Gasification furnace and combustion method

Abstract

The present invention provides a gasification combustion furnace that burns unburned material discharged from the primary combustion chamber in the secondary combustion chamber, while suppressing high temperatures, particularly near the entrance of the secondary combustion chamber (near the connected area), where the risk of clinker buildup is high. [Solution] The gasification combustion furnace (1) comprises a primary combustion section (10), a secondary combustion section (20), a communication section (30), and a supply device (40). The secondary combustion section (20) includes a secondary combustion chamber (21) having a wall (210), an internal space (210b), a receiving section (210a), and a secondary discharge section (261), a first introduction section (221), a second introduction section (241), and a third introduction section (231). The supply device (40) introduces an amount of air (A2) from the first introduction section (221) such that the air ratio is smaller than the air ratio of the air (A2) introduced from the second introduction section (241) and the third introduction section (231), respectively.

Description

Technical Field

[0001] The present invention relates to a gasification combustion furnace for incinerating incineration waste.

Background Art

[0002] A gasification combustion furnace is configured to introduce incineration waste such as municipal waste into a combustion chamber for combustion. In the combustion chamber, two stages are carried out: the thermal decomposition (gasification) of the incineration waste and the combustion of unburned components (gases) such as combustible gas (H2), carbon monoxide (CO), and char (carbon content) generated by the thermal decomposition (gasification). Further, a gasification combustion furnace is known in which the thermal decomposition of the incineration waste and the combustion of the unburned components are carried out in separate combustion chambers.

[0003] For example, Patent Document 1 discloses an incineration waste incineration device including a primary combustion chamber, a secondary combustion chamber, and a tangential connection part connecting the primary combustion chamber and the secondary combustion chamber. The tangential connection part is connected tangentially to the side wall of the secondary combustion chamber. Further, secondary air supply paths for introducing secondary air into the tangential connection part are connected at two positions in the tangential connection part.

[0004] The primary combustion chamber incinerates (gasifies) the incineration waste in a fluidized bed to generate primary combustion gas such as carbon dioxide (CO2) and water vapor (H2O), and primary combustion products (exhaust gas) containing unburned components such as combustible gas (H2), carbon monoxide (CO), and char (carbon content). The primary combustion products (exhaust gas) flow through the tangential connection part. The primary combustion products (exhaust gas) flowing through the tangential connection part are mixed with secondary air from the secondary air supply path and then introduced into the secondary combustion chamber.

[0005] According to the incinerator described in Patent Document 1, the secondary combustion chamber further incinerates the unburned material with secondary air, generating secondary combustion material (exhaust gas after combustion of unburned material) containing secondary combustion gases (gas after combustion of unburned material) such as carbon dioxide (CO2) and water vapor (H2O). Specifically, a swirling flow is formed in the secondary combustion chamber by the primary combustion material (exhaust gas) mixed with secondary air, and the swirling flow further promotes the mixing of the primary combustion material (exhaust gas) and secondary air, thereby generating secondary combustion material (exhaust gas after combustion of unburned material). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 07-324717 [Overview of the project] [Problems that the invention aims to solve]

[0007] In the incinerator described in Patent Document 1 above, supplying all secondary air into the tangential connection section (duct) posed a risk of ignition within the duct, and if ignition occurred, high temperatures (over 1000°C) would be reached inside the duct and at the inlet of the secondary combustion chamber, leading to a risk of clinker adhesion and growth. Furthermore, the diameter of the duct was narrower than the diameter of the secondary combustion chamber, increasing the risk of clinker adhesion and growth due to the high temperatures.

[0008] The object of the present invention is to provide a gasification combustion furnace, a combustion method, and a method for manufacturing a gasification combustion furnace that can burn unburned material discharged from the primary combustion section in the secondary combustion chamber, while suppressing high temperatures, particularly near the inlet of the secondary combustion chamber (near the connected position), where the risk of clinker adhesion and growth is high. [Means for solving the problem]

[0009] As a means to solve the aforementioned problems, the present invention provides a gasification combustion furnace comprising: a primary combustion section having a primary combustion chamber, in which incinerators are gasified within the primary combustion chamber; a secondary combustion section for burning unburned portions of exhaust gas discharged from the primary combustion section; a communication section for guiding the exhaust gas, including the unburned portions, discharged from the primary combustion section to the secondary combustion section; and a supply device for supplying air to the secondary combustion section, wherein the secondary combustion section comprises a wall, an internal space defined by the wall and extending in a predetermined direction, a receiving section for receiving the exhaust gas, including the unburned portions, from the communication section, and a discharge device provided downstream of the receiving section in the predetermined direction for discharging the gas generated in the internal space. The gasification combustion furnace includes a secondary combustion chamber having a secondary discharge section, a first introduction section provided near the receiving section for introducing the air into the internal space, a second introduction section arranged in the wall downstream of the first introduction section in a predetermined direction for introducing the air into the internal space, and a third introduction section arranged in the wall downstream of the second introduction section in a predetermined direction and upstream of the secondary discharge section in a predetermined direction for introducing the air into the internal space, wherein the supply device introduces an amount of air from the first introduction section that has an air-to-air ratio smaller than the air-to-air ratio of the air introduced from each of the second and third introduction sections.

[0010] In this way, when the exhaust gas discharged from the primary combustion section flows in a predetermined direction within the internal space, a small amount of air with a low air-to-air ratio is introduced near the receiving section. Subsequently, while the exhaust gas discharged from the primary combustion section flows in the predetermined direction within the internal space, a large amount of air with a high air-to-air ratio is introduced at two locations, the second and third inlet sections, which are located downstream of the receiving section in the predetermined direction. Compared to the case where a large amount of air with a high air-to-air ratio is introduced at the receiving section, this method suppresses the rapid reaction between the unburned portion of the exhaust gas discharged from the primary combustion section and the air. As a result, it is possible to suppress the temperature of the walls (especially near the receiving section). In other words, it is possible to suppress the generation, adhesion, and growth of clinker from the exhaust gas discharged from the primary combustion section.

[0011] Specifically, it is preferable that the air-to-air ratio of the air introduced into the internal space from the first inlet is 0.10 or more and 0.20 or less.

[0012] When the air-fuel ratio is between 0.10 and 0.20, it is possible to suppress the formation, adhesion, and growth of clinker from the exhaust gas discharged from the primary combustion section, while more reliably igniting the unburned portion of the exhaust gas discharged from the primary combustion section.

[0013] Furthermore, in the present invention, it is preferable that the air-to-air ratio of the air introduced into the primary combustion chamber is 0.30 or more and 0.50 or less.

[0014] When the air-to-air ratio is between 0.30 and 0.50, the incinerated material can be gasified more reliably.

