JPH1122934A - Waste gasification and melting furnace - Google Patents

Abstract

(57) [Problem] To provide a furnace capable of keeping a fixed bed (moving bed) layer height level of a gasification melting furnace constant. SOLUTION: This is a waste melting furnace in which the upper part of a sedimentary layer composed of waste and auxiliary materials is a fluidized bed and the lower part is a moving bed (fixed bed), and an armored pipe 2 for supplying auxiliary materials from the upper part of the furnace. And the lower end of the deposition position when the auxiliary material discharged from the charging pipe tip is deposited blows a fluid medium for flowing the upper part of the deposition layer. A waste gasification / melting furnace arranged to be lower than the position of No. 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upper fluidized bed waste gasification and melting furnace for directly melting and processing waste.

[0002]

2. Description of the Related Art In an upper fluidized waste gasification and melting furnace, the waste to be charged into the furnace is dried and thermally decomposed in an upper fluidized portion, and is burned and melted in the lower part of the furnace to produce incombustible waste. Is discharged out of the furnace as slag.

[0003] The waste gasification and melting furnace is a shaft type furnace as shown in FIG. 2. The lower part of the furnace has a shaft part for storing the deposited waste and the deposit composed of the auxiliary materials, and the upper part thereof has a shaft part. Has a large space for raising the temperature of the generated gas to reform the gas properties (Japanese Patent Laid-Open No. 5-34621).
8, JP-A-5-346220).

[0004] In addition, the charged waste is dried, pyrolyzed,
It has a multistage (usually three-stage) air outlet (tuyere) for burning and melting. Coke and limestone are used as auxiliary materials for melting the waste.

The main tuyere 7 installed near the bottom of the furnace forms a high-temperature melting zone in the furnace by adding oxygen to melt the non-combustible portion of the waste. Tuyere (sub tuyere) 8 installed in the middle stage
Blows air to which steam is added to dry and thermally decompose waste while flowing the sedimentary layer. The combustion air supplied from the three-stage tuyere 9 installed in the upper stage combusts the generated gas and suppresses the generation of dioxin by maintaining the gas temperature at about 1000 ° C.

[0006] In the waste gasification and melting furnace, it is necessary to control the level of the fixed layer (moving layer) portion of the sedimentary layer in order to convert incombustible waste into molten slag. When the level of the fixed layer (moving layer) portion is low, heat exchange becomes insufficient, so that the melting temperature decreases and slag does not occur. When the level of the fixed layer portion becomes higher and becomes higher than the level above the sub tuyere, a high temperature region is formed at the tip of the sub tuyere, a clinker is generated, and troubles such as hanging on a shelf occur. For this reason, the level of the fixed layer was measured by a sounding device.

[0007]

In a waste gasification / melting furnace, a sounding device has been used as a method for measuring the level of a fixed bed. However, the level of the fixed bed can be accurately measured based on the state of waste in a flowing part. In many cases, the sounding wire was exposed to high temperatures, and it was necessary to replace the wire, which was easily broken. In addition, it has been difficult to measure accurately over a long period of time even with other measurement methods due to deposits on the furnace wall and blockage of the measurement port.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described difficulty in measuring a fixed bed, and has a fixed bed portion level in a sedimentary bed in an upper fluidized bed waste gasification / melting furnace. Furnace structure.

[0009]

The waste gasification and melting furnace of the present invention is a waste melting furnace in which the upper part of a sedimentary layer consisting of waste and auxiliary materials is a fluidized bed and the lower part is a moving bed (fixed bed). ,
An armored pipe is provided from the upper part of the furnace to supply auxiliary materials, and the position of the tip of the charging pipe is set at the lower end of the stacking position when the auxiliary material discharged from the charging pipe is deposited. It is arranged so as to be lower than the position of the air outlet for blowing the fluid medium for flowing the sedimentary layer (FIG. 1).

[0010] In this case, the operation method is such that the auxiliary material is supplied from the auxiliary material-incorporated pipe without directly passing through the fluidized portion in the waste gasification and melting furnace according to claim 1. The operation is performed so as to maintain the auxiliary material level in the pipe at a predetermined position.

When the auxiliary material is consumed in the main tuyere portion, the height of the fixed layer decreases. When the height of the fixed bed decreases, a space opens between the charging pipe and the fixed bed, so that new auxiliary materials are supplied from the charging pipe maintained at a predetermined level so as to fill the space. Is supplied with the waste carbide that accumulates in the wastewater.

