JP2003302041A - Method and device for fire prevention in unburned combustible conveying line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the necessity of nitrogen gas. <P>SOLUTION: An ash melting furnace 4 is connected to the downstream side of a rotary stoker incineration furnace 1 through an ash carrier conveyor 5. An economizer 9 is connected to a waste heat boiler 8 located above the secondary combustion chamber 1b of the rotary stoker incineration furnace 1, and a stack 16 is connected to the downstream side of the economizer through a flue gas line 10 having a gas temperature reducing tower 11, a bag filter 12, an induced draft fan 13 a flue gas reheater 14, and a catalytic reactor 15. A flue gas branch line 39 branched from the flue gas line 10 on the upstream side of the stack 16 is connected to an injection nozzle 37 installed in the ash carrier conveyor 5. When hot burned ash 3 taken out of the rotary stoker incineration furnace 1 is carried by the ash carrier conveyor 5, burned flue gas 7 with a low oxygen concentration led from the flue gas line 10 through the flue gas branch line 39 is blown into the conveyor to bring the atmosphere inside the ash carrier conveyor 5 to a low oxygen concentration to prevent the unburned combustibles in the burned ash 3 from being ignited. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to high-temperature unburned substances taken out from a furnace, such as incineration ash containing unburned substances discharged from an incinerator and pyrolysis residues discharged from a pyrolysis gasification furnace. The present invention relates to a fire prevention method and apparatus for an unburned matter transport line used to prevent ignition of the unburned matter in a transported unburnt matter transport line.

[0002]

2. Description of the Related Art Incineration has been widely used as a method for treating waste, and one of the treatment methods is as follows.
There is a direct combustion method in which the waste is put into the incinerator as it is and burned.

As shown in FIG. 3, a waste treatment facility of a type in which the above waste is directly burned in an incinerator is, as an incinerator, for example, a stalker furnace main body 1a horizontally rotatably driven, and the stalker furnace. A rotary stoker-type incinerator 1 including a secondary combustion chamber 1b provided at an upper position on the outlet side of the main body 1a and a post-combustion device 1c provided at a lower position on the outlet side of the stoker furnace main body 1a is installed. Together with the incinerator 1
After combustion of the rotary stoker type incinerator 1, in order to completely burn the incineration ash 3 containing unburned matter generated by supplying the waste 2 to and burning it, The ash melting furnace 4 is connected to the downstream side of the outlet of the incineration ash 3 that has passed through the device 1c through an ash transport conveyor 5 as an unburned material transport conveyor, and the incineration discharged from the rotary stoker incinerator 1 is performed. Ashes 3 and ash conveyor 5
It is transported to the ash-melting furnace 4, melted in the ash-melting furnace 4, and then recovered as slag 6 to significantly reduce the volume of the landfill disposal object and at the same time to dioxins. It is designed to be able to decompose and stabilize heavy metals.

On the other hand, the combustion exhaust gas 7 generated by the combustion of the waste 2 in the rotary stoker incinerator 1 is circulated to the waste heat boiler 8 and the economizer 9 to recover the waste heat,
Combustion after being used for recovery of waste heat in the waste heat boiler 8 and the economizer 9 in order to remove soot and acid gas contained in the combustion exhaust gas 7 and then to send to the chimney 16. In the exhaust gas line 10 for guiding the exhaust gas 7 to the chimney 16, a gas temperature reducing tower 11, a bag filter 12, an induced air blower 13, an exhaust gas reheater 14, and a catalytic reaction tower 15 are sequentially provided from the upstream side, and the induced air blower 13 is provided. When the combustion exhaust gas 7 is circulated in the exhaust gas line 10 by
After the exhaust gas temperature is lowered to the required temperature in the gas temperature reducing tower 11 so that the temperature corresponds to the processing temperature of the bag filter 12 in the subsequent stage, the bag filter 12 performs dust removal processing. The flue gas 6 treated with dust is reheated by the exhaust gas reheater 14 to the catalytic activation temperature of the catalytic reaction tower 15 in the subsequent stage, and then circulated to the catalytic reaction tower 15 to decompose the dioxins and denitrify. The clean flue gas 7 is carried out and the clean flue gas 7 is converted into the chimney 1.
It is sent to No. 6 to be released into the atmosphere.