[0015] Furthermore, in the present invention, it is preferable that the second introduction portion is positioned higher than the first introduction portion.

[0016] In this way, for example, the exhaust gas after incineration does not come into contact with the non-combustible material that accumulates in the hopper located at the bottom, thus suppressing the sintering of the non-combustible material.

[0017] Furthermore, in the present invention, the primary combustion section includes a primary discharge section located above the primary combustion chamber, and the communication section further includes one end connected to the primary discharge section, the other end connected to the receiving section, and an intermediate section located between the one end and the other end and extending in the vertical direction, wherein the receiving section is preferably located below the primary discharge section to which the one end of the communication section is connected.

[0018] In this way, even when the exhaust gas discharged from the primary combustion chamber is configured to flow upward through the secondary combustion chamber, the connecting section provides an intermediate section through which the exhaust gas discharged from the primary combustion chamber flows downward, thus suppressing an increase in the height of the secondary combustion chamber.

[0019] Furthermore, in the present invention, it is preferable that one of the second introduction section and the third introduction section has a swirling supply section, the other of the second introduction section and the third introduction section has a central supply section, the wall has a cylindrical shape with a central axis extending in the predetermined direction, the swirling supply section is connected to the wall so as to generate a swirling flow in the internal space formed by the swirling of the air in an orthogonal cross-section perpendicular to the central axis, and the central supply section is connected to the wall so as to generate an airflow of the air toward the central axis in the orthogonal cross-section.

[0020] In this way, the exhaust gas discharged from the primary combustion section and the air are efficiently mixed in the internal space, allowing for the efficient incineration of any unburned exhaust gas flowing through the internal space.

[0021] As a means to solve the aforementioned problems, the present invention provides a combustion method comprising: a primary combustion step of gasifying incinerator in a primary combustion chamber; and a secondary combustion step of burning the unburned portion of exhaust gas discharged from the primary combustion step in the internal space of a secondary combustion chamber having a wall and an internal space defined by the wall, extending in a predetermined direction and communicating with the primary combustion chamber through a communication portion, while flowing the unburned portion of exhaust gas discharged from the primary combustion step in the predetermined direction, wherein the secondary combustion step involves introducing an amount of air that results in a first air-fuel ratio into the internal space from the communication portion. The present invention provides a combustion method comprising: a first introduction step of introducing air into the exhaust gas; a second introduction step of introducing an amount of air into the exhaust gas that has flowed through the internal space in a predetermined direction after the execution of the first introduction step, resulting in a second air ratio greater than the first air ratio; a third introduction step of introducing an amount of air into the exhaust gas that has flowed through the internal space in a predetermined direction after the execution of the second introduction step, resulting in a third air ratio greater than the first air ratio; and a discharge step of discharging the exhaust gas after the combustion of the unburned portion that has flowed through the internal space in a predetermined direction after the execution of the third introduction step from the secondary discharge section of the secondary combustion chamber.

[0022] By doing so, when flowing the exhaust gas discharged from the primary combustion part in a predetermined direction in the internal space, secondary air in an amount that results in a small air ratio is introduced into the exhaust gas flowing into the internal space from the communication part. Then, while flowing the exhaust gas in the internal space in a predetermined direction, air in an amount that results in a large air ratio is introduced twice in the second introduction step and the third introduction step after the execution of the first introduction step. Therefore, compared with the case of introducing air in an amount that results in a large air ratio at the communication part, it is possible to suppress the rapid progress of the reaction between the unburned components of the exhaust gas discharged from the primary combustion part and the secondary air. As a result, it is possible to suppress the local high temperature of the wall. That is, it is possible to suppress the generation, adhesion, and growth of clinkers from the exhaust gas discharged from the primary combustion part.

[0023] As a means for solving the above problems, the present invention is a method for manufacturing a gasification combustion furnace that manufactures the gasification combustion furnace installed at the predetermined location by using a gasification melting furnace installed at the predetermined location. As the gasification melting furnace, it is installed at the predetermined location, has a primary combustion chamber, and a primary combustion part that gasifies incinerated matter in the primary combustion chamber. It also has a melting part installed adjacent to the primary combustion part at the predetermined location and having a melting furnace that melts the ash contained in the exhaust gas discharged from the primary combustion part, and a communication part for the melting part that communicates the primary combustion part and the melting part. The method includes a step of removing the communication part for the melting part from the primary combustion chamber and removing the melting part from the predetermined location, a step of installing a secondary combustion chamber having a wall and an internal space defined by the wall and extending in a predetermined direction as a secondary combustion part, and a step of attaching a communication part for the combustion furnace to the primary combustion chamber and attaching the communication part for the combustion furnace to the secondary combustion chamber so as to be able to burn the unburned components of the exhaust gas discharged from the primary combustion part of the gasification melting furnace, thereby communicating the primary combustion chamber and the secondary combustion chamber.

[0024] By doing so, it is possible to manufacture a gasification combustion furnace at a low cost by using the primary combustion part of the gasification melting furnace.

Effect of the Invention

[0025] As described above, according to the present invention, it is possible to provide a gasification combustion furnace, a combustion method, and a method for manufacturing a gasification combustion furnace that can suppress the temperature rise in the vicinity of the inlet of the secondary combustion chamber (near the connected position), where the risk of clinker adhesion and growth is particularly high, while burning unburned components discharged from the primary combustion section in the secondary combustion chamber.

Brief Description of the Drawings

[0026] [Figure 1] It is a diagram showing an outline of a gasification combustion furnace according to a first embodiment of the present invention. [Figure 2] It is a cross-sectional view showing an outline of a secondary combustion section in a plane passing through a receiving section according to the first embodiment. [Figure 3] It is a cross-sectional view showing an outline of a secondary combustion section in a plane above the cross-sectional position shown in FIG. 2. [Figure 4] It is a cross-sectional view showing an outline of a secondary combustion section in a plane above the cross-sectional position shown in FIG. 3. [Figure 5] It is a flowchart showing a primary combustion product introduction step and a secondary combustion step according to the first embodiment. [Figure 6] It is a cross-sectional view showing an outline of a secondary combustion section in a plane passing through a receiving section according to the second embodiment. [Figure 7] It is a cross-sectional view showing an outline of a secondary combustion section in a plane passing through a receiving section according to the third embodiment. [Figure 8] It is a cross-sectional view showing an outline of a secondary combustion section according to a fourth embodiment of the present invention. [[ID=3o]] [Figure 9] H It is a cross-sectional view showing an outline of a secondary combustion section in a plane above the cross-sectional position shown in FIG. 8. [Figure 10] It is a diagram showing an outline of a gasification melting furnace according to the present embodiment. [Figure 11] It is a flowchart showing a manufacturing method according to the present embodiment.

