Combustion equipment

Abstract

We provide combustion equipment that achieves low NOx emissions. [Solution] The combustion equipment comprises a furnace body equipped with a stoker, a furnace into which the exhaust gas after combustion flows, a primary combustion zone formed below the furnace inside the furnace body, a secondary combustion zone formed below the furnace above the primary combustion zone, and a nozzle that supplies a portion of the exhaust gas discharged from the furnace body as a swirling flow generating gas. The nozzle is positioned eccentrically toward the right wall or the left wall side of the rear wall, rather than the center of the right wall and the left wall, so that the swirling flow generating gas is injected from the rear wall into the primary combustion zone.

Description

[Technical Field]

[0001] This disclosure relates to waste incineration equipment. [Background technology]

[0002] There is a need to reduce NOx emissions from waste incineration facilities. In order to achieve low NOx combustion in a stoker furnace, it is important to reduce the amount of air supplied to the furnace. However, reducing the amount of air suppresses the combustion of waste, and the problem is that unburned gases, especially CO, tend to remain at the outlet.

[0003] Patent Document 1 discloses a method for achieving complete combustion through secondary combustion with a long effective residence time while oxygen is sufficiently diffused, and suppressing the generation of unburned gases, by supplying secondary air in such a way that an airflow swirls around a virtual centerline perpendicular to the flow direction of the combustion gases during the combustion process. However, the method in Patent Document 1 cannot promote the mixing of air and unburned gases in the primary combustion region because it forms a swirling flow in the secondary combustion region. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 04-366307 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Technologies to reduce NOx emissions are needed.

[0006] This disclosure provides a combustion system that can solve the above-mentioned problems. [Means for solving the problem]

[0007] The combustion equipment of this disclosure includes a furnace body equipped with a stoker that transports the material to be incinerated while burning it, a furnace connected above the furnace body into which the exhaust gas after combustion flows, and a primary combustion area formed below the furnace inside the furnace body, enclosed by a right wall, a left wall, a front ceiling extending forward from the furnace, a ceiling extending backward from the furnace, a rear wall extending downward from the rear end of the ceiling, and the stoker, where the upstream side in the transport direction of the material to be incinerated is referred to as the front, the downstream side in the transport direction as the rear, and the right side and left side when viewed from front to rear as the right and left sides respectively, the furnace body comprises a primary combustion area formed below the furnace inside the furnace body, a secondary combustion area formed above the primary combustion area and below the furnace, and a nozzle that supplies a portion of the exhaust gas discharged from the furnace body as a swirling flow generating gas, wherein the nozzle is When the primary combustion region is viewed from above, and the position at the same location as the front wall of the furnace is designated as the front nose, and the position at the same location as the rear wall of the furnace is designated as the rear nose, in order to generate a swirling flow by the swirling flow generating gas between the front nose and the rear nose in the primary combustion region, the rear of the furnace body The swirling flow generating gas is located at a position eccentric to the right wall side or the left wall side, relative to the center of the right wall portion and the left wall portion. Rear of the furnace body It is installed to be injected from there into the primary combustion area. [Effects of the Invention]

[0008] The combustion equipment described herein can reduce NOx emissions. [Brief explanation of the drawing]

[0009] [Figure 1] This is the first figure showing an example of the configuration of a combustion equipment according to the embodiment. [Figure 2] This is a plan view of the furnace body according to the embodiment. [Figure 3A] This is the first figure showing an example of the installation position and direction of the nozzle according to the embodiment. [Figure 3B] This is a second figure showing an example of the installation position and direction of the nozzle according to the embodiment. [Figure 3C] This is a third figure showing an example of the installation position and direction of the nozzle according to the embodiment. [Figure 3D] This is the fourth figure, which shows an example of the installation position and direction of the nozzle according to the embodiment. [Figure 4A]It is a first diagram showing an example of an EGR gas flow according to an embodiment. [Figure 4B] It is a second diagram showing an example of an EGR gas flow according to an embodiment. [Figure 5] It is a third diagram showing an example of an EGR gas flow according to an embodiment. [Figure 6] It is a diagram for explaining the installation angle of a nozzle according to an embodiment. [Figure 7A] It is a first diagram showing an example of the installation position and direction of a nozzle in the case of two lanes according to an embodiment. [Figure 7B] It is a second diagram showing an example of the installation position and direction of a nozzle in the case of two lanes according to an embodiment. [Figure 7C] It is a third diagram showing an example of the installation position and direction of a nozzle in the case of two lanes according to an embodiment. [Figure 8A] It is a first diagram showing an example of the installation position and direction of a nozzle in the case of three lanes according to an embodiment. [Figure 8B] It is a second diagram showing an example of the installation position and direction of a nozzle in the case of three lanes according to an embodiment. [Figure 8C] It is a third diagram showing an example of the installation position and direction of a nozzle in the case of three lanes according to an embodiment. [Figure 9] It is a second diagram showing an example of the configuration of combustion equipment according to an embodiment. [Figure 10] It is a third diagram showing an example of the configuration of combustion equipment according to an embodiment.

Mode for Carrying Out the Invention

[0010] <Embodiment> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. And the overlapping descriptions of those components may be omitted. The following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0011] Furthermore, in the embodiments described below, for the sake of explanation, the side on which the furnace body 2 is located relative to the fuel supply mechanism 3 shown in Figure 1 is defined as "rear," and the opposite side is defined as "front." In addition, the upstream side in the direction of transport of the material to be incinerated may be referred to as "front," and the downstream side in the same transport direction may be referred to as "rear." In addition, the "front side" may be referred to as the "furnace front side," and the "rear side" may be referred to as the "furnace tail side." Furthermore, "left" and "right" are defined based on the direction from the fuel supply mechanism 3 toward the furnace body 2.

[0012] (Combustion equipment) The combustion equipment is a stoker-type combustion furnace that incinerates materials such as municipal solid waste, industrial waste, or biomass. The "material to be incinerated" is referred to as "waste." The waste is the fuel used to generate the combustion reaction within the combustion furnace.

[0013] As shown in Figure 1, the combustion equipment 100 includes a combustion furnace 1, a waste heat recovery boiler 12, a cooling tower 13, a dust collector 14, an outlet passage 15, a chimney 16, an induced draft fan 17, an ash extrusion device 19, an ash pit 20, an exhaust gas recirculation system 21, an exhaust gas concentration acquisition unit 25, and a control device 30.

[0014] (combustion furnace) Combustion furnace 1 is a furnace that burns waste W while transporting it inside. As waste W is burned in combustion furnace 1, exhaust gas is generated from combustion furnace 1. The generated exhaust gas is sent to a waste heat recovery boiler 12 connected to the top of combustion furnace 1.

