JP2019178808A - Waste incinerator - Google Patents

Abstract

To provide a waste incinerator capable of securely burning unburnt components in a combustion gas by eliminating a deviation in combustion gas flow rate in an exhaust passage.SOLUTION: A waste incinerator (1) comprises: a burning device (7) which burns waste (W) while conveying it substantially horizontally; a re-burning chamber (9) which is connected to a burning chamber (5) where the burning device (7) is arranged and which re-burns unburnt components in a combustion gas (BG) produced in the burning chamber (5), the re-burning chamber (9) being extended upward from a downstream part of the burning chamber (5); and an exhaust passage (17) extending perpendicularly upward from a downstream end of the re-burning chamber and then folded back perpendicularly downward. The waste incinerator (1) is provided with an injection nozzle (29) which is provided at a top wall (27) of a folded-back part of the exhaust passage and injects a flow velocity adjusting gas (AG) to an upstream side of an upstream part (17a) of the exhaust passage extending perpendicularly upward.SELECTED DRAWING: Figure 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 the combustion gas containing unburned components is forcibly deflected by the structure of the flow path, thereby stirring and mixing the unburned gas and the secondary combustion air. There is an advantage that unburned components can be burned with a small amount of secondary combustion air input.

Japanese Patent Laying-Open No. 2015-090221

  On the other hand, in a parallel flow incinerator, by deflecting the combustion gas flow, in the recombustion chamber into which the combustion gas flow flows and the exhaust passage downstream thereof, the flow velocity in the region outside the deflection portion increases. An uneven flow velocity distribution occurs. As a result, unburned components may not be sufficiently burned in the high-speed flow portion of the combustion gas.

  Accordingly, an object of the present invention is to provide a waste incinerator capable of reliably burning the unburned components in the combustion gas by eliminating the unevenness of the exhaust gas flow velocity distribution in the exhaust passage in order to solve the above problems. Is to provide.

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 recombustion chamber that is connected to a combustion chamber in which the incinerator is disposed and recombusts unburned components in the combustion gas generated in the combustion chamber, and extends upward from a downstream portion of the combustion chamber. A recombustion chamber,
An exhaust passage connected to the downstream side of the recombustion chamber, extending vertically upward from the downstream end of the recombustion chamber, and then turning back downward in the vertical direction;
An injection nozzle that is provided on the top wall of the folded portion of the exhaust passage and injects a flow rate adjusting gas toward the upstream side of the upstream portion of the exhaust passage extending vertically upward;
It has.
The “flow rate adjusting gas” in this specification means a gas injected into the exhaust passage for the purpose of adjusting the deviation of the flow velocity distribution of the exhaust gas in the exhaust passage.

  According to this configuration, in the parallel flow incinerator that forcibly deflects the combustion gas, the flow rate adjustment gas is injected from the injection nozzle, thereby adjusting the deviation of the flow velocity distribution of the hot exhaust gas in the exhaust passage. Can be homogenized. Thereby, it is possible to reliably burn the unburned components in the exhaust gas.

  In an embodiment of the present invention, the injection nozzle may be configured to be able to inject only in a high speed region that is a flow velocity region higher than an average flow velocity of the exhaust gas flow in the upstream portion of the exhaust passage. According to this configuration, the exhaust gas flow velocity distribution can be effectively uniformed with a necessary and sufficient gas injection amount.

  In one Embodiment of this invention, the said injection nozzle may be provided only in the part which faces the said high speed area | region of the said top wall. As an example, the injection nozzle may be provided only in a portion of the top wall opposite to the combustion chamber from the center of the exhaust passage. When the range of the high-speed region in the exhaust passage is constant and can be assumed, this configuration can effectively equalize the exhaust gas flow velocity distribution with a simple structure.

  In an embodiment of the present invention, a plurality of the injection nozzles are provided apart from each other at a portion of the top wall facing the upstream portion of the exhaust passage, and the flow velocity distribution of the exhaust gas flow in the upstream portion of the exhaust passage is determined. You may further provide the flow velocity distribution measuring apparatus to measure, and the control apparatus which selects the said injection nozzle based on the measurement result of the said flow velocity distribution measuring apparatus. According to this configuration, it is possible to perform optimal injection according to the flow velocity distribution in the exhaust passage, and the exhaust gas flow velocity distribution can be effectively uniformed with a necessary and sufficient amount of gas injection.

  As described above, according to the waste incinerator according to the present invention, it is possible to eliminate the unevenness of the exhaust gas flow velocity distribution in the exhaust passage and to reliably burn the unburned components in the combustion gas.

