JP2019178800A - Waste incinerator - Google Patents

Abstract

An object of the present invention is to effectively suppress clinker adhesion in a parallel flow type waste incinerator. An incinerator for incinerating waste (W) while transporting the waste (W) in a substantially horizontal direction, and the incinerator are arranged, and the incinerator is reduced in a downward direction from an upstream part (5a) to a downstream part (5b). A combustion chamber (5) forming a passage (GP) for the combustion gas generated in the incinerator (7), and a re-combustion chamber (9) forming a combustion gas passage deflecting upward from the downstream end of the combustion chamber. A waste incinerator (1) provided with a secondary combustion assisting gas injection port (19) provided upstream of the combustion chamber, the side wall (23) of the combustion chamber upstream of the combustion chamber. A cooling gas injection port (25) for injecting a cooling gas (CG) downward along the line. [Selection diagram] Fig. 1

Description

  The present invention relates to a waste incinerator for incinerating waste such as general waste and industrial waste.

  Conventionally, as a waste incinerator, a stoker type incinerator having an incinerator for incineration while conveying waste by a plurality of arranged grate (stalker) is generally employed. Also, as a stoker-type incinerator, the so-called parallel flow system in which unburned components generated in the waste incineration process are flowed to the downstream side of the combustion chamber along the waste conveyance direction and then deflected upward. Is known (for example, see Patent Document 1). In a stoker-type incinerator, generally, air for secondary combustion is supplied to a combustion chamber in order to completely burn unburned components and reduce harmful substances such as NOx and dioxins. According to the parallel flow incinerator, the flow of gas containing unburned components is forcibly deflected by the structure of the flow path, which facilitates stirring and mixing of unburned components and secondary combustion air. In addition, there is an advantage that unburned components can be combusted by introducing a smaller amount of secondary combustion air.

Japanese Patent Laying-Open No. 2015-090221

  By the way, in a waste incinerator, so-called clinker adhesion in which soot and dust in the gas generated in the furnace melts on the furnace wall surface and accumulates in a lump may be a problem. While the parallel flow incinerator has the above-mentioned advantages, due to the structure of the incinerator, there is a region where the clinker tends to adhere to the combustion chamber due to combustion of unburned components and secondary combustion air. Since the burden of maintenance work on the incinerator increases due to the clinker adhesion, it is required to suppress the clinker adhesion.

  Accordingly, an object of the present invention is to effectively suppress the adhesion of clinker in a parallel flow type waste incinerator in order to solve the above-described problems.

In order to achieve the above-described object, the waste incinerator according to the present invention is:
An incinerator that incinerates waste while transporting it almost horizontally,
A combustion chamber in which the incinerator is disposed, the combustion chamber forming a passage for the combustion gas generated in the incinerator, which shrinks downward from an upstream portion to a downstream portion;
A recombustion chamber that forms a combustion gas passage that deflects upward from a downstream end of the combustion chamber in the conveying direction of the incinerator;
A secondary auxiliary gas injection port provided upstream of the combustion chamber;
With
An injection port for injecting gas downward along the side wall is provided on the side wall of the upstream portion of the combustion chamber.

  According to this configuration, because of the structure of the so-called parallel-flow waste incinerator, high-temperature combustion gas tends to stay, and secondary combustion of the combustion gas due to the addition of secondary auxiliary combustion gas tends to cause high temperature, so the clinker is attached. It is possible to provide a cooling gas injection port on the side wall of the upstream portion, which is an easy-to-do place, and to inject the cooling gas along the side wall. Thereby, the temperature rise of a combustion chamber side wall surface is suppressed and clinker adhesion can be suppressed effectively.

  In one embodiment of the present invention, an injection port for injecting gas upward along the side wall may be provided on the side wall of the downstream portion of the combustion chamber. According to this configuration, since the passage area is narrow and close to the incinerator, the temperature tends to be high, and the cooling gas injection port is provided on the side wall of the downstream portion where the clinker is likely to adhere. By spraying, the temperature rise of the side wall surface is suppressed and clinker adhesion can be effectively suppressed.

