may be provided.

[0029] The exhaust gas, from which heat has been recovered by the boiler 4, flows through the flue 21 to a dust removal device 23, which consists of, for example, a bag filter. In the flue 21, chemicals such as slaked lime and activated carbon are blown into the exhaust gas from, for example, a chemical supply device 22. When chemicals are blown into the exhaust gas in the flue 21, they bind to acidic gases such as hydrogen chloride and sulfur oxides contained in the exhaust gas.

[0030] One example of a dust removal unit is the dust removal device 23, which collects and removes dust and chemicals bound to acidic gases contained in the exhaust gas that flows through the flue 21. An induced draft fan 24a is connected to the dust removal device 23. A sensor group 74 is provided between the dust removal device 23 and the induced draft fan 24a. The sensor group 74 measures at least pressure, temperature, O2 concentration, H2O concentration, CO2 concentration, and CO concentration at its installed location. The sensor group 74 transmits the measured values ​​such as pressure, temperature, O2 concentration, H2O concentration, CO2 concentration, and CO concentration to the control unit 100. The induced draft fan 24a draws in the exhaust gas that has been dust-removed by the dust removal device 23. The exhaust gas drawn in by the induced draft fan 24a is sent to the wet scrubber 51.

[0031] The airflow rate of the induced draft fan 24a is controlled by the control unit 100, which will be described later. The control unit 100 controls the rotation amount of the induced draft fan 24a according to the pressure measurement results measured by the sensor group 74, and by controlling the airflow rate of the induced draft fan 24a, the furnace pressure in the combustion chamber 2 can be changed. Specifically, increasing the airflow rate of the induced draft fan 24a increases the amount of exhaust gas drawn from the combustion chamber 2 to the induced draft fan 24a, and the pressure in the combustion chamber 2 decreases. Decreasing the airflow rate of the induced draft fan 24a decreases the amount of exhaust gas drawn from the combustion chamber 2 to the induced draft fan 24a, and the pressure in the combustion chamber 2 increases.

[0032] The wet scrubber 51 is a device that cleans and dehumidifies exhaust gas. For example, it brings an aqueous sodium hydroxide solution into contact with the exhaust gas to remove sulfides, chlorides, and other substances that could not be removed by chemicals, and also cools the exhaust gas to remove most of the moisture. Downstream of the exhaust gas flow from the wet scrubber 51, an exhaust gas circulation fan 24b is installed. The exhaust gas containing carbon dioxide that has been cleaned and dehumidified by the wet scrubber 51 branches into an exhaust gas supply line 30 that is drawn to the exhaust gas circulation fan 24b and a line that goes to the liquefaction device 120.

[0033] The liquefaction unit 120 is a device that liquefies carbon dioxide. The liquefaction unit 120 cleans, dehumidifies, deodorizes, compresses, and cools the exhaust gas, and liquefies the carbon dioxide contained in the exhaust gas.

[0034] The exhaust gas supply line 30 is connected to dampers 32a, 32b, 32d, and 32e. The exhaust gas supply line 30 is also connected to damper 34c. Damper 32a is connected to damper 34a, and damper 32b is connected to damper 34b. Damper 32d is connected to a downstream nozzle 39 located in the combustion chamber 2, and damper 32e is connected to the supply line 31e, which will be described later.

[0035] Furthermore, the waste incineration system SYS is equipped with an oxygen supply line 35 and an oxygen supply unit 60. The oxygen supply line 35 is connected to the oxygen supply unit 60. The oxygen supply unit 60 separates oxygen from air using techniques such as cryogenic separation or PSA, producing a gas (O2 main component gas) with an O2 concentration of 50% or more and close to 100%, and sends the O2 main component gas to the oxygen supply line 35. The oxygen supply line 35 is connected to dampers 37a to 37c and 37e, which adjust the flow rate of the O2 main component gas.

[0036] Damper 37a is connected to dampers 34a and 32a, damper 37b is connected to dampers 34b and 32b, and damper 37c is connected to damper 34c and exhaust gas supply line 30. Damper 37e is connected to supply line 31e.

