JP2003130321A - Operating method of waste gasification and melting furnace and waste gasification and melting furnace - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide an operating method of a waste gasification / melting furnace capable of promptly detecting shelf formation inside a furnace and performing stable operation. A method for operating a waste gasification and melting furnace, comprising: a furnace temperature above a waste deposit layer in the melting furnace;
A waste gasification / melting furnace characterized by measuring the temperature in the furnace below the waste sedimentary layer and controlling the amount of waste supplied into the melting furnace based on the measured temperature values. Driving method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention monitors the temperature in the furnace during operation of a waste gasification and melting furnace and controls the amount of waste, coke, and limestone supplied to the furnace to ensure stable operation. And a waste gasification and melting furnace.

[0002]

2. Description of the Related Art As a technology for treating waste, a gasification melting process in which waste such as municipal waste and shredder dust is pyrolyzed to generate flammable gas, and the pyrolysis residue is melted and discharged as slag. There is. There are several types of melting furnaces for performing the above-mentioned treatment, and one of them is a shaft type waste melting furnace. This shaft-type waste melting furnace has, for example, the configuration disclosed in Japanese Patent Application Laid-Open No. 9-60830, in which the coke deposited on the bottom of the furnace is burned, and the waste is put on this high-temperature coke. It is a furnace of a system in which it is charged, pyrolyzed and gasified, and then the pyrolysis residue is melted to form slag. Therefore, in the shaft-type waste melting furnace, the functions of the furnace body are roughly divided into three in the vertical direction.

That is, a freeboard portion having a large space is provided above the furnace body, a waste deposit layer is provided under the freeboard portion, and a melting portion is provided below the waste deposit layer. Has been. Then, the oxygen-containing gas is blown into each of the above parts. The freeboard unit is provided with a three-stage tuyere that blows air for partially burning the pyrolyzed gas (combustible gas) generated by thermally decomposing waste to maintain the inside at a predetermined temperature. The waste accumulation layer is provided with an auxiliary tuyere for blowing in air for thermally decomposing the waste deposited and partially burned and causing the waste to gently flow. In addition, the melting portion is provided with a main tuyere for blowing oxygen-enriched air for burning the charged and accumulated coke to melt the pyrolysis residue.

As described above, the waste gasification and melting furnace is equipment for pyrolyzing, gasifying and melting wastes such as municipal waste and shredder dust in one furnace. The input waste is pyrolyzed and separated into gas and residue. The gas contains a large amount of combustible gas and burns in the secondary combustion furnace, and heat is recovered in the boiler. The pyrolysis residue moves downward in the furnace and is melted in the lower part of the furnace to become slag and metal.

However, the thermal decomposition residues sometimes fuse with each other to form a shelf (hanging). When the shelves are formed, the wastes supplied from the top are piled up on the tops of the shelves. If you do not take measures such as stopping the supply of waste at this point, the shelf will collapse (shelf drop),
The situation inside the furnace deteriorates and the operation is hindered. for that reason,
Conventionally, the height of the waste layer in the furnace is measured at regular intervals,
Had estimated the formation of shelves.

As a method for measuring the height of the waste layer,
A method is used in which the weight is lowered from the upper part using a chain with a weight attached to the tip, and the height of landing on the waste layer is measured. Since the measurement frequency was about once every 10 to 20 minutes, it was difficult to judge whether it was suspended from the shelf or excessively supplied when the height of the waste abruptly increased. In addition, since the chain passes through the high temperature part of the furnace, the life of the chain becomes a problem.If the number of measurements is reduced to extend the life of the chain, the discovery of the shelf may be delayed and the shelf may be dropped. .

Therefore, there has been a demand for a method of finding a shelf by a method other than measuring the height of the waste layer.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to operate a waste gasification and melting furnace capable of quickly detecting shelf formation in the furnace and performing stable operation, and waste gasification. It is to provide a melting furnace.

[0009]

In order to achieve the above object, in the method for operating a waste gasification and melting furnace according to the present invention, the furnace temperature above the waste deposit layer and the waste deposit layer The temperature in the furnace below the temperature is monitored, and when it is determined that a shelf is formed, the supply of waste and the like is immediately stopped to prevent the shelf from falling.