  In one embodiment of the present invention, the cooling gas may be an exhaust gas discharged from the waste incinerator. According to this configuration, since exhaust gas having a low oxygen concentration is used as the cooling gas, cooling can be performed while preventing combustion promotion due to an increase in oxygen concentration at a portion where the clinker is likely to adhere, so that the clinker can be more effectively attached. Can be suppressed.

  In one embodiment of the present invention, the cooling gas injection port may be provided at least downstream of the secondary auxiliary gas injection port. Further, when a plurality of the secondary auxiliary gas injection ports are provided from the upstream side toward the downstream side, at least the secondary auxiliary gas injection port on the most upstream side and the secondary auxiliary gas injection side on the most downstream side are provided. The cooling gas injection port may be provided between the gas injection ports. According to this configuration, it is possible to efficiently inject the cooling gas into a portion of the combustion chamber side wall that is likely to reach a particularly high temperature due to the secondary combustion by introducing the secondary auxiliary combustion gas.

  In one embodiment of the present invention, a determination device that determines the quality of the incinerated waste, and a control device that controls a gas injection amount from the cooling gas injection port based on a determination result of the determination device. You may have. According to this structure, clinker adhesion can be suppressed by the optimal gas injection amount according to the quality of waste. Therefore, clinker adhesion can be suppressed while improving the efficiency of the entire waste incinerator.

  In an embodiment of the present invention, a plurality of the cooling gas injection ports are provided from the upstream side toward the downstream side, and the control device is configured to output the plurality of cooling gas injection ports based on the determination result of the determination device. Of these, an injection port for injecting gas may be selected. According to this structure, the optimal gas injection position according to the quality of waste can be selected, and clinker adhesion can be suppressed. Therefore, clinker adhesion can be suppressed while further improving the efficiency of the entire waste incinerator.

  As described above, according to the waste incinerator according to the present invention, it is possible to effectively suppress the adhesion of clinker in the parallel flow type waste incinerator.

It is a side view which shows the incinerator 1 which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the cooling gas injection port in the upstream part of the combustion chamber of the incinerator 1 of FIG. It is sectional drawing which shows typically the cooling gas injection port in the downstream part of the combustion chamber of the incinerator 1 of FIG. It is sectional drawing which shows the modification of the incinerator 1 of FIG. It is a side view which shows the incinerator 1 which concerns on the modification of FIG. It is a block diagram which shows the determination apparatus and control apparatus which are used for embodiment of FIG.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments.

  FIG. 1 shows a waste incinerator (hereinafter simply referred to as “incinerator”) 1 according to a first embodiment of the present invention. In the incinerator 1, the waste W to be incinerated input from the inlet 3 is incinerated by the incinerator 7 installed in the combustion chamber 5, and is generated in the incinerator 7 when the waste W is incinerated. Unburned components contained in the combustion gas BG are recombusted in the recombustion chamber 9 connected to the downstream end of the combustion chamber 5. That is, the region above the incinerator 7 of the combustion chamber 5 and the recombustion chamber 9 form a passage for the combustion gas BG. The exhaust gas EG burned in the recombustion chamber 9 is discharged from the incinerator 1 and then circulated into the combustion chamber 5 and reused as described later. The exhaust gas EG may be used as a heat source of a heating device (not shown) such as a boiler connected further downstream of the recombustion chamber 9. The incinerator 7 incinerates the waste W while conveying it in a substantially horizontal direction (the direction from the left side to the right side in the figure). Ash generated by incineration of the waste W in the incinerator 7 is discharged from the discharge chute 11.

  In the present specification, the “substantially horizontal direction” as the conveyance direction of the waste W includes not only the horizontal direction but also a direction including a horizontal direction component. Therefore, for example, the conveyance direction inclined in the vertical direction from the horizontal direction is also included in the “substantially horizontal direction”. Further, as will be described later, when the incinerator 7 is composed of a plurality of arranged stalkers, even if there is a place where the waste W moves vertically downward between adjacent stalkers, the entire incinerator 7 (That is, from the upstream end to the downstream end of the incinerator 7), the transport direction of the waste W is included in the “substantially horizontal direction” if it includes a horizontal component.