[0015] The waste heat recovery boiler 12 generates steam by heating water through heat exchange between the exhaust gas and the water. The generated steam is used, for example, by equipment such as a steam turbine (not shown) outside the combustion equipment 100. After passing through the waste heat recovery boiler 12, the exhaust gas is cooled in the cooling tower 13 and then sent to the dust collector 14. After soot and dust are removed from the exhaust gas in the dust collector 14, it is discharged into the atmosphere through the outlet passage 15 and the chimney 16.

[0016] Here, an induced draft fan (IDF) is positioned midway through the outlet passage 15, capable of drawing exhaust gas generated in the combustion furnace 1 towards the chimney 16. The induced draft fan 17 draws exhaust gas from inside the combustion furnace 1, thereby maintaining a negative pressure state inside the combustion furnace 1.

[0017] The combustion furnace 1 comprises a furnace body 2, a fuel supply mechanism 3, a stoker 4, a wind box 5, a discharge chute 6, a furnace 7, a forced-air fan 8, a primary air line 9, and a secondary air line 11.

[0018] (Furnace body) The furnace body 2 is composed of multiple partitions. Inside the furnace body 2, a processing space V is defined for transporting waste W while burning it. In the processing space V, the waste W is transported in the transport direction (from "front" to "back") while burning. The waste W that has been incinerated in the processing space V is discharged to the outside of the furnace body 2 through the discharge chute 6.

[0019] The furnace body 2 has a ceiling section 200, a furnace tail section 201, and a front ceiling section 202. The furnace tail section 201 is part of the partition wall in the furnace body 2. The furnace tail section 201 is made of refractory material or the like. The furnace tail section 201 is located behind the rear combustion stage 52, which is partitioned by the wind box 5. The furnace tail section 201 is connected to the discharge chute 6 from above. The ceiling section 200 is part of the partition wall in the furnace body 2. The ceiling section 200 is made of refractory material or the like. The ceiling section 200 is located above the furnace tail section 201. The ceiling section 200 is inclined so that its height decreases vertically towards the rear. The rear end of the ceiling section 200 is connected to the furnace tail section 201. The front ceiling section 202 is part of the partition wall in the furnace body 2. The front ceiling section 202 is made of refractory material or the like. The front ceiling section 202 extends forward from the furnace 7 above the stoker 4 and is connected to the outlet section 302 of the fuel supply mechanism 3.

[0020] (Fuel supply mechanism) The fuel supply mechanism 3 is a mechanism that receives waste W from outside the combustion furnace 1 and supplies the received waste W to the processing space V inside the furnace body 2. The fuel supply mechanism 3 in this embodiment has a hopper 300 and a feeder 310. The hopper 300 is the inlet of the combustion furnace 1 for supplying waste W into the furnace body 2. Waste W is fed into the hopper 300 from outside the combustion furnace 1 by a crane. The hopper 300 has an inlet 301 and an outlet 302. Waste W fed into the inlet 301 falls to the outlet 302 below due to gravity. The outlet 302 guides the waste W to the processing space V inside the furnace body 2. The outlet 302 has a storage space R inside for temporarily storing waste W before supplying it to the processing space V inside the furnace body 2.

[0021] The feeder 310 is a device that supplies waste W from the hopper 300 to the processing space V inside the furnace body 2. The feeder 310 is positioned to reciprocate in the front-rear direction relative to the floor surface 302a. The feeder 310 has an upper surface 311 and an extrusion surface 312 connected to the upper surface 311 and facing the rear. By reciprocating in the front-rear direction at predetermined timings, the feeder 310 intermittently pushes the waste W in the storage space R toward the processing space V.

[0022] (Stalker) The stoker 4 is composed of multiple grates (not shown), and these multiple grates form a stoker surface 4a to which waste W is supplied in layers by the fuel supply mechanism 3. The grates include a fixed grate and a movable grate.

[0023] The fixed grate is fixed to the surface of the windbox 5, facing upwards. The movable grate moves back and forth at a constant speed, agitating and mixing the waste W on the movable grate and the fixed grate (on the stoker surface 4a) as it is transported downstream. The stoker 4 burns the waste W supplied in layers to the stoker surface 4a and transports it toward the discharge chute 6.

[0024] Here, the furnace body 2 has, in order from the front, a drying stage 50, a combustion stage 51, and a post-combustion stage 52. These drying stage 50, combustion stage 51, and post-combustion stage 52 divide the processing space V in the conveying direction. The drying stage 50 is the region where the waste W supplied from the hopper 300 is dried on the stoker 4 prior to combustion. That is, in the drying stage 50, moisture volatilizes, so mainly steam is generated from the drying stage 50.

[0025] The combustion stage 51 and the post-combustion stage 52 are regions where dry waste W is burned on the stoker 4. In the combustion stage 51, diffusion combustion occurs due to the pyrolysis gas generated from the waste W, producing a bright flame F. In the post-combustion stage 52, fixed carbon combustion occurs in the waste W after diffusion combustion, so no bright flame F is produced. Therefore, the bright flame F produced during combustion is mainly formed in the combustion stage 51.

[0026] (Wind box) The air chamber 5 supplies combustion air (primary air) from below the stoker 4 toward the processing space V. Multiple air chambers 5 are arranged in the direction of waste transport.

[0027] (Discharge chute) The discharge chute 6 is a device that drops the waste W, which has turned into ash after combustion, into an ash extrusion device 19 located below the furnace body 2. The discharge chute 6 is located at the rear end of the post-combustion stage 52.

[0028] (furnace) The furnace 7 extends upward from the furnace body 2. The exhaust gas generated by the combustion of waste W in the processing space V is sent to the waste heat recovery boiler 12 through the furnace 7. The furnace 7 extends vertically and has a cylindrical shape. The furnace 7 includes a front wall 7a located at the front of the space through which the exhaust gas flows, and a rear wall 7b located at the rear. Exhaust gas is generated in the processing space V as waste is burned. The space 60 above the stoker 4, enclosed by the front ceiling 202, the ceiling 200, the furnace tail 201, the right wall 203R (Figure 2), and the left wall 203L (Figure 2), is called the primary combustion zone. The space 61 connected to the upper side of the primary combustion zone and forming the lower part of the furnace 7 above the primary combustion zone is called the secondary combustion zone. The exhaust gas flows from the stoker 4 upward from the primary combustion zone to the secondary combustion zone.

[0029] The furnace 7 is connected to the outlet 302 of the hopper 300 from the rear. Therefore, the furnace 7 is located between the ceiling 200 and the outlet 302. In this embodiment, the furnace 7 is located directly above the combustion stage 51.