According to the research conducted so far, when a shelf is formed in the waste accumulation layer, the temperature in the furnace below the shelf increases,
The temperature in the upper furnace decreases. Normally, when there are no shelves, the air blown from the main tuyere is warmed by the combustion of coke and moves upward in the furnace, where the waste is partially burned and combustible gas is generated. Is kept at a high temperature. However, when a shelf is formed, the proportion of heated air that goes upwards decreases, so
The temperature inside the furnace above the shelf will be low. On the contrary, since the heated air stays below the shelf, the temperature inside the furnace rises. If the formed shelves are small in size, by stopping the supply for a while, the fused pyrolysis residue is separated and the shelves are eliminated. Therefore, the stable operation of the furnace can be performed by detecting the formation of the shelves at an early stage.

That is, according to the present invention, there is provided a method of operating a waste gasification and melting furnace, wherein the furnace temperature is above the waste deposit layer in the melting furnace and the furnace temperature is below the waste deposit layer. A method for operating a waste gasification and melting furnace is provided, which comprises measuring the temperature and controlling the amount of waste supplied into the melting furnace based on these temperature measurements.

By measuring the temperature in the furnace above the waste accumulation layer in the melting furnace, the temperature in the furnace above the formed shelf is measured, and the temperature in the furnace below the waste accumulation layer is measured. By measuring, by measuring the temperature in the furnace below the formed shelves, the formation of shelves is detected and the amount of waste supply is reduced or stopped so as to eliminate the shelves.

Further, according to the present invention, there is provided a waste gasification and melting furnace for melting and treating waste, and a first thermometer for measuring the temperature in the furnace above the waste accumulation layer. ,
Controlling the amount of waste supplied to the melting furnace based on the second thermometer for measuring the temperature in the furnace below the waste accumulation layer and the measured values of the first and second thermometers A waste gasification and melting furnace is provided.

The operating method of the present invention can detect the racking state more accurately by combining it with the conventional technique of lowering a chain with a weight into the furnace and measuring the layer height.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a waste gasification and melting furnace according to the present invention. Reference numeral 1 denotes a vertical furnace main body, and the furnace main body 1 includes a cylindrical freeboard portion 1a located at an upper portion thereof and a bosh portion 1b having a diameter increased upward.
And the furnace bottom 1c. At the top of the furnace body 1 is provided a charging port 2 for waste and carbonaceous auxiliary fuel such as coke, and at the side of the furnace body 1 are provided tuyere for blowing oxygen-containing gas. There is. This tuyere is
A plurality of sets are provided as a set on the circumference of three levels along the height direction of the furnace body 1.

The tuyere of one set is the upper tuyere (three-step tuyere) 3 provided at a level corresponding to the upper surface of the waste deposit layer 50, and the other tuyere of the other set. Is a middle tuyere (sub tuyere) 4 provided at a level corresponding to the upper part of the waste deposit layer 50, and yet another set of tuyere is a melting portion in which carbonaceous auxiliary fuel such as coke is deposited. The lower tuyere (main tuyere) 5 provided at a level corresponding to 51.

Of these, the tuyere 4 in the middle stage is the waste accumulation layer 5
Zero waste is pyrolyzed and provided at a level corresponding to a zone where it is decomposed into combustible gas and residue. By adjusting the flow rate of the oxygen-containing gas blown from the tuyere 4 in the middle stage, the flow state of the waste deposit layer 50 can be controlled. Further, by adjusting the flow rate of the oxygen-containing gas blown from the tuyere 5 in the lower stage, it is possible to control the combustion of coke in the melting portion 51 and control the melting state of ash and the like.

In the figure, 6 is a melt discharge port, and 7 is a combustion exhaust gas discharge port. Further, in the waste gasification and melting furnace according to the present invention, thermometers (for example, thermocouples) for continuously measuring the temperature in the melting furnace are provided above and below the waste accumulation layer. By measuring the temperature in the furnace above the deposited layer in the melting furnace, the temperature in the furnace above the formed shelf, and the temperature in the furnace below the deposited layer in the melting furnace. By measuring the temperature in the furnace below the formed shelves, the formation of shelves is detected, and the supply amount of waste is reduced or stopped so as to eliminate the shelves.

