JP2009041897A - Roasting facility juxtaposed to incinerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roasting facility juxtaposed to an incinerator, lower in device installation cost than a conventional one and sharply reduced in the amount of fuel used for re-combustion of exhaust gas in a roasting furnace compared with the conventional one. <P>SOLUTION: The roasting facility juxtaposed to the incinerator having a primary combustion area for burning an incinerated object with primary air, and a secondary combustion area for burning combustion gas generated in the primary combustion area, with secondary air, and also having an exhaust gas treating facility for treating exhaust gas generated in the secondary combustion area, roasts ashes containing heavy metals and dioxin, in an reductive atmosphere while holding the ashes to a fusing point temperature or lower, wherein a passage for exhausting exhaust gas generated in the roasting facility is connected to the primary combustion area of the incinerator, and the exhaust gas generated in the roasting facility is led into the incinerator and burned again at 850°C or higher at which the dioxin is pyrolyzed and reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention has a primary combustion zone in which incinerated materials are partially combusted by primary air, and a secondary combustion zone in which combustion gas generated in the primary combustion zone is burned by secondary air, and is generated in the secondary combustion zone. And an incinerator equipped with an exhaust gas treatment facility for treating exhaust gas, which relates to a roasting facility for roasting in a reducing atmosphere while maintaining ash containing heavy metals and dioxins at a temperature below the melting point, Specifically, the exhaust gas generated in the roasting equipment is introduced into the incinerator to be installed, and the exhaust gas from the roasting equipment is reburned in the incinerator, so that the processing of the exhaust gas generated in the roasting furnace can be performed by the incinerator and incinerator. The present invention relates to roasting equipment performed in exhaust gas treatment equipment.

  Various types of heavy metals and dioxins are contained in incineration ash and fly ash generated by incinerating general waste and industrial waste. Incinerators that do not have heavy metal treatment facilities may leak heavy metal-containing substances into the atmosphere, soil, and groundwater. In addition, there are environmental standards in soils such as factory sites and landfills. Heavy metals may be present in concentrations higher than those specified in. Many heavy metals are highly toxic and not only adversely affect the environment but also accumulate in the body and cause harm. For this reason, environmental regulations for heavy metals contained in incineration ash, fly ash, soil, etc. have been established, and there is a tendency for regulations on heavy metals to become stricter. Technology that renders substances that contain heavy metals harmless and recyclable Development is becoming more important.

  Therefore, as a method for detoxifying and recycling a material containing heavy metals, Patent Document 1 discloses that incineration ash containing heavy metals is heated in a roasting furnace that keeps the melting point or less to volatilize heavy metals. After that, a method of cooling and separating and recovering has been proposed. However, many heavy metals contained in incinerated products exist in the form of oxides, and heavy metals present in the form of oxides are high boiling point compounds that are difficult to remove and may remain in the treated product. There is.

In addition, examples of the resource product derived from incinerated ash include molten slag, and in recent years, in addition to the conventional elution regulations, the regulation of the content has been set for heavy metals in the molten slag. Reducing the content of lead, which has a high boiling point even by itself, is a major issue.
Thus, a method is known in which a chlorine-based gas is supplied to a substance containing heavy metals, and the heavy metals are chlorinated and volatilized. For example, Patent Documents 2 and 3 disclose the method.

  Using the technologies described above, detoxification and recycling of materials containing heavy metals such as incineration ash and fly ash generated from incinerators that incinerate general waste and industrial waste, and dioxins, and dioxins In the case of using a furnace, a roasting furnace is often attached to the incinerator in order to improve the efficiency of conveying ash and the like.

FIG. 8 is a schematic flow diagram of a conventional incinerator and a roasting furnace in which ash containing heavy metals and dioxins attached to the incinerator is maintained at a temperature below the melting point and roasted in a reducing atmosphere to make it harmless. It is an example of a figure. A conventional flow will be described with reference to FIG.
Garbage such as general waste and industrial waste is introduced into the incinerator 101. Incinerator 101 incinerates garbage at about 900 ° C., and generates high-temperature combustion gas together with incineration ash containing heavy metals and dioxins. The high-temperature combustion gas generated in this way is supplied to the boiler 104, and high-temperature steam is generated in the boiler 104 using the sensible heat of the high-temperature combustion gas. The generated high-temperature steam is guided to a power generation facility 106 provided in the boiler 104 and used for power generation.
The exhaust gas after heat recovery by the boiler 104 is processed by the exhaust gas processing facility 105 and released into the atmosphere from a chimney or the like. The exhaust gas treatment facility 105 has the same configuration as an exhaust gas treatment facility 110 described later.

Incineration ash containing heavy metals, dioxins and the like generated in the incinerator 101 is supplied to the roasting furnace 102. The ash supplied to the roasting furnace 102 may be introduced from the outside in addition to the ash generated in the incinerator 101.
In the roasting furnace 102, the received ash is kept at a temperature below the melting point and roasted in a reducing atmosphere, whereby the metal oxide and the volatilized metal are separated and recovered, and the ash is rendered harmless. The detoxified ash is reused as roasted ash as soft ground improvement material, cement aggregate, concrete secondary products, etc., and the exhaust gas of the roasting furnace generated in the roasting furnace 102 is dioxins in the recombustion chamber 109. After complete combustion at 850 ° C. or higher, which is thermally decomposed and reduced, it is treated by the exhaust gas treatment facility 110 and released from the chimney to the atmosphere.