Modes for Carrying Out the Invention

[0027] (First Embodiment) [Overall Structure of a Fluidized Bed Type Gasification Combustion Furnace] The fluidized bed gasification furnace 1 of the first embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic diagram of the gasification furnace 1 of the first embodiment. As shown in Figure 1, the fluidized bed gasification furnace 1 of the first embodiment comprises a fluidized bed gasifier 10, a secondary combustion section 20, and a duct 30 connecting the fluidized bed gasifier 10 and the secondary combustion section 20. The fluidized bed gasifier 10 corresponds to an example of the "primary combustion section" in the present invention. The duct 30 corresponds to an example of the "communication section" in the present invention. The fluidized bed gasification furnace 1 carries out the thermal decomposition (gasification) of waste SS and the combustion of the unburned portion of the exhaust gas (primary combustion material) discharged from the waste SS in separate combustion chambers. Waste SS is such as municipal waste and corresponds to an example of "incinerated material" in the present invention. "Unburned portion" refers to the organic matter remaining due to incomplete combustion during the incineration process.

[0028] [Fluidized bed gasifier] The fluidized bed gasifier 10 generates primary combustion gas and primary combustible material (exhaust gas) containing unburned components by incinerating waste SS in the furnace body 11 with a fluidized medium RR and primary air A1. Examples of the fluidized medium RR include silica sand. Primary air A1 contains oxygen (O2) at a predetermined concentration. Examples of primary combustion gas include carbon dioxide (CO2) and water vapor (H2O). Examples of unburned components include carbon monoxide (CO), char (carbon), and combustible gas (H2).

[0029] In detail, the fluidized bed gasifier 10 incinerates waste SS at a first predetermined temperature using primary air A1 and a fluidized medium RR in an amount that results in a first predetermined air ratio, thereby generating primary combustible material (exhaust gas) and uncombustible material NB that remains unburned. The air ratio is the amount of air actually used relative to the theoretical amount of air, and the theoretical amount of air is the amount of air theoretically required to completely combust combustible material. Furthermore, since the fluidized bed gasification combustion furnace 1 has a secondary combustion section 20 located downstream of the fluidized bed gasifier 10, the first predetermined air ratio in the fluidized bed gasifier 10 is between 0.30 and 0.50. As a result, the first predetermined temperature is between 500°C and 600°C.

[0030] Specifically, the fluidized bed gasifier 10 comprises a furnace body 11 and a fluidized medium RR that forms a fluidized bed 14. The furnace body 11 corresponds to an example of a "primary combustion chamber" in the present invention.

[0031] The furnace body 11 is formed in a vertically elongated cylindrical shape. A supply port 11a for supplying waste SS is provided on the side of the furnace body 11, an outlet 11b for releasing primary combustible material (exhaust gas) to the outside of the furnace body 11 is provided on the upper part of the furnace body 11, and an inlet 11c for introducing primary air A1 is provided on the lower part of the furnace body 11. The outlet 11b corresponds to an example of a "primary discharge section" in this invention. In addition, a bottom wall 16 is provided inside the furnace body 11 to support the fluid medium RR from below. An outlet 16a for discharging non-combustible material NB is formed approximately in the center of the bottom wall 16.

[0032] [Primary combustion process] The operating method of the fluidized bed gasifier 10 will now be described in detail. The operating method of the fluidized bed gasifier 10 corresponds to an example of the "primary combustion process" in the present invention.

[0033] First, the fluidized medium RR is fluidized by supplying primary air A1 through the bottom wall 16 in an amount such that the air ratio is between 0.30 and 0.50. As a result, a fluidized bed 14 is formed. Next, a predetermined amount of waste SS is supplied to the fluidized bed 14 through the supply port 11a. Then, the predetermined amount of waste SS is partially combusted in the fluidized bed 14 at a temperature between 500°C and 600°C, generating primary combustion gas, unburned material, and non-combustible material NB. The primary combustion gas, unburned material, and some of the non-combustible material NB flow out of the furnace body 11 through the outlet 11b and enter the secondary combustion section 20 through the duct 30. Meanwhile, the mixture of most of the non-combustible material NB remaining uncombustible in the fluidized bed 14 and the fluidized medium RR is discharged from the outlet 16a to the bottom of the furnace body 11.

[0034] [duct] Next, the duct 30 and the secondary combustion section 20 will be described with reference to Figure 1.

[0035] As shown in Figure 1, the duct 30 connects the fluidized bed gasifier 10 and the secondary combustion section 20, guiding the primary combustible material (exhaust gas) generated in the fluidized bed gasifier 10 to the secondary combustion section 20. The duct 30 is formed in a cylindrical shape. In the first embodiment, the duct 30 is formed in a cylindrical shape. Specifically, the duct 30 comprises one end 30a connected to the outlet 11b, another end 30b connected to the receiving section 210a of the wall 210 (described later) and extending horizontally, and an intermediate section 30c positioned between the one end 30a and the other end 30b and extending vertically. The duct 30 is also made of refractory material (insulating structure).

[0036] [Secondary combustion section] The secondary combustion section 20 generates exhaust gas (secondary combustion material) containing secondary combustion gas (gas after combustion of unburned material) by completely burning the unburned portion of the primary combustion material (exhaust gas) with secondary air A2 while the primary combustion material (exhaust gas) flows upward. The secondary air A2 is the same as the primary air A1 and contains oxygen (O2) at a predetermined concentration. The secondary combustion gas is the same as the primary combustion gas and includes carbon dioxide (CO2), water vapor (H2O), etc.

[0037] In detail, the secondary combustion section 20 generates secondary combustion gas by incinerating unburned material at a second predetermined temperature while flowing it upward with secondary air A2 in an amount that results in a second predetermined air-to-air ratio. The upward direction is an example of a "predetermined direction" in this invention. The second predetermined air-to-air ratio is between 0.80 and 1.50. As a result, in the first embodiment, although the details will be described later, the second predetermined temperature is, for example, 850°C or higher.

[0038] The secondary combustion section 20 comprises a secondary combustion chamber 21 having an exhaust pipe 261 at its upper end, and a non-combustible waste discharge section 262 provided at the lower part of the secondary combustion chamber 21. Specifically, the secondary combustion chamber 21 has a cylindrical wall 210 having a central axis extending in the vertical direction, and an internal space 210b defined by the wall 210 and extending in the vertical direction.

[0039] The secondary combustion chamber 21 further includes a receiving section 210a that receives primary combustion material (exhaust gas) from the other end 30b of the duct 30. The receiving section 210a is located at the bottom of the wall 210. More specifically, the receiving section 210a is located below the outlet 16a. The receiving section 210a has an opening that penetrates the wall 210. The other end 30b of the duct 30 is connected to the receiving section 210a. As a result, primary combustion material (exhaust gas) is introduced from the other end 30b of the duct 30 into the internal space 210b. Subsequently, the primary combustion material (exhaust gas) is incinerated as it flows upward through the internal space 210b.