The molten exhaust gas 17 discharged from the ash melting furnace 4 when the incineration ash 3 is melted in the ash melting furnace 4
Since the unburned gas is contained in the ash melting furnace 4, a smelting furnace secondary combustion chamber 18 is provided on the downstream side of the ash melting furnace 4, and the smelting exhaust gas from the ash melting furnace 4 is provided in the melting furnace secondary combustion chamber 18. The unburned gas contained in the melting furnace is guided to 17 and completely burned.
As shown in FIG. 3, the combustion exhaust gas 7a generated at the time of complete combustion of 7 is introduced through the exhaust gas line 19 to the exhaust gas line 10 at the downstream side position of the gas temperature reduction tower 11 as shown in FIG. The bag filter 12 is used to perform a dedusting process together with the combustion exhaust gas 7 that is guided to the chimney 16 through the exhaust gas line 10, or is guided to the exhaust gas line 10 at a position upstream or downstream of the induction blower 13 through the exhaust gas line 19, In the reaction tower 15, dioxins are decomposed and denitrated, and then emitted into the atmosphere through the chimney 16.

Another method of incinerating waste is to pyrolyze the waste into a pyrolysis gas and a pyrolysis residue, and then supply the pyrolysis gas and the pyrolysis residue together to a melting furnace. The incineration and ash contents are melted and slag is formed by burning it to make it possible to significantly reduce the volume and stabilize the landfill disposal object, and heat the valuable metals without oxidizing them. Can be recovered from decomposition residues, and
There is a pyrolysis gasification and melting method that makes it possible to supply most of the thermal energy required in the facility.

As shown in FIG. 4, the waste treatment facility using such a pyrolysis gasification and melting system has a pyrolysis furnace, for example, a rotary pyrolysis kiln 21 as a pyrolysis furnace downstream of the waste dryer 20. Provide the waste 2 and the waste 20
After being dried in, it is supplied to the pyrolysis kiln 21 and heated by external heat in a low oxygen atmosphere to be pyrolyzed,
The pyrolysis gas 22 and the pyrolysis residue 23 generated by the pyrolysis are separated in a separation chamber 21a provided at the downstream end of the pyrolysis kiln 21, respectively. After being taken out by the pyrolysis residue taking-out device 24 connected to the bottom of the separation chamber 21a,
The pyrolysis residue crusher 25 is connected to the downstream side of the pyrolysis residue extraction device 24 via a pyrolysis residue transport conveyor 27a so that the pyrolysis residue crusher 25 crushes it.
The iron / aluminum sorting machine 26 connected via the pyrolysis residue transport conveyor 27b sorts and collects iron and aluminum 29, and the remaining pyrolysis residue 23 is stored by the pyrolysis residue transport conveyor 27c. After being introduced into the tank 34 and temporarily stored, it can be supplied to the melting furnace 28 in a fixed amount, while the pyrolysis gas 22 is taken out from the top of the separation chamber 21a of the pyrolysis kiln 21 and is not shown in the figure. The pyrolysis gas 22 and the pyrolysis residue 23 are burnt together in the fusion furnace 28 through the attached pyrolysis gas transfer line 30 to generate a high temperature, thereby generating a combustible substance. Is completely burned and at the same time, ash and incombustibles are melted and can be recovered as slag 6 from the bottom of the melting furnace 28.

The gas containing unburned gas generated in the melting furnace 28 is sent to a secondary combustion chamber 31 provided on the downstream side of the melting furnace 28 for complete combustion. Combustion exhaust gas 32 generated by combustion in the chamber 31
Is the waste heat boiler 3 provided on the downstream side of the secondary combustion chamber 31.
Exhaust gas line 1 shown in Fig. 3 after heat recovery at 3
After dedusting by introducing the gas temperature reduction tower 11, bag filter 12, induced air blower 13, exhaust gas reheater 14, and catalytic reaction tower 15 to the chimney 16 through the exhaust gas line 10 in the same manner as 0, After decomposing and denitrifying dioxins to make clean combustion exhaust gas 32,
It is designed to be discharged into the atmosphere through the chimney 16.

