JPH01260206A - Waste material incinerator - Google Patents

Abstract

PURPOSE:To perform a stable combustion while attaining some advantages of a fluidized bed type incinerator by a method wherein a combustion in the fluidized bed type incinerator is separated into a front stage and a rearward stage, an combustion processing such as a thermal decomposition and the like is carried out at the front stage and a uniform combustion such as cracked gas and the like is ignited at the rearward stage. CONSTITUTION:A first combustion chamber 1 is provided with a gas dispersion pipe 5. An upper part of the first combustion chamber 1 is provided with a fluidizing medium feeding port 6 and a waste material feeding port 7. A second combustion chamber 2 is arranged adjacent to the first combustion chamber 1 so as to communicate with an opening 12 and an injection flow nozzle 13 is arranged at a bottom part. An upper part of a second combustion chamber 2 forms a riser 14 for performing a post- combustion of waste material. An upper part of the riser 14 is connected to a cyclone 18 for use in recovering fluidized bed medium. The waste material dried and thermally decomposed in the first combustion chamber 1 is moved to the second combustion chamber 2 together with the fluidized medium, shows a complete combustion with air fed from the nozzle 13 while being blown up and the fluidized medium is collected at a cyclone 18 and then returned back to the first combustion chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a novel waste incinerator that can absorb fluctuations in the amount of waste supplied and perform stable combustion with good thermal efficiency.

"Prior Art" Conventionally, the following fluidized bed incinerator has been known as a waste incinerator for the purpose of incinerating waste such as municipal garbage.

In other words, a fluidized bed incinerator blows out air from an internal aeration pipe, supplies waste and a fluid medium such as sand above the aeration pipe, and flows the waste and fluid medium above the aeration pipe. The waste is thermally decomposed and combusted while the waste is being oxidized, and the non-combustible materials are taken out along with the fluidized medium from the outlet provided below the air diffuser pipe. It is to be supplied again on top of.

"Problems to be Solved by the Invention" The fluidized bed incinerator described above has the advantage of having a large heat capacity, allowing the incineration residue to heat up quickly and causing less loss. Stabilization is difficult, for example, immediately after a large amount of waste is introduced, it instantly thermally decomposes and burns, producing a large amount of decomposed gas.
There is a problem that the amount of air supplied cannot keep up with this large amount of decomposed gas, and the decomposed gas and soot are discharged to the outside as they are.

The instability of combustion caused by fluctuations in the waste supply 1 can be avoided by injecting the waste into a part of the furnace where there is little change in flow and causing slow combustion, but this method However, there is a limit and it cannot deal with large fluctuations in the supply amount, resulting in unstable combustion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a waste incinerator that can perform stable combustion while taking advantage of the advantages of a fluidized bed incinerator.

"Means for Solving the Problems" In the present invention, air is injected from an internally provided aeration pipe to fluidize the fluid medium located above and the waste to be thrown in, thereby drying the waste. A fluidized bed section that performs thermal decomposition and partially incinerates the waste and discharges noncombustibles contained in the waste from a lower outlet; , a circulating fluidized bed section in which the partially incinerated waste is blown upward by air supplied from a lower nozzle together with a fluidized bed for post-combustion; It is characterized by being equipped with a cyclone that returns the water to the layer.

"Operation" The waste input into the fluidized bed section is fluidized together with the fluidized medium, and is dried, thermally decomposed, and partially incinerated by the reaction heat of the waste and the return heat of the fluidized medium.

The dried, thermally decomposed waste is then transferred to the circulating fluidized bed section, where it is blown up with the fluidized medium by air, and is efficiently combusted while passing through the upper riser of the circulating fluidized bed section or the circulation path following it. be done. Unburnt gas in the fluidized bed is drawn into the riser through openings or gas channels and is simultaneously combusted.

The fluidized medium blown up in the circulating fluidized bed section is collected by a cyclone and returned to the fluidized bed section.

"Example" Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The drawing shows a schematic configuration of the entire incinerator according to the present invention. As can be seen from this drawing, the combustion chamber of this incinerator consists of a first combustion chamber (fluidized bed section) l and a second combustion chamber (circulating fluidized bed section). )
It is divided into 2.

At a position slightly lower than the center in the height direction of the first combustion chamber 1, a plurality of air diffusers 5 (only one is shown in the figure) are provided so as to extend parallel to each other and horizontally.
A fluidized medium inlet 6 and a waste inlet lower are provided on the upper furnace wall or ceiling.

A fluidizing air supply pipe 9 is connected to the aeration pipe 5 via a header 8 (extending in a direction perpendicular to the plane of paper in the figure), and the air sent from the fluidizing air supply pipe 9 is transferred to the aeration pipe 5.
It is ejected from a nozzle provided in the aeration pipe 5 to fluidize the waste and fluidized medium such as sand to form a fluidized bed. A dust feeder 10 is connected to the waste input lower, so that waste is continuously input into the first combustion chamber l.

At the lower end of the furnace, an outlet la is provided for discharging the fluidized medium flowing down from between the diffuser pipes 5 and incombustibles contained in the waste.
A discharge machine (not shown) such as a screw conveyor is connected to this outlet 1a. The discharging machine is connected to a classifier that separates non-combustibles and fluid media, and the non-combustibles separated by the classifier are discharged to the outside, while the fluid media that has been separated and recovered is transferred to a circulation line such as a conveyor. Said input port 6
Alternatively, it is returned to the first combustion chamber 1 from another input port.