[0030] (Forced air blower) As shown in Figure 1, the forced air blower 8 is a device that pressurizes and pumps air into the combustion furnace 1 for burning waste W in the processing space V. The forced air blower 8 has a first forced air blower 81 and a second forced air blower 82. The first forced air blower 81 pressurizes and pumps combustion air (primary air) towards the wind box 5 through the primary air line 9. The second forced air blower 82 pressurizes and pumps combustion air (secondary air) towards the furnace 7 through the secondary air line 11.

[0031] (Primary air line) The primary air line 9 is a pipe connecting the first forced-air blower 81 and the wind box 5. When the first forced-air blower 81 is driven, air necessary for the combustion of waste W is supplied to the wind box 5 through the primary air line 9. The primary air line 9 is connected to the wind box 5 from below. The air supplied to the wind box 5 goes from below the stoker 4 towards the waste W. The air supplied to the inside of the furnace body 2 through the primary air line 9 is called "primary air". The primary air line 9 has a primary air damper 90. The primary air damper 90 is located in the middle of the primary air line 9 and regulates the flow rate of primary air A1 in the primary air line 9 by the opening of the damper 90.

[0032] (Air preheater) The air preheater 27 is a heat exchanger that preheats the air supplied from the first forced-air blower 81. The air preheater 27 is located midway through the primary air line 9 and preheats the combustion air flowing from the first forced-air blower 81 toward the wind box 5. The combustion air preheated by the air preheater 27 is supplied into the processing space V and used for the combustion of waste W.

[0033] (Secondary air line) The secondary air line 11 is a pipe connecting the second forced-air blower 82 and the furnace 7. When the second forced-air blower 82 is driven, air necessary for the combustion of waste W is supplied into the furnace 7 through the secondary air line 11. The secondary air line 11 penetrates the furnace 7 from the outside. The tip of the secondary air line 11 may be positioned inside the inner surface of the furnace 7. The secondary air supplied into the furnace 7 is directed towards the waste W from above the stoker 4. The air supplied into the furnace body 2 through the secondary air line 11 is called "secondary air". The secondary air line 11 has a secondary air damper 110. The secondary air damper 110 is installed in the middle of the secondary air line 11 and regulates the flow rate of secondary air A2 by the opening of the damper of the secondary air damper 110.

[0034] (Ash extrusion device) The ash extrusion device 19 is a device that receives waste W (ash) that has fallen below the furnace body 2 through the discharge chute 6 and pushes it into the subsequent ash pit 20. The ash extrusion device 19 has an extrusion device body 190 and an extrusion mechanism (not shown). The extrusion device body 190 receives the waste W that has turned into ash after combustion in the processing space V and temporarily stores it. The extrusion device body 190 is located below the furnace body 2. The extrusion device body 190 is connected to the discharge chute 6 from below. The extrusion mechanism pushes the waste W (ash) that has fallen into the extrusion device body 190 toward the ash pit 20.

[0035] (Gray pit) The ash pit 20 is a chamber that receives and stores waste W from the extruder. In this embodiment, the ash pit 20 is connected to the extruder body 190 from the rear. The waste W stored in the ash pit 20 is transported to the outside of the combustion equipment 100 by, for example, an ash crane (not shown).

[0036] (Exhaust gas recirculation system) The exhaust gas recirculation system 21 is an EGR (Exhaust Gas Recirculation) system that recirculates a portion of the post-combustion exhaust gas flowing through the outlet passage 15 back into the furnace body 2. The exhaust gas recirculation system 21 includes an exhaust gas recirculation line 22, a nozzle 23, and a fan 24.

[0037] (Exhaust gas recirculation line) The exhaust gas recirculation line 22 connects the outlet passage 15 and the furnace body 2. In this embodiment, one end of the exhaust gas recirculation line 22 is connected to the vicinity of the dust collector 14 in the outlet passage 15, and the other end of the exhaust gas recirculation line 22 is connected to the furnace tail 201 in the furnace body 2 via a nozzle 23.

[0038] (nozzle) The nozzle 23 supplies (discharges) exhaust gas supplied through the exhaust gas recirculation line 22 into the interior of the furnace body 2. The nozzle 23 is connected to the other end of the exhaust gas recirculation line 22. For example, the nozzle 23 is cylindrical in shape. The nozzle 23 is fixed to the furnace tail 201, passing through it. The nozzle 23 opens into the interior of the furnace body 2, facing inward. In this embodiment, the exhaust gas discharged by the nozzle 23 spreads conically from the opening of the nozzle 23. The nozzle 23 is also called an EGR nozzle. The exhaust gas discharged by the nozzle 23 is also called EGR gas. The nozzle 23 may be installed parallel to the ground, or it may be installed facing upward at a predetermined angle (for example, 15 degrees).

[0039] (fan) Fan 24 supplies EGR gas to nozzle 23 through exhaust gas recirculation line 22. As shown in Figure 1, fan 24 is positioned midway through exhaust gas recirculation line 22. When driven, fan 24 pressurizes a portion of the exhaust gas in outlet passage 15 to nozzle 23. Fan 24 is controlled by control device 30 located outside the combustion furnace 1. Specifically, fan 24 receives a signal indicating its rotational speed from control device 30 via wired or wireless communication. That is, fan 24 rotates based on the rotational speed indicated by the signal, drawing a portion of the exhaust gas in outlet passage 15 out of outlet passage 15 and supplying it to nozzle 23. Fan 24 also transmits a signal indicating its output rotational speed to control device 30 via wired or wireless communication at predetermined time intervals.

[0040] (Exhaust gas concentration acquisition unit) The exhaust gas concentration acquisition unit 25 acquires the concentrations of CO and NOx contained in the exhaust gas generated from the combustion furnace 1. The exhaust gas concentration acquisition unit 25 is located within the outlet flow path 15. For example, the exhaust gas concentration acquisition unit 25 has a CO sensor 25a and a NOx sensor 25b.

[0041] The CO sensor 25a acquires the CO concentration of the exhaust gas flowing through the outlet channel 15 at predetermined time intervals and transmits a signal indicating the CO concentration to the control device 30 via wired or wireless communication. The NOx sensor 25b acquires the NOx concentration of the exhaust gas flowing through the outlet channel 15 at predetermined time intervals and transmits a signal indicating the NOx concentration to the control device 30 via wired or wireless communication. In this embodiment, the CO sensor 25a and NOx sensor 25b acquire, for example, the CO concentration and NOx concentration in the exhaust gas per unit flow rate.