  Specifically, the incinerator 7 is configured as a stoker-type incinerator in which a plurality of grate (stalkers) are arranged side by side along the conveyance direction of the waste W. The incinerator 7 is divided into three blocks of a drying block 7a, a combustion block 7b, and a post-combustion block 7c in order from the upstream side. The waste W input from the inlet 3 in the drying block 7a is dried, the waste W dried in the combustion block 7b is combusted, and the waste W uncombusted in the combustion block 7b in the post-combustion block 7c. Burn the remainder of the combustion. The primary air A <b> 1 is supplied to each block of the incinerator 7 from below.

  Since the recombustion chamber 9 is connected to the downstream end of the combustion chamber 5 in which the incinerator 7 is installed in the conveying direction of the incinerator 7, the combustion gas containing unburned components generated in the combustion chamber 5 BG flows in the combustion chamber 5 substantially in parallel with the conveyance direction of the waste W. The incinerator 1 is configured as a so-called parallel incinerator having such a structure. In the present embodiment, the combustion chamber 5 forms a passage (hereinafter referred to as “combustion gas passage”) GP of the combustion gas BG generated in the incinerator 7, which shrinks downward from the upstream portion 5 a to the downstream portion 5 b.

  The upstream portion 5a of the combustion chamber 5 is covered with a top wall 13 that bulges upward. In the illustrated example, the top wall 13 is inclined upward as it goes downstream. A recombustion chamber 9 is connected to the downstream portion 5 b of the combustion chamber 5. The recombustion chamber 9 is deflected upward from the downstream portion 5 b of the combustion chamber 5. More specifically, in the illustrated example, the recombustion chamber 9 extends in a direction inclined toward the upstream side of the combustion chamber 5. An intermediate wall in the combustion chamber 5 between the top wall 13 and the lower side wall 25 of the recombustion chamber 9 is recessed downward from the top wall 13 and continues to the lower side wall of the recombustion chamber 9. 15 is provided. Thus, the combustion chamber 5 has the upstream part 5a that forms a combustion gas passage that bulges upward, and the downstream part 5b that forms a combustion gas passage that shrinks downward from the upstream part 5a. . In other words, the upstream portion 5 a of the combustion chamber 5 is a portion below the top wall 13 in the combustion chamber 5, and the downstream portion 5 b is a portion on the downstream side of the upstream portion 5 a covered with the top wall 13. It is.

  The specific configuration of the combustion chamber 5 is not limited to the illustrated example. For example, the ceiling wall 13 is not limited to the illustrated example, and may extend in the horizontal direction and may be inclined downward toward the downstream side. Further, the intermediate wall 15 may not be provided.

  In the upstream portion 5 a of the combustion chamber 5, a second secondary air A 2 that is a secondary combustion gas for secondary combustion of unburned components in the combustion gas BG in the combustion chamber 5 is injected into the upstream portion 5 a. A secondary air injection port 19 is provided. In the illustrated example, a first secondary air injection port 19 is provided in the top wall 13 of the upstream portion 5 a of the combustion chamber 5. The intermediate wall 15 of the combustion chamber 5 is provided with a second secondary air injection port 21 that injects the secondary air A <b> 2 to the downstream portion 5 b of the combustion chamber 5.

  The first secondary air injection port 19 may be provided not on the top wall 13 but on the side wall 23 in the vicinity of the top wall 13. In any case, in order to effectively mix the combustion gas BG generated in the lower incinerator 7 and the secondary air A2, the first secondary air injection port 19 injects the secondary air A2 downward. It is preferable that it is comprised.

  Further, the secondary auxiliary combustion gas is not limited to air. For example, the exhaust gas EG discharged from the incinerator 1 may be used as the secondary auxiliary gas, but in the following description, the secondary air A2 is used as the secondary auxiliary combustion gas. This will be described as gas.

  The side wall 23 of the combustion chamber 5 is provided with a cooling gas injection port 25 that injects the cooling gas CG along the side wall 23. Specifically, the side wall 23 of the upstream portion 5 a of the combustion chamber 5 is provided with a first cooling gas injection port 25 </ b> A that injects the cooling gas CG downward along the side wall 23. In the present embodiment, a second cooling gas injection port 25 </ b> B that injects the cooling gas CG upward along the side wall 23 is further provided on the side wall 23 of the downstream portion 5 b of the combustion chamber 5. In the following description, when there is no need to distinguish between the first cooling gas injection port 25A and the second cooling gas injection port 25B, they are collectively referred to as “cooling gas injection port 25”.