[0037] The O2 main component gas that passes through damper 37a from oxygen supply line 35 is mixed with exhaust gas flowing from damper 32a and flows to damper 34a. The O2 main component gas that passes through damper 37b from oxygen supply line 35 is mixed with exhaust gas flowing from damper 32b and flows to damper 34b. The O2 main component gas that passes through damper 37c from oxygen supply line 35 is mixed with exhaust gas flowing from exhaust gas supply line 30 and flows to damper 34c. The O2 main component gas that passes through damper 37e from oxygen supply line 35 is mixed with exhaust gas that has passed through damper 32e and flows to supply line 31e.

[0038] Damper 34a adjusts the flow rate of the mixed gas, which is a mixture of O2-based gas and exhaust gas. The mixed gas, whose flow rate has been adjusted by damper 34a, is supplied to the wind box 7a via supply line 31a. Damper 34b adjusts the flow rate of the mixed gas, which is a mixture of O2-based gas and exhaust gas. The mixed gas, whose flow rate has been adjusted by damper 34b, is supplied to the wind box 7b via supply line 31b. Damper 34c adjusts the flow rate of the mixed gas, which is a mixture of O2-based gas and exhaust gas. The mixed gas, whose flow rate has been adjusted by damper 34c, is supplied to the wind box 7c via supply line 31c.

[0039] The wind boxes 7a to 7c are located at the bottom of the combustion chamber 2. Specifically, wind box 7a is located below the drying grate 5a, wind box 7b is located below the combustion grate 5b, and wind box 7c is located below the post-combustion grate 5c. Wind box 7a supplies the mixed gas to the drying grate 5a, wind box 7b supplies the mixed gas to the combustion grate 5b, and wind box 7c supplies the mixed gas to the post-combustion grate 5c. Alternatively, the exhaust gas and the O2-based gas may be mixed within wind boxes 7a to 7c by directly connecting dampers 32a and 37a to wind box 7a, dampers 32b and 37b to wind box 7b, and the exhaust gas supply line 30 and damper 37c to wind box 7c. The wind boxes 7a-7c, supply lines 31a-31c, 31e, dampers 32a, 32b, 32d, 32e, dampers 34a-34c, dampers 37a-37c, 37e are an example of a mixed gas supply unit that supplies a mixture of exhaust gas and O2-based gas.

[0040] The combustion chamber 2 is equipped with a front nozzle 38 and a rear nozzle 39. The front nozzle 38 and the rear nozzle 39 each function as counter-flow nozzles.

[0041] The front nozzle 38 is located above the space between the drying grate 5a and the combustion grate 5b, for example, on the ceiling of the combustion chamber 2. The front nozzle 38 is supplied with an oxidizing agent adjusted to have a relatively high O2 concentration, such as an O2-containing gas with an O2 concentration of 15% to 25%.

[0042] The downstream nozzle 39 is located above the space between the combustion grate 5b and the post-combustion grate 5c, for example, on the ceiling of the combustion chamber 2. The downstream nozzle 39 is supplied with exhaust gas from the damper 32d, which mainly consists of exhaust gas and has a relatively low O2 concentration, for example, exhaust gas adjusted to have an O2 concentration of less than 5%. Alternatively, the downstream nozzle 39 may be supplied with gas that has been mixed with exhaust gas containing O2 or O2 as the main component to adjust the O2 concentration.

[0043] An injection nozzle 40 is provided in the secondary combustion chamber 11 at the outlet of the combustion chamber 2. The injection nozzle 40 is connected to a supply line 31e to which dampers 32e and 37e are connected. The injection nozzle 40 is supplied with a secondary combustion gas, which is an oxidizer adjusted to have a relatively high O2 concentration, for example, an O2 concentration of more than 25% and 35% or less.

[0044] A sensor group 71 is installed upstream of the waste material W in the combustion chamber 2, along the direction of transport. The sensor group 71 measures at least the pressure, temperature, O2 concentration, and carbon monoxide concentration (CO concentration) inside the combustion chamber 2 at its installed location. The sensor group 71 transmits the measured values, such as pressure, temperature, O2 concentration, and CO concentration, to the control unit 100.

[0045] Furthermore, a sensor group 72 is provided downstream along the direction of transport of waste W within the combustion chamber 2. The sensor group 72 measures at least the pressure, temperature, O2 concentration, CO concentration, and nitrogen oxide concentration (NOx concentration) within the combustion chamber 2 at its installed location. The sensor group 72 measures the measured pressure, temperature, O2 concentration, CO concentration, and NOx concentration. x The measured values, such as concentration, are transmitted to the control unit 100.