[0042] (Control device) The control device 30 adjusts the flow rate of EGR gas discharged from the nozzle 23 by sending and receiving signals with the various devices described above. For example, if the CO concentration and NOx concentration are within an appropriate range, the control device 30 reduces the rotation speed of the fan 24, and if the CO concentration and NOx concentration are outside an appropriate range, it increases the rotation speed of the fan 24. The control device 30 controls the rotation speed of the first forced-air fan 81 and the second forced-air fan 82. In this embodiment, the supply amount of primary air and secondary air can be reduced by the swirling flow described below (by reducing the rotation speed of the first forced-air fan 81 and the second forced-air fan 82). While controlling the fan 24, the control device 30 operates the first forced-air fan 81 and the second forced-air fan 82 at a lower rotation speed compared to the normal case. This reduces the amount of air supplied to the furnace and achieves low NOx emissions. The "normal case" refers to the case where the nozzle 23 is installed in the central part 201M (Figure 2) of the furnace tail 201 without being tilted horizontally, rather than the installation method of the nozzle 23 of this embodiment described below, and EGR gas is supplied into the furnace.

[0043] (Horizontal installation position of the nozzle) Next, the horizontal installation position and spray direction of the nozzle 23 will be explained using Figures 2 to 3D. Figure 2 shows a top view of the main part of the primary combustion zone of the furnace body 2. In Figure 2, the front nose position is the same as the front wall 7a of the furnace 7 in the primary combustion zone, the rear nose position is the same as the rear wall 7b of the furnace 7, and the rear wall is the furnace tail 201. Also, the right side of the boiler is the right wall 203R of the furnace body 2 when viewed from the hopper 300 towards the furnace tail 201, and the left side of the boiler is the left wall 203L of the furnace body 2 when viewed from the hopper 300 towards the furnace tail 201. As shown in the figure, in this embodiment, the EGR nozzle 23 is installed at an eccentric position to either the left or right, rather than in the center 201M of the right and left sides of the boiler. If the coordinate of the left end of the furnace tail 201 in the vertical direction of the paper is 0 and the coordinate of the right end is 1, then it is desirable to install the nozzle 23 in the range of 0 to 1 / 3 or 2 / 3 to 1. For example, it may be attached at position 201L, which is shifted to the left of the center 201M by about 1 / 4 of the width between the right and left cans, or it may be attached at position 201R, which is shifted to the right by the same amount.

[0044] Figures 3A and 3B show examples of the EGR nozzle 23 being installed at position 201L. In the example shown in Figure 3A, the EGR nozzle 23 is positioned such that its longitudinal direction, as viewed from above, is perpendicular to the furnace tail 201. With this configuration, the EGR gas is injected parallel to the left wall 203L. In the example shown in Figure 3B, the EGR nozzle 23 is positioned with a horizontal inclination such that the angle between the direction of EGR gas injection from the nozzle 23 and the furnace tail 201, as viewed from above, is less than 90 degrees. With this inclination, the EGR gas injected from the EGR nozzle 23 is injected towards the right wall 203R.

[0045] Figures 3C and 3D show examples in which the EGR nozzle 23 is installed at position 201R. In the example shown in Figure 3C, the EGR nozzle 23 is positioned so that the direction of EGR gas discharge is parallel to the right wall 203R. In the example shown in Figure 3D, the EGR nozzle 23 is positioned so that the EGR gas is injected toward the left wall 203L.

[0046] (Movement of EGR gas released from the nozzle) Next, using Figures 4A to 5, we will explain the flow of EGR gas released into the furnace body 2 by the nozzle 23. Figure 4A shows the flow of EGR gas when the nozzle 23 is installed in the installation position and direction shown in Figure 3A, indicated by arrows 41a to 43a. The EGR gas injected from the nozzle 23 travels in a straight line as indicated by arrow 41a, and collides with the front wall of the furnace 7 or interferes with the primary air supplied from below the stoker 4, causing a flow that folds back in the opposite direction as indicated by arrow 42a, and a swirling flow 43a is generated on the left wall 203L side between the front nose position and the rear nose position in the primary combustion region.

[0047] Figure 4B shows the flow of EGR gas when the nozzle 23 is installed in the installation position and direction shown in Figure 3B, indicated by arrows 41b to 43b. The EGR gas injected from the nozzle 23 travels straight toward the right wall, as indicated by arrow 41b, and collides with the right wall of the can or interferes with the primary air A supplied from below, resulting in a flow that turns to the right when viewed from the direction of gas flow, as indicated by arrow 42b, and a swirling flow 43b is generated on the right wall 203R side between the front nose position and the rear nose position in the primary combustion region.

[0048] Although not shown in the diagram, the same applies when the nozzle 23 is installed on the right side of the can. When the nozzle 23 is installed in the position and direction shown in Figure 3C, a swirling flow 43a is generated on the right wall 203R side between the front nose position and the rear nose position in the primary combustion region. When the nozzle 23 is installed in the position and direction shown in Figure 3D, a swirling flow is generated on the left wall 203L side between the front nose position and the rear nose position in the primary combustion region.

[0049] Figure 5 shows a cross-sectional view of the combustion furnace 1 from the side. As shown in Figure 5, the swirling flows 43a and 43b generated in the primary combustion region rise within the furnace 7, forming a swirling flow 44 in the secondary combustion region. It has been confirmed that the CO concentration in the exhaust gas decreases more when the nozzle 23 is horizontally eccentric to generate linear recovery, as shown in Figures 3A and 3C, than when the nozzle 23 is placed in the central part 201M without eccentricity or horizontal tilt. Furthermore, the CO concentration in the exhaust gas decreases even more when the nozzle 23 is tilted, as shown in Figures 3B and 3D, in addition to being horizontally eccentric, as shown in Figures 3A and 3C. A decrease in CO concentration means that there is no need to supply air for unburned CO, so the supply amounts of primary and secondary air can be reduced. Reducing the air supply reduces O2, thus enabling low NOx emissions.

[0050] In this embodiment, the nozzle 23 is installed at a position eccentrically in the horizontal direction from the central part 201M of the furnace tail 201. EGR gas (EGR gas is an example of a swirling flow generating gas) is then introduced into the primary combustion zone from the nozzle 23. By introducing the EGR gas from an eccentric position, the gas is swirled in the primary combustion zone. This enhances the mixing of air and unburned gas in the primary combustion zone, and allows NOx generated in the primary combustion zone to come into contact with reducing agents (NHx and XCN) derived from nitrogen contained in the waste, thereby enhancing the reduction of NOx. By enhancing the mixing of unburned gas (HC and CO) in the primary combustion zone with O2 in the combustion air, the outflow of unburned gas into the secondary combustion zone can be suppressed (effect a). In addition, since the swirling flow formed in the primary combustion zone remains in the secondary combustion zone, the contact between O2 and unburned gas in the secondary combustion zone can be promoted, thereby reducing the amount of unburned gas in the exhaust gas (effect b). Through (action a) and (action b), unburned gas can be suppressed even with reduced primary and secondary air supply, and the power consumption of the first forced-air blower 81 and the second forced-air blower 82 required for supplying primary and secondary air can be reduced. Furthermore, suppression of NOx generation in the secondary combustion region and reduction of chemical costs due to reduced exhaust gas volume can be achieved. Through (action a) and (action b), unburned gas can be suppressed with less primary and secondary air, and the total air ratio (total oxygen ratio) can be reduced. The total air ratio is the ratio of the amount of air actually supplied to the theoretical value of the amount of air required for waste combustion. As the total air ratio decreases, the O2 concentration in the EGR gas decreases, reducing the oxidizing power of the EGR gas and further suppressing NOx generation. It is also possible to combine the method of forming a swirling flow by introducing EGR gas from the furnace tail of this embodiment with the method of forming a swirling flow in the secondary combustion region by OFA (Over Fire Air) disclosed in Patent Document 1.