As shown in FIG. 9, the exhaust gas treatment facility 110 is generally composed mainly of a temperature reducing tower 110a, a bag filter 110b, a smoke washing device 110c, a reheater 110d, and a denitration device 110e, and the exhaust gas treated by the exhaust gas treatment facility 110. Is emitted from the chimney 111 to the atmosphere. The exhaust gas completely combusted in the recombustion chamber 109 is introduced into the temperature reducing tower 110a and cooled by spraying the cooling water, and the acidic gas such as NOx and HCl is neutralized by the supply of slaked lime and introduced into the bag filter 110b. Dust is removed. Fly ash collected by the temperature reducing tower 110a and the bag filter 110b is introduced into the roasting furnace 101 and processed. The exhaust gas discharged from the bag filter 110b is cooled and wet-cleaned by the smoke cleaning device 110c, and the cleaned exhaust gas is heated through the heater 110d and then NOx is removed by supplying ammonia in the denitration device 110e. The air is emitted from the chimney 111 to the atmosphere. Note that the supply of slaked _lime, NO x, the case of the neutralization of the HCl and the like, Araikemuri device 110c need not be installed.
Further, the exhaust gas treatment device 105 generated from the incinerator 101 has the same configuration.

  However, in the roasting furnace attached to the conventional incinerator shown in FIGS. 8 and 9, the exhaust gas treatment facilities 105 and 110 are apparatuses having the same configuration, and there is a problem that the installation cost of the apparatus increases. Therefore, Patent Document 4 discloses a technique in which the smoke cleaning apparatus and the subsequent components are shared among the incinerator and the exhaust gas treatment facility for the main ash melting furnace discharged from the incinerator. In addition, the above-mentioned Patent Document 1 discloses a technique in which the ash is roasted in a temperature range including the decomposition temperature range of dioxin, the recombustion chamber is omitted, and the exhaust gas treatment equipment of the incinerator and the roasting device is shared. ing.

JP 2001-132930 A JP 2002-192118 A JP 2004-181323 A Japanese Patent No. 3285922

  However, as disclosed in Patent Document 4, when the technology for sharing a part of the incinerator exhaust gas and roasted exhaust gas treatment device is applied to the roasting furnace, the equipment installation cost is reduced by the commonization. Although it becomes low, a recombustion chamber for recombusting exhaust gas discharged from the roasting furnace is necessary, and the cost reduction effect is not sufficient. Further, the exhaust gas temperature discharged from the roasting furnace is about 300 ° C., and it is necessary to burn at a high temperature of 850 ° C. or higher in order to thermally decompose dioxins and completely burn the exhaust gas of the roasting furnace in the recombustion chamber. Therefore, since a large amount of fuel is required in the recombustion chamber, a large running cost is necessary.

  In addition, as disclosed in Patent Document 1, the ash is roasted in a temperature range including the decomposition temperature range of dioxin, thereby omitting the recombustion chamber and sharing the exhaust gas treatment equipment of the incinerator and the roasting device. In this case, since the temperature of the roasting furnace is limited to the decomposition temperature range of dioxin, there is a limit to the types of ash that can be roasted in the roasting furnace. In addition, as disclosed in Patent Document 1, when the exhaust gas treatment equipment of the incinerator and the roasting apparatus is made common and the temperature of the roasting furnace is not limited, it can be roasted in the roasting furnace. Although there is no limitation on the type of ash, the recombustion chamber cannot be omitted, and it cannot be said that the equipment installation cost can be sufficiently reduced. Also, a large amount of fuel is required in the recombustion chamber, so that a running cost is also required.

  Therefore, in view of the problems of the prior art, the present invention is provided with an incinerator in which the installation cost of the apparatus is lower than before and the amount of fuel used for reburning the exhaust gas of the roasting furnace is significantly reduced compared to the conventional one. The purpose is to provide an improved roasting facility.

In order to solve the above problems, in the present invention,
It has a primary combustion zone for burning the incinerated product with primary air and a secondary combustion zone for burning combustion gas generated in the primary combustion zone with secondary air, and treats exhaust gas generated in the secondary combustion zone In the incinerator equipped with an incinerator equipped with an exhaust gas treatment facility, in which the ash containing heavy metals and dioxins is maintained at a temperature below the melting point and roasted in a reducing atmosphere,
A flow path for discharging exhaust gas generated in the roasting equipment is connected to at least one of a primary combustion area or a secondary combustion area (hereinafter referred to as a primary / secondary combustion area) of the incinerator, and roasting is performed. The exhaust gas generated in the facility is introduced into an incinerator and recombusted at 850 ° C. or higher where dioxins are thermally decomposed and reduced.

  For example, waste incinerators and the like normally incinerate waste that is an incinerator at about 900 ° C., and this temperature is a temperature range in which dioxins are thermally decomposed and reduced. Therefore, by introducing the exhaust gas generated in the roasting furnace into the incinerator and combusting it together with the incinerator (garbage), dioxins contained in the exhaust gas generated in the roasting furnace can be thermally decomposed and reduced. .

In addition, because the exhaust gas generated in the roasting furnace is reburned in the incinerator, there is no need for a recombustion chamber, which was necessary in the past, and the exhaust gas generated by reburning the exhaust gas from the roasting furnace incinerates garbage Because it can be treated together with the exhaust gas generated by this, an exhaust gas treatment facility for treating the exhaust gas generated in the roasting furnace is not necessary, and not only can the initial cost of the facility be greatly reduced than before. Equipment installation space can also be greatly reduced.
In addition, when the incinerator is an industrial waste incinerator that incinerates industrial waste, etc., it can burn by itself, so the fuel that was conventionally necessary in the recombustion chamber for recombusting the exhaust gas generated in the roasting furnace And the running cost can be reduced.

