JP7027227B2 - Waste incinerator - Google Patents

Description

The present invention relates to a waste incinerator that incinerates waste such as general waste and industrial waste.

Conventionally, as a waste incinerator, a stoker-type incinerator equipped with an incinerator that incinerates while transporting waste by a plurality of grate (stoker) arranged side by side is generally adopted. In addition, as a stoker-type incinerator, a so-called parallel flow method in which unburned components generated in the waste incinerator process are flowed to the downstream side of the combustion chamber along the waste transport direction and then deflected upward. Incinerators are known (see, for example, Patent Document 1).

In a stoker-type incinerator, air for secondary combustion is generally 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 type incinerator, the flow of combustion gas containing unburned components is forcibly deflected by the structure of the flow path, so that the unburned gas and the air for secondary combustion can be agitated and mixed. It is promoted and has the advantage that the unburned component can be burned with a smaller amount of secondary combustion air input.

Japanese Patent Application Laid-Open No. 2015-090221

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

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

In order to achieve the above-mentioned object, the waste incinerator according to the present invention is
An incinerator that incinerates waste while transporting it almost horizontally,
A reburning chamber that is connected to a combustion chamber in which the incineration device is arranged and reburns unburned components in the combustion gas generated in the combustion chamber, and extends upward from the downstream portion of the combustion chamber. Reburning chamber and
An exhaust passage that is connected to the downstream side of the reburning chamber, extends upward in the vertical direction from the downstream end of the reburning chamber, and then folds downward in the vertical direction.
An injection nozzle provided on the top wall of the folded portion of the exhaust passage and injecting a flow velocity adjusting gas toward the upstream side of the upstream portion of the exhaust passage extending vertically upward.
It is equipped with.
The "flow velocity adjusting gas" in the present 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 a parallel flow type incinerator that forcibly deflects the combustion gas, the deviation of the flow velocity distribution of the high-temperature exhaust gas in the exhaust passage is adjusted by injecting the gas for adjusting the flow velocity from the injection nozzle. , Can be homogenized. This makes it possible to reliably burn the unburned components in the exhaust gas.

In one embodiment of the present invention, the injection nozzle may be configured to be capable of injecting only in a high-speed region, which is a flow velocity region higher than the average flow velocity of the exhaust gas flow in the upstream portion of the exhaust passage. According to this configuration, it is possible to effectively make the exhaust gas flow velocity distribution uniform with a necessary and sufficient gas injection amount.

In one embodiment of the present invention, the injection nozzle may be provided only on the portion of the top wall facing the high-speed region. As an example, the injection nozzle may be provided only in a portion of the top wall opposite to the center of the exhaust passage and opposite to the combustion chamber. When the range of the high-speed region in the exhaust passage is constant and can be assumed, this configuration can effectively make the flow velocity distribution of the exhaust gas uniform with a simple structure.

In one embodiment of the present invention, a plurality of the injection nozzles are provided at portions of the top wall facing the upstream portion of the exhaust passage so as to be separated from each other, and the flow velocity distribution of the exhaust gas flow in the upstream portion of the exhaust passage is measured. A flow velocity distribution measuring device to be measured and a control device for selecting the injection nozzle based on the measurement result of the flow velocity distribution measuring device may be further provided. According to this configuration, it is possible to perform optimum injection according to the flow velocity distribution in the exhaust passage, and it is possible to effectively make the exhaust gas flow velocity distribution uniform with a necessary and sufficient gas injection amount.

As described above, according to the waste incinerator according to the present invention, it is possible to eliminate the bias of the exhaust gas flow velocity distribution in the exhaust passage and 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 schematically showing the schematic structure and operation of the waste incinerator of FIG. 1. It is a bottom view which shows the example of the arrangement mode of the injection nozzle of the waste incinerator of FIG. It is a bottom view which shows the other example of the arrangement mode 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 mode 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, but the present invention is not limited to this embodiment.

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, which is input from the charging port 3, is incinerated by the incinerator 7 installed in the combustion chamber 5, and is incinerated by the incinerator 7 when the waste W is incinerated. The unburned component contained in the generated combustion gas BG is reburned in the reburning chamber 9 connected to the downstream side of the burning chamber 5. The high-temperature exhaust gas EG burned in the reburning chamber 9 is used as a heat source for a heating device (not shown) such as a boiler connected to the downstream side of the reburning chamber 9. The incinerator 7 incinerates the waste W while transporting it in a substantially horizontal direction (direction from the left side to the right side in the figure). The ash generated by incinerating the waste W in the incinerator 7 is discharged from the discharge chute 11.