[0040] The exhaust pipe 261 discharges primary and secondary combustion gases to the outside of the secondary combustion chamber 21. The exhaust pipe 261 is formed in a cylindrical shape with a central axis extending along the vertical direction. The cross-sectional area of ​​the exhaust pipe 261 perpendicular to the vertical direction is designed to be smaller than the cross-sectional area of ​​the internal space 210b.

[0041] The non-combustible waste discharge section 262 discharges some of the non-combustible waste NB that has descended through the internal space 210b to the outside of the secondary combustion chamber 21. Specifically, the non-combustible waste discharge section 262 is a hopper section.

[0042] Here, we will explain the air ratio and gas temperature near the receiving section 210a. When the air ratio of the fluidized bed gasifier 10 is 0.3 to 0.5, the temperature of the primary combustible material (exhaust gas) will be 500°C to 600°C. When secondary air A2 with an air ratio of 0.20 or higher is injected into the primary combustible material (exhaust gas), it is assumed that the temperature of the primary combustible material (exhaust gas) will exceed 900°C. On the other hand, when secondary air A2 with an air ratio of less than 0.10 is injected, there is a risk that the unburned portion will not ignite and combustion will become unstable. Furthermore, if secondary air A2 is not injected at all near the receiving section 210a, and is injected upstream (downstream) of the receiving section 210a, there is a possibility that the unburned portion will not ignite and complete combustion will not be possible. Therefore, it is necessary to burn the material to 600°C to 800°C with secondary air A2 near the receiving section 210a, and then complete combustion will be carried out in the secondary combustion chamber 21.

[0043] Next, with reference to Figures 2 to 4, a method for introducing secondary air A2 into the internal space 210b in the first embodiment will be described. Figure 2 is a schematic cross-sectional view of the secondary combustion section 20 in a plane P1 perpendicular to the vertical direction and passing through the receiving section 210a. Figure 3 is a schematic cross-sectional view of the secondary combustion section 20 in a plane P2 above the cross-sectional position shown in Figure 2. Figure 4 is a schematic cross-sectional view of the secondary combustion section 20 in a plane P3 above the cross-sectional position shown in Figure 3. As shown in Figures 2 to 4, in addition to the secondary combustion chamber 21, the secondary combustion section 20 further includes a first introduction section 221 for introducing secondary air A21 from the secondary air A2 into the internal space 210b, a second introduction section 241 for introducing secondary air A22 from the secondary air A2 into the internal space 210b, and a third introduction section 231 for introducing secondary air A23 from the secondary air A2 into the internal space 210b.

[0044] Here, with reference to Figure 2, the first introduction section 221 and the duct 30 will be described in detail. As shown in Figure 2, the receiving section 210a is located in a predetermined area of ​​the wall 210. Specifically, the receiving section 210a is located on the side of the wall 210 in a predetermined direction in plane P1. The other end 30b of the duct 30 is connected to the receiving section 210a. The other end 30b of the duct 30 introduces primary combustion material (exhaust gas) along the wall 210 in plane P1. Specifically, the other end 30b of the duct 30 is connected to the wall 210 in a tangential direction. As a result, a swirling flow of primary combustion material (exhaust gas) is formed in the internal space 210b along a predetermined circumferential direction CD.

[0045] Furthermore, the first introduction section 221 is located near the receiving section 210a. Specifically, the first introduction section 221 is positioned on the wall 210 so as to intersect with the plane P1. In other words, the first introduction section 221 is positioned at the same height as the receiving section 210a. For example, on the wall 210 in plane P1, the first introduction section 221 is positioned at a 40° angle to the receiving section 210a.

[0046] More specifically, the first inlet section 221 comprises at least one inlet pipe 221a perpendicular to the vertical direction. Specifically, the first inlet section 221 comprises a plurality of inlet pipes 221a. Each of the plurality of inlet pipes 221a is an air supply nozzle. More specifically, the first inlet section 221 comprises three inlet pipes 221a arranged at predetermined intervals along the central axis of the wall 210. Each of the three inlet pipes 221a is formed in a cylindrical shape (it may be cylindrical, rectangular, or the like).

[0047] Each of the three inlet pipes 221a introduces secondary air A21 in the axial direction DX of the other end 30b of the duct 30. Specifically, in plane P1, each of the three inlet pipes 221a is positioned to be inclined at a predetermined angle α with respect to the axial direction DX of the other end 30b of the duct 30. The predetermined angle α is, for example, 40°. As a result, the secondary air A21 from each of the three inlet pipes 221a is efficiently mixed with the primary combustion material (exhaust gas).

[0048] Next, with reference to Figure 3, the second inlet section 241 will be described in detail. As shown in Figure 3, the second inlet section 241 is positioned on the wall 210 so as to be downstream of the first inlet section 221 in a predetermined direction. In other words, the second inlet section 241 is positioned higher than the first inlet section 221. The second inlet section 241 includes at least one inlet pipe 241a perpendicular to the vertical direction. Specifically, the second inlet section 241 includes a plurality of inlet pipes 241a. Each of the plurality of inlet pipes 241a is an air supply nozzle. More specifically, the second inlet section 241 includes six inlet pipes 241a arranged at equal intervals along the circumferential direction of the wall 210. Each of the six inlet pipes 241a is formed in a cylindrical shape (it may be formed in a cylindrical shape, a rectangular shape, etc.).

[0049] Each of the six inlet pipes 241a introduces secondary air A22 toward the central axis of the wall 210 in a plane (orthoaxial cross-section) P2 perpendicular to the vertical direction (central axis of the wall 210). The six inlet pipes 241a are an example of the "central supply section" in the present invention. Specifically, in plane P2, each of the six inlet pipes 241a is arranged along the radial direction RD of the wall 210. In other words, the six inlet pipes 241a are six inlet pipes 241a for generating an airflow of secondary air A22 toward the central axis of the wall 210 in plane P2, and are connected to the wall 210 so that the secondary air A22 reaches the center of the wall 210.

