JPH09112857A - Refuse incinerating plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refuse incinerating plant which does not increase the operating cost by thermally decomposing waste plastic to recover it as fuel in view of the effective use of the waste plastic as high-calorie fuel, and utilizing it as thermal energy for melting the incinerated ash from an incinerating furnace. SOLUTION: The refuse incinerating plant comprises an incinerating furnace facility A, an incinerated ash melting facility B for melting the incinerated ash from the facility A, and a waste plastic gasifying facility C for thermally decomposing the waste plastic to recover the fuel gas from the plastic. The fuel gas recovered by the facility C is utilized as the fuel of the facility B to largely reduce the operating cost of the plant, and since the plastic which is difficult for its disposal is utilized as the fuel, it makes it possible to attempt to conduct the resource conservation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incineration plant that uses inflammable gas generated by thermally decomposing waste plastic as fuel for an incinerator ash melting furnace in a general municipal waste incineration facility discharged from homes. Regarding

[0002]

2. Description of the Related Art General combustible waste discharged from homes, including plastics, is collectively incinerated in a refuse incinerator, but the incineration ash discharged from the refuse incinerator has a limited volume reduction rate. However, securing dump sites is becoming increasingly difficult. Therefore, it is also attempted to reduce the volume by melting the incineration ash in an ash melting furnace and converting it into slag, but the thermal energy for melting the incineration ash becomes enormous, so the operating cost is too high. There is a point. Further, when plastics are burned in an incinerator, it is difficult to completely burn them, and high temperature causes burning of the furnace, which is not preferable and treatment of waste plastics has become a social problem.

The present invention focuses on the fact that waste plastic can be effectively used as a high-calorie fuel, and thermally decomposes the waste plastic to recover it as a fuel, and heat energy for melting the incineration ash. The purpose of the present invention is to provide a refuse incineration plant that does not require operating costs by utilizing the above.

[0004]

[Means for Solving the Problems] Incinerator facility, incinerator ash melting facility for melting ash from the incinerator, waste plastic gasification for thermally decomposing waste plastic and recovering fuel gas from the waste plastic The facility is characterized in that the fuel gas recovered in the waste plastic gasification facility is used as fuel in the incineration ash melting facility.

[0005]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is an overall schematic view of a plant for carrying out the present invention. This plant is roughly classified into an incinerator facility A, an incinerator ash melting facility B, and a waste plastic gasification facility C.
And auxiliary equipment. The incinerator facility A used in the present invention is a well-known incinerator facility, and when the combustible waste other than the plastic carried in the combustible waste pit 2 is thrown into the incinerator 1 by the crane 3, the sliding stage fire is performed. While moving on the lattice 4, it is burned by itself. Then, the exhaust gas from the incinerator is treated by the heat recovery device 5 and the gas cooling device 6 to reduce the temperature of the gas and is treated by the exhaust gas treatment device 7 such as an electrostatic precipitator. Is used as the gas for the pyrolysis furnace, and the rest is diffused into the atmosphere from the chimney 9. On the other hand, the incineration ash discharged from the bottom of the incinerator 1 is conveyed to the storage tank 10 of the incineration ash melting facility B.

A known melting furnace 11 is used as the incineration ash melting facility. The illustrated one uses a rotary kiln. The incineration ash once stored in the storage tank 10 is put into the melting furnace 11 while being cut out in a fixed amount. And the melting furnace 1
By using the combustible gas from the waste plastic gasification facility C, which will be described later, as fuel for No. 1
It is heated to a high temperature of 1400 ° C., melted, converted into slag, reduced in volume, and discharged to the slag pit 13 by the slag conveyor 12. Exhaust gas from the melting furnace 11 is treated by an exhaust gas treatment device 7'through a heat recovery device 5'such as an air preheater to lower the temperature of the exhaust gas, and is attracted to a chimney 9 by an induction fan 8 '.

A known thermal decomposition apparatus is used for the waste plastic gasification facility. As shown, a known fluidized bed type pyrolysis furnace 14 is used. The waste plastic put into the thermal decomposition furnace 14 from the waste plastic storage tank 14a is agitated and mixed with the fluidized sand 14c fluidized by the incinerator exhaust gas blown from the air diffuser 14b provided at the bottom of the furnace, and the waste plastic The amount of combustion of the oxygen is controlled to maintain the temperature in the furnace at 600 to 800 ° C. and decomposes into hydrocarbon gas and solid carbon by thermal decomposition. Then, the hydrocarbon gas is mixed with the exhaust gas from the incinerator to be 2000 to 3000 Kca.
It becomes a combustible gas of 1 / Nm ³ and is supplied as fuel to the melting furnace 11 through the cooling device 6.

The incinerator exhaust gas blown from the above-mentioned air diffuser 14b has a low oxygen concentration in the exhaust gas at the place where it leaves the induction fan 8 and has a width of 3 to 6%.
The oxygen concentration is controlled to 6 to 8% according to the temperature in the furnace by supplying air into the exhaust gas by means of 6, and the pressure is increased to 1500 to 2000 mm of water column by the pressure boosting blower 17. The solid carbon generated by the thermal decomposition is the fluidized sand 14c.
At the same time, it is discharged to the outside of the furnace through the discharge pipe 14d, passed through the sieve 15, separated from the fluidized sand 14c, and conveyed to the incineration ash storage tank 10. The fluidized sand 14c is returned to the furnace 14 and reused.

[0009]

EFFECTS OF THE INVENTION According to the present invention, the waste plastic which is difficult to dispose is pyrolyzed and recovered as a gas fuel and used as the fuel for the incinerator ash melting furnace. It is extremely effective as a resource.

[Brief description of the drawings]

FIG. 1 is an overall schematic view of a plant of the present invention.

[Explanation of symbols]

1 Incinerator 2 Combustible Waste Pit 3 Crane 4 Sliding Stage Grate 5 Heat Recovery Device 6 Gas Cooling Device 7 Exhaust Gas Treatment Device 8 Induction Fan 9 Chimney 10 Storage Tank 11 Melting Furnace 12 Slag Conveyor 13 Slag Pit 14 Fluidized Bed Type Pyrolysis Furnace 14a Waste plastic storage tank 14b Air diffuser 14c Fluidized sand 14d Discharge pipe 15 Sieve 16 Air blower 17 Booster blower A Incinerator facility B Incinerator ash melting facility C Waste plastic gasification facility

Claims (4)

[Claims] 1. An incinerator facility (A), an incinerator ash melting facility (B) for melting incinerator ash from the incinerator facility, and a pyrolysis of waste plastic to recover fuel gas from the waste plastic. And a waste plastic gasification facility (C) for using the fuel gas recovered in the waste plastic gasification facility as a fuel for the incineration ash melting facility. 2. The refuse incineration plant according to claim 1, wherein the melting furnace (11) in the incineration ash melting facility according to claim 1 is a rotary kiln. 3. The waste incineration plant according to claim 1 or 2, wherein the waste plastic pyrolysis apparatus used in the ash plastic gasification facility according to claim 1 is a fluidized bed pyrolysis furnace. 4. The oxygen concentration of the exhaust gas from the incinerator facility is increased, and the gas is supplied to the fluidized sand (14) of a fluidized bed pyrolysis furnace (14).
The refuse incineration plant according to claim 3, which is used as the fluidizing gas of c).