[0051] Next, with reference to Figure 6, the installation angle of the nozzle 23 will be explained. As shown in the figure, the coordinates of the front nose position O on the right side of the can are (0,0). The coordinates of the rear nose position B on the right side of the can are (x,0), the coordinates of the front nose position D on the left side of the can are (0,D), the coordinates of the rear nose position C on the left side of the can are (x,D), and the coordinates of the intersection point U of the EGR gas injection direction and the front wall 7a are (0,u). The rectangle with vertices O, B, C, and D represents the region of the secondary combustion area viewed from above, and if there is a constriction from the primary combustion area to the secondary combustion area, it shows the region on the secondary combustion area side, not the constricted part. Here, if we let (v,w) be the coordinates of the nozzle installation position E, which is eccentrically positioned to the left of the can by 1 / 4 of the can's width from the center, then the inclination angle θ of the nozzle 23 (nozzle angle θ in Figure 6), relative to the setting direction of the nozzle 23, when the direction of EGR gas ejection from the nozzle 23 is perpendicular to the front wall 7a, satisfies the following relationship (1).

[0052] 0≦θ <arttan(w / (v-x))···(1)

[0053] In other words, the nozzle angle θ is the angle formed between the line drawn from point E to point U and the perpendicular line OD in Figure 6. The maximum angle θ is the angle θ when the direction of EGR gas ejection coincides with the line connecting point E and point B.

[0054] The virtual center of the swirling flow formed when EGR gas is injected in the direction of nozzle angle θ is point A in Figure 6, and the radius of the swirling flow is r.

[0055] Furthermore, R and φ related to the nozzle 23 are designed such that the value of the swirl number S, defined by the following formula, is S > 0.3.

[0056]

number

[0057] Here is the G EGR This is the mass flow rate of the EGR gas. Airis the mass flow rate of combustion air (primary air). R is the radius of the nozzle 23. r is the turning radius r shown in FIG. 6. φ is the vertical angle (e.g., 15 degrees) formed by the nozzle 23 with the horizontal plane . Also, the gas mass G released from the refuse layer ごみ When it is known, G in the denominator of Equation (2) Air + G EGR Add G to ごみ (G Air + G EGR + G ごみ ) 2 / πr 2 Let it be.

[0058] So far, the installation method of the nozzle 23 in the case of 1 lane has been described. Below, the installation method of the nozzle 23 when the stoker units are arranged side by side in 2 to 3 lanes in the width direction of the furnace body 2 (the depth direction of the paper surface in FIG. 1) will be described. Here, a lane is a unit of a stoker unit composed of a stoker, a beam supporting it, and a pressing device. There is no partition or the like at the boundary between multiple lanes, and multiple lanes form one space (primary combustion zone).

[0059] (In the case of 2 lanes) FIG. 7A shows an example of the installation method of the nozzles 23a and 23b in the case of 2 lanes. The nozzle 23a in lane 1 on the left side of the can is installed at a position eccentric to the left wall 203L side from the center of lane 1, and the nozzle 23b in lane 2 on the right side of the can is installed at a position eccentric to the right wall 203R side from the center of lane 2. Further, the nozzle 23a is installed so that the EGR gas injection port faces the line L1 on the boundary between lane 1 and lane 2. The nozzle 23b on the right wall 203R side is also installed so that the injection port faces the line L1. By installing in this way, the EGR gases injected from the nozzles 23a and 23 collide with each other and strengthen the flow, generating swirling flows 71a and 71b.

[0060] Figure 7B shows an example of how to install nozzles 23a and 23b in the case of two lanes. Nozzle 23a of lane 1 on the left side of the can is installed off-center towards the left wall 203L from the center of lane 1, and nozzle 23b of lane 2 on the right side of the can is installed off-center towards the left wall 203L from the center of lane 2. Furthermore, nozzle 23a is installed at an angle so that the EGR gas injection port faces line L1 on the boundary between lane 1 and lane 2. Nozzle 23b is installed at an angle so that the injection port faces the right wall 203R. Compared to the case in Figure 7A, it is thought that swirling flow will be less likely to form, but by installing them in this way, it is possible to expect the generation of swirling flow from the EGR gas injected by nozzles 23a and 23b.

[0061] Figure 7C shows an example of how to install nozzles 23a and 23b in the case of two lanes. Nozzle 23a of lane 1 is installed at a position eccentrically toward line L1 from the center of lane 1, and nozzle 23b of lane 2 is installed at a position eccentrically toward line L1 from the center of lane 2. Furthermore, nozzle 23a is installed at an angle so that the EGR gas injection port faces the left wall 203L. Nozzle 23b is installed at an angle so that the injection port faces the right wall 203R. Compared to the case in Figure 7A, it is thought that swirling flow will be less likely to form, but by installing them in this way, it is possible to expect the generation of swirling flow from the EGR gas injected by nozzles 23a and 23b.

[0062] (In the case of 3 lanes) Figure 8A shows an example of how to install nozzles 23a, 23b, and 23c in the case of three lanes. Nozzle 23a of lane 1 on the left side of the can is installed off-center towards the left wall 203L from the center of lane 1. Nozzle 23b of lane 2 in the center is installed off-center towards the left wall 203L from the center of lane 2. Nozzle 23c of lane 3 on the right side of the can is installed off-center towards the left wall 203L from the center of lane 3. Furthermore, nozzle 23a is installed at an angle so that the nozzle faces line L1 on the boundary between lane 1 and lane 2. Nozzle 23b is installed at an angle so that the nozzle faces line L2 on the boundary between lane 2 and lane 3. Nozzle 23c is installed at an angle so that the nozzle faces the right wall 203R. By installing them in this way, it is possible to expect the generation of a swirling flow from the EGR gas injected by nozzles 23a, 23b, and 23c.