By the way, the high temperature incineration ash 3 discharged from the rotary stoker type incinerator 1 shown in FIG. 3 contains unburned components, and the pyrolysis kiln 21 shown in FIG. The high temperature pyrolysis residue 23 extracted by the residue extraction device 24 contains a large amount of unburned components. Therefore, in the ash transport conveyor 5 shown in FIG. 3 and the pyrolysis residue transport conveyors 27a, 27b, and 27c shown in FIG. 4, unburned substances and high-temperature heat in the high-temperature incinerated ash 3 to be transported are respectively transferred. It is necessary to prevent the unburned matter in the decomposition residue 23 from igniting and causing a fire. Therefore, conventionally, in the ash transport conveyor 5 as shown in FIG. 3, the ash transport conveyor 5 has an upstream end portion in the transport direction. From the injection nozzle 37 provided, a nitrogen gas 36 introduced through a nitrogen gas supply line 35 from a nitrogen gas supply unit (not shown) is injected and purged so that the inside is always in a nitrogen gas atmosphere. In the pyrolysis residue transport conveyors 27a, 27b, and 27c as shown in FIG. 5, the downstream end portion of the pyrolysis residue extraction device 24, which is on the upstream side in the transport direction of the pyrolysis residue transport conveyor 27a,
The downstream end of the pyrolysis residue transport conveyor 27b in the transport direction,
A nitrogen gas supply line 35 from a nitrogen gas supply unit (not shown) to the injection nozzle 37 provided in the pyrolysis residue storage tank 34 on the downstream side of the pyrolysis residue transport conveyor 27c in the transport direction, as in the case of the ash transport conveyor 5. By injecting and purging the nitrogen gas 36 introduced through the above, the inside of each of the pyrolysis residue transport conveyors 27a, 27b, 27c is made to have an atmosphere of the nitrogen gas 36, respectively, to prevent a fire.

In FIGS. 3 and 4, 38 is an ash transport conveyor 5 and pyrolysis residue transport conveyors 27a, 27.
b and 27c, which are gas outlets respectively provided to the ash transport conveyor 5 and the pyrolysis residue transport conveyors 27a and 27.
The nitrogen gas 36 injected into b and 27c and purged is collected from the gas outlet 38 and sent to a required device.

[0011]

However, the ash conveyor 5 for conveying the incinerated ash 3 of the conventional rotary stoker incinerator 1 and the thermal decomposition for conveying the thermal decomposition residue 23 generated in the thermal decomposition kiln 21. Residue transport conveyor 27a, 27
In b and 27c, the nitrogen gas 36 is purged in order to prevent the ignition of the high temperature unburned matter. Therefore, the direct combustion treatment method of the waste 2 using the rotary stoker incinerator 1 is adopted. In both the waste treatment equipment and the waste treatment equipment of the thermal decomposition gasification and melting method of the waste 2 which employs the pyrolysis kiln 21, it is necessary to attach a nitrogen gas generator for producing nitrogen gas. This is the actual situation, and there is a problem in that the facility cost required to attach the nitrogen gas generator and the running cost required to operate the nitrogen gas generator increase.

In view of the above, the present invention provides a ash transport conveyor for transporting incinerated ash such as produced in a rotary stoker incinerator, a pyrolysis residue transport conveyor for transporting pyrolysis residue such as produced in a pyrolysis kiln, and the like. It is possible to prevent ignition of high-temperature unburned materials without using nitrogen gas for the unburned-material transfer line that carries the discharged high-temperature unburned materials, eliminating the need to attach a nitrogen gas generator. The present invention aims to provide a method and a device for preventing fire in an unburned matter conveying line, which are made possible.