In the present specification, the "almost horizontal direction" as the transport direction of the waste W includes not only the horizontal direction but also the direction including the horizontal component. Therefore, for example, the transport direction inclined from the horizontal direction to the vertical direction is also included in the above-mentioned "almost horizontal direction". Further, as described later, when the incinerator 7 is composed of a plurality of stokers arranged, even if there is a place where the waste W moves vertically downward between the adjacent stokers, the entire incinerator 7 is used. If the transport direction of the waste W is the direction including the horizontal component (that is, from the upstream end to the downstream end of the incinerator 7), it is included in the "almost horizontal direction".

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 transport direction of the waste W. The incinerator 7 is divided into three blocks, a drying block 7a, a combustion block 7b, and a post-combustion block 7c, in order from the upstream side. The waste W charged from the charging port 3 is dried in the drying block 7a, the dried waste W is burned in the combustion block 7b, and the waste W unburned in the combustion block 7b in the post-combustion block 7c. Burn the rest of the combustion. Primary air A1 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 transport direction by the incinerator 7, the combustion gas containing the unburned component generated in the combustion chamber 5 is connected. The BG flows in the combustion chamber 5 substantially in parallel with the transport 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 transport direction C of the waste W (that is, the flow direction of the combustion gas BG in the combustion chamber 5) C is referred to as the "front side", and the downstream side is referred to as the "rear side". Called.

The upper portion of the combustion chamber 5 on the upstream side 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. The re-combustion chamber 9 is connected to the downstream portion of the combustion chamber 5, that is, the upper part of the portion where the post-combustion block 7c is arranged. The re-combustion chamber 9 extends upward from the downstream portion of the combustion chamber 5. In the illustrated example, the reburning chamber 9 is inclined toward the upstream portion side of the combustion chamber 5. An intermediate portion between the upper wall 13 and the lower side wall 25 of the reburning chamber 9 in the combustion chamber 5, that is, substantially above the combustion block 7b, is recessed downward from the upper wall 13 to form the reburning chamber 9. 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 re-combustion chamber 9 extends from the downstream end of the re-combustion chamber 9 substantially upward in the vertical direction. The exhaust gas EG is sent to, for example, a heating device that uses the exhaust gas EG as a heat source through the exhaust passage 17. In the present specification, regarding the reburning chamber 9 and the exhaust passage 17, among the passage dimensions in the directions orthogonal to the extending direction of the passage, the directions orthogonal to the plane parallel to the vertical direction and the transport direction C (on the paper in FIG. 1). The passage dimension in the vertical direction) is called "passage width", and the passage dimension orthogonal 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 may extend in the horizontal direction or may be inclined downward toward the downstream side, not limited to the embodiment shown in the illustrated example. The reburning chamber does not have to be inclined toward the upstream portion side of the combustion chamber 5. Further, the intermediate wall 15 does not have to be provided. Further, it is not essential that the heating device is connected to the exhaust passage 17, and the exhaust gas EG may be simply discharged to the outside of the waste incinerator 1 from 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 the 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 upward in the vertical direction from the downstream end of the reburning chamber and then folds downward in the vertical direction. That is, the exhaust passage 17 has an upstream portion 17a extending vertically upward from the downstream end of the reburning chamber 9, and a downstream portion 17b folded downward from the upstream portion 17a. In the illustrated example, the downstream portion 17b is folded back to the rear side. By having such a structure in the exhaust passage 17, even when the heating device is connected to the downstream of the exhaust passage 17, the entire system including the heating device can be compactly configured.

The folded-back portion 17c from the upstream portion 17a to the downstream portion 17b of the exhaust passage 17 is covered with a flat plate-shaped 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 top wall 27 is provided substantially horizontally, but may be inclined upward, for example, toward the downstream side.

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

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 greatly deflected at an angle of 90 ° or more when flowing into the reburning chamber 9. This deflection promotes the mixing of the combustion gas BG and the secondary air A2. However, due to this deflection, the flow velocity distribution is biased in the passage height direction H in the reburning chamber 9 and the exhaust passage 17 following it. That is, a biased flow velocity distribution occurs in which the flow velocity in the region behind the reburning chamber 9 and the exhaust passage 17 increases (state A in the figure). Therefore, in the present embodiment, the combustion gas BG and the secondary air in the recombustion chamber 9 due to the deflection are injected by injecting the flow velocity adjusting gas AG in the direction opposite to the flow direction of the exhaust gas EG in the upstream portion 17a of the exhaust passage 17. The flow velocity distribution in the passage height direction H in the exhaust passage 17 is made uniform without interfering with 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).

Therefore, if the type and amount of the waste W to be incinerated is within a predetermined range and a predetermined high-speed region in which the flow rate adjusting gas AG should be injected can be roughly specified in the exhaust passage 17, the upstream portion 17a of the top wall 27 The injection nozzle 29 can be provided only in the portion facing the high speed region in the above. As an example in which the injection nozzle 29 is arranged in this way, in the illustrated example, the injection nozzle 29 is provided only on the portion rearward from the center of the upstream facing portion 27a of the top wall 27.