Since the newly supplied auxiliary material spreads at a specific angle, the level of the fixed layer is the same as the level before the auxiliary material was consumed. Therefore, without directly measuring the level of the fixed bed, it is possible to always keep the level of the fixed bed constant by maintaining the level of the auxiliary material in the charging pipe at an appropriate level.

[0013] This makes it possible to stably melt the waste without changing the heat exchange conditions in the fixed bed portion. Also,
Since no coke is supplied to the flowing portion, no coke is consumed by the combustion air supplied from the sub tuyere.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. This waste melting furnace has a sedimentary layer composed of waste and auxiliary materials on the shaft part at the lower part of the furnace, and the sedimentary layer is composed of an upper fluidized part 4 and a lower fixed layer (moving layer) part 5.
Consisting of The upper part of the melting furnace is a large space and is called a free board part 3.

The waste is supplied from a waste supply port 1 below the side surface of the free board, and the auxiliary material is supplied from a charging pipe 2 charged from the furnace top. In the present embodiment, the tip position of the armored tube is at the same level as the sub tuyere 8. In addition, municipal solid waste was used, and coke and limestone were used as auxiliary materials.

The combustion air is blown into the furnace from tuyeres provided in three stages on the side wall of the melting furnace. The supplied waste is dried and carbonized by the combustion air supplied from the sub tuyere 8.
The superficial velocity is controlled so that this portion becomes a fluidized bed, and the temperature in the layer is controlled to be approximately uniform and about 600 ° C. Therefore, the plastic in the waste that softens and fuses at low temperature does not cause ventilation failure or hanging on the shelf. In addition, since the properties of the carbonized waste in the fluidized portion are stable, stable operation is possible in the molten portion at the lower part of the furnace. The waste carbonized in the fluidizing section forms a fixed bed (moving bed) 5 at the lower part of the furnace together with auxiliary materials supplied from the charging pipe. Main tuyere 7
The combustibles and coke of the waste in the fixed bed are burned by the combustion air added with oxygen from the blown air to form a high-temperature combustion region of 2000 ° C. or more near the main tuyere, and the residue of the dry distillation of the waste is formed. And the sub-materials fall into the hot combustion zone. In this process, the high-temperature gas generated by the combustion exchanges heat with the solid matter, and the temperature gradually rises until the incombustible matter melts. In the present embodiment, the distance between the main tuyere and the tip of the charging tube 2 was set to 1.6 m.

The layer height was controlled by the sounding device 11 only for the auxiliary material in the charging pipe 2. 1 in 15 minutes
The level of the auxiliary material supplied into the charging pipe is measured from the tip of the charging pipe 2 by 3 to 3.5.
m.

Since the dry distillation residue and the auxiliary materials of the supplied waste were constant and the fixed bed level was constant, stable melting treatment was possible. The melt drops between the solids and accumulates at the bottom of the furnace. The accumulated melt is 1 from the slag port 6.
Discharged once every hour. Melt temperature is 1450
〜1550 ° C.

[0019]

[Effect of the Invention] Even if the level of the fixed layer is not directly measured,
By maintaining the level of the secondary material in the charging pipe at an appropriate level, the level of the fixed bed can always be kept constant. Thereby, the stable melting treatment of the waste can be performed without changing the heat exchange conditions in the fixed bed portion. Further, since no coke is supplied to the flowing portion, no coke is consumed by the combustion air supplied from the sub tuyere.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory view of a conventional general waste gasification and melting furnace.

[Explanation of symbols]

2 ... charging tube, 4 ... fluidized section, 5 ... fixed bed (moving bed), 7 ...
Main tuyere, 8 ... sub tuyere, 9 ... three-stage tuyere, 11 ... sounding device.

Continuing from the front page (72) Inventor Masahiro Sudo 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Inventor Yuichi Yamakawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Stock Inside the company (72) Inventor Yasuo Suzuki 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (2)

[Claims] 1. A waste melting furnace in which the upper part of a sedimentary layer composed of waste and auxiliary materials is a fluidized bed and the lower part is a moving bed (fixed bed), and an armored tube for supplying auxiliary materials from the upper part of the furnace. And the lower end of the deposition position when the auxiliary material discharged from the charging pipe tip is deposited blows a fluid medium for flowing the upper part of the deposition layer. Waste gasification and melting furnace arranged below the position of. 2. The waste gasification / melting furnace according to claim 1, wherein the auxiliary material is supplied directly from the auxiliary material-incorporated pipe without passing through the flowing portion, and the sub-material level in the auxiliary material-incorporated pipe is adjusted. A method for operating a waste gasification and melting furnace, wherein the method is operated so as to be maintained at a predetermined position.