It is a side view which shows the waste incinerator which concerns on 1st Embodiment of this invention. It is a side view which shows typically the schematic structure and effect | action of the waste incinerator of FIG. It is a bottom view which shows the example of the arrangement | positioning aspect of the injection nozzle of the waste incinerator of FIG. It is a bottom view which shows the other example of the arrangement | positioning aspect of the injection nozzle of the waste incinerator of FIG. It is a side view which shows the waste incinerator which concerns on 2nd Embodiment of this invention. It is a bottom view which shows the example of the arrangement | positioning aspect of the injection nozzle of the waste incinerator 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 1 according to the first embodiment of the present invention. In the waste 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 the incinerator 7 incinerates the waste W. Unburned components contained in the generated combustion gas BG are recombusted in the recombustion chamber 9 connected to the downstream side of the combustion chamber 5. The high-temperature exhaust gas EG burned in the recombustion chamber 9 is 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 following description, the upstream side of the waste incinerator 1 in the conveyance direction of the waste W (that is, the flow direction of the combustion gas BG in the combustion chamber 5) C is referred to as “front side”, and the downstream side is “rear side”. Call it.

  The upper part on the upstream side of the combustion chamber 5 is covered with an upper wall 13 that bulges upward. In the illustrated example, the upper wall 13 is inclined upward toward the downstream side. A recombustion chamber 9 is connected to a downstream portion of the combustion chamber 5, that is, an upper portion of a portion where the post-combustion block 7c is disposed. The recombustion chamber 9 extends upward from the downstream portion of the combustion chamber 5. In the illustrated example, the recombustion chamber 9 is inclined toward the upstream portion side of the combustion chamber 5. In the combustion chamber 5, an intermediate portion between the upper wall 13 and the lower side wall 25 of the recombustion chamber 9, that is, substantially above the combustion block 7 b, is recessed downward from the upper wall 13. An intermediate wall 15 connected to the lower side wall 25 is provided.

  An exhaust passage 17 for discharging the high-temperature exhaust gas EG burned in the recombustion chamber 9 extends substantially upward in the vertical direction from the downstream end of the recombustion chamber 9. The exhaust gas EG is sent through the exhaust passage 17 to, for example, a heating device that uses the exhaust gas EG as a heat source. In the present specification, regarding the recombustion chamber 9 and the exhaust passage 17, among the passage dimensions in the direction perpendicular to the extending direction of the passage, the direction perpendicular to the plane parallel to the vertical direction and the conveyance direction C (on the paper surface of FIG. 1). The passage dimension in the vertical direction) is called “passage width”, and the passage dimension perpendicular to the passage width direction is called “passage height”.

  The specific configuration of the combustion chamber 5 is not limited to the illustrated example. For example, the upper 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. The recombustion chamber may not be inclined toward the upstream portion side of the combustion chamber 5. Further, the intermediate wall 15 may not be provided. Further, it is not essential that a heating device is connected to the exhaust passage 17, and the exhaust gas EG may simply be discharged from the waste incinerator 1 through the exhaust passage.

  The upper wall 13 and the intermediate wall 15 of the combustion chamber 5 are provided with a secondary air injection nozzle 19 that injects secondary air A2 to be mixed with the combustion gas BG in the combustion chamber 5.

  In the present embodiment, the exhaust passage 17 has a structure that extends vertically upward from the downstream end of the recombustion chamber and then turns back downward in the vertical direction. That is, the exhaust passage 17 has an upstream portion 17a that extends vertically upward from the downstream end of the recombustion chamber 9, and a downstream portion 17b that is folded downward from the upstream portion 17a. In the illustrated example, the downstream portion 17b is folded back. With the exhaust passage 17 having such a structure, the entire system including the heating device can be made compact even when a heating device is connected downstream of the exhaust passage 17.

  A folded portion 17 c from the upstream portion 17 a to the downstream portion 17 b of the exhaust passage 17 is covered with a flat plate-like top wall 27. The exhaust gas flowing through the exhaust passage 17 collides with the top wall 27 from the upstream portion 17a and flows into the downstream portion 17b. In the illustrated example, the ceiling wall 27 is provided substantially horizontally, but may be inclined upward, for example, toward the downstream side.

  In the present embodiment, an injection nozzle 29 that injects the flow rate adjusting gas AG is provided on the top wall 27 of the exhaust passage 17. The injection nozzle 29 is provided so as to inject the flow rate adjusting gas AG toward the upstream side of the upstream portion 17 a of the exhaust passage 17. In the illustrated example, an injection nozzle 29 that injects the flow rate adjusting gas AG downward in the vertical direction is provided in a portion (hereinafter referred to as “upstream facing portion”) 27a of the top wall 27 that faces the upstream portion 17a.

