JPH0735321A - Combustible waste treatment equipment - Google Patents

Abstract

(57) [Summary] [Purpose] In the treatment of flammable waste using a pyrolysis furnace, the provision of means that prevents the occurrence of ash fusion problems and enables stable operation. [Composition] When the combustible waste is pyrolyzed in the pyrolysis furnace and the pyrolysis residue is post-combusted in the post-combustion chamber, the generated gas outlet space of the pyrolysis furnace is connected to the space for post-combustion of the pyrolysis residue. A gas flow resistance is provided to the portion to be filled by a pyrolysis residue packed bed or a shutoff valve to prevent the gases in both spaces from mixing. In addition, the re-combustion chamber for combusting the generated gas when pyrolyzed and the post-combustion chamber for the residue can be arranged in the same furnace space. Further, the thermal decomposition furnace and the post-combustion chamber are connected via a residue transfer conveyor to maintain the residual heat as much as possible and facilitate ashing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention contains waste plastic, waste glass, aluminum cans, etc., and has a higher calorific value than general municipal waste, and is not suitable for incineration, or plastic, rubber, paper, wood waste, oil mud, waste oil. The present invention relates to a thermal decomposition treatment device for industrial waste containing a relatively large amount of heat.

[0002]

2. Description of the Related Art Conventionally, an apparatus for incineration using a rotary kiln-type incinerator for waste that contains waste plastic, waste glass, aluminum cans, etc. and has a higher calorific value than general municipal waste and is inappropriate for incineration For example, it is disclosed in "Cleaning Technique" issued in 1989, and has a device configuration in which a reburn chamber is constituted by a rotary kiln furnace bottom fixed hood, and a post combustion chamber is arranged below it.

FIG. 2 shows the device. As shown in the same figure, this device is a device in which a rotary kiln 3 and a stoker 4 are connected, a post combustion chamber 6 is formed immediately above the stoker 4, and a recombustion chamber 5 is connected to the upper part thereof. The high-temperature, low-oxygen combustion exhaust gas discharged from the electrostatic precipitator 8 by the exhaust gas recirculation fan 14 is charged into the space between the dust supply device 2 and the rotary kiln 3 from the upper part of the front hood of the rotary kiln 3 and the pushing fan 15 blows air. Is operated by a partial combustion system, that is, a suppression combustion system, in which air is introduced from an air port provided in the front hood of the rotary kiln 3.

The apparatus by the suppression combustion method charges combustion exhaust gas or air in the range of the oxygen amount equal to or less than the theoretical combustion oxygen amount, causes a part of combustible components to undergo a combustion reaction, and utilizes the generated heat to generate another gas. It is a method of thermally decomposing the combustible components of the above into combustible gas and thermal decomposition residue consisting of ash, incombustibles, fixed carbon, etc., which is difficult to apply to the conventional stoker type incinerator Compared to the case of direct burning, black smoke is generated because it has a lot of plastics and has applicability to waste that is not suitable for combustion and has a high calorific value. It is said to contribute to prolonging the life of the final waste disposal equipment, as it has the feature that it can effectively suppress fusion problems.

That is, when a substance having a large amount of gasification components such as plastics and oils is directly burned, not only the incomplete combustion which produces black smoke due to lack of oxygen but also the non-combustible content on the inner wall of the rotary kiln 3 due to local overheating is caused. However, the suppression combustion burns combustibles with a small amount of oxygen below the theoretical oxygen at a slow rate, so the combustion is stable, the furnace temperature is easily controlled, and local overheating is caused. There are no fusion problems.

In order to completely incinerate the combustibles by the suppression combustion system, fixed carbon contained in the pyrolysis residue is post-combusted in the post-combustion chamber 6 on the stoker 4 following the rotary kiln 3. The combustible gas generated in the rotary kiln 3 is burned by providing a heat source and combustion air to achieve complete combustion of combustible components.

That is, the heat radiation from the post-combustion on the stoker 4 is used as a heat source, and the combustion air is not sufficiently contacted only with the air charged from the lower part of the stoker 4, so the furnace temperature cooling fan 16 causes the combustion chamber 5 to enter the reburn chamber 5. Also, combustion air was sent in for complete combustion.