[0013]

In order to solve the above-mentioned problems, the present invention provides an unburned matter transfer line which is connected to a downstream side of a furnace and which conveys unburned matter in a high temperature state taken out from the furnace,
Method for blowing combustion exhaust gas with low oxygen concentration, and exhaust gas line for introducing combustion exhaust gas discharged from furnace to chimney to unburned material transfer line for transferring high temperature unburned material taken out from furnace An apparatus having a configuration in which an exhaust gas branch line branched from an intermediate position of is connected so that a part of low-oxygen concentration combustion exhaust gas can be blown into the unburned matter transport line through the exhaust gas branch line. To do.

When the high temperature unburned matter taken out of the furnace is conveyed through the unburned matter conveying line, a low oxygen concentration combustion exhaust gas is blown into the unburned matter conveying line, and the inside is in a low oxygen concentration atmosphere. Therefore, it is possible to eliminate the risk of ignition of the unburned matter in the high temperature state.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows, as an embodiment of the fire prevention method and apparatus for an unburned matter conveying line of the present invention, an unburned matter conveying line in a waste incineration treatment facility similar to that shown in FIG. It shows a case where it is applied to the ash transport conveyor 5.

That is, as shown in FIG. 3, the injection nozzle 3 to the ash transport conveyor 5 as an unburned material transport line is provided.
7, the nitrogen gas supply line 35 for guiding the nitrogen gas 36 from a nitrogen gas generator (not shown) is connected to inject the nitrogen gas 36, instead of the exhaust gas line 10 at the upstream side of the chimney 16. The exhaust gas branch line 39 provided by further branching is connected to the injection nozzle 37 of the ash transport conveyor 5 to be discharged from the rotary stoker incinerator 1 and processed while passing through the exhaust gas line 10 immediately before entering the chimney 16. A part of the low-oxygen concentration combustion exhaust gas 7 is collected through the exhaust gas branch line 39 and blown into the ash transport conveyor 5 from the injection nozzle 37.

Further, the gas outlet 3 of the ash transport conveyor 5
8 is connected to the melting furnace secondary combustion chamber 18 at the other end of the gas recovery line 40 having one end connected to the blower 41, and the other end of the gas recovery line 40 is always injected into the ash transport conveyor 5 by the injection nozzle 37. The excess amount of the combustion exhaust gas 7 to be filled is sent from the gas outlet 38 to the melting furnace secondary combustion chamber 18 through the gas recovery line 40.

Other configurations are the same as those shown in FIG. 3, and the same components are designated by the same reference numerals.

In the incinerator having the above structure, when the waste 2 is supplied to the rotary stoker incinerator 1 to be incinerated as in the conventional case, the waste 2 in the rotary stoker incinerator 1 is removed. Of the incineration ash 3 and the combustion exhaust gas 7 generated during combustion, the incineration ash 3 is transported to the ash melting furnace 4 by the ash transport conveyor 5, and is melted in the ash melting furnace 4 to be slag 6. On the other hand, the combustion exhaust gas 7 generated in the rotary stoker type incinerator 1 and having the waste heat recovered by the waste heat boiler 8 and the economizer 9 is the gas temperature reduction tower 11, which is provided in the exhaust gas line 10 as in the conventional case. Bug filter 1
2, when it is introduced into the chimney 16 after passing through the exhaust gas line 10 on the downstream side of the catalytic reaction tower 15 after being made into clean combustion exhaust gas 7 through the induction blower 13, the exhaust gas reheater 14, and the catalytic reaction tower 15. Then, when a part thereof is taken out to the exhaust gas branch line 39 and is injected from the injection nozzle 37 to the ash transport conveyor 5 through the exhaust gas branch line 39, the combustion exhaust gas 7 has a low oxygen concentration (oxygen concentration of about 6%). )
Therefore, the inside of the ash transport conveyor 5 is always kept under a low oxygen concentration atmosphere, and therefore, it is possible to eliminate the risk of ignition of unburned matter in the high temperature incineration ash 3. .