  More specifically, in the present embodiment, as shown in FIG. 2, a first nozzle convex portion 27 that is thick on the inside is provided at the upper end portion of the side wall 23 of the upstream portion 5 a, and the first A first injection nozzle 29 that injects the cooling gas CG downward from the step surface 27 a of the first nozzle protrusion 27 is provided inside the nozzle protrusion 27. The first injection nozzle 29 forms a first cooling gas injection port 25A.

  As shown in FIG. 3, the second cooling gas injection port 25 </ b> B is provided below the intermediate wall 15 in the side wall 23 of the downstream portion 5 b of the combustion chamber 5. Specifically, in the present embodiment, as shown in FIG. 3, a second nozzle convex portion 31 that is thick on the inside is provided at the lower end portion of the side wall 23 (in the vicinity of the incinerator 7). A second injection nozzle 33 that injects the cooling gas CG upward from the step surface 31 a of the second nozzle protrusion 31 is provided inside the second nozzle protrusion 31. The second injection nozzle 33 forms a second cooling gas injection port 25B.

  As shown in FIG. 1, in the present embodiment, a plurality of cooling gas injection ports 25 are provided from the upstream side to the downstream side in the combustion chamber 5. Specifically, a plurality of first cooling gas injection ports 25A are provided from the upstream side to the downstream side in the upstream portion 5a. More specifically, in the illustrated example, the plurality of first cooling gas injection ports 25 </ b> A are arranged in a line in the direction along the inclination of the top wall 13 and arranged at equal intervals. But the arrangement | sequence aspect of the some 1st cooling gas injection opening 25 is not limited to this example.

  Moreover, the 2nd cooling gas injection port 25B is provided with two or more along the downstream from the upstream in the downstream part 5b. More specifically, in the illustrated example, the plurality of second cooling gas injection ports 25B are arranged in a substantially horizontal direction at equal intervals.

  In the parallel flow type incinerator 1 according to the embodiment of FIG. 1, the outlet of the combustion gas BG from the combustion chamber 5 (the connection portion with the recombustion chamber 9) is not the downstream end (that is, the intermediate portion). Therefore, the high-temperature combustion gas BG tends to stay in the upper portion of the combustion chamber 5 in the upstream portion 5a. A first secondary air injection port 19 is provided on the top wall 13 of the upstream portion 5a of the combustion chamber 5 (or the side wall 23 near the top wall 13) to inject secondary air A2, and the secondary air A2 and combustion gas BG. Since the secondary combustion of the unburned components in the combustion gas BG occurs in the region where the gas is mixed, high-temperature combustion gas tends to be generated in the vicinity of the top wall 13 of the upstream portion 5a. Accordingly, since the clinker tends to adhere to the side wall 23 in the region near the top wall 13 of the upstream portion 5a, the first cooling gas injection port 25A for injecting the cooling gas CG is provided in this region. Further, since the second secondary air injection port 21 is provided in the intermediate wall 15 of the downstream portion 5b of the combustion chamber 5 and the secondary air A2 is injected, the intermediate wall 15 of the downstream portion 5b and the incinerator 7 are High-temperature combustion gas is likely to be generated in the intermediate region, and this region is likely to become hot because the passage area is narrow. Therefore, since the clinker tends to adhere to the side wall 23 in the region between the intermediate wall 15 of the downstream portion 5b and the incinerator 7, the second cooling gas injection port 25B for injecting the cooling gas CG is provided in this region.

  The vertical position of each first cooling gas injection port 25A in the upstream portion 5a is not particularly limited. However, in order to efficiently inject the cooling gas CG into the region where the clinker is likely to adhere in the upstream portion 5a, It is preferable that one cooling gas injection port 25 </ b> A is located above an intermediate position between the upper end of the incinerator 7 and the lower end of the first secondary air injection port 19.