[0063] Figure 8B shows an example of how to install nozzles 23a, 23b, and 23c in the case of three lanes. Nozzle 23a of lane 1 on the left side of the can is installed off-center towards the left wall 203L from the center of lane 1. Nozzle 23b of lane 2 in the center is installed off-center towards the right wall 203R from the center of lane 2. Nozzle 23c of lane 3 on the right side of the can is installed off-center towards the left wall 203L from the center of lane 3. Furthermore, nozzle 23a is installed at an angle so that the nozzle faces line L1. Nozzle 23b is installed at an angle so that the nozzle faces line L1. Nozzle 23c is installed at an angle so that the nozzle faces the right wall 203R. By installing them in this way, it is possible to expect the generation of a swirling flow from the EGR gas injected by nozzles 23a, 23b, and 23c.

[0064] Figure 8C shows an example of how to install nozzles 23a and 23b in the case of three lanes. The example in Figure 8C is one in which EGR gas is injected into three lanes using two units of nozzles 23 to form a swirling flow. The nozzle 23a on the left side of the can is installed off-center to the left wall 203L from the center of lanes 1 to 3, and the nozzle 23b on the right side of the can is installed off-center to the right wall 203R from the center of lanes 1 to 3. Furthermore, nozzle 23a is installed at an angle so that the nozzle opening faces the central line L3 of lanes 1 to 3. Nozzle 23b is also installed at an angle so that the nozzle opening faces line L3. By installing them in this way, the EGR gases injected from nozzles 23a and 23 collide with each other, reinforcing the flow and generating swirling flows 81a and 81b. In cases where the number of lanes is odd, a set of two nozzles 23 arranged so that their EGR gases collide with each other, as shown in Figure 8C, may be used to form a swirling flow by installing one or more sets of nozzles at the furnace tail 201.

[0065] Although not shown in the diagram, the number of lanes when multiple lanes are provided is not limited to 2 or 3, but may be 4 or more. For example, in the case of 4 lanes (as in Figure 8A, adjacent lanes are referred to as lanes 1 to 4 in order from the left wall 203L side; this will be the same hereafter), by setting one set of nozzles 23a and 23b shown in Figure 7A as one set, and setting one set of nozzles in lanes 1 and 2, and setting one set of nozzles in lanes 3 and 4, a swirling flow spanning the first and second combustion zones can be formed. For example, in the case of 5 lanes, nozzles may be arranged in lanes 1 and 2 in the same way as in Figure 7A, and nozzles may be arranged in lanes 3 to 5 in the same way as in Figure 8C. This will form a swirling flow spanning the first and second combustion zones. Similarly, in the case of 6 lanes, nozzles may be set in lanes 1 and 2, lanes 3 and 4, and lanes 5 and 6 in the same way as in Figure 7A. Alternatively, nozzles may be set in lanes 1 and 3, and lanes 4 and 6, in the same way as in Figure 8C. Furthermore, for example, in the case of 7 lanes, nozzles may be arranged in lanes 1-2 and 3-4 as in Figure 7A, and nozzles may be installed in lanes 5-7 as in Figure 8C, or nozzles may be arranged in lanes 1-2 and 6-7 as in Figure 7A, and nozzles may be installed in lanes 3-5 as in Figure 8C. The same applies to cases with 8 or more lanes. This makes it possible to form a swirling flow spanning from the first combustion zone to the second combustion zone, even when multiple lanes are provided in the furnace.

[0066] (effect) In order to achieve low NOx emissions in a stoker furnace, it is important to reduce the ratio of fuel (waste) to air in the furnace body 2. However, reducing the air ratio makes it easier for unburned gases such as CO to remain at the furnace outlet. In contrast, according to this embodiment, by introducing EGR gas into the primary combustion zone from an eccentric position at the furnace tail 201, a swirling combustion field is formed spanning the primary and secondary combustion zones, promoting the mixing of excess air and unburned gases and suppressing CO at the furnace outlet. Since unburned gases do not remain at the furnace outlet even when the total air ratio is reduced, NOx generation can be suppressed and NOx emissions reduced by reducing the total air ratio (by reducing the supply of primary and secondary air).

[0067] (Other Embodiment 1) In the above embodiment, EGR gas is injected from the nozzle 23, but a mixture of EGR gas and air may be supplied from the nozzle 23 to the primary combustion area. An example of the configuration of the combustion equipment in this case is shown in Figure 9. The combustion equipment 100a includes, in addition to the configuration in Figure 1, a third forced-air blower 83 and an air supply line 211. The air supply line 211 is a pipe connecting the third forced-air blower 83 and the exhaust gas recirculation line 22. When the third forced-air blower 83 is driven, air is supplied to the exhaust gas recirculation line 22 through the air supply system 211. In the exhaust gas recirculation line 22, EGR gas and air are mixed, and this mixed gas is supplied to the inside of the furnace body 2. The operation of the third forced-air blower 83 is controlled by the control device 30. A valve (not shown) is provided in the air supply line 211, and the control device 30 may control the flow rate of air supplied to the exhaust gas recirculation line 22 by adjusting the opening of this valve.

[0068] According to the combustion equipment 100a shown in Figure 9, the swirling combustion field formed in the primary to secondary combustion regions by introducing a mixed gas (the mixed gas is an example of a swirling flow generating gas) from an eccentric position at the furnace tail 201 promotes the mixing of excess air and unburned gas, thereby suppressing CO at the furnace outlet. Because the supply of the mixed gas prevents unburned gas from remaining at the furnace outlet even when the supply amounts of primary and secondary air are reduced, NOx emissions can be reduced by reducing the total air ratio (the reduction in primary and secondary air supplied to the furnace is greater than the amount of air contained in the mixed gas).

[0069] (Another Embodiment 2) Furthermore, only air may be supplied from the nozzle 23 to the primary combustion area. An example of the configuration of the combustion equipment in this case is shown in Figure 10. Compared to the configuration in Figure 1, the combustion equipment 100b does not have an exhaust gas recirculation system 21, but includes a third forced-air blower 83 and an air supply line 211. (The combustion equipment 100b may include an exhaust gas recirculation system 21 if it is not connected to the nozzle 23.) The air supply line 211 is a pipe connecting the third forced-air blower 83 and the nozzle 23. When the third forced-air blower 83 is driven, air is supplied to the inside of the furnace body 2 through the air supply line 211 and the nozzle 23. The operation of the third forced-air blower 83 is controlled by the control device 30. A valve (not shown) is provided in the air supply line 211, and the control device 30 may control the flow rate of air supplied to the exhaust gas recirculation line 22 by adjusting the opening of this valve.