However, in the case of having such an apparatus structure, in the post combustion chamber above the stoker 4, which is the combustion space for the pyrolysis residue, the gas generated from the rotary kiln 3 is mixed and burned, and the pyrolysis is performed. Since the residue and the generated gas are preheated in the rotary kiln 3, this combustion is rapid.

[0009]

When the solid combustion and the gas combustion are in the same space as described above, the high temperature combustion cannot be performed in order to avoid the fusion trouble of the solid ash, but the high temperature combustion from the lower part of the stoker 4 is caused. When the pyrolysis residue is combusted with the supply air and the generated gas from the rotary kiln 3 is combusted with the surplus air, it is difficult to uniformly control the rapid combustion temperature and the temperature tends to be locally high. Is. Radiant heating due to this locally heated combustion flame has the disadvantage that clinker is generated by overheating and fusing the ash in the residue on the furnace bottom of the rotary kiln 3 and the stoker 4, This clinker makes continuous operation difficult.

In addition, this apparatus configuration is incapable of extracting the pyrolysis product gas, and there is a disadvantage that it cannot be used as fuel gas for heat utilization equipment such as a waste liquid incinerator.

The present invention solves the problem in the complete incineration of combustibles in the above-mentioned conventional suppression combustion system, and treats combustible wastes which can be burned at high temperature without fear of fusion problems due to generated gas. To provide a device.

[0012]

The apparatus for treating combustible waste according to the present invention is a combustible waste in which the combustible waste is pyrolyzed in a pyrolysis furnace and the pyrolysis residue is post-combusted in a post-combustion chamber. In the treatment device of No. 3, the flammable waste is disposed by providing a gas flow resistance by the packed bed and / or shutoff valve of the pyrolysis residue at the part connecting the gas outlet space of the pyrolysis furnace and the space for post-combustion of the pyrolysis residue. It is characterized in that the generated gas generated when the substance is thermally decomposed and the combustion exhaust gas generated when the thermal decomposition residue is post-combusted are not mixed gas.

Further, it is possible to adopt a structure in which the re-combustion chamber for combusting the generated gas generated during the thermal decomposition and the post-combustion chamber for the thermal decomposition residue are arranged in the same furnace space.

[0014]

According to the present invention, the pyrolysis space and the post-combustion space are separated by the connection portion, and the connection portion is provided with gas flow resistance. Therefore, the generated gas generated when the combustible waste is pyrolyzed And the combustion exhaust gas generated when the pyrolysis residue is post-combusted do not become a mixed gas, and the generated gas can be taken out of the thermal decomposition furnace and effectively used as fuel gas for other processes. High temperature combustion is possible without worrying about fusion problems.

When the thermal decomposition residue is discharged and transferred from the thermal decomposition furnace to the post combustion chamber of the thermal decomposition residue, the thermal decomposition residue is not exposed to the atmosphere, is not directly cooled by water, and is temporarily stored in a storage tank. Ashing in the post-combustion chamber by maintaining the heat of the pyrolysis residue at the outlet of the pyrolysis furnace as much as possible by connecting the pyrolysis furnace and the post-combustion chamber of the pyrolysis residue via the pyrolysis residue transfer conveyor without It contributes to high temperature combustion, reduction of exhaust gas amount, improvement of heat recovery efficiency, and suppression of unburned matter.

Further, in the case where the re-combustion chamber for burning the generated gas produced in the pyrolysis furnace is arranged in the same furnace space above the post combustion chamber, the generated gas and the pyrolysis residue are separated from each other. Since the combustion air is used for combustion, each can be controlled to an optimum state. That is, the lower pyrolysis residue combustion is burned at a relatively low temperature at which ash does not fuse, and the gas burner in the upper reburn chamber is located at a position where radiation of the gas combustion flame does not lead to local overheating of the residue. Since it is possible to make the gas combustion high temperature combustion by arranging
The fusion trouble can be effectively prevented, and even if an unburned component is generated in the lower residue combustion, the complete combustion can be performed in the upper gas combustion space.