After the combustion exhaust gas 7 having a low oxygen concentration is filled in the ash conveying conveyor 5, the combustion exhaust gas 7 flowing out from the gas outlet 38 is driven by the blower 41 to pass through the gas recovery line 40 and the secondary combustion chamber 18 of the melting furnace. It is transported to and is incinerated.

As described above, according to the present invention, the ash transport conveyor 5 for transporting the high temperature incinerated ash 3 discharged from the rotary stoker incinerator 1 does not need to inject the nitrogen gas 36 as in the conventional case. Since it is possible to prevent the ignition of unburned substances in the incineration ash 3 and to prevent the occurrence of fire, it is possible to eliminate the need to attach a nitrogen gas generator to the waste treatment facility, thereby reducing equipment costs and running costs. It becomes possible to reduce.

Next, FIG. 2 shows, as another embodiment of the present invention, the pyrolysis residue transport as an unburned matter transport line in the pyrolysis gasification and melting treatment facility for wastes similar to that shown in FIG. The case where the present invention is applied to the conveyors 27a, 27b, and 27c is shown.

That is, as shown in FIG. 4, the downstream end of the pyrolysis residue extraction device 24 on the upstream side in the transport direction of the pyrolysis residue transport conveyor 27a as an unburned material transport line, the pyrolysis residue transport conveyor. Nitrogen gas 36 is supplied from a nitrogen gas generator (not shown) to the injection nozzles 37 provided in the downstream end of the transport direction of 27b and the downstream side of the pyrolysis residue transport conveyor 27c in the transport direction of the pyrolysis residue storage tank 34, respectively.
Nitrogen gas feed line 35 for connecting the
In place of the configuration in which the exhaust gas is injected, an exhaust gas branch line 39, which is provided by branching from the exhaust gas line 10 at the upstream side of the chimney 16, is connected to the pyrolysis residue transport conveyor 27.
a downstream end of the pyrolysis residue extraction device 24 that is upstream in the transport direction of a, the downstream end in the transport direction of the pyrolysis residue transport conveyor 27b, and thermal decomposition residue that is the downstream side in the transport direction of the pyrolysis residue transport conveyor 27c. The secondary combustion chamber 31 of the melting furnace 28 is connected to each injection nozzle 37 provided in the storage tank 34.
Is discharged from the exhaust gas and processed while passing through the exhaust gas line 10,
A part of the combustion exhaust gas 32 having a low oxygen concentration immediately before entering the chimney 16 is recovered through the exhaust gas branch line 39, and the pyrolysis residue transport conveyor 27 is supplied from the injection nozzles 37.
Blow into a, 27b, and 27c, respectively.

Further, the pyrolysis residue transfer conveyor 27 is used.
The blower 4 is provided on the way to the gas outlets 38 of a, 27b, and 27c.
The secondary combustion chamber 31 of the melting furnace 28 is connected via the gas recovery line 40 provided with 1, and each of the pyrolysis residue transport conveyors 27a, 27b, 27 is injected from the injection nozzle 37 and is injected.
Excessive amount of the combustion exhaust gas 32 that constantly fills c is sent from the gas outlet 38 through the gas recovery line 40 to the secondary combustion chamber 31 of the melting furnace 28 for incineration treatment.

The other structure is similar to that shown in FIG. 4, and the same components are designated by the same reference numerals.

According to the present embodiment, the pyrolysis kiln 21
When the high-temperature pyrolysis residue 23 generated by the pyrolysis in the pyrolysis residue extraction device 24 is transferred to the melting furnace 28 by the pyrolysis residue transfer conveyors 27a, 27b, and 27c, the pyrolysis residue transfer is performed. Conveyors 27a, 27b,
Combustion exhaust gas 3 having a low oxygen concentration extracted from the exhaust gas line 10 through the exhaust gas branch line 39 inside 27c.
Since 2 can be injected from the injection nozzle 37 and the inside of each of the pyrolysis residue transport conveyors 27a, 27b, 27c can be maintained under a low oxygen concentration atmosphere, as in the embodiment shown in FIG. It is possible to eliminate the risk of ignition of unburned substances in the thermal decomposition residue 23 without using the nitrogen gas 36, and thus to eliminate the need to attach a nitrogen gas generator to the thermal decomposition gasification and melting treatment facility for waste. As a result, it is possible to reduce equipment costs and running costs.