[0050] Next, with reference to Figure 4, the third inlet section 231 will be described in detail. As shown in Figure 4, the third inlet section 231 is positioned on the wall 210 so as to be downstream of the second inlet section 241 in a predetermined direction and upstream of the discharge pipe 261 in a predetermined direction. In other words, the third inlet section 231 is positioned above the second inlet section 241. Also, the third inlet section 231 is positioned below the discharge pipe 261. The third inlet section 231 includes at least one inlet pipe 231a perpendicular to the vertical direction. Specifically, the third inlet section 231 includes a plurality of inlet pipes 231a. Each of the plurality of inlet pipes 231a is an air supply nozzle. More specifically, the third inlet section 231 includes six inlet pipes 231a arranged at equal intervals along the circumferential direction of the wall 210. Each of the six inlet pipes 231a is formed in a cylindrical shape (it may be formed in a cylindrical shape, a rectangular shape, etc.).

[0051] Each of the six inlet pipes 231a introduces secondary air A23 along the wall 210 in a plane (orthoaxial cross-section) P3 perpendicular to the vertical direction. The six inlet pipes 231a correspond to an example of the "swirling supply section" in the present invention. Specifically, in plane P3, each of the six inlet pipes 231a is arranged to intersect the radial direction RD of the wall 210 at a predetermined angle β. The predetermined angle β is, for example, 20°. In other words, the six inlet pipes 231a are connected to the wall 210 in such a way that a swirling flow formed by the swirling of secondary air A23 in plane P3 is generated in the internal space 210b. As a result, a swirling flow of secondary air A23 is formed in the internal space 210b in the direction opposite to a predetermined circumferential direction CD. In other words, a reverse swirling flow of secondary air A23 is formed in the internal space 210b.

[0052] Referring again to Figures 2 to 4, the cooling mechanism (not shown) will be described. The secondary combustion section 20 further includes a cooling mechanism for cooling the wall 210. The cooling mechanism is located at the positions where the second inlet 241 and the third inlet 231 are located in the wall 210. Specifically, the cooling mechanism covers the outer circumferential surface of the wall 210.

[0053] Referring again to Figure 1, the supply device 40 will be described. As shown in Figure 1, the fluidized bed gasification combustion furnace 1 is further equipped with a supply device 40. For example, the supply device 40 consists of three supply pipes 40a and three dampers 40b, each of which is located in one of the three supply pipes 40a.

[0054] The supply device 40 introduces an amount of secondary air A2 into the secondary combustion chamber 21 from the first inlet 221 that results in an air ratio smaller than that of the secondary air A2 introduced from the second inlet 241 and the third inlet 231, respectively. It is preferable that the air ratio of the secondary air A2 introduced from the second inlet 241 is the same as that of the secondary air A2 introduced from the second inlet 241. Specifically, as the primary combustion material (exhaust gas) flows upward through the secondary combustion chamber 21, the supply device 40 adjusts the opening of the three dampers 40b to introduce an amount of secondary air A21 from the first inlet 221 that results in a first air ratio of 0.10 to 0.20, an amount of secondary air A22 from the second inlet 241 that results in a second air ratio of 0.30 to 0.70, and an amount of secondary air A23 from the third inlet 231 that results in a third air ratio of 0.30 to 0.70.

[0055] As explained above, in the fluidized bed gasification combustion furnace 1 of the first embodiment, when the primary combustible material (exhaust gas) is flowed upward in the internal space 210b, a small amount of secondary air A21 is introduced at the position of the plane P1 through which the receiving section 210a passes. Subsequently, while the primary combustible material (exhaust gas) is flowed upward in the internal space 210b, a large amount of secondary air A22 and A23 is introduced at two locations, the second introduction section 241 and the third introduction section 231, which are located above the receiving section 210a. Therefore, compared to the case where a large amount of secondary air A2 is introduced at the receiving section 210a, it is possible to suppress the rapid progress of the reaction between the unburned portion of the primary combustible material (exhaust gas) and the secondary air A2. As a result, it is possible to suppress the temperature of the wall 210 (especially near the receiving section 210a). In other words, it is possible to suppress the generation, adhesion, and growth of clinker from the primary combustible material (exhaust gas).

[0056] Furthermore, secondary air A23 is introduced along the wall 210 in the third inlet 231, and secondary air A22 is introduced toward the central axis of the wall 210 in the second inlet 241. Because secondary air A2 is introduced using different mixing methods, the primary combustible material (exhaust gas) generated in the fluidized bed gasifier 10 and the secondary air A2 are efficiently mixed in the internal space 210b, allowing for efficient incineration of unburned primary combustible material (exhaust gas) flowing through the internal space 210b. As a result, the discharge of unburned primary combustible material (exhaust gas) from the discharge pipe 261 can be suppressed.

[0057] Furthermore, even when the primary combustion material (exhaust gas) is configured to flow upward through the secondary combustion chamber 21, the duct 30 includes an intermediate section 30c through which the primary combustion material (exhaust gas) flows downward, thus preventing the height of the secondary combustion section 20 from increasing.

[0058] [Method of combustion] Next, the combustion method will be explained in detail. The combustion method comprises the primary combustion process, the primary combustion material introduction process, and the secondary combustion process. Figure 5 is a flowchart of the primary combustion material introduction process and the secondary combustion process. As shown in Figure 5, the combustion method comprises the primary combustion material introduction process (step S101), the first introduction process (step S102), the second introduction process (step S103), the third introduction process (step S104), and the discharge process (step S105). In the fluidized bed gasifier 10, if a predetermined amount of waste SS is continuously supplied, the primary combustion material introduction process (step S101), the first introduction process (step S102), the second introduction process (step S103), the third introduction process (step S104), and the discharge process (step S105) will be executed simultaneously for a long period of time. However, here we will explain the case where a predetermined amount of waste SS is supplied to the fluidized bed gasifier 10 only once.

[0059] In the primary combustion product introduction process (step S101), primary combustion products (exhaust gas) generated at a temperature of 500°C to 600°C are introduced into the internal space 210b from the other end 30b of the duct 30.

[0060] In the first introduction process (step S102), a quantity of secondary air A21 resulting in a primary air ratio of 0.10 to 0.20 is introduced into the internal space 210b from the first introduction section 221. This mixes the primary combustion material (exhaust gas) with the secondary air A21 resulting in a primary air ratio of 0.10 to 0.20. As a result, a first-order amount of unburned material in the primary combustion material (exhaust gas) is incinerated by the secondary air A21 at 600°C to 800°C. The primary combustion material (exhaust gas) mixed with the secondary air A21 resulting in a primary air ratio of 0.10 to 0.20 flows upward.

[0061] In the second introduction step (step S103), secondary air A22 in an amount that results in a second air ratio of 0.30 to 0.70 is introduced into the internal space 210b from the second introduction section 241. This mixes the primary combustion material (exhaust gas) with the secondary air A21 in an amount that results in a first air ratio of 0.10 to 0.20 and the secondary air A22 in an amount that results in a second air ratio of 0.30 to 0.70. In other words, the primary combustion material (exhaust gas) is mixed with secondary air A2 in an amount that results in an air ratio of 0.40 to 0.90. As a result, the second-largest amount of unburned material in the primary combustion material (exhaust gas) is incinerated at 850°C or higher by the secondary air A22. The primary combustion material (exhaust gas) mixed with secondary air A2 in an amount that results in an air ratio of 0.40 to 0.90 flows upward.