The second combustion chamber 2 is provided adjacent to the first combustion chamber 1,
An opening 1 formed below a partition wall 11 that separates the two
They communicate with each other via 2.

A jet nozzle 13 is disposed at the bottom of the second combustion chamber 2, and is connected to the flowing air supply pipe 9. The air jetted from the jet nozzle 13 causes the second
The waste and fluid medium in the combustion chamber 2 are blown upwards as shown in the figure.

Further, a riser 14 is formed above the second combustion chamber 2, which has a slightly smaller diameter than the second combustion chamber 2 but is wide enough to post-combust the waste.

The intermediate portion of the riser 14 is also connected to the first combustion chamber 1 via a gas flow path 16 in which a damper 15 is interposed.

The top of riser 14 is connected to cyclone 18 .

In the cyclone 18, the fluidized medium blown up together with the waste in the second combustion chamber 2 is recovered. The lower part of the cyclone 18 is connected to a fluidized medium feeder 20 via a fluidized medium return pipe 19, and the tip of the fluidized medium feeder 20 is connected to the inlet 6 in the furnace wall of the first combustion chamber.

A heat exchanger 22 is provided at a portion where the exhaust pipe 21 connected to the upper part of the cyclone 18 and the fluidizing air supply pipe 9 overlap, and thereby the heat of the high-temperature gas discharged from the exhaust pipe 21 is recovered.

Next, the operation of the waste incinerator having the above configuration will be explained.

Waste is supplied from the dust supply device 10 to the first combustion chamber 1 via the input lower, while a fluid medium such as sand is supplied to the first combustion chamber 1 from the circulation line. Further, fluidizing air is ejected from the aeration pipe 5 to fluidize the waste and the fluidization medium on the aeration pipe 5.

The fluidizing medium is heated by the heat of reaction of the wastes and sequentially dries, thermally decomposes and partially burns the wastes.

In this way, when waste is subjected to processing such as drying or thermal decomposition in the first combustion chamber l, by adjusting the damper 15, the amount of air supplied to the first combustion chamber l is too large and the waste is It is possible to prevent complete combustion from occurring or, conversely, from being unable to thermally decompose the waste as desired due to too small an amount of supplied air.

Note that the adjustment of the damper is performed using the opening 12 below the partition wall 11.
This can also be done automatically by installing a gas sensor in the combustion chamber and determining whether or not processing such as thermal decomposition, which is the first stage of combustion, is being performed normally on the waste.

In the second combustion chamber 2, the fluidized medium above the jet nozzle 13 is constantly blown up by the air supplied from the nozzle 13, so when looking at the combustion chamber as a whole, the upper fluidized bed is A flow is formed that moves from the combustion chamber 2 to the second combustion chamber 2. Due to this fluidized bed flow, the pyrolyzed waste is transferred together with the fluidized medium to the second combustion chamber 2, where the nozzle! The air supplied from 3 is blown upward together with the fluidizing medium. And the second combustion chamber 2
The gas generated by the decomposition of the waste in the upper part of the riser 14 and in the riser 14 is completely combusted, and at the same time, unburned components scattered in the gas are also combusted.

The fluidized medium blown up is collected by the cyclone 18 and returned to the first combustion chamber l via the return pipe 19 and the fluidized medium feeder 20.

On the other hand, the incombustibles are discharged together with the fluidized medium from the outlet 1a in the lower part of the furnace, and the separated fluidized medium is returned to the first combustion chamber 1.

"Effects of the Invention" As explained above, according to the present invention, the waste introduced into the fluidized bed section is fluidized together with the fluidized medium, dried, thermally decomposed, and partially incinerated. The dried, pyrolyzed, etc. waste is then transferred to the circulating fluidized bed section, blown up by air together with the fluidized medium, and is afterburned as it passes through the circulating fluidized bed section or the following circulation path.

In this way, combustion is separated into the first stage and the second stage, and combustion processing such as thermal decomposition is performed slowly in the fluidized bed section of the first stage, absorbing fluctuations in the amount of waste supplied, and the circulating fluidized bed section of the second stage is carried out slowly. At this point, the decomposed gas, etc. burns evenly, resulting in stable combustion with little generation of NOx and pollutants. As a result, stable combustion can be achieved even if there is some fluctuation in the amount of waste supplied.

[Brief explanation of the drawing]

The drawing is a diagram showing a schematic configuration of an incinerator showing an embodiment of the present invention. l...First combustion chamber (fluidized bed section), la...
...Outlet, 2...Second combustion chamber (circulating fluidized bed section), 5...
... air diffuser, 13... nozzle, l8... cyclone. Applicant Ishikawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] Air is injected from the air diffuser installed inside to fluidize the fluid medium located above and the waste to be thrown in.
There is a fluidized bed section that dries, thermally decomposes, and partially incinerates the waste, and discharges incombustible materials contained in the waste from a lower outlet. a circulating fluidized bed section in which the dried, thermally decomposed, and partially incinerated waste is blown upward with a fluidized medium by air supplied from a lower nozzle for post-combustion; and a fluidized medium blown up in the circulating fluidized bed section. a cyclone that collects and returns the waste to the fluidized bed section.