[0046] Furthermore, a sensor group 73 is provided at the outlet of the combustion chamber 2. The sensor group 73 measures at least the pressure, temperature, O2 concentration, H2O concentration, CO2 concentration, and CO concentration at the outlet of the combustion chamber 2 at its installed location. The sensor group 73 transmits the measured values ​​such as pressure, temperature, O2 concentration, H2O concentration, CO2 concentration, and CO concentration to the control unit 100.

[0047] The control unit 100 specifically includes a processor such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and an FPGA (Field-Programmable Gate Array), as well as a main memory unit such as RAM (Random Access Memory) and ROM (Read Only Memory) (none of which are shown). Alternatively, the control unit 100 may be composed of an information processing device such as a computer equipped with a memory unit. In this case, the memory unit of the control unit 100 consists of a storage medium selected from volatile memory such as RAM, non-volatile memory such as ROM, EPROM (Erasable Programmable ROM), hard disk drive (HDD), and removable media. Removable media include, for example, USB (Universal Serial Bus) memory, or disk recording media such as CD (Compact Disc), DVD (Digital Versatile Disc), or BD (Blu-ray® Disc). Alternatively, the memory unit may be configured using a computer-readable recording medium such as an externally insertable memory card. The control unit 100 controls dampers 32a, 32b, 32d, 32e, 34a-34c, and dampers 37a-37c and 37e based on the measurement results of sensor group 71 and sensor group 72. The control unit 100 also controls the slide gate valve 81, the flap valve 82, the dampers provided in the replacement gas supply passage 83, and the dampers provided in the exhaust passage 84. Furthermore, the control unit 100 controls the airflow rate of the induced draft fan 24a based on the pressure measured by sensor groups 71, 72, and 74.

[0048] In the waste incineration system SYS, the pressure inside the combustion chamber 2 is controlled to, for example, 0 to 5 kPaG by controlling the airflow rate of the induced draft fan 24a. When the pressure measured by the sensor groups 71 and 72 is less than the above range, the control unit 100 reduces the airflow rate of the induced draft fan 24a. Conversely, when the pressure measured by the sensor groups 71 and 72 is greater than the above range, the control unit 100 increases the airflow rate of the induced draft fan 24a. In this way, by controlling the airflow rate of the induced draft fan 24a according to the pressure measured by the sensor groups 71 and 72, the inside of the combustion chamber 2 can be maintained at atmospheric pressure or a positive pressure exceeding atmospheric pressure.

[0049] In the SYS waste incineration system, the mixing ratio of exhaust gas and O2-dominant gas in the mixed gas can be adjusted by controlling dampers 32a, 32b, 32e and dampers 37a-37c, 37e. Specifically, the control unit 100 can control the flow rate of exhaust gas by controlling dampers 32a, 32b, and 32e, and can control the flow rate of O2-dominant gas by controlling dampers 37a-37c, 37e. Furthermore, the control unit 100 can control the O2 concentration of the O2-containing gas supplied to the upstream nozzle 38. With this configuration, the control unit 100 can individually and independently control the O2 concentration of the gas supplied to the wind box 7 (7a, 7b), grate 5 (5a, 5b), upstream nozzle 38, and injection nozzle 40.

[0050] Next, the operation when sending waste W to the combustion chamber 2 will be described. When sending waste W to the combustion chamber 2, the control unit 100 first controls the drive device of the slide gate valve 81 and moves the valve body 81a diagonally to the horizontal into the waste chute 80 as shown in Figure 2B, thereby bringing the first contact portion 81b into contact with the first seal portion 81d and the second contact portion 81c into contact with the second seal portion 81e. When the first contact portion 81b contacts the first seal portion 81d and the second contact portion 81c contacts the second seal portion 81e, the waste chute 80 is closed. The control unit 100 also controls the drive device of the flap valve 82 to close the waste chute 80 with the flap valve 82.