[0062] In the third introduction step (step S104), secondary air A23 in an amount that results in a second air ratio of 0.30 to 0.70 is introduced into the internal space 210b from the third introduction section 231. As a result, the primary combustible material (exhaust gas) is mixed with secondary air A21 in an amount that results in a first air ratio of 0.10 to 0.20, secondary air A22 in an amount that results in a second air ratio of 0.30 to 0.70, and secondary air A23 in an amount that results in a third air ratio of 0.30 to 0.70. In other words, the primary combustible material (exhaust gas) is mixed with secondary air A2 in an amount that results in an air ratio of 0.70 to 1.60. As a result, the third amount of unburned material in the primary combustible material (exhaust gas) is incinerated at 850°C or higher by secondary air A23. The primary combustible material (exhaust gas) mixed with secondary air A2 in an amount that results in an air ratio of 0.70 to 1.60 flows upward.

[0063] In the discharge process (step S105), the primary and secondary combustion gases are discharged into the atmosphere through the discharge pipe 261.

[0064] As explained above, in the fluidized bed gasification furnace 1 of the first embodiment, when the primary combustible material (exhaust gas) is flowed upward in the internal space 210b, a small amount of secondary air A2 is introduced into the primary combustible material (exhaust gas) that has flowed into the internal space 210b from the duct 30, resulting in a small air-to-body ratio. Subsequently, while the primary combustible material (exhaust gas) is flowed upward in the internal space 210b, a large amount of secondary air A2 is introduced twice, in the second introduction step (step S103) and the third introduction step (step S104), after the first introduction step (step S102). Therefore, compared to the case where a large amount of secondary air A2 is introduced in the duct 30, it is possible to suppress the rapid progress of the reaction between the unburned portion of the primary combustible material (exhaust gas) and the secondary air A2. As a result, it is possible to suppress the temperature of the wall 210 (especially near the receiving section 210a). In other words, it is possible to suppress the generation, adhesion, and growth of clinker from the primary combustible material (exhaust gas).

[0065] Based on the design principles described in relation to the first embodiment, the designer can construct various structures to suppress localized high temperatures on the walls 210 of the secondary combustion chamber 21.

[0066] (Second Embodiment) The duct 730 and the secondary combustion section 720 will be described with reference to Figure 6. Figure 6 is a schematic cross-sectional view showing the secondary combustion section 720 in the plane passing through the receiving section 910a. As shown in Figure 6, the fluidized bed gasification combustion furnace 1 according to the second embodiment and the fluidized bed gasification combustion furnace 1 according to the first embodiment differ mainly in the structure in the plane passing through the receiving section 910a.

[0067] [Secondary combustion section] The other end of the duct 730 is connected to the receiving section 910a. Specifically, the duct 730 is connected toward the central axis of the wall 910 of the secondary combustion chamber 721. As a result, unlike the first embodiment, the duct 730 introduces the secondary air A21 toward the central axis of the wall 910.

[0068] Furthermore, the first inlet section 921 is positioned at the same height as the receiving section 910a. The first inlet section 921 includes at least one inlet pipe 921a perpendicular to the vertical direction. Specifically, the first inlet section 921 includes three inlet pipes 921a.

[0069] Each of the three inlet pipes 921a introduces secondary air A21 toward the central axis of the wall 910 in a plane perpendicular to the vertical direction. Specifically, unlike the first embodiment, each of the three inlet pipes 921a is arranged along the radial direction of the wall 910. For example, each of the three inlet pipes 921a is arranged at an angle of, for example, 40° with respect to the duct 730 toward the central axis.

[0070] [duct] The duct 730 is formed in a cylindrical shape. In the second embodiment, the duct 730 is formed in a cylindrical shape.

[0071] (Third embodiment) The duct 630 will be described with reference to Figure 7. Figure 7 is a schematic cross-sectional view showing the secondary combustion section 620 in the plane passing through the receiving section 910a. As shown in Figure 6, the fluidized bed gasification combustion furnace 1 according to the third embodiment and the fluidized bed gasification combustion furnace 1 according to the second embodiment differ mainly in the structure in the plane passing through the receiving section 910a.

[0072] [duct] The duct 630 is formed in a cylindrical shape. In the third embodiment, the duct 630 is formed in a rectangular cylindrical shape.

[0073] (Fourth Embodiment) Next, the secondary combustion section 520 will be described with reference to Figures 8 and 9. Figure 8 is a schematic cross-sectional view of the secondary combustion section 520. Figure 9 is a schematic cross-sectional view of the secondary combustion section 520 in a plan view above the cross-sectional position shown in Figure 8. As shown in Figures 8 and 9, the fluidized bed gasification combustion furnace 1 according to the fourth embodiment and the fluidized bed gasification combustion furnace 1 according to the first embodiment have different secondary combustion sections 520.

[0074] [Secondary combustion section] Unlike the first embodiment, the secondary combustion section 520 further includes a boiler (not shown) for cooling the rectangular cylindrical wall 510. Specifically, the boiler covers the outer circumferential surface of the wall 510.

[0075] The second inlet section 531 is positioned on the wall 510 so as to be downstream of the first inlet section 221 in a predetermined direction. The second inlet section 531 comprises a plurality of inlet pipes 531a that are perpendicular to the vertical direction. More specifically, unlike the first embodiment, the second inlet section 531 comprises eight inlet pipes 531a arranged along the circumferential direction of the wall 510.

[0076] Each of the eight inlet pipes 531a introduces secondary air A22 along the wall 510 in a plane perpendicular to the vertical direction. Specifically, each of the eight inlet pipes 531a is positioned on the wall 510 such that two of the eight inlet pipes 531a are positioned parallel to one of the four walls 510. As a result, a swirling flow of secondary air A22 is formed in the internal space 510b.

[0077] The third inlet section 541 is positioned on the wall 510 so as to be downstream of the second inlet section 531 in a predetermined direction and upstream of the discharge pipe in a predetermined direction. The third inlet section 541 comprises a plurality of inlet pipes 541a perpendicular to the vertical direction. More specifically, unlike the first embodiment, the third inlet section 541 comprises eight inlet pipes 541a arranged at equal intervals along the circumferential direction of the wall 510.

[0078] Each of the eight inlet pipes 541a introduces secondary air A23 toward the central axis of the wall 510 in a plane perpendicular to the vertical direction. Specifically, each of the eight inlet pipes 541a is positioned along the radial direction RD of the wall 510.