[0070] According to the combustion equipment 100b shown in Figure 10, the swirling combustion field formed in the primary and secondary combustion regions by introducing air (air is an example of a swirling flow generating gas) from an eccentric position at the furnace tail 201 (to an extent that does not increase the total air ratio) promotes the mixing of excess air and unburned gas, thereby suppressing CO at the furnace outlet. Because the supply of mixed gas prevents unburned gas from remaining at the furnace outlet even when the supply amounts of primary and secondary air are reduced, NOx emissions can be reduced by reducing the total air ratio (the reduction in primary and secondary air is greater than the amount of air required to form the swirling flow supplied from the nozzle 23).

[0071] As described above, several embodiments relating to this disclosure have been explained, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0072] <Note> The combustion equipment described in the embodiment can be understood, for example, as follows:

[0073] (1) The combustion equipment according to the first embodiment includes a furnace body equipped with a stoker that carries the material to be incinerated while burning it, a furnace connected above the furnace body into which the exhaust gas after combustion flows, and, when the upstream side in the direction of transport of the material to be incinerated is referred to as the front, the downstream side in the direction of transport as the rear, the right side when viewed from the front as the rear, and the left side as the left, the furnace body comprises a right wall section, a left wall section, a front ceiling section extending forward from the furnace, a ceiling section extending backward from the furnace, and the rear end of the ceiling section The furnace body comprises a primary combustion region formed below the furnace, enclosed by a rear wall extending downward and the stoker; a secondary combustion region formed above the primary combustion region and below the furnace; and a nozzle that supplies a portion of the exhaust gas discharged from the furnace body as a swirling flow generating gas. The nozzle is positioned eccentrically on the right wall side or the left wall side of the center of the right wall portion and the left wall portion of the rear wall, so that the swirling flow generating gas is injected from the rear wall into the primary combustion region. This allows for the formation of swirling flows in the primary and secondary combustion regions, resulting in reduced air intake and thus lower NOx emissions.

[0074] (2) The combustion equipment according to the second embodiment includes a furnace body equipped with a stoker that carries the material to be incinerated while burning it, a furnace connected above the furnace body into which the exhaust gas after combustion flows, and, when the upstream side in the direction of transport of the material to be incinerated is referred to as the front, the downstream side in the direction of transport as the rear, the right side when viewed from the front as the right, and the left side as the left, the furnace body comprises a right wall section, a left wall section, a front ceiling section extending forward from the furnace, a ceiling section extending backward from the furnace, and a rear section extending downward from the rear end of the ceiling section. The furnace comprises a primary combustion region formed below the furnace inside the furnace body, surrounded by a wall and the stoker; a secondary combustion region formed above the primary combustion region and below the furnace; and a nozzle that supplies a mixture of a portion of the exhaust gas discharged from the furnace body and air, or air only, as a swirling flow generating gas. The nozzle is positioned eccentrically on the right wall side or the left wall side of the center of the right wall portion and the left wall portion of the rear wall, so that the swirling flow generating gas is injected from the rear wall into the primary combustion region. This allows for the formation of swirling flows in the primary and secondary combustion regions, resulting in reduced air intake and thus lower NOx emissions.

[0075] (3) The combustion equipment according to the third embodiment is the combustion equipment of (1) to (2), which is installed such that the horizontal injection direction of the swirling flow generating gas is diagonally forward. This allows for the formation of swirling flows in the primary and secondary combustion regions, resulting in reduced NOx emissions through reduced air intake.

[0076] (4) The combustion equipment according to the fourth embodiment is the combustion equipment of (1) to (2), which is installed such that the horizontal injection direction of the exhaust gas swirling flow generated gas is forward. This allows for the formation of swirling flows in the primary and secondary combustion regions, resulting in reduced air intake and thus lower NOx emissions.

[0077] (5) The combustion equipment according to the fifth embodiment is the combustion equipment of (1) to (4), wherein a plurality of stokers are provided in parallel in the direction from the right wall to the left wall inside the furnace body, and the space separated for each stoker is called a lane, and when an even number of stokers are provided, the space separated for each of two adjacent lanes from the right wall is called a unit space, and the unit space comprises a first nozzle and a second nozzle, and the first nozzle is connected to the boundary on the right wall side of the rear wall of the unit space and the left wall The swirling flow generating gas is installed at a position eccentric to the left wall side of the center of the side boundary, so as to be ejected from the rear wall diagonally to the right and forward, and the second nozzle is installed at a position eccentric to the right wall side of the center of the boundary between the right wall side and the left wall side of the rear wall of the unit space, so as to be ejected from the rear wall diagonally to the left and forward, and when an odd number of stokers are provided, the space divided into the interior of the furnace body by two adjacent lanes is called the first unit space, and the space divided into the interior of the furnace body by three adjacent lanes is called the second unit space When the inside of the furnace body is divided into one second unit space and zero or one or more first unit spaces, the first unit space comprises a third nozzle and a fourth nozzle, the third nozzle is positioned eccentrically toward the left wall side of the center of the boundary between the right wall side and the left wall side of the rear wall of the first unit space, so that the swirling flow generating gas is injected diagonally forward to the right from the rear wall, and the fourth nozzle is positioned eccentrically toward the right wall side of the center of the boundary between the right wall side and the left wall side of the rear wall of the first unit space The swirling flow generating gas is installed at an eccentric position to the side, so as to be ejected from the rear wall diagonally to the left and forward, and the second unit space comprises the fifth nozzle and the sixth nozzle, the fifth nozzle is installed at a position eccentric to the left wall side of the center between the boundary on the right wall side and the boundary on the left wall side of the rear wall of the second unit space, so as to be ejected from the rear wall diagonally to the right and forward, and the sixth nozzle is installed at a position eccentric to the right wall side of the center between the boundary on the right wall side and the boundary on the left wall side of the rear wall of the second unit space,The swirling flow generating gas is installed to be ejected from the rear wall diagonally to the left and forward. This allows for the formation of swirling flows in both the primary and secondary combustion regions, even in the case of multiple lanes, and enables the reduction of NOx emissions through reduced air volume. [Explanation of symbols]

[0078] 1... Combustion furnace, 2... Furnace body, 3... Fuel supply mechanism, 4... Stoker, 4a... Stoker surface, 5... Wind box, 6... Discharge chute, 7... Furnace, 8... Forced blower, 9... Primary air line, 11... Secondary air line, 12... Waste heat recovery boiler, 13... Cooling tower, 14... Dust collector, 15... Outlet flow path, 16... Chimney, 17... Induced draft fan, 19... Ash extrusion device, 20... Ash pit, 21... Exhaust gas recirculation system, 22... Exhaust gas recirculation line, 23... Nozzle, 24... Fan, 25... Exhaust gas concentration acquisition unit, 25a... CO sensor, 25b…NOx sensor, 27…Air preheater, 30…Control device, 50…Drying stage, 51…Combustion stage, 52…Post-combustion stage, 81…First forced blower, 82…Second forced blower, 90…Primary air damper, 100…Combustion equipment, 110…Secondary air damper, 190…Extruder body, 200…Ceiling section, 201…Furnace end, 203R…Right wall, 203L…Left wall, 300…Hopper, 301…Inlet section, 302…Outlet section, 302a…Floor surface, 310…Feeder, 311…Top surface, 312…Extrusion surface