Furthermore, since the exhaust gas generated in the roasting furnace is a low-oxygen gas that normally contains about 5% oxygen, the combustion temperature can be lowered by introducing it into the primary combustion zone of the incinerator and is generated in the incinerator. This is effective for reducing nitrogen oxides (NOx) in the exhaust gas.
Moreover, in this invention, it is more suitable to connect the flow path which discharges | emits the waste gas generated with the said roasting equipment to the primary combustion area of the said incinerator. This is because it is possible to promote primary combustion by oxygen contained in the roasted exhaust gas, and to increase the residence time in the combustion zone of the roasted exhaust gas, and to reduce the unburned content in the roasted exhaust gas. Complete combustion is possible.

The incinerator is provided with a burner having a combustion capacity that can be heated to 850 ° C. or higher so that the exhaust gas introduced from the roasting equipment is thermally decomposed and reduced by dioxins, so that the incinerator is not supplied to the incinerator. The exhaust gas introduced from the roasting facility by the burner can be reburned.
Thus, even when the incineration object is not incinerated in the incinerator, the exhaust gas generated in the roasting furnace can be recombusted in the incinerator.

In addition, a plurality of the burners are installed in the incinerator, and the number of burners to be used can be selected according to the amount of exhaust gas introduced from the roasting facility when the incinerator is not supplied to the incinerator.
By selecting the number of burners to be used according to the amount of exhaust gas introduced from the roasting equipment in this way, it is possible to minimize the running costs for using the burners without using more burners than necessary. Can do.

Further, a plurality of the burners are installed in the incinerator, and can be used as a combustion auxiliary burner when supplying the incinerator to the incinerator.
Thereby, the burner installed in the incinerator can be used more efficiently.

  Further, an induction fan is provided in the flow path of the exhaust gas generated in the roasting facility, and the exhaust gas of the roasting facility is introduced into the incinerator using the attractive force of the induction fan, and the exhaust gas is in the flow path. A dust removing device is provided on the upstream side of the attracting fan. Further, in the exhaust gas flow path, on the upstream side of the dust removing device, heat exchange with the air introduced from the outside, the heat exchanger to reduce the exhaust gas of the roasting equipment below the heat resistance temperature of the induction fan, A cyclone dust collector is provided further upstream of the heat exchanger.

In order to reduce the nitrogen oxide (NOx) in the exhaust gas generated in the incinerator by introducing the exhaust gas from the roasting furnace into the incinerator, the extent to which the exhaust gas from the roasting furnace is mixed with the combustion gas in the incinerator It is necessary to introduce at a momentum. By providing an induction fan to boost the exhaust gas from the roasting furnace and introducing it into the incinerator, the exhaust gas from the roasting furnace is reliably mixed with the combustion gas in the incinerator and more efficiently nitrogen oxide (NOx) Is reduced.
Furthermore, it is possible to protect the equipment of the induction fan by providing a heat exchanger in which the exhaust gas temperature of the roasting furnace is not higher than the heat resistance temperature of the induction fan. In addition, you may make it lower the exhaust gas temperature of a roasting furnace using the temperature reduction tower which sprays cooling water instead of a heat exchanger.
Furthermore, the exhaust gas of the roasting furnace usually contains about 30-60 g / Nm ³ of dust, and when introduced into the heat exchanger as it is, there is a possibility that the dust will adhere to the inside of the heat exchanger. By removing the dust with, dust can be prevented from adhering inside the heat exchanger.
In addition, in order to remove the dust solidified by cooling by the heat exchanger and prevent the dust from entering the induction fan, a dust removing device such as a bag filter is provided downstream of the heat exchanger and upstream of the induction fan. Also good. In this case, the heat exchanger must lower the exhaust gas from the roasting furnace to a temperature that does not exceed the heat resistance temperature of either the induction fan or the bag filter.

  Further, by using the air heated by heat exchange with the gas of the roasting equipment by the heat exchanger as at least part of the combustion air of the roasting equipment, the heated air is effectively used. be able to.

Further, a flow path for discharging exhaust gas generated in the roasting facility is connected to a first roasting exhaust gas flow path connected to a primary / secondary combustion zone of the incinerator, and an incinerator input side of the incinerator. A first damper for branching into a second roasting exhaust gas channel to be connected, and controlling an exhaust gas flow rate introduced into the primary / secondary combustion zone on the first roasting exhaust gas channel; and the second roasting exhaust gas A second damper for controlling the flow rate of exhaust gas introduced to the incinerated product inlet side on the flow path;
An incineration exhaust gas return passage for returning exhaust gas generated in the incinerator to the incinerator input side of the incinerator, and a flow rate of exhaust gas introduced to the incineration input side on the incineration exhaust gas return channel is controlled. A third damper is provided,
Control for detecting temperature of the secondary combustion zone is provided, and control for controlling the opening degree of the first damper, the second damper, and the third damper based on the temperature detected by the temperature detecting means, respectively. A device is provided.

  As a result, the temperature adjustment range in the incinerator and the secondary combustion zone is widened, and appropriate temperature and combustion management can be performed even for garbage such as industrial waste whose properties are easily changed. In addition, the roasting exhaust gas has a lower oxygen concentration than the incineration exhaust gas, and is effective in the case of suppressed combustion, so that the incinerator can be operated smoothly by introducing the roasting exhaust gas into the incinerator, By controlling the introduction amount of the incineration exhaust gas according to the introduction amount of the roasting exhaust gas, it becomes possible to perform appropriate circulating exhaust gas control and stable operation. Furthermore, when the temperature of the secondary combustion zone is likely to decrease, the incineration exhaust gas is reduced and the roasting exhaust gas is supplied, so that the operation can be continued without reducing the processing amount of the roasting equipment.