[0079] [Manufacturing method] Here, an example of a manufacturing method for the gasification combustion furnace 1 will be described. Compared to stoker furnaces and fluidized bed incinerators, gasification melting furnaces (see Figure 10) have higher running costs, such as electricity costs and repair costs. One way to reduce these running costs is to convert them into gasification combustion furnaces 1. When converting, it is desirable to reuse existing gasification melting furnace equipment as much as possible and to be able to install it in an existing building. Therefore, in this embodiment, a gasification melting furnace installed in a predetermined location is used to manufacture a gasification combustion furnace 1 to be installed in a predetermined location.

[0080] An example of a manufacturing method will be described with reference to Figures 1 and 10. Figure 10 is a schematic diagram of the gasification and melting furnace 2 according to this embodiment. As shown in Figure 10, the gasification and melting furnace 2 is installed in a predetermined location S. Specifically, the fluidized bed gasification and melting furnace 2 comprises a fluidized bed gasifier 10, a melting furnace 60, and a melting section connecting the fluidized bed gasifier 10 and the melting furnace 60. In the fluidized bed gasification and melting furnace 2, similar to the gasification combustion furnace 1, the thermal decomposition (gasification) of waste SS is carried out in the fluidized bed gasifier 10, and the molten slag SU formed by the melting of the ash is then recovered in the melting furnace 60.

[0081] [Fluidized bed gasifier] The fluidized bed gasifier 10 is installed in the first area S1 of a designated location S. The fluidized bed gasifier 10 has the same configuration as the fluidized bed gasifier 10 of the gasification combustion furnace 1 in Figure 1. A detailed explanation of the fluidized bed gasifier 10 is omitted here.

[0082] [Melting furnace] The melting furnace 60 is installed in a second area S2 adjacent to a first area S1 in a predetermined location S. The melting furnace 60 generates molten slag SU and secondary combustion gas by incinerating and melting primary combustible material (exhaust gas) at a third predetermined temperature using a burner flame and secondary air A2. The secondary combustion gas is the same as the primary combustion gas and includes carbon dioxide (CO2), water vapor (H2O), etc. The third predetermined temperature is approximately 1300°C in order to melt the ash and form molten slag SU.

[0083] [Connecting section for molten parts] The melting section connecting section 70 connects the fluidized bed gasifier 10 and the melting furnace 60, guiding the primary combustion material (exhaust gas) generated in the fluidized bed gasifier 10 to the melting furnace 60. The melting section connecting section 70 is formed in a cylindrical shape. In this embodiment, the melting section connecting section 70 is formed in a cylindrical shape (it may be formed in a cylindrical or rectangular shape, etc.). In detail, the melting section connecting section 70 comprises one end connected to the outlet 11b and the other end connected to the melting furnace 60 and extending horizontally.

[0084] Secondary air A2 is supplied to the molten section communication section 70. Specifically, the secondary air A2 is supplied to the combustion chamber 63 so that the air ratio to the primary combustible material (exhaust gas) is approximately 1.0.

[0085] [Manufacturing method] Here, we will describe in detail the manufacturing method for producing the gasification combustion furnace 1 using the gasification melting furnace 2. Figure 11 is a flowchart of the manufacturing method. As shown in Figure 11, the manufacturing method comprises a gasification melting furnace preparation step (step S201), a melting section removal step (step S202), a secondary combustion section preparation step (step S203), and a connection step (step S204).

[0086] In the gasification and melting furnace preparation process (step S201), the gasification and melting furnace 2, which is installed at a predetermined location S, is prepared.

[0087] In the molten section removal process (step S202), the molten section communication section 70 is removed from the furnace body 11, and the molten furnace 60 is removed from the second region S2.

[0088] In the secondary combustion section preparation step (step S203), the secondary combustion section 20 is installed in the second region S2. In the manufacturing method according to this embodiment, an example is shown in which the secondary combustion section 20 includes a first inlet 221, a second inlet 241, and a third inlet 231. However, the secondary combustion section 20 may not include the first inlet 221, the second inlet 241, and the third inlet 231.

[0089] In the connection process (step S204), one end 30a of the duct 30 is attached to the furnace body 11, and the other end 30b of the duct 30 is attached to the secondary combustion chamber 21, thereby connecting the fluidized bed gasifier 10 and the secondary combustion section 20. Specifically, one end 30a of the duct 30 is attached to the furnace body 11, and the other end 30b of the duct 30 is attached to the secondary combustion chamber 21, so that the primary combustible material (exhaust gas) discharged from the fluidized bed gasifier 10 of the gasification melting furnace 2 is introduced into the internal space 210b of the secondary combustion chamber 21 and incinerated by secondary air A2, thereby generating secondary combustible material (exhaust gas after combustion of unburned material) containing secondary combustion gas.

[0090] As explained above, the gasification combustion furnace 1 can be manufactured inexpensively using the fluidized bed gasifier 10 of the gasification melting furnace 2. Furthermore, the gasification combustion furnace 1 can be manufactured using the second area S2 where the melting furnace 60 was located. In addition, since the duct 30 is equipped with an intermediate section 30c through which the primary combustion material (exhaust gas) flows downward, the height of the secondary combustion section 20 can be suppressed, and the gasification combustion furnace 1 can be installed in an existing building.

[0091] (Other embodiments) It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims.

[0092] (1) In the above embodiment, the secondary combustion section 20 is shown to include a first introduction section 221, a second introduction section 241, and a third introduction section 231. However, it may further include a fourth introduction section arranged downstream of the third introduction section in a predetermined direction for introducing secondary air A2 into the internal space 210b, and a fifth introduction section arranged downstream of the fourth introduction section in a predetermined direction for introducing secondary air A2 into the internal space 210b.

[0093] (2) In the above embodiment, an example was shown in which secondary air A2 is introduced in a different mixing method such that secondary air A22 is introduced along the wall 210 in the third introduction section 231 and secondary air A23 is introduced toward the central axis of the wall 210 in the second introduction section 241. However, secondary air A2 may be introduced in a different mixing method such that secondary air A2 is introduced toward the central axis of the wall 210 in the third introduction section 231 and secondary air A2 is introduced along the wall 210 in the second introduction section 241. Secondary air A2 may be introduced in the same mixing method such that secondary air A2 is introduced toward the central axis of the wall 210 in the third introduction section 231 and secondary air A2 is introduced toward the central axis of the wall 210 in the second introduction section 241. Secondary air A2 may be introduced in the same mixing method such that secondary air A2 is introduced along the wall 210 in the third introduction section 231 and secondary air A2 is introduced along the wall 210 in the second introduction section 241.