Claims

1. A furnace body including a drying stage, a combustion stage, and a post-combustion stage, and equipped with a stoker that conveys the material to be incinerated while burning it, A furnace connected above the aforementioned furnace body, into which the exhaust gas after combustion flows, When the upstream side in the direction of transport of the material to be incinerated is referred to as the front, the downstream side in the direction of transport as the rear, and the right side when viewed from the front to the rear as the right and the left side as the left, the furnace body comprises a right wall, a left wall, a front ceiling extending forward from the furnace, a ceiling extending backward from the furnace, a rear wall extending downward from the rear end of the ceiling, and the stoker, forming a primary combustion area below the furnace inside the furnace body. A secondary combustion region is formed above the primary combustion region and at the lower part of the furnace, A nozzle provided at the rear of the furnace body supplies a portion of the exhaust gas discharged from the furnace body as a swirling flow generating gas, Equipped with, The aforementioned nozzle is When the primary combustion region is viewed from above, and the front nose is defined as the same position as the front wall of the furnace, and the rear nose is defined as the same position as the rear wall of the furnace, the swirling flow generating gas is installed to be injected from the rear of the furnace body into the primary combustion region at a position eccentric to the right wall side or the left wall side of the center of the right wall and the left wall side of the rear of the furnace body, in order to generate a swirling flow between the front nose and the rear nose in the primary combustion region. Combustion equipment.

2. A furnace body including a drying stage, a combustion stage, and a post-combustion stage, and equipped with a stoker that conveys the material to be incinerated while burning it, A furnace connected above the aforementioned furnace body, into which the exhaust gas after combustion flows, When the upstream side in the direction of transport of the material to be incinerated is referred to as the front, the downstream side in the direction of transport as the rear, and the right side when viewed from the front to the rear as the right and the left side as the left, the furnace body comprises a right wall, a left wall, a front ceiling extending forward from the furnace, a ceiling extending backward from the furnace, a rear wall extending downward from the rear end of the ceiling, and the stoker, forming a primary combustion area below the furnace inside the furnace body. A secondary combustion region is formed above the primary combustion region and at the lower part of the furnace, A nozzle provided at the rear of the furnace body supplies a mixture of a portion of the exhaust gas discharged from the furnace body and air, or air alone, as a swirling flow generating gas. Equipped with, The aforementioned nozzle is When the primary combustion region is viewed from above, and the front nose is defined as the same position as the front wall of the furnace, and the rear nose is defined as the same position as the rear wall of the furnace, the swirling flow generating gas is installed to be injected from the rear of the furnace body into the primary combustion region at a position eccentric to the right wall side or the left wall side of the center of the right wall and the left wall side of the rear of the furnace body, in order to generate a swirling flow between the front nose and the rear nose in the primary combustion region. Combustion equipment.

3. The nozzle is provided only once at the rear of the furnace body, The combustion apparatus according to claim 1.

4. The nozzle is installed such that the horizontal injection direction of the swirling flow-generating gas is diagonally forward. The combustion apparatus according to claim 1 or claim 2.

5. The nozzle is installed such that the horizontal injection direction of the swirling flow-generating gas is forward. The combustion apparatus according to claim 1 or claim 2.

6. The nozzle is provided in one of the three regions obtained by dividing the right wall portion into three equal parts from the left wall portion, either in the region on the right wall portion side or the region on the left wall portion side. The combustion apparatus according to claim 1 or claim 2.

7. The front nose on the right wall is taken as the origin, the x-axis is taken in the direction toward the rear wall along the right wall, the y-axis is taken in the direction from the front nose on the right wall toward the front nose on the left wall, the coordinates of the rear nose on the right wall are (x, 0), the nozzle is provided at a position eccentrically offset by 1 / 4 from the center of the rear wall toward the right wall or the left wall, and the coordinates of the nozzle are (v, w), the angle θ between the nozzle and the right wall is 0≦θ<arttan(w / (v−x)) The nozzle was installed in such a manner, The combustion apparatus according to claim 4.

8. If multiple stokers are arranged in parallel within the furnace body, from the right wall to the left wall, then the space separated by each stoker is referred to as a lane. If an even number of stokers are provided, The space that divides the inside of the furnace body for each of the two adjacent lanes, starting from the right wall, is called a unit space. The unit space comprises the first nozzle and the second nozzle, The first nozzle is The swirling flow generating gas is installed at a position eccentric to the left wall side, rather than the midpoint between the boundary on the right wall side and the boundary on the left wall side at the rear of the furnace body in the aforementioned unit space, so that it is injected diagonally to the right and forward from the rear of the furnace body. The second nozzle is The swirling flow generating gas is installed at a position eccentric to the right wall side, more than the midpoint between the boundary on the right wall side and the boundary on the left wall side at the rear of the furnace body in the unit space, so that it is injected diagonally to the left and forward from the rear of the furnace body. If an odd number of stokers are provided, The space obtained by dividing the inside of the furnace body by two adjacent lanes is called the first unit space, and the space obtained by dividing the inside of the furnace body by three adjacent lanes is called the second unit space. When the inside of the furnace body is divided by one second unit space and zero or one or more first unit spaces, The first unit space comprises the third nozzle and the fourth nozzle, The third nozzle is The swirling flow generating gas is installed at a position eccentric to the left wall side, more than the midpoint between the boundary on the right wall side and the boundary on the left wall side at the rear of the furnace body of the first unit space, so that it is injected diagonally to the right and forward from the rear of the furnace body. The fourth nozzle is, The swirling flow generating gas is installed at a position eccentric to the right wall side of the midpoint between the boundary on the right wall side and the boundary on the left wall side at the rear of the furnace body of the first unit space, so as to be injected diagonally to the left and forward from the rear of the furnace body. The second unit space comprises the fifth nozzle and the sixth nozzle, The fifth nozzle is, The swirling flow generating gas is installed at a position eccentric to the left wall side, more than the midpoint between the boundary on the right wall side and the boundary on the left wall side at the rear of the furnace body in the second unit space, so that it is injected diagonally to the right and forward from the rear of the furnace body. The sixth nozzle is, The swirling flow generating gas is installed at a position eccentric to the right wall side of the midpoint between the boundary on the right wall side and the boundary on the left wall side at the rear of the furnace body of the second unit space, so as to be injected diagonally to the left and forward from the rear of the furnace body. The combustion apparatus according to claim 1 or claim 2.

Images