Further, the control device controls the opening degree of the first damper so that the temperature of the secondary combustion zone is within a temperature range of 850 to 950 ° C. based on the temperature detected by the temperature detecting means. Is preferred.
Of the above temperature range, the lower temperature limit value of 850 ° C. is for suppressing the generation of dioxins, and the upper temperature limit value of 950 ° C. is for suppressing the generation of NO _x . Therefore, by maintaining the secondary combustion region within the above temperature range, it is possible to prevent harmful substances from being generated in the exhaust gas and to perform an appropriate exhaust gas treatment.

Furthermore, pressure detection means for detecting exhaust gas pressure is provided in a flow path for discharging exhaust gas generated in the roasting facility, and the control device is configured to detect the second damper based on the pressure detected by the pressure detection means. The opening degree is controlled.
In this way, by controlling the second damper based on the pressure of the roasting exhaust gas, it is possible to stably introduce a certain amount of the roasting exhaust gas into the incinerator even when there is a change in the amount of the roasting exhaust gas. It is possible to operate the incinerator smoothly.

Furthermore, an air supply path for supplying air to the workpiece input side of the incinerator is provided, and air is supplied from the air supply path when promoting combustion in the incinerator.
Thereby, even when there is a change in the properties and components of the incineration object, the incineration reaction in the incinerator can be appropriately controlled.

  As described above, according to the present invention, the installation cost of the apparatus is lower than the conventional one, and the roasting facility provided with the incinerator in which the amount of fuel used for reburning the exhaust gas of the roasting furnace is significantly reduced compared to the conventional one. A baked facility can be provided.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  FIG. 1 shows an incinerator according to the first embodiment, and a roasting furnace that is attached to the incinerator and ash containing heavy metals and dioxins is maintained at a temperature below the melting point and roasted in a reducing atmosphere to make it harmless. It is an example of the general | schematic flowchart of these. The flow of the present embodiment will be described based on FIG.

  Garbage such as general waste and industrial waste is introduced into the incinerator 1. The incinerator 1 incinerates garbage at about 900 ° C., and generates high-temperature combustion gas together with incineration ash containing heavy metals and dioxins. The high-temperature combustion gas generated in this way is supplied to the boiler 4, and high-temperature steam is generated in the boiler 4 using the sensible heat of the high-temperature combustion gas. The generated high-temperature steam is guided to a power generation facility 6 provided in the boiler 4 and used for power generation.

Incineration ash containing heavy metals and dioxins generated in the incinerator 1 and ash from the outside are supplied to the roasting furnace 2. The ash supplied to the roasting furnace 2 may be introduced from the outside in addition to the ash generated in the incinerator 1.
In the roasting furnace 2, the received ash is kept at a temperature below the melting point and roasted in a reducing atmosphere, whereby the metal oxide and the volatilized metal are separated and recovered, and the ash is rendered harmless. The detoxified ash is reused as roasted ash as soft ground improvement material, cement aggregate, concrete secondary products, etc., and the exhaust gas generated in the roasting furnace 2 is reduced in temperature and removed by the temperature reduction / dust removal device 7. After that, it is attracted by the attracting fan 8 and introduced into the incinerator 1. The temperature reducing device in the temperature reducing / dust removing device 7 includes a temperature reducing tower that cools the exhaust gas by water spray or the like, or a heat exchanger that recovers heat by exchanging the exhaust gas with air or cooling water.

The exhaust gas from the roasting furnace 2 introduced into the incinerator 1 is combusted together with garbage in the incinerator 1. Incinerator 1 incinerates waste at about 900 ° C, and dioxins are thermally decomposed and reduced to 850 ° C or higher, so the exhaust gas from roasting furnace 2 is completely decomposed by incinerator 1 and dioxins are thermally decomposed. After being combusted, it is treated with the exhaust gas generated in the incinerator 1 in the exhaust gas treatment facility 5 and discharged from a chimney or the like.
The exhaust gas treatment facility 5 has the same configuration as the conventionally used exhaust gas treatment facilities 105 and 110 shown in FIGS. 8 and 9, and a description thereof will be omitted. In addition, according to the property of exhaust gas, it can also be set as the structure which does not have the smoke washing apparatus 110c, the reheater 110d, and the denitration apparatus 110e, and these apparatus structures can be selected suitably.

  As shown in FIG. 1, exhaust gas generated in the roasting furnace 2 is completely burned in the incinerator 1, so that the recombustion chamber 109 and the exhaust gas treatment equipment 110 for the roasting furnace that are necessary in the past are not necessary, and reburning is performed. The installation space and the installation cost of the chamber 109 and the exhaust gas treatment facility 110 are not required, and the fuel supplied to the recombustion chamber 109, which has been necessary in the past, is not required, and the cost can be reduced.

2 is a schematic flow diagram when the temperature reduction / dust removal device 7 shown in FIG. 1 includes a temperature reduction tower, and FIG. 3 shows a schematic flow diagram when the temperature reduction / dust removal device 7 includes a heat exchanger. .
First, based on FIG. 2, the flow of the temperature reduction / dust removal apparatus of the present embodiment will be described. The exhaust gas generated in the roasting furnace 2 is attracted by the induction fan 8 and introduced into the incinerator 1. The temperature reducing / dust removing device 7 is provided on the downstream side of the roasting furnace 2 and on the upstream side of the induction fan, and mainly includes a temperature reducing tower 71 and a bag filter 72.