  For the same reason, it is preferable that the first cooling gas injection port 25 </ b> A is provided at least on the downstream side of the first secondary air injection port 19. When a plurality of first secondary air injection ports 19 are provided from the upstream side toward the downstream side as in the present embodiment, at least the first secondary air injection port 19 on the most upstream side and the most downstream side. The first cooling gas injection port 25A is preferably provided between the first secondary air injection port 19 and the first cooling air injection port 19 on the downstream side of the first secondary air injection port 19 on the most downstream side. More preferably, a gas injection port 25A is provided.

  In this embodiment, as shown in FIG. 2, a circulation path 35 for circulating the exhaust gas EG (FIG. 1) discharged from the incinerator 1 to the combustion chamber 5 is provided, and the exhaust gas EG supplied from the circulation path 35 is cooled with the cooling gas. Used as CG. By using the exhaust gas EG having a low oxygen concentration as the cooling gas CG, it becomes possible to cool the portion where the clinker tends to adhere while preventing the promotion of combustion due to the increase in the oxygen concentration. Thereby, adhesion of clinker can be suppressed very effectively. As the cooling gas CG, instead of the exhaust gas EG from the incinerator 1, for example, a low oxygen concentration gas such as exhaust gas from another facility installed may be used. However, the cooling gas CG may be air, for example, air supplied from a passage (not shown) branched from the supply passage 37 of the secondary air A2, or independent of the secondary air A2. You may utilize the air supplied from the supply source as the cooling gas CG.

  In addition, the cooling gas injection port 25 does not need to be provided as the injection nozzles 29 and 33 illustrated in FIGS. For example, as shown as a modification in FIG. 4, the side wall 23 may be divided in the vertical direction, and the passage of the cooling gas CG and the cooling gas injection port 25 may be formed by a gap between the side walls 23. In the example shown in the drawing, the upper divided side wall 23A is formed thicker on the inner side than the lower divided side wall 23B, and the inner wall surface portion is downward so as to face the wall surface of the upper end portion of the lower side wall 23B. It protrudes. A gap between the protruding portion 23Aa of the upper divided side wall 23A and the lower divided side wall 23B forms a first cooling gas injection port 25A for injecting the cooling gas CG downward along the side wall 23. .

  When the first cooling gas injection port 25A is formed between the side walls 23 thus divided, as schematically shown in FIG. 5, the gap between the side walls 23 in the direction from the upstream side to the downstream side in the combustion chamber 5 is provided. By providing the partition wall 39 that divides the above, a plurality of first cooling gas injection ports 25A can be provided from the upstream side to the downstream side of the combustion chamber 5. 4 and 5 can be similarly applied not only to the first cooling gas injection port 25A but also to the second cooling gas injection port 25B.

  In addition, as shown in FIG. 6, the incinerator 1 according to the present embodiment includes a determination device 41 that determines the quality of the incinerated waste W. The incinerator 1 further includes a control device 43 that controls the gas injection amount from the cooling gas injection port 25 based on the determination result of the determination device 41. The “quality of the waste W” here means specifically the amount of heat generated per unit weight of the waste W.

  Specifically, for example, when the incinerator 1 is provided with a boiler B that uses exhaust gas, the determination device 41 measures and calculates the amount of water vapor generated with respect to the weight of the treated waste, thereby calculating the waste W Judge the quality.

  Moreover, in this embodiment, based on the determination result of the determination apparatus 41, the control apparatus 43 is cooling gas CG among the some cooling gas injection ports 25 provided from the upstream to the downstream as mentioned above. Is selected.

  When the waste is of high quality (high calorific value), the waste W is combusted mainly in the upstream stage of the incinerator 7, so that the high temperature region in the combustion chamber 5 is also an upstream portion. On the other hand, when the waste W is of low quality (low calorific value), the waste W is burned mainly in the downstream stage of the incinerator 7, so that the high temperature region in the combustion chamber 5 is also a downstream portion. That is, the high temperature region in the combustion chamber 5 varies depending on the quality of the waste W, and the region where the clinker tends to adhere may vary correspondingly. Therefore, the control device 43 selects which region of the cooling gas injection port 25 the cooling gas CG is injected according to the quality of the waste W determined by the determination device 41.

