JPS59183209A - Fluidized-bed combustion method for refuse containing large amount of waste plastic - Google Patents

Abstract

PURPOSE:To simplify a refuse carrying device and to improve the quality of combustion, by a method wherein refuse, decreased in volume, is fed to a fluidized-bed furnace. CONSTITUTION:Mixture of high temperature fluidized medium, such as silica sand, discharged from a fluidized-bed furnace 1, and an incombustible substance is fed to a separating device 2 such as vibratory screen to separate the high temperature fluidized medium from an incombustible substance. The high temperature fluidized medium is fed to a mixer 3 where the medium is mixed with refuse cintaining a large amount of waste plstic and the mixture is agitated. The waste plastic is brought into contact with the heated fluidized medium, and is softened and decreased in volume, and the fluidized medium is adhered thereto to produce the granulated mixture of the fluidized medium, the softened waste plastic, and the refuse, the refuse is increased in apparant specific gravity and decreased in volume, and can be suplied in a determined quantity. The mixture, granulated by the mixer 3, of the fluidized medium, the waste plastic, and the refuse is fed to a feeder 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently and safely burning waste containing a large amount of waste plastic in a fluidized bed furnace.

When waste containing a large amount of waste plastic is burned in a fluidized bed furnace, the waste plastic has a small apparent specific gravity. That is, since the volume per weight is large and bulky, there are problems in that the transport device becomes large and it is difficult to supply a fixed amount. Furthermore, since bulky items are handled, it is difficult to seal the inside of the furnace, and the gas from inside the furnace melts and gasifies the waste plastic at low temperatures, sometimes causing backfire problems.

The present invention has been made to solve the above problems, and involves forcibly extracting a fluidized medium such as high-temperature silica sand heated from a fluidized bed furnace from the bottom of the furnace.
0 to 300°C) and garbage containing a large amount of waste plastic to soften, melt, and melt the thermoplastic.
By shrinking the entire waste to increase its specific gravity, i.e., reduce its bulk, and supplying this increased specific gravity to a fluidized bed, the waste conveyance device is simplified and the combustibility is improved. The present invention aims to provide a fluidized bed combustion method for waste containing a large amount of waste plastic.

Hereinafter, the configuration of the present invention will be explained based on the drawings.

In FIG. 1, a mixture of a fluidized medium such as high-temperature silica sand and incombustibles discharged from a fluidized bed furnace 1 is sent to a separator 2 such as a vibrating sieve, where it is separated into a high-temperature fluidized medium and incombustibles. The high-temperature fluid medium is sent to mixer B, where it is mixed and stirred with garbage containing a large amount of waste plastic.

Since most waste plastics soften at temperatures above about 100°C, this property can be used to add a fluid medium heated to 150 to 300°C to the waste plastics as described above to soften the waste contained in the waste. Softens and melts plastic,
Reduce the size and increase the apparent weight of garbage. In other words, the waste plastic comes into contact with the heated fluidized medium, softens and shrinks, and the fluidized medium adheres to it, forming a granule of the fluidized medium, softened waste plastic, and garbage, and the apparent specific gravity of the garbage decreases. This height reduces the bulk, making it possible to supply a fixed amount of waste. In mixer B, the fluid medium is cooled by the moisture in the waste, and is sufficiently cooled when it is fed into the supply feeder 4. However, if the moisture in the waste is low, for safety reasons, the fluid medium is cooled near the outlet of mixer B. Inject water.

As the mixer 6, it is also possible to use a paddle mixer type mixer 6a as shown in FIG. 2 instead of the kiln type mixer as shown in FIG.

Gases such as water vapor and partially decomposed gas from waste plastics generated in the mixer 6 are sucked by the blower 5 and introduced into the combustion chamber (free board) 6 at the upper part of the fluidized bed furnace 1, where the decomposed gas from the waste plastics is absorbed. High-temperature oxidation decomposition of etc.

The mixture of the fluidized medium, softened waste plastic, and garbage, which has been turned into granules by the mixer 3, is sent to the supply feeder 4.

This mixture has a large apparent specific gravity, a small bulk, and is easily compacted in the supply feeder 4, which improves sealing performance, prevents flashback, and facilitates quantitative cutting. Also in the supply feeder 4,
Supply water or cooled air for cooling for safety.

In the consolidated mixture, since the fluidized medium is attached to and entangled with the waste plastic, the apparent specific gravity of the waste plastic itself becomes thicker and more likely to sink into the fluidized bed 7 of the fluidized bed furnace 1. , the combustion rate within the fluidized bed 7 increases, and operational operability can be further improved. 8 is an air distribution plate, 9 is a wind box, and 10 is a fluidized medium discharge device.

As explained above, the apparent specific gravity of waste containing waste plastics pretreated by the method of the present invention can be made much larger than that without pretreatment.
It is easy to transport, prevents backfire problems, and enables effective use of the entire fluidized bed instead of combustion only at the interface of the fluidized bed as in the past. The effect is that it is possible to achieve complete combustion of garbage containing waste plastics.

[Brief explanation of drawings]

FIG. 1 is a systematic explanatory diagram showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is an explanatory diagram showing another example of a mixer. 1... Fluidized bed furnace, 2... Separation device, 6.3a...
Mixer, 4... Supply feeder, 5... Blower, 6.
... Combustion chamber, 7... Fluidized bed, 8... Air distribution plate, 9
...Wind box, 10...Patent applicant for fluidized medium discharge device Makoto Shiide, patent attorney representing Kawasaki Heavy Industries, Ltd. -1・-'

Claims (1)

[Claims] 1 Pull out the high temperature fluidized medium from the bottom of the fluidized bed furnace,
The feature is that this high-temperature fluid medium is mixed with waste containing a large amount of waste plastic to soften, melt, and shrink the thermoplastic plastic, and then the waste with increased specific gravity is supplied to a fluidized bed furnace. Fluidized bed combustion method for waste containing large amounts of plastic.