The exhaust gas of about 300 ° C. generated in the roasting furnace 2 is introduced into the temperature reducing tower 71 by the attractive force of the attractive fan 8. The temperature-decreasing tower 71 is provided with cooling means such as water spraying means, where the exhaust gas is cooled to about 200 ° C. by the cooling means. The cooling temperature is about 200 ° C. in this embodiment, but is not particularly limited as long as it does not exceed the heat resistance temperature of the bag filter 72 and the induction fan 8 described later. Further, when the water spraying means is provided as the cooling means, the dust in the exhaust gas is knocked down by the water spray and removed together with the cooling of the exhaust gas.
The exhaust gas of the roasting furnace 2 cooled by the temperature reducing tower 71 is introduced into the bag filter 72 by the attractive force of the induction fan 8, and the dust remaining in the exhaust gas is solidified and precipitated by cooling by the temperature reducing tower 71. Removed with dust.
In this way, the temperature reduction and dust removal apparatus 7 mainly composed of the temperature reduction tower 71 and the bag filter 72 performs temperature reduction and dust removal, and the exhaust gas of the roasting furnace 2 is incinerated using the attractive force of the induction fan 8. 2 is introduced.

  As another configuration of the temperature reduction / dust removal apparatus 7, FIG. 3 shows a configuration including a heat exchanger instead of the temperature reduction tower. In the figure, the exhaust gas generated in the roasting furnace 2 is attracted by the induction fan 8 and introduced into the incinerator 1. The temperature reducing / dust removing device 7 is provided on the downstream side of the roasting furnace 2 and on the upstream side of the induction fan, and mainly includes a cyclone 74, a heat exchanger 75, and a bag filter 72.

The exhaust gas of about 300 ° C. generated in the roasting furnace 2 is first introduced into the cyclone 74 by the attractive force of the attractive fan 8. The exhaust gas of the roasting furnace 2 contains about ³⁰ to 60 g / Nm ³ of soot and is removed here. This can prevent dust from adhering inside the heat exchanger 75 described later.
The exhaust gas removed by the cyclone 74 is further introduced into the heat exchanger 75 by the attractive force of the attractive fan 8. The heat exchanger 75 is a shell tube type heat exchanger and is cooled to about 200 ° C. by exchanging heat with air introduced from the outside. The cooling temperature is the same as in FIG. The air 73 heated by exchanging heat with the exhaust gas from the roasting furnace 2 is introduced into the roasting furnace and used as at least a part of the combustion air.
The exhaust gas of the roasting furnace 2 cooled by the heat exchanger 75 is introduced into the bag filter 72 by the attractive force of the induction fan 8, solidified by the cooling by the heat exchanger 75, and removed by the cyclone 74. Dust that was not cut is removed.
In this way, the temperature reduction / dust removal device 7 mainly composed of the cyclone 74, the heat exchanger 75, and the bag filter 72 performs temperature reduction (heat recovery) and dust removal, and roasting using the attractive force of the induction fan 8. The exhaust gas from the furnace 2 is introduced into the incinerator 2.

FIG. 4 is a schematic configuration diagram of the incinerator 1 in the first embodiment, and FIG. 5 is a cross-sectional view taken along line AA in FIG.
The incinerator 1 used in the first embodiment is a rotary kiln type stoker furnace composed of an incineration kiln (rotary kiln) 11, a post-combustion stoker furnace 12, and a recombustion chamber 16. In the first embodiment, a rotary kiln type stoker furnace is used, but the incinerator 1 is not particularly limited as long as it is an incinerator having a primary combustion zone and a secondary combustion zone. In the incinerator 1, a charging hopper 13 is provided in an incineration kiln 11, and a recombustion chamber 16 having a rear combustion stoker 12 is connected to the incineration kiln 11 on the rear side opposite to the charging hopper 13. ing. A primary combustion zone is formed immediately above the stalker 12, and combustion air (primary air) is supplied from the lower portion of the stalker 12. A secondary combustion zone 17 is formed in the space above the stoker 12, and a secondary air inlet for supplying secondary air from the furnace wall is provided.

  In such an incinerator 1, garbage such as general waste and industrial waste is introduced from an input hopper 13 into an incineration kiln 11 that forms the incinerator 1. The incineration kiln 11 is slightly inclined downward in the outlet direction, and the incineration kiln 11 is slowly rotated to stir the garbage, heat it while moving it forward, and dry and pyrolyze it.

The thermal decomposition residue generated while rotating and stirring the garbage in the incineration kiln 11 falls on the post-combustion stoker 12 and is ashed. The post-combustion stalker 12 is a stepped stalker and does not have air holes on the upper surface, and combustion air is fed from only the vertical surface, so even sandy ash can be ashed without falling below the stalker.
Further, the ash and unburned matter are moved forward while sliding down the stairs of the post-combustion stalker 12 by driving the stalker 12, and are agitated when dropping, and by the air inserted from under the stalker, Burned.

The incinerator kiln 11 can incinerate fluid oil mud, waste plastic, and sludge that becomes powder when dried. The rotary kiln rotates to efficiently gasify and burn waste, but combustion air cannot be sent from the bottom of the garbage. After-combustion cannot be performed, and therefore, the pyrolysis residue remaining after gasifying wood waste, paper waste, etc. remains unburned in the incineration kiln 11 and may cause clinker if forced to burn.
Therefore, by using a rotary kiln-type stoker furnace integrated with the post-combustion stoker 12, the post-combustion of the carbide can be completed by the air inserted from the lower part of the post-combustion stoker, and the generation of clinker can be prevented. The combination of combustors with different characteristics makes it possible to incinerate various types of waste.

  Further, the incinerator 1 introduces secondary air into the secondary combustion zone 17 to incinerate liquid waste, and burn combustion gas generated in the incineration kiln 11 and the post-combustion stoker 12.