Further, since the residue combustion in the lower part is subjected to the radiant heating of the gas combustion from the upper part, the combustion of the residue can be promoted and the residue can be completely incinerated.

[0018]

FIG. 1 shows an embodiment of the present invention.

In the figure, reference numeral 1 denotes a dust hopper, which communicates with a dust throwing device 2 at a lower portion. This dust throwing device 2 is provided with a hydraulic unit 19 which operates to adjust the amount of waste fed into the kiln.

A rotary kiln 3 has a vertical pyrolysis residue filling layer 20 connected to the lower part of the furnace bottom fixed hood, and a pyrolysis residue transfer conveyer 21 is connected to the lower part thereof, and the transfer conveyer 21 is a stoker. After arranging 4 is connected to the combustion chamber 6.

The residue filling layer 20 and the residue transfer conveyor 21 have a function of transferring the residue by connecting the rotary kiln 3 which is a pyrolysis furnace, the stoker 4 for post-combusting the pyrolysis residue and the post-combustion chamber 6, and the gas flow resistance. Has a function of preventing the gas generated in the rotary kiln 3 and the combustion exhaust gas obtained by post-combusting the pyrolysis residue from becoming a mixed gas.
The shut-off valve 27 provided to shut off the outlet side opening of the transfer conveyor 21 may have the above function.

The stoker 4 in the post combustion chamber 6 is an ash cooling device 17
The ash 18 is discharged from the ash cooling device 17 which has been water granulated and cooled.

Reference numeral 5 denotes a reburn chamber in which a gas burner 23 is arranged.

The gas burner 23 is a rotary kiln 3
Combustible gas generated from the above is taken out from the upper part of the furnace butt fixing hood via the cyclone 22 and is air-mixed and burned by the combustion air from the pushing fan 15 and can be burned at a high temperature for gas combustion.

Further, the flame radiation of the high temperature air combustion reaches the lower stoker 4, promotes the post combustion of the pyrolysis residue, brings about complete ashing, and the boiler 7 forming the wall of the reburn chamber 5 Heat is effectively removed from the water cooling wall.

Further, even if unburned gas is generated in the post combustion of the pyrolysis residue, the unburned gas can be completely burned in the high temperature gas combustion zone provided in the upper space.

In the boiler 7, after cooling the high temperature combustion exhaust gas, the electrostatic precipitator 8, the economizer 9, the attracting fan 1
3, the cooling absorption tower 10 and the gas reheater 11 are discharged from the chimney.

As shown in FIG. 1, the combustible gas taken out from the upper part of the furnace bottom fixing hood of the rotary kiln 3 is partially branched by the high temperature gas duct connected to the outlet of the cyclone 22, and the front fixing hood of the furnace is connected via the steam ejector 24. By providing the external circulation duct 25 connected to the gas burner 26 provided in the above, it is possible to further stabilize the suppression combustion, improve the gasification rate of combustibles, and reduce the amount of residue burned.

That is, since a part of the combustible gas discharged from the rotary kiln is combusted with the air from the forced draft fan 15 and the gas burner 26, most of the amount of heat required for the thermal decomposition of the combustible component is generated in the rotary kiln 3. Since it can be supplied with stable burner combustion, the temperature T _{1 at the} rotary kiln outlet can be easily controlled by adjusting the amount Q _{2 of} combustible gas circulated outside and the amount Q ₁ of air supply, and the exhaust gas of conventional high temperature and low oxygen is circulated. More stable suppression combustion than the method used.

In addition, the suppressive combustion by the gas burner combustion can suppress rapid coking of the combustible material without solid combustion in the vicinity of the combustible material, and as a result, highly efficient gasification can be achieved. Gasify in a rotary kiln.