  In addition, instead of the determination device 41 or in addition to the determination device 41, temperature sensors are attached to a plurality of locations on the surface of the side wall 23 in the combustion chamber 5, and the temperature of the surface of the side wall 23 in the combustion chamber 5 measured by the temperature sensor. Based on the distribution, the control device 43 may select which region of the cooling gas injection port 25 to inject the cooling gas CG.

  Further, the cooling gas injection port 25 is configured to be capable of changing the injection direction of the cooling gas CG, and is directed to a region where clinker adhesion is predicted by the control device 43 based on the measurement result of the determination device 41 and / or the temperature sensor. Then, the cooling gas CG may be controlled to be injected.

  As described above, the controller 43 can suppress clinker adhesion with an optimum gas injection amount corresponding to the quality of the waste W. Moreover, it becomes possible to select the optimal gas injection position according to the quality of the waste W by the control apparatus 43, and to suppress clinker adhesion. As a result, clinker adhesion can be suppressed while improving the efficiency of the entire incinerator 1. However, the determination device 41 and the control device 43 may be omitted.

  According to the waste incinerator 1 according to the present embodiment described above, high-temperature combustion gas tends to stay due to the structure of a so-called parallel flow type waste incinerator, and the combustion gas BG 2 by the introduction of the secondary air A2 is retained. Since it is likely to become high temperature by the next combustion, an injection port 25A for the cooling gas CG is provided in the side wall 23 of the combustion chamber upstream portion 5a where the clinker is likely to adhere, and the cooling gas CG is injected along the side wall 23. it can. Thereby, the temperature rise of the side wall surface of the combustion chamber 5 is suppressed, and clinker adhesion can be effectively suppressed.

  Furthermore, since the passage area is narrow and close to the incinerator 7, the clinker adheres to the side wall 23 of the downstream portion 5b, which is a place where the clinker easily attaches, by providing the injection port 25B for the cooling gas CG. It becomes possible to suppress.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such a thing is also included in the scope of the present invention.

1 Waste incinerator 5 Combustion chamber 5a Upstream portion 5b of combustion chamber 7 Downstream portion of combustion chamber 7 Incinerator 9 Recombustion chamber 13 Top wall 21 Injection nozzle 23 Side wall 25 of combustion chamber Cooling gas injection port 25A First cooling gas injection port 25B Second cooling gas injection port 35 determination device 37 control device CG cooling gas BG combustion gas

Claims (7)

An incinerator that incinerates waste while transporting it almost horizontally,
A combustion chamber in which the incinerator is disposed, the combustion chamber forming a passage for the combustion gas generated in the incinerator, which shrinks downward from an upstream portion to a downstream portion;
A recombustion chamber that forms a combustion gas passage that deflects upward from a downstream end of the combustion chamber in the conveying direction of the incinerator;
A secondary auxiliary gas injection port provided upstream of the combustion chamber;
A waste incinerator comprising:
A waste incinerator provided with a cooling gas injection port for injecting a cooling gas downward along the side wall on the side wall of the upstream portion of the combustion chamber.   The waste incinerator according to claim 1, wherein a cooling gas injection port for injecting a cooling gas upward along the side wall is provided on a side wall of the downstream portion of the combustion chamber.   The waste incinerator according to claim 1 or 2, wherein the cooling gas is an exhaust gas discharged from the waste incinerator.   The waste incinerator according to any one of claims 1 to 3, wherein the cooling gas injection port is provided at least downstream of the secondary auxiliary gas injection port. In the waste incinerator according to claim 4,
A plurality of secondary auxiliary gas injection ports are provided from the upstream side toward the downstream side,
A waste incinerator in which the cooling gas injection port is provided at least between the secondary auxiliary gas injection port on the most upstream side and the secondary auxiliary gas injection port on the most downstream side.   The waste incinerator according to any one of claims 1 to 5, further comprising: a determination device that determines the quality of the incinerated waste; and a cooling gas injection port based on a determination result of the determination device. A waste incinerator comprising a control device for controlling the amount of gas injection. In the waste incinerator according to claim 6,
A plurality of the cooling gas injection ports are provided from the upstream side toward the downstream side,
The control device selects a cooling gas injection port for injecting gas among the plurality of cooling gas injection ports based on a determination result of the determination device.
Waste incinerator.

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