Furthermore, as a characteristic configuration of the present invention, a roasting exhaust gas inlet 14a that introduces exhaust gas generated in the roasting furnace 2 downstream of the secondary air inlet and attracted by the induction fan 8; 14b is provided. Since the exhaust gas of the roasting furnace 2 input from the roasting exhaust gas inlets 14a and 14b is energized by the attracting force of the induction fan 8 and introduced into the incinerator 1, it is incinerated when introduced into the incinerator 1. It is mixed with the combustion gas in the furnace and recombusted, and contributes to NOx reduction.
The roasted exhaust gas inlet is at least one of the roasted exhaust gas inlet 14a installed immediately above the post-combustion stoker 12 that is the primary combustion zone or the roasted exhaust gas inlet 14b installed in the secondary combustion zone 17. Is provided. The number of roasting exhaust gas inlets provided in each is not particularly limited. Preferably, the roasting exhaust gas inlet is provided below the primary combustion zone or the secondary air inlet of the secondary combustion zone 17.
When the roasting exhaust gas inlet 14a is provided in the primary combustion area, that is, below the recombustion chamber 16, the post-combustion can be promoted by the air contained in the roasting exhaust gas. On the other hand, when the roasting exhaust gas inlet 14b is provided in the secondary combustion zone 17, that is, in the middle or above the recombustion chamber 16, combustion can be made uniform by supplying the roasting exhaust gas in the secondary combustion. Of course, it is good also as a structure which provided both the roasting waste gas input ports 14a and 14b.

Further, as shown in FIGS. 4 and 5, the incinerator 1 is provided with a plurality of burners 15 a, 15 b, 15 c, and the exhaust gas from the roasting furnace 2 even when no waste is supplied to the incinerator 1. Can be reburned at 850 ° C. or higher where dioxins are thermally decomposed and reduced using the burners 15a, 15b and 15c.
The number of burners 15a, 15b, and 15c to be used can be selected according to the amount of exhaust gas in the roasting furnace 2 to be introduced, and the exhaust gas from the roasting furnace 2 is reduced by dioxins being thermally decomposed at 850 ° C. It has a combustion capacity that can be heated.
The burners 15a, 15b, and 15c may be used as incineration auxiliary burners when supplying waste to the incinerator 1. In this embodiment, three burners are provided, but the number of burners to be provided is not limited. Absent.

Here, as an application example of the first embodiment, FIGS. 6 and 7 show a configuration including an exhaust gas circulation control device.
First, with reference to FIG. 6, a configuration and a control method including an exhaust gas circulation control device will be described.
The incineration exhaust gas generated in the incinerator 1 passes through the temperature reducing tower 51 and the bag filter 52 and then is discharged to the outside by the induction fan 9 and part of it is branched and passes through the incineration exhaust gas return passage 32. The incineration kiln 11 is returned to the incineration exhaust gas inlet provided on the input hopper 13 side. The return incineration exhaust gas is used to form a reducing atmosphere in the incineration kiln 11 because the oxygen concentration is about 10% lower than that of normal air and the temperature is relatively high at about 170 ° C. A third damper 41 that controls the flow rate of the incineration exhaust gas introduced into the incineration kiln 11 is installed on the incineration exhaust gas return flow path 32.

  On the other hand, the roasting exhaust gas generated in the roasting furnace (roasting kiln) 2 passes through the temperature reducing tower 71 and the bag filter 72 (a cyclone is installed if necessary), and then the roasting exhaust gas passage by the induction fan 8. 35 is introduced into the incinerator 1. Since the roasting exhaust gas has an oxygen concentration of about 5 to 8% and a temperature of about 200 ° C., the roasting exhaust gas is used to form a reducing atmosphere in the incineration kiln 11 like the incineration exhaust gas. In addition, as described above, by introducing the entire amount of the roasted exhaust gas into the incinerator 1, it is not necessary to newly install an exhaust gas facility for the roasted exhaust gas.

The roasting exhaust gas channel 35 is branched into a first roasting exhaust gas channel 36 and a second roasting exhaust gas channel 37, and the first roasting exhaust gas channel 36 is charged with the roasting exhaust gas in the recombustion chamber 16. The second roasting exhaust gas passage 37 is connected to the ports 14 a and 14 b (see FIG. 4), and is connected to a roasting exhaust gas input port provided on the input hopper side of the incineration kiln 11. The roasting exhaust gas inlets 14 a and 14 b are as described above, and are provided in at least one of the primary combustion zone and the secondary combustion zone 17.
A first damper 42 for controlling the flow rate of exhaust gas introduced into the recombustion chamber 16 is installed on the first roasting exhaust gas passage 36, and introduced into the incineration kiln 11 on the second roasting exhaust gas passage 37. A second damper 43 for controlling the exhaust gas flow rate is installed.
The roasting exhaust gas inlet of the second roasting exhaust gas passage 36 is the same as the incineration exhaust gas inlet, provided with switching means, and switching the switching means as necessary to switch between the roasting exhaust gas and the incineration exhaust gas. You may make it introduce | transduce suitably.

Further, in the above configuration, a control device 50 for controlling the circulation amount of the incineration exhaust gas and the roasting exhaust gas is provided. The control device 50 controls the opening degree of the first damper 42, the second damper 43, and the third damper 41 based on the secondary combustion zone temperature of the recombustion chamber 16, and adjusts the circulation amount of each exhaust gas. . The temperature of the recombustion chamber 16 is measured by the temperature detection means 45. The temperature detecting means 45 may be any of a contact thermometer such as a thermocouple, a non-contact thermometer such as a radiation thermometer, or a means for calculating from the side wall heat radiation in the water pipe of the recombustion chamber 16. There is no particular limitation.
Preferably, the opening degree of each damper 41, 42, 43 is controlled so that the temperature of the recombustion chamber 16 falls within the range of 850 to 950 ° C. The lower temperature limit value of 850 ° C. is for suppressing the generation of dioxins, and the upper temperature limit value of 950 ° C. is for suppressing the generation of NO _x .