Furthermore, in the present embodiment, as the thermal decomposition furnace, the suppression combustion rotary kiln in which the combustible waste is partially combusted with the interposition of oxygen gas and thermally decomposed is described, but the combustible waste is shielded from the oxygen gas. It goes without saying that the same operation and effect as the suppression combustion furnace of the present embodiment can be achieved by a dry distillation furnace such as a dry distillation rotary kiln and a dry distillation vertical type packed bed furnace that are heated and pyrolyzed in this state.

[0032]

The present invention has the following effects.

(1) When the pyrolysis furnace and the post-combustion space are separated and the connection has a gas flow resistance, when the combustible waste is pyrolyzed, the generated gas and the pyrolysis residue are post-combusted. The produced combustion exhaust gas does not become a mixed gas.

(2) Since the pyrolysis furnace and the post-combustion space are separated, stable long-term continuous operation can be performed without causing fusion problems due to the conventional connecting portion being a communication space.

(3) The combustible gas is separated from the pyrolysis furnace in a state where it is not mixed with the combustion exhaust gas of the pyrolysis residue and taken out,
It can be effectively used as a fuel gas for other processes.

(4) Although the pyrolysis furnace and the post-combustion space are separated, the residue generated from the pyrolysis furnace can be supplied to the post-combustion chamber without cooling, so that the residue can be completely combusted and ashed. .

(5) A re-combustion chamber for burning combustible gas generated in the pyrolysis furnace is disposed in the upper space of the post-combustion chamber, and the radiant heating of gas combustion is used to accelerate the combustion of the residue. , Can be completely incinerated.

(6) The re-combustion chamber for burning the combustible gas generated in the pyrolysis furnace is disposed in the upper space of the post-combustion chamber, and the upper gas combustion is performed at high temperature, so that the lower residue post-combustion is performed. Even if unburned components are generated, complete combustion can be performed in the upper gas combustion space, and high temperature combustion by this contributes to reduction of exhaust gas amount and improvement of heat recovery efficiency.

[Brief description of drawings]

1 shows the overall equipment for carrying out the invention.

FIG. 2 shows a prior art example.

[Explanation of symbols]

1 Garbage hopper 2 Garbage feeder 3 Rotary kiln 4 Stoker (grate) 5 Reburning chamber 6 Post-combustion chamber 7 Boiler 8 Electric dust collector 9 Economizer 10 Cooling absorption tower 11 Gas reheater 12 Chimney 13 Induction fan 14 Exhaust gas recirculation fan 15 Pushing fan 16 Reactor cooling fan 17 Ash cooling water tank 18 Ash of waste 19 Hydraulic unit 20 Pyrolysis residue packed bed 21 Pyrolysis residue transfer conveyor 22 Cyclone 23 Gas burner 24 Steam ejector 25 External circulation duct 26 Gas burner 27 Blocking valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Mitarai 59 Nippon Steel Plant Design Co., Ltd., 46 Nakahara, Tobata-ku, Kitakyushu, Fukuoka

Claims (2)

[Claims] 1. A treatment apparatus for flammable waste, which thermally decomposes flammable waste in a pyrolysis furnace and post-combusts the pyrolysis residue in a post-combustion chamber, in a gas outlet space of the pyrolysis furnace and the pyrolysis. A gas flow resistance is provided by a pyrolysis residue packed bed and / or a shutoff valve at the part connecting with the space for post-combustion of the residue, and post-combustion of the gas generated when the combustible waste is pyrolyzed and the pyrolysis residue The combustible waste treatment device is characterized in that the combustion exhaust gas generated at that time is prevented from becoming a mixed gas. 2. An apparatus for treating flammable waste, which thermally decomposes combustible waste in a pyrolysis furnace and post-combusts the pyrolysis residue in a post-combustion chamber, with a gas outlet space of the pyrolysis furnace and the pyrolysis. A recombustion chamber in which a gas flow resistance is provided by a pyrolysis residue packed bed and / or a shutoff valve at a portion connecting with a space for post-combustion of the residue, and the generated gas produced when the combustible waste is pyrolyzed is combusted. An apparatus for treating combustible waste, characterized in that the post combustion chamber of the pyrolysis residue and the post combustion chamber are arranged in the same furnace space.