In the present embodiment, as shown in FIG. 3, a plurality of (four in the illustrated example) injection nozzles 29 are equal to the WI in the passage width direction of the top wall 27 in the portion rearward from the center of the upstream facing portion 27a. Arranged at intervals. However, the number and arrangement of the injection nozzles 29 in the region where the injection nozzles 29 should be provided are not limited to this example. For example, as shown in FIG. 4, the positions in the front-rear direction 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 rearward from the center of the upstream facing portion 27a of the top wall 27.

In the present embodiment, the flow velocity adjusting air supply passage 41 for supplying the flow velocity adjusting 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 is provided. A part of the air in the supply passage 41 is used. However, the supply system of the flow velocity adjusting gas AG is not limited to this example, and the flow velocity adjusting gas AG may be supplied from a supply source independent of the secondary air A2, for example. Further, the flow velocity adjusting gas AG is not limited to air, and 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 velocity adjusting gas AG.

According to the waste incinerator 1 according to the first embodiment described above, in the parallel flow type incinerator 7 that forcibly deflects the combustion gas BG, the gas for adjusting the flow velocity is injected from the injection nozzle 29. , The flow velocity distribution of the combustion gas BG in the exhaust passage 17 can be made uniform. This makes it 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 on the portion of the top wall 27 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, such a configuration can effectively make the flow velocity distribution of the exhaust gas EG uniform with a simple structure.

FIG. 5 shows the waste incinerator 1 according to the second embodiment of the present invention. The waste incinerator 1 according to the present embodiment has the same basic configuration as the first embodiment except for the configuration for injecting the flow velocity adjusting gas AG into the exhaust passage 17. The configuration for injecting the flow velocity adjusting gas AG into the exhaust passage 17 is common to the first embodiment in that the injection nozzle 29 is provided on the top wall 27 of the exhaust passage 17, but is required in advance. Rather than providing the injection nozzles 29 only at the position of, a plurality of injection nozzles 29 are provided apart from each other at the upstream facing portion 27a of the top 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 an injection nozzle 29 for injecting the flow velocity adjusting gas AG based on the measurement result of the flow velocity distribution measuring device 35. Hereinafter, the points different from the first embodiment will be mainly described, and the points 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 27a of the top wall 27. In the illustrated example, a plurality of (four in this example) injection nozzles 29 are arranged at equal intervals along the width direction (width direction of the exhaust passage 17) WI of the top wall 27. Further, a plurality of (three in this example) injection nozzle rows 29R arranged in this way, which are indicated by broken lines, are provided in the passage height direction H. In addition, 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.

Further, as shown in FIG. 5, in the present embodiment, the exhaust passage 17 is provided with a flow velocity distribution measuring device 35 for measuring 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 is provided with a control device 37 that selects an injection nozzle 29 for injecting the flow velocity adjusting gas AG based on the measurement result of the flow velocity distribution measuring device 35.

In the waste incinerator 1 according to the present 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 the control device 37 measures the flow velocity distribution based on the measurement result. The flow velocity adjusting gas AG is selectively injected from the injection nozzle 29 provided at a position corresponding to a predetermined high-speed region (for example, a region below the average flow velocity).

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

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

As described above, the preferred embodiment of the present invention has been described with reference to the drawings, but various additions, changes or deletions can be made without departing from the spirit of the present invention. Therefore, such things are also included within the scope of the present invention.

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

Claims (5)

An incinerator that incinerates waste while transporting it almost horizontally,
A reburning chamber that is connected to a combustion chamber in which the incineration device is arranged and reburns unburned components in the combustion gas generated in the combustion chamber, and extends upward from the downstream portion of the combustion chamber. Reburning chamber and
An exhaust passage that is connected to the downstream side of the reburning chamber, extends upward in the vertical direction from the downstream end of the reburning chamber, and then folds downward in the vertical direction.
An injection nozzle provided on the top wall of the folded portion of the exhaust passage and injecting a flow velocity adjusting gas toward the upstream side of the upstream portion of the exhaust passage extending vertically upward.
A waste incinerator equipped with. In the waste incinerator according to claim 1, the incinerator is configured so that the injection nozzle can inject only into a high-speed region which is a flow velocity region higher than the 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 on the portion of the top wall facing the high-speed region. In the waste incinerator according to claim 3, the injection nozzle is provided only in the portion of the top wall on the downstream side in the waste transport direction from the center of the upstream portion of the exhaust passage. Waste incinerator. In the waste incinerator according to claim 2.
A plurality of the injection nozzles are provided at portions of the top wall facing the upstream portion of the exhaust passage so as to be separated from each other.
A flow velocity distribution measuring device for measuring the flow velocity distribution of the exhaust gas flow in the upstream portion of the exhaust passage, and a flow velocity distribution measuring device.
A control device that selects the injection nozzle based on the measurement result of the flow velocity distribution measuring device, and
Further equipped with a waste incinerator.

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