Here, a control flow of exhaust gas circulation in the control device 50 will be described.
In the control device 50, the temperature detecting means 45 detects the temperature of the recombustion chamber 16 (secondary combustion zone 17) intermittently or continuously, and the temperature detected by the temperature detecting means 45 falls below the above temperature range. In this case, it is determined that the introduction amount of the roasting exhaust gas into the recombustion chamber 16 is excessive, and the flow rate of the roasting exhaust gas introduced into the recombustion chamber 16 is reduced by controlling the first damper 42 to the closed side. . Furthermore, in this embodiment, in order to introduce the entire amount of the roasting exhaust gas into the incinerator 1, the second damper 43 is controlled to the open side, and the remaining roasting exhaust gas is introduced into the incineration kiln 11 side. On the other hand, the third damper 41 for controlling the introduction amount of the incineration exhaust gas is controlled to close according to the opening degree of the second damper 43 so that the reaction in the incineration kiln 11 is smoothly performed. 11 controls the total amount of exhaust gas introduced into the interior.

  On the contrary, when the temperature of the recombustion chamber 16 detected by the temperature detecting means 45 exceeds the above temperature range, it is determined that the amount of the roasted exhaust gas introduced into the recombustion chamber 16 is too small, and the first damper The flow rate of the roasted exhaust gas introduced into the recombustion chamber 16 is increased by controlling 42 to the open side. In response to this, the second damper 43 is controlled to the closed side to reduce the flow rate of the roasted exhaust gas introduced into the incineration kiln 11 side. Moreover, the 3rd damper 41 is controlled to an open side as needed, and the total exhaust gas amount introduce | transduced in the incineration kiln 11 is controlled.

  Further, in this configuration, an air supply path 38 for introducing air into the furnace may be provided on the charging hopper side of the incineration kiln 11. A fourth damper 44 is installed on the air supply path 38, and air is appropriately supplied into the incineration kiln 11 by controlling the opening and closing of the damper 44. The fourth damper 44 is controlled to open when the combustion in the combustion kiln 11 is to be promoted, so that the oxygen concentration in the kiln is increased.

According to this configuration, the temperature adjustment range in the incineration kiln 11 and the recombustion chamber 16 is widened, and appropriate temperature and combustion management can be performed even for garbage such as industrial waste whose properties are easily changed.
In addition, since the roasted exhaust gas has a lower oxygen concentration than the incinerated exhaust gas and is effective in the case of controlled combustion, the operation of the incinerator 1 can be smoothly performed by introducing the entire amount of the roasted exhaust gas into the incinerator 1. In addition, since the introduction amount of the incineration exhaust gas is controlled in accordance with the introduction amount of the roasting exhaust gas, appropriate circulating exhaust gas control becomes possible.
Furthermore, when the temperature of the recombustion chamber 16 is likely to be lowered, the operation can be continued without reducing the processing amount of the roasting furnace 2 by reducing the incineration exhaust gas and supplying the roasting exhaust gas.

Next, with reference to FIG. 7, a configuration and a control method including an exhaust gas circulation control device which is an application example different from FIG. 6 will be described.
In the figure, in addition to the configuration shown in FIG. 6, a pressure detection means 46 for detecting the pressure of the roasting exhaust gas passage 35 is provided.
The control device 50 controls the opening / closing of the first damper 42 based on the temperature detected by the temperature detecting means 45, and controls the opening / closing of the second damper 43 based on the pressure detected by the pressure detecting means 46. . The pressure detection means 46 may be installed on the first roasting exhaust gas flow channel 36 in addition to the roasting exhaust gas flow channel 35.

In this configuration, the control device 50 detects the temperature of the recombustion chamber 16 (secondary combustion zone 17) and the roasting exhaust gas pressure intermittently or continuously with the temperature detecting means 45 and the pressure detecting means 46, and the detected temperature. Is lower than the above temperature range, the flow rate of the roasting exhaust gas introduced into the recombustion chamber 16 is controlled by controlling the first damper 42 to the closed side, and the pressure of the roasting exhaust gas is set to a preset pressure. The second damper 43 is controlled to the open side so as to be within the range.
On the other hand, when the temperature detected by the temperature detecting means 45 exceeds the above temperature range, the flow rate of the roasted exhaust gas introduced into the recombustion chamber 16 by controlling the first damper 42 to the open side is increased. The second damper 43 is controlled to close so that the pressure of the roasting exhaust gas falls within a preset pressure range.
As in this configuration, by controlling the second damper based on the pressure of the roasting exhaust gas, even if there is a change in the amount of roasting exhaust gas, a fixed amount of roasting exhaust gas is stably introduced into the incinerator 1 This makes it possible to operate the incinerator 1 smoothly.

  The installation cost of the apparatus can be used as a roasting facility provided with an incinerator in which the cost of installing the apparatus is lower than before and the amount of fuel used for reburning the exhaust gas of the roasting furnace is significantly reduced compared to the conventional one.