[0051] In this state, the operator uses a crane (not shown in the illustration) to feed the waste W into the input port 3. Subsequently, the control unit 100 opens the slide gate valve 81 as shown in Figure 2A, and the waste W fed into the input port 3 is pushed out to the waste chute 80 by the extruder 3a. The waste W pushed out by the extruder 3a accumulates on top of the flap valve 82.

[0052] Next, the control unit 100 controls the drive mechanism of the slide gate valve 81 and moves the valve body 81a diagonally to the horizontal into the waste chute 80 as shown in Figure 2B, thereby bringing the first contact portion 81b into contact with the first seal portion 81d and the second contact portion 81c into contact with the second seal portion 81e. When the first contact portion 81b contacts the first seal portion 81d and the second contact portion 81c contacts the second seal portion 81e, the waste chute 80 is closed.

[0053] In the case of a slide gate valve where the valve body is horizontal and moves horizontally, in order to prevent the gas generated in the combustion chamber 2 from flowing to the inlet 3, it is necessary to press the valve body, which has moved into the waste chute 80, upward or downward so that no gap is created between the valve body and the waste chute 80. In this case, a mechanism is required to press the valve body upward or downward.

[0054] In this embodiment, as the valve body 81a moves diagonally with respect to the horizontal, a force is automatically generated that pushes upward the first contact portion 81b and the second contact portion 81c, which are located outside the passage of the waste chute 80, thus eliminating the need for a separate pressing mechanism required in a configuration where the valve body moves horizontally. Furthermore, if the exposed portion is configured as a horizontal first contact portion 81b that presses against the first seal portion 81d, and as a horizontal second contact portion 81c that presses against the second seal portion 81e, higher sealing performance can be obtained. As the first contact portion 81b is pressed against the first seal portion 81d and the second contact portion 81c is pressed against the second seal portion 81e, the waste chute 80 is closed, thereby preventing the gas generated in the combustion chamber 2 from flowing from the waste chute 80 to the inlet 3.

[0055] The control unit 100 opens the dampers of the replacement gas supply passage 83 and the exhaust passage 84, and controls the replacement gas supply unit 86 to supply replacement gas between the slide gate valve 81 and the flap valve 82 of the waste chute 80. When the replacement gas is supplied between the slide gate valve 81 and the flap valve 82, the air between the slide gate valve 81 and the flap valve 82 is exhausted through the exhaust passage 84.

[0056] The control unit 100 closes the dampers of the replacement gas supply passage 83 and the exhaust passage 84 if the pressure value between the slide gate valve 81 and the flap valve 82 measured by the sensor 85 exceeds a predetermined pressure value, and the concentration of the replacement gas between the slide gate valve 81 and the flap valve 82 measured by the sensor 85 satisfies predetermined conditions. Here, the predetermined pressure value is, for example, any pressure value in the range of 0 to 5 kPa, and specifically, a pressure value greater than the pressure value in the combustion chamber 2 measured by the sensor group 71. Here, the predetermined conditions are the conditions when the carbon dioxide concentration exceeds a predetermined threshold, or the conditions when the oxygen concentration is less than a predetermined threshold. Next, the control unit 100 opens the flap valve 82 and drops the waste W that had accumulated on the flap valve 82. At this time, since the pressure of the replacement gas between the slide gate valve 81 and the flap valve 82 is higher than the pressure in the combustion chamber 2, it is possible to suppress the gas in the combustion chamber from flowing back through the waste chute 80. After all the waste W has fallen from the flap valve 82, the control unit 100 closes the flap valve 82. The waste material W that falls from the flap valve 82 is pushed into the combustion chamber 2 by the dust feeder 3b.

[0057] In this embodiment, a mixed gas, which is a mixture of carbon dioxide contained in the circulated exhaust gas and high-concentration O2, is supplied to the drying grate 5a, the combustion grate 5b, and the post-combustion grate 5c. Compared to conventional incinerators that supply air to the grate 5, this mixed gas contains less nitrogen, resulting in a higher concentration of carbon dioxide in the exhaust gas generated in the combustion chamber 2, which can then be efficiently liquefied by the liquefaction device 120.

[0058] Furthermore, in this embodiment, when the waste W is moved to the combustion chamber 2, the amount of nitrogen entering the combustion chamber 2 can be reduced by suppressing the movement of air along with the waste W. As a result, the concentration of carbon dioxide in the exhaust gas generated in the combustion chamber 2 becomes high, and this carbon dioxide can be efficiently liquefied by the liquefaction device 120.