  In the parallel flow type waste incinerator 1, as shown in FIG. 2, the combustion gas BG flow generated in the combustion chamber 5 is largely deflected at an angle of 90 ° or more when flowing into the recombustion chamber 9. This deflection promotes mixing of the combustion gas BG and the secondary air A2. However, this deflection causes a deviation in the flow velocity distribution in the passage height direction H in the recombustion chamber 9 and in the exhaust passage 17 that follows. That is, a biased flow velocity distribution is generated in which the flow velocity in the region behind the recombustion chamber 9 and the exhaust passage 17 is increased (state A in the figure). Therefore, in the present embodiment, the flow rate adjusting gas AG opposite to the flow direction of the exhaust gas EG is injected in the upstream portion 17a of the exhaust passage 17, thereby causing the combustion gas BG and the secondary air in the recombustion chamber 9 due to deflection. The flow velocity distribution in the passage height direction H in the exhaust passage 17 is made uniform without hindering the mixing of A2.

  More specifically, preferably, the flow velocity adjusting gas AG is injected from the injection nozzle 29 into a region where the flow velocity is higher than the average flow velocity of the exhaust gas EG in the passage height direction H (hereinafter simply referred to as “high-speed region”). As a result, the flow velocity distribution of the exhaust gas EG is made uniform (state B in the figure).

  Accordingly, when the type and amount of the waste W to be incinerated are within a predetermined range and a predetermined high speed region where the flow rate adjusting gas AG should be injected in the exhaust passage 17 can be roughly specified, the upstream portion 17a of the ceiling wall 27 The injection nozzle 29 can be provided only in the portion facing the high speed region. As an example in which the injection nozzle 29 is arranged in this manner, in the example shown in the figure, the injection nozzle 29 is provided only in a portion behind the center of the upstream facing portion 27 a of the top wall 27.

  In the present embodiment, as shown in FIG. 3, a plurality (four in the illustrated example) of the injection nozzles 29 are arranged in the passage width direction WI of the top wall 27 in the rear portion of the center of the upstream facing portion 27a. Arranged at intervals. But the number and arrangement | positioning of the injection nozzle 29 in the area | region which should provide the injection nozzle 29 are not limited to this example. For example, as shown in FIG. 4, the front-rear direction positions of the plurality of injection nozzles 29 arranged in the passage width direction WI of the top wall 27 may be alternately shifted. Further, only one injection nozzle 29 may be provided in a portion on the rear side of the center of the upstream facing portion 27a of the top wall 27.

  In the present embodiment, a flow rate adjustment air supply passage 41 for supplying the flow rate adjustment gas AG injected from the injection nozzle 29 shown in FIG. 1 is provided by branching from the supply passage 43 of the secondary air A2, and the secondary air A2 Part of the air in the supply passage 41 is used. However, the supply system of the flow rate adjusting gas AG is not limited to this example, and the flow rate adjusting gas AG may be supplied from a supply source independent of the secondary air A2, for example. Further, the flow rate adjusting gas AG is not limited to air. For example, the exhaust gas EG discharged from the supply source independent of the secondary air A2 through the exhaust passage 17 may be used as the flow rate adjusting gas AG.

  According to the waste incinerator 1 according to the first embodiment described above, in the parallel flow incinerator 7 that forcibly deflects the combustion gas BG, by injecting the gas for adjusting the flow velocity from the injection nozzle 29. The flow velocity distribution of the combustion gas BG in the exhaust passage 17 can be made uniform. Thereby, it is possible to reliably burn the unburned components in the exhaust gas EG. In particular, in the present embodiment, the injection nozzle 29 is provided only in a portion of the top wall 27 that is behind the center of the upstream facing portion 27a. When the range of the high-speed region in the recombustion chamber 9 is constant and can be assumed, with such a configuration, the flow velocity distribution of the exhaust gas EG can be effectively uniformed with a simple structure.

  FIG. 5 shows a waste incinerator 1 according to the second embodiment of the present invention. The waste incinerator 1 according to this embodiment has the same basic configuration as that of the first embodiment except for the configuration for injecting the flow rate adjusting gas AG into the exhaust passage 17. The configuration for injecting the flow rate adjusting gas AG into the exhaust passage 17 is the same as that of the first embodiment in that the injection nozzle 29 is provided on the top wall 27 of the exhaust passage 17. Rather than providing the injection nozzle 29 only at the position, a plurality of injection nozzles 29 are provided apart from each other at the upstream facing portion 27a of the ceiling wall 27, and the flow velocity distribution of the exhaust gas EG flow in the exhaust passage 17 is measured. It differs from the first embodiment in that it further includes a flow velocity distribution measuring device 35 and a control device 37 that selects the injection nozzle 29 that injects the flow velocity adjusting gas AG based on the measurement result of the flow velocity distribution measuring device 35. Hereinafter, differences from the first embodiment will be mainly described, and descriptions of points that are common to the first embodiment will be omitted.