It is a schematic flowchart of the incinerator concerning this Example 1, and the roasting furnace attached to this incinerator. It is a schematic flowchart of a temperature reduction and dust removal apparatus. It is a schematic flowchart of a heat recovery / dust removal apparatus. 1 is a schematic configuration diagram of an incinerator in Example 1. FIG. It is AA sectional drawing in FIG. FIG. 5 is a schematic flowchart of a configuration including an exhaust gas circulation control device in an application example of the first embodiment. FIG. 7 is a schematic flow diagram of a configuration including an exhaust gas circulation control device in an application example different from FIG. 6. It is a general | schematic flowchart of the conventional incinerator and the roasting furnace attached to this incinerator. 1 is a schematic flow diagram of an exhaust gas treatment facility used in the prior art and in Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incinerator 2 Roasting furnace 5 Exhaust gas processing equipment 7 Heat recovery and dust removal device 8, 9 Induction fan 11 Incineration kiln 12 Post combustion stoker 14 Roasting exhaust gas inlet 15a, 15b, 15c Burner 16 Recombustion chamber 32 Incineration exhaust gas return flow Path 35 roasting exhaust gas flow path 36 first roasting exhaust gas flow path 37 second roasting exhaust gas flow path 38 air supply path 41 third damper 42 first damper 43 second damper 44 fourth damper 45 temperature detecting means 46 pressure detection Means 50 Control device 51, 71 Temperature reducing tower 52, 72 Bag filter 73 Heated air 74 Cyclone 75 Heat exchanger

Claims (12)

It has a primary combustion zone for burning the incinerated product with primary air and a secondary combustion zone for burning combustion gas generated in the primary combustion zone with secondary air, and treats exhaust gas generated in the secondary combustion zone In the incinerator equipped with an incinerator equipped with an exhaust gas treatment facility, in which the ash containing heavy metals and dioxins is maintained at a temperature below the melting point and roasted in a reducing atmosphere,
A flow path for discharging exhaust gas generated in the roasting equipment is connected to at least one of a primary combustion area or a secondary combustion area (hereinafter referred to as a primary / secondary combustion area) of the incinerator, and roasting is performed. An incinerator equipped with an incinerator, wherein exhaust gas generated in the facility is introduced into an incinerator and re-combusted at 850 ° C. or more where dioxins are thermally decomposed and reduced.   The roasting facility provided with the incinerator according to claim 1, wherein a flow path for discharging exhaust gas generated in the roasting facility is connected to a primary combustion zone of the incinerator.   The incinerator is provided with a burner having a combustion capacity that can be heated to 850 ° C. or more, in which the exhaust gas introduced from the roasting equipment is thermally decomposed and reduced by dioxins, and even when the incinerated object is not supplied to the incinerator, The roasting facility provided with the incinerator according to claim 1, wherein the exhaust gas introduced from the roasting facility can be reburned.   A plurality of the burners are installed in the incinerator, and the number of burners to be used can be selected according to the amount of exhaust gas introduced from the roasting facility when the incineration object is not supplied to the incinerator. A roasting facility attached to the incinerator described.   The roasting facility provided with the incinerator according to claim 3 or 4, wherein a plurality of the burners are installed in the incinerator and can be used as a combustion auxiliary burner at the time of supplying the incinerator to the incinerator. An induction fan is provided in the flow path of the exhaust gas generated in the roasting facility, and the exhaust gas of the roasting facility is introduced into the incinerator using the attractive force of the induction fan.
The roasting apparatus provided with the incinerator according to any one of claims 1 to 5, wherein a dust removing device is provided in the exhaust gas flow path and upstream of the attracting fan. A heat exchanger that is in the flow path of the exhaust gas, heat-exchanges with air introduced from the outside on the upstream side of the dust removal device, and makes the exhaust gas of the roasting equipment less than the heat-resistant temperature of the induction fan;
7. A roasting facility provided with an incinerator according to claim 6, wherein a cyclone dust collector is provided further upstream of the heat exchanger.   The incinerator according to claim 7, wherein air heated by heat exchange with the gas of the roasting equipment by the heat exchanger is used as at least part of combustion air of the roasting equipment. Roasting equipment. A flow path for discharging exhaust gas generated in the roasting facility is connected to a first roasting exhaust gas flow path connected to a primary / secondary combustion zone of the incinerator and an incinerator input side of the incinerator. A first damper for branching into a second roasting exhaust gas channel and controlling an exhaust gas flow rate introduced into the primary / secondary combustion zone on the first roasting exhaust gas channel; and on the second roasting exhaust gas channel And a second damper for controlling the flow rate of exhaust gas introduced to the incinerated product inlet side,
An incineration exhaust gas return passage for returning exhaust gas generated in the incinerator to the incinerator input side of the incinerator, and a flow rate of exhaust gas introduced to the incineration input side on the incineration exhaust gas return channel is controlled. A third damper is provided,
Control for detecting temperature of the secondary combustion zone is provided, and control for controlling the opening degree of the first damper, the second damper, and the third damper based on the temperature detected by the temperature detecting means, respectively. A roasting facility provided with the incinerator according to any one of claims 1 to 8, wherein an apparatus is provided.   The control device controls the opening degree of the first damper so that the temperature of the secondary combustion zone is within a temperature range of 850 to 950 ° C. based on the temperature detected by the temperature detecting means. A roasting facility provided with the incinerator according to claim 9. In the flow path for discharging the exhaust gas generated in the roasting equipment, a pressure detection means for detecting the exhaust gas pressure is provided,
The roasting facility provided with the incinerator according to claim 9, wherein the control device controls the opening degree of the second damper based on the pressure detected by the pressure detecting means.   An air supply path for supplying air to the workpiece input port side of the incinerator is provided, and air is supplied from the air supply path when combustion in the incinerator is promoted. A roasting facility that is attached to the incinerator according to any one of 11 above.

Images