[0059] Furthermore, in this embodiment, when the waste W is moved to the combustion chamber 2, the amount of nitrogen entering the combustion chamber 2 can be reduced by suppressing the movement of air along with the waste W. As a result, the concentration of carbon dioxide in the exhaust gas generated in the combustion chamber 2 becomes high, and this carbon dioxide can be efficiently liquefied by the liquefaction device 120.

[0060] When the carbon dioxide concentration in the exhaust gas is low, the gases other than carbon dioxide, which make up the majority of the exhaust gas, also undergo compression and cooling, requiring a large amount of energy to liquefy the carbon dioxide. On the other hand, in this embodiment, the amount of nitrogen entering the combustion chamber 2 can be reduced to increase the carbon dioxide concentration in the exhaust gas, thus reducing the amount of gases other than carbon dioxide in the exhaust gas. Therefore, the liquefaction device 120 can efficiently liquefy carbon dioxide and reduce the energy consumed for liquefaction.

[0061] [Differentiation] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be implemented in various other forms. For example, the present invention may be implemented by modifying the embodiments described above as follows. The embodiments described above and the following modifications may be combined with each other. The present invention is also included in configurations that appropriately combine the components of each embodiment and each modification described above. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, broader embodiments of the present invention are not limited to the embodiments and modifications described above, and various modifications are possible.

[0062] In the embodiment described above, the replacement gas supplied by the replacement gas supply unit 86 is carbon dioxide, but the replacement gas supply unit 86 may also supply steam instead of carbon dioxide.

[0063] In the embodiment described above, the waste W is pushed onto the slide gate valve 81 by the extruder 3a, but the waste W may be dropped directly onto the slide gate valve 81 by a crane without the extruder 3a.

[0064] In the embodiment described above, replacement gas may be supplied from the replacement gas supply unit 86 to the opening 81h. This configuration prevents gas generated in the combustion chamber 2 from leaking out of the waste chute 80.

[0065] In this invention, for example, a carbon dioxide separation and recovery device may be installed before the liquefaction device 120. In this case as well, since the carbon dioxide concentration in the exhaust gas is high, it is possible to improve the efficiency of separation and recovery and reduce energy consumption. [Explanation of Symbols]

[0066] 1. Waste Incinerator 2 Combustion chambers 4 Boiler 21 Flue 22. Drug supply device 23 Dust removal equipment 24a Induced draft fan 24b Exhaust gas circulation fan 51 Wet Scrubber 80 Waste Chute 81 Slide gate valve 81a Valve body 81b 1st contact part 81c 2nd contact part 81d First seal section 81e Second seal section 81f First containment area 81g Second storage compartment 82 Flap valve 83 Replacement gas supply channel 84 Exhaust passage 85 Sensors 86 Replacement gas supply unit 100 Control Unit 120 Liquefaction equipment SYS Waste Incineration System W Waste

Claims

[Claim 1] A combustion chamber in which waste is burned while being transported by a grate, The input port into which the aforementioned waste is put, A waste chute connected to the aforementioned input port and forming a passage through which waste to be fed into the combustion chamber passes, A slide valve having a plate-shaped valve body inclined with respect to the horizontal direction, wherein the valve body moves diagonally upward with respect to the horizontal direction to close the passage of the waste chute when the passage of the waste chute is open, and the valve body moves diagonally downward with respect to the horizontal direction to open the passage of the waste chute when the passage of the waste chute is closed, A second valve is provided downstream of the first valve and opens and closes the passage of the waste chute, Equipped with, The first valve has a horizontal plate-shaped first contact portion connected to the upper end of the valve body which is inclined with respect to the horizontal direction, and a horizontal plate-shaped second contact portion connected to the lower end of the valve body which is inclined with respect to the horizontal direction. The waste chute has a first sealing portion that the upper surface of the first contact portion contacts, and a second sealing portion that the upper surface of the second contact portion contacts, A waste incineration system in which, as the valve body moves diagonally upward, the first contact portion moves diagonally upward and contacts the first seal portion, and as the valve body moves diagonally upward, the second contact portion moves diagonally upward and contacts the second seal portion to close the waste chute.

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