The present invention is not limited to the above-described embodiment, and the furnace may be an incinerator other than the rotary stoker incinerator 1 or a thermal decomposition furnace other than the thermal decomposition kiln 21. The furnace may be a furnace that treats materials other than waste 2 as a raw material for incineration or thermal decomposition, and further conveys high temperature unburned materials discharged from the furnace. If it is a line, it is applied to an unburned material transport line for transporting unburned materials other than the ash transport conveyor 5 for transporting the incinerated ash 3 and the thermal decomposition residue transport conveyors 27a, 27b, 27c for transporting the thermal decomposition residue 23. What you can do,
As the combustion exhaust gas to be blown into the unburned matter transport line, if the oxygen concentration is low, the combustion exhaust gas generated in combustion furnaces other than the secondary combustion chamber 31 of the rotary stoker incinerator 1 or the melting furnace 28 is used. Of course, various modifications may be made without departing from the scope of the present invention.

[0029]

As described above, according to the present invention, a low oxygen concentration combustion line is connected to the unburned material transfer line that is connected to the downstream side of the furnace and transfers the unburned material in a high temperature state taken out from the furnace. Fire prevention method for the unburned matter transfer line that blows in exhaust gas, and to guide the combustion exhaust gas discharged from the furnace to the chimney in the unburned matter transfer line that conveys the unburned material in the high temperature state taken out of the furnace An exhaust gas branch line branched from an intermediate position of the exhaust gas line is connected so that a portion of the low-oxygen concentration combustion exhaust gas can be blown into the unburned matter transport line through the exhaust gas branch line. Since this is a fire prevention device for the unburned material transfer line, it is possible to prevent ignition of unburned material inside the unburned material transfer line without using nitrogen gas, so a nitrogen gas generator is installed. To be able to eliminate the need, there is exhibited an excellent effect that it is possible to reduce the equipment cost and the running cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a fire prevention method and apparatus for an unburned material transport line of the present invention.

FIG. 2 is a schematic diagram showing another embodiment of the present invention.

FIG. 3 is a schematic diagram showing an example of a waste incineration facility that employs a conventional rotary stoker incinerator.

FIG. 4 is a schematic diagram showing an example of a thermal decomposition gasification and melting facility for waste that employs a conventional thermal decomposition kiln.

[Explanation of symbols]

1 Rotating stoker type incinerator (furnace) 3 Incinerated ash (unburnt matter) 5 Ash transport conveyor (unburnt matter transport line) 7 Combustion exhaust gas 10 Exhaust gas line 16 Chimney 21 Pyrolysis kiln (furnace) 23 Pyrolysis residue (unburned) 27a, 27b, 27c Pyrolysis residue transfer conveyor (unburned material transfer line) 32 Combustion exhaust gas 39 Exhaust gas branch line

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3K061 AA08 AB02 BA01 FA12 FA21                       PB02                 3K070 DA06 DA75 DA76                 3K091 AA09 BB06 CC12 GA02 GA14                       GA27 GA29

Claims (2)

[Claims] 1. An unburned material transfer line that is connected to a downstream side of the furnace and transfers unburned material in a high temperature state taken out from the furnace,
A fire prevention method for an unburned matter transportation line, which comprises blowing combustion exhaust gas having a low oxygen concentration. 2. An exhaust gas branch line branched from an intermediate position of an exhaust gas line for guiding combustion exhaust gas discharged from the furnace to a chimney, to an unburned material transfer line for transferring unburned materials in a high temperature state taken out from the furnace. And a part of the low-oxygen concentration combustion exhaust gas can be blown into the unburned matter transfer line through the exhaust gas branch line. Preventive device.