  As shown in FIG. 6, in the present embodiment, a plurality of injection nozzles 29 are provided in the upstream facing portion 27 a of the top wall 27. In the illustrated example, a plurality (four in this example) of injection nozzles 29 are arranged at equal intervals along the width direction WI of the top wall 27 (width direction of the exhaust passage 17) WI. Furthermore, a plurality (three in this example) of injection nozzle rows 29R indicated by broken lines arranged in this way are provided in the passage height direction H. Note that only one injection nozzle 29 may be provided at each passage height direction H position, and these injection nozzles may be provided apart from each other in the passage height direction H.

  As shown in FIG. 5, in the present embodiment, the exhaust passage 17 is provided with a flow velocity distribution measuring device 35 that measures the flow velocity distribution in the passage height direction H of the exhaust passage 17. As the flow velocity distribution measuring device 35, for example, an oxygen concentration meter can be used. Further, the waste incinerator 1 includes a control device 37 that selects the injection nozzle 29 that injects the flow rate adjusting gas AG based on the measurement result of the flow rate distribution measuring device 35.

  In the waste incinerator 1 according to this embodiment, the flow velocity distribution measuring device 35 measures the flow velocity distribution of the exhaust gas EG in the passage height direction H of the exhaust passage 17, and based on the measurement result, the control device 37 The flow rate adjusting gas AG is selectively injected from an injection nozzle 29 provided at a position corresponding to a predetermined high speed region (for example, a region below the average flow rate).

  According to the waste incinerator 1 according to the second embodiment described above, in the parallel flow type waste incinerator 1 that forcibly deflects the unburned gas UG from the injection nozzle 29, as in the first embodiment. By injecting the gas AG for adjusting the flow velocity, the deviation in the flow velocity distribution of the combustion gas BG in the recombustion chamber 9 can be adjusted. Thereby, it is possible to reliably burn the unburned components in the exhaust gas EG. In particular, in this embodiment, since the injection nozzle 29 that injects the flow rate adjusting gas AG is selected based on the measurement result of the flow rate distribution measuring device 35, optimal injection according to the flow rate distribution in the exhaust passage 17 is performed. Therefore, the flow velocity distribution of the exhaust gas EG can be effectively uniformed with a necessary and sufficient gas injection amount.

  In any of the embodiments, a heater for heating the flow rate adjusting gas AG injected from the injection nozzle 29 may be provided in order to prevent a temperature drop in the exhaust passage 17.

  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.

DESCRIPTION OF SYMBOLS 1 Waste incinerator 5 Combustion chamber 7 Incinerator 9 Recombustion chamber 17 Exhaust passage 17a Upstream part 27 of exhaust passage 29 Top wall 29 Injection nozzle 35 Flow velocity distribution measuring device 37 Control device AG Flow velocity adjustment gas BG Combustion gas EG Exhaust gas

Claims (5)

An incinerator that incinerates waste while transporting it almost horizontally,
A recombustion chamber that is connected to a combustion chamber in which the incinerator is disposed and recombusts unburned components in the combustion gas generated in the combustion chamber, and extends upward from a downstream portion of the combustion chamber. A recombustion chamber,
An exhaust passage connected to the downstream side of the recombustion chamber, extending vertically upward from the downstream end of the recombustion chamber, and then turning back downward in the vertical direction;
An injection nozzle that is provided on the top wall of the folded portion of the exhaust passage and injects the flow rate adjusting gas toward the upstream side of the upstream portion of the exhaust passage extending upward in the vertical direction;
A waste incinerator.   2. The waste incinerator according to claim 1, wherein the injection nozzle is configured to be able to inject only in a high speed region that is a flow velocity region higher than an average flow velocity of the exhaust gas flow in the upstream portion of the exhaust passage. .   The waste incinerator according to claim 2, wherein the injection nozzle is provided only in a portion of the top wall facing the high speed region.   4. The waste incinerator according to claim 3, wherein the injection nozzle is provided only in a portion of the top wall that is downstream of the upstream portion of the exhaust passage in the transport direction of the waste. Waste incinerator. In the waste incinerator according to claim 2,
A plurality of the injection nozzles are provided apart from each other at a portion of the top wall facing the upstream portion of the exhaust passage;
A flow velocity distribution measuring device for measuring a flow velocity distribution of the exhaust gas flow in the upstream portion of the exhaust passage;
A control device for selecting the injection nozzle based on the measurement result of the flow velocity distribution measuring device;
A waste incinerator further equipped with.

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