FIG. 2 shows an example of the arrangement of thermometers provided in the melting furnace body 1. The thermometer is arranged at a position A corresponding to the vicinity of the tuyere 3 in the upper stage, as a position above the upper limit of the upper surface of the waste accumulation layer 50. Since the position of the upper surface of the waste accumulation layer 50 may fluctuate depending on the operating conditions, when the upper surface of the waste accumulation layer 50 is lowered, the position above the waste accumulation layer 50 is set as the position of the tuyere 4 in the middle stage. A thermometer is arranged at a position B corresponding to the upper side. Further, the thermometer is set at a position below the waste accumulation layer 50, for example, the tuyere 4 in the middle stage.
And the tuyere 5 at the lower stage.

Of these thermometers, the first thermometer is the thermometer 20 arranged at the position A near the tuyere 3 in the upper stage or the thermometer 21 arranged at the position B above the tuyere 4 in the middle stage. As the second thermometer, the thermometer 22 arranged at the position C between the middle tuyere 4 and the lower tuyere 5 is used.

Further, in the waste gasification and melting furnace of the present invention,
Control means (not shown) is provided for controlling the amount of waste or the like supplied to the melting furnace based on the measured values of these thermometers.

With the gasification and melting furnace having the above structure,
When the waste is gasified and melted, first, the waste, the coke which is one of the carbon-based auxiliary fuels, the slag adjusting agent such as limestone, and the like are charged from the charging port 2, and the waste deposit layer 5
0 is formed. The waste in the waste accumulation layer 50 is appropriately fluidized by the air blown from the tuyere 4 in the middle stage, and part of the waste is burned together with the high-temperature gas generated by the combustion of coke in the lower part. The heat of combustion heats and thermally decomposes the waste to generate combustible gas.

The residue and ash produced by the thermal decomposition descend from the upper part of the waste deposit layer 50 to the melting part at the bottom of the furnace, and the residual carbon is blown by the oxygen-containing gas blown from the tuyere 5 at the lower stage. The coke and coke are burnt, ashed, melted, and extracted from the melt discharge port 6.

In the present invention, while operating the melting furnace,
The temperature inside the furnace is constantly measured and monitored by the above-mentioned thermometers. Then, the measurement value of the first thermometer at a position (A, B) above the waste deposition layer 50 is below a predetermined temperature, and / or at a second position C below the waste deposition layer 50. When the measurement value of the thermometer exceeds the predetermined temperature, it is determined that a shelf is formed in the furnace, and the control means (not shown) immediately puts waste, coke, limestone, etc. into the furnace. Reduce or stop the supply.

As described above, when a shelf is formed in the furnace, the temperature inside the furnace above the shelf falls and the temperature inside the furnace below the shelf rises. Therefore, it is possible to detect shelf formation in the furnace by measuring changes in temperature above and below the waste accumulation layer.

After the shelf formation is detected, the shelf disappears due to the stoppage of the supply of waste and the like into the furnace, and the measurement value of the first thermometer at the position (A, B) above the waste accumulation layer. Rise and / or the measurement value of the second thermometer at the position C below the waste accumulation layer decreases and returns to the respective predetermined temperature ranges. , Increase the supply of limestone, or start again.

As described above, by measuring the temperature in the furnace, it is possible to quickly detect the formation of shelves inside the furnace. Therefore, while the scale of the formed shelves is small, the supply of waste or the like is reduced or stopped, Shelf can be dismantled. as a result,
By preventing shelves from falling off, the melting furnace can be operated stably.

[0029]

EXAMPLES (Examples) The results of gasification and melting treatment of wastes using a test apparatus having the same configuration as in FIG. 1 will be described. The waste charged in this test was shredder dust.

In this embodiment, the thermometer is located at a position A (near tuyere 3 on the upper stage) and at a position C (between tuyere 4 on the middle stage and tuyere 5 on the lower stage) shown in FIG. It was arranged so that the temperature in the furnace during operation could be continuously measured.