[0094] (3) In the above embodiment, an example was shown in which the receiving section 210a is located at the lower part of the wall 210, but the receiving section 210a may also be located at the upper part of the wall 210. In this case, the secondary combustion section 20 may burn off the unburned portion of the primary combustion material (exhaust gas) with secondary air A2 while the primary combustion material (exhaust gas) flows downward.

[0095] (4) A temperature measuring unit may be provided near the receiving section 210a of the secondary combustion chamber 21 (for example, in the hopper section 262), and the airflow rate of the primary combustion material (exhaust gas) flowing through the receiving section 210a and the airflow rate of the secondary air A21 flowing through the first introduction section 221 may be adjusted according to the temperature.

[0096] (5) In the above embodiment, the number and angle of the air inlet pipes (air supply nozzles) 221a, 231a, and 241a, and the flow velocity of the injected secondary air A2 are examples and can be changed depending on the size of the secondary combustion chamber 21, etc. [Explanation of symbols]

[0097] 1. Gasification combustion furnace 10. Fluidized bed gasifier (primary combustion section) 20 Secondary combustion section 21 Secondary combustion chamber 30 Communication part 40 Feeding device 210 Wall 210a Reception Department 210b Interior space 221 First Introduction 231 Third introduction 241 Second Introduction 261 Secondary discharge section A2 Secondary air

Claims

1. It is a gasification combustion furnace, A primary combustion unit having a primary combustion chamber, in which the incinerator is gasified, A secondary combustion section burns the unburned portion of the exhaust gas discharged from the primary combustion section, A communication section that guides the exhaust gas, including the unburned portion, discharged from the primary combustion section to the secondary combustion section, It includes a supply device for supplying air to the secondary combustion section, The aforementioned secondary combustion section is A secondary combustion chamber having a wall, an internal space defined by the wall and extending in a predetermined direction, a receiving section having an opening that penetrates the wall and receives the exhaust gas containing the unburned portion from an end of the communicating section extending in a direction perpendicular to the predetermined direction, and a secondary discharge section provided downstream of the receiving section in the predetermined direction and discharging the exhaust gas after the unburned portion has been burned in the internal space, A first introduction section is provided at the same position as the opening formed in the wall in the predetermined direction, for introducing the air into the internal space, A second inlet is positioned in the wall so as to be downstream in the predetermined direction from the first inlet, and introduces the air into the internal space. It includes a third inlet positioned in the wall such that it is downstream of the second inlet in the predetermined direction and upstream of the secondary discharge in the predetermined direction, and which introduces the air into the internal space, The supply device is a gasification combustion furnace that introduces an amount of air from the first inlet that has an air-to-air ratio smaller than the air-to-air ratio of the air introduced from the second inlet and the third inlet, respectively.

2. A gasification combustion furnace, A primary combustion unit having a primary combustion chamber, in which the incinerator is gasified, A secondary combustion section burns the unburned portion of the exhaust gas discharged from the primary combustion section, A communication section that guides the exhaust gas, including the unburned portion, discharged from the primary combustion section to the secondary combustion section, It includes a supply device for supplying air to the secondary combustion section, The aforementioned secondary combustion section is A secondary combustion chamber having a wall, an internal space defined by the wall and extending in a predetermined direction, a receiving section that receives the exhaust gas including the unburned portion from the communication section, and a secondary discharge section provided downstream of the receiving section in the predetermined direction for discharging the exhaust gas after the unburned portion has been burned in the internal space, A first introduction section is provided near the receiving section for introducing the air into the internal space, A second inlet is positioned in the wall so as to be downstream in the predetermined direction from the first inlet, and introduces the air into the internal space. It includes a third inlet positioned in the wall such that it is downstream of the second inlet in the predetermined direction and upstream of the secondary discharge in the predetermined direction, and which introduces the air into the internal space, The supply device introduces an amount of air from the first inlet into the first inlet such that the temperature of the exhaust gas present near the first inlet is 600°C or higher and 800°C or lower, and such an amount of air has a smaller air-to-body ratio than the air introduced from the second inlet and the third inlet, respectively. A gasification combustion furnace in which the air ratio of the air introduced into the internal space from the first inlet is 0.10 or more and 0.20 or less.

3. In the gasification combustion furnace according to claim 2, A gasification combustion furnace in which the air-to-air ratio of the air introduced into the primary combustion chamber is 0.30 or more and 0.50 or less.

4. In the gasification combustion furnace according to claim 1, The second inlet is a gasification combustion furnace positioned higher than the first inlet.

5. In the gasification combustion furnace according to claim 4, The primary combustion section includes a primary discharge section located above the primary combustion chamber. The communication portion further comprises one end connected to the primary discharge portion, the other end connected to the receiving portion, and an intermediate portion positioned between the one end and the other end and extending in the vertical direction. The receiving section is located below the primary discharge section to which one end of the communicating section is connected, in a gasification combustion furnace.

6. In the gasification combustion furnace according to any one of claims 1 to 5, One of the second introduction section and the third introduction section has a rotating supply section, and the other of the second introduction section and the third introduction section has a center supply section. The wall has a cylindrical shape with a central axis extending in the predetermined direction, The swirling supply unit is connected to the wall such that it generates a swirling flow in the internal space by the swirling of the air in an orthogonal cross-section perpendicular to the central axis, The central supply unit is connected to the wall such that it generates an airflow of the air toward the central axis in a cross section perpendicular to the axis, in a gasification combustion furnace.

7. A method of combustion, The primary combustion process involves gasifying the incinerator in the primary combustion chamber, The secondary combustion chamber comprises a wall and an internal space defined by the wall, extending in a predetermined direction and communicating with the primary combustion chamber through a connecting portion, wherein the unburned portion of the exhaust gas discharged from the primary combustion process is burned in the internal space while the unburned portion of the exhaust gas discharged from the primary combustion process flows in the predetermined direction. The aforementioned secondary combustion process is A first introduction step involves introducing an amount of air with a first air-to-air ratio of 0.10 to 0.20 into the exhaust gas flowing into the internal space from the communication section, such that the temperature of the exhaust gas is 600°C or more and 800°C or less. A second introduction step is performed, in which, after the execution of the first introduction step, an amount of air is introduced into the exhaust gas that has flowed through the internal space in the predetermined direction, resulting in a second air ratio that is greater than the first air ratio, A third introduction step is performed, in which, after the execution of the second introduction step, an amount of air is introduced into the exhaust gas that has flowed through the internal space in the predetermined direction, resulting in a third air ratio greater than the first air ratio, A combustion method comprising a discharge step of discharging the exhaust gas after combustion of the unburned portion, which has flowed through the internal space in a predetermined direction after the execution of the third introduction step, from the secondary discharge section of the secondary combustion chamber.

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