After the operation of the gasification and melting furnace was started, when the operation was stable, both the measured values of the thermometer at position A and the thermometer at position C were stable at about 700 to 800 ° C.
However, during operation, the measured value of the thermometer at position A dropped to about 600 ° C. in about 5 minutes, while the measured value of the thermometer at position C rose to about 900 ° C. in about 5 minutes. Then, when it was judged that a shelf had been formed, and the supply of shredder dust and the like was stopped, the measured values of the thermometers at both positions returned to their original values within about 5 minutes, the shelf disappeared, and the melting furnace became stable. Driving was resumed.

As described above, in this embodiment, since the hanging can be detected and the countermeasure can be taken within a short time of about 5 minutes after the hanging is generated, the shelf is immediately eliminated and the melting furnace We were able to maintain stable operation.

(Comparative Example) In the same manner as in the example, the gasification and melting treatment of the waste was carried out by using the test apparatus having the same configuration as in FIG. However, as a method of detecting the hanging in operation, a method of measuring the height of the upper surface of the waste accumulation layer 50 every 15 minutes using a chain with a weight is not used, instead of measuring the temperature in the furnace using a thermometer. Using.

After starting the operation of the gasification and melting furnace, the height of the waste deposit layer 50 from the furnace bottom was about 2200 mm for each measurement when the operation was stable. However, since the measured value exceeded 2500 mm during operation, it was judged that a shelf had been formed, and the supply of shredder dust and the like was stopped, but it took more than 30 minutes before the height of the upper surface of the waste accumulation layer 50 returned to the original level. Needed.

In this way, in the height measurement of the waste accumulation layer, since it is measured at intervals of about 15 minutes for the reason of the durability life of the chain, since hanging is detected at the worst 15 minutes after the occurrence of hanging, the hanging is detected. Since the measures were delayed, the shelves were not immediately resolved, and it took time to restore stable operation of the melting furnace.

[0036]

As described in detail above, according to the present invention,
(EN) Provided are a waste gasification and melting furnace operating method and a waste gasification and melting furnace capable of rapidly detecting shelf formation inside the furnace and performing stable operation. The detection of hanging of a shelf is important for stable operation, and the earlier the detection, the easier it is to take countermeasures. Therefore, according to the present invention, the stability of the operation of the melting furnace can be significantly improved as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a waste gasification and melting furnace according to the present invention.

FIG. 2 is a diagram showing an example of a furnace body of a waste gasification and melting furnace according to the present invention.

[Explanation of symbols]

1 ... Furnace body 1a ... Free board 1b ... morning glory 1c ... Furnace bottom 2 ... entrance 3, 4, 5 ... Tuyere 6 ... Melt discharge port 7 ... Exhaust port for combustion exhaust gas 20, 21, 22 ... Thermometer 50 ... Waste deposit layer 51 ... Melting part

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F27D 19/00 F27D 19/00 Z 21/00 21/00 G (72) Inventor Nao Nakamura Chiyoda-ku, Tokyo Marunouchi 1-Chome 1-2, Nihon Kokan Co., Ltd. F term (reference) 3K061 AA16 AB02 AB03 AC01 BA02 CA08 3K062 AA16 AB02 AB03 AC01 BA02 CA02 CB03 DA01 DB01 DB30 4K045 AA01 BA10 DA04 DA07 4K056 AA05 BA01 CA20 FA01 FA02 FA13

Claims (2)

[Claims] 1. A method of operating a waste gasification and melting furnace, comprising: a furnace temperature above a waste deposit layer in the melting furnace;
A waste gasification and melting furnace characterized by measuring the temperature in the furnace below the waste accumulation layer and controlling the amount of waste supplied into the melting furnace based on these temperature measurements. Driving method. 2. A waste gasification and melting furnace for melting and treating waste, wherein a first thermometer for measuring the temperature inside the furnace above the waste accumulation layer, and the waste accumulation layer A second thermometer for measuring the temperature in the furnace below the temperature, and control means for controlling the amount of waste supplied into the melting furnace based on the measured values of the first and second thermometers. A waste gasification and melting furnace comprising: