JP2008020184A - Blow-in device for combustible dust in waste fusion furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blow-in device for combustible dust capable of preventing a blow-in pipe from being plugged, and capable of preventing the blow-in pipe from being abraded. <P>SOLUTION: In this blow-in device 2 for the combustible dust capable of collecting the combustible dust from a waste fusion furnace, and of connecting the collected combustible dust respectively to a plurality of tuyeres formed along a circumferential direction of the furnace by the blow-in pipes 1c, a driving source 2a of the each blow-in device 2 is formed into an independent system, a flowmeter 5 is provided in the each blow-in pipe, and a means is provided, when a blow-in flow rate is reduced, for stopping tentatively only the blow-in device 2 for the combustible dust in the plugged tuyere, so as to stop feed, and for supplying continuously conveying air to perform blowing by clean air. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a combustible dust blowing device that blows combustible dust generated in a waste melting furnace for melting waste such as general waste and industrial waste into a tuyere by airflow conveyance.

  As a waste disposal method such as general waste and industrial waste, waste is charged into a shaft furnace type waste melting furnace, and the waste is dried, preheated, pyrolyzed, combusted, melted, slag and metal There is known a thermal decomposition melting method to be taken out as

  In the operation of the waste melting furnace, the combustible component in the charge is thermally decomposed in the furnace to generate a residue. The generated pyrolysis residue is combusted by the air sent from the tuyere or accumulated in the furnace, but the fine one is not burned by the air sent from the tuyere, Ride as a flammable dust from the furnace.

  For example, Japanese Patent Application No. 11-283391, filed by the present applicant, blows flammable dust from a tuyere as a technique for treating flammable dust scattered in a waste melting furnace.

  FIG. 6 is a schematic diagram of the combustible gas blowing line of the application.

  The combustible dust scattered from the waste melting furnace is collected by the dust remover 11 and stored in the combustible dust hopper 10.

  When a predetermined amount of flammable dust is stored in the flammable dust hopper 10, the damper 12 is opened and falls to the intermediate hopper 13 through the screw conveyor 14, the water-cooled screw conveyor 15, and the sieve device 16. In the intermediate hopper, the upper damper 13a and the lower damper 13b are alternately opened and closed to drop the combustible dust into the blowing hopper 1 without mixing the combustible gas and the carrier air.

  Thereafter, combustible dust in the blowing hopper 1 is blown into the furnace from each tuyere 17 by the blower 4.

  Before combustible dust is blown into the tuyere, as shown in Japanese Patent Application No. 11-283391, a sieve device is installed on the upstream side of the blowing device, and the large particle size is liable to cause blockage at the curved portion of the blowing pipe. In order to prevent the blockage of the blow-in piping, it was previously removed.

  Although the dust collected by the cyclone is fine particles of about 100 μm, there are rarely particles with a particle size of about 3 to 10 mm, and their terminal velocity is about 7 to 8 m / s. Was required to have a 1 mm sieve to remove them. However, when the sieve installed on the upstream side of the blowing device is made as fine as about 1 mm, it is not practical because it leads to a large amount of generation on the sieve due to a reduction in the sieve efficiency and the treatment on the sieve is troubled.

  Therefore, the present invention provides a flammable dust blowing device that prevents blockage of the blowing pipe and prevents wear of the blowing pipe.

  The combustible dust blowing device of the present invention collects the combustible dust from the waste melting furnace and blows the collected combustible dust into each of the tuyere formed in the circumferential direction of the furnace. In the combustible dust blowing device connected in the above, the drive source of each blowing device is an independent drive system, and a flow meter is provided for each blowing pipe, and when the blowing flow rate decreases, the closed tuyere is combustible In this case, there is provided means for temporarily stopping only the driving source of the dust blowing device and stopping the cutting, and continuously supplying the carrier air and blowing with clean air.

  Further, the blowing device of the present invention collects combustible dust from a waste melting furnace, and connects the collected combustible dust to each of tuyere formed in the circumferential direction of the furnace with a blow pipe. In the combustible dust blowing device that blows in combustible dust, a sieve device is disposed upstream of the blowing device, a blowing hopper that stores the combustible dust under the sieve is disposed, and the blowing hopper Supply devices corresponding to the number of tuyere at the lower part are arranged at equal intervals in the circumferential direction, and the supply device comprises a supply panel that rotates on the lower table of the blowing hopper, Is provided with a cylindrical flammable dust receptacle that is partitioned into a plurality of parts and is opened up and down, while an outlet for discharging flammable dust is provided in the lower table, and a blowing pipe is arranged above and below the drain outlet, Characterized in that a flow meter blowing pipe.

  According to the present invention, the cutting device for each individual tuyere independently detects the blockage by a decrease in the conveyance flow rate, stops the cutout to the tuyere, and enables blowing with clean air to prevent the blockage. be able to.

  Also, since the flow velocity of the carrier air can be suppressed to about 12 m / s near the end speed compared to the conventional method of 20 m / s, it is possible to overwhelm the wear of the piping. It was.

  In the present invention, the diameter of the sieve installed on the upstream side of the blowing device is set to about 5 mm to prevent mass generation on the sieve, and the flow rate of combustible dust is about 12 m / s, which is just below the end speed of the dust. By transporting at a low flow rate, it is possible to prevent wear of piping.

    FIG. 4 is a graph of a pipe wear test showing the relationship between the flow rate of combustible dust of 5 mm or less and the wear amount. Although the combustible dust is highly wearable, the blowing flow rate is as shown in the graph of FIG. If it can be suppressed to about 12 m / s, pipe wear can be suppressed to a wear rate that can withstand practical actual use.

    FIG. 5 is a graph showing the relationship between the flow rate of combustible dust of 5 mm or less and the blockage frequency, and it can be seen that the blockage frequency is greatly reduced at a low flow rate of about 12 m / s. Therefore, in the present invention, it is possible to prevent the wear and blockage of the piping by suppressing the blowing flow rate of the combustible dust of 5 mm or less to about 12 m / s.

    Therefore, in a dust blowing device that has a dust cutting device for conveying piping and its individual tuyere, it detects clogging by detecting the dust conveying flow rate, and stops cutting flammable dust to the branch pipe whose flow rate has dropped due to blocking. By doing so, the clogging in the piping is blown with clean air, and after being blown for a certain period of time, cutting is resumed.

    In the present invention, it is necessary that the cutting device for each individual tuyere is independent. If it is not independent, the clogging of individual tuyere will need to stop the dust cutting to all tuyere. Long-term cessation of blowing leads to consumption of coke and increases coke ratio. However, if the cutting device for each individual tuyere is independent, the blockage is detected by a decrease in the conveyance flow rate, and the cutout of dust to that tuyere is stopped, so that the closed tuyere with clean air Blowing is possible, and it is only necessary to stop cutting into individual tuyers out of a plurality of tuyere, and the effect on the inside of the furnace is limited, so that the coke ratio is not increased.

    Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

    FIG. 1 is a schematic view of a blowing device according to the present invention, FIG. 2 shows a main part of the blowing device, (a) is a longitudinal sectional view, and (b) is a plan view.

    In the lower part of the blowing hopper 1, a plurality of supply devices 2 corresponding to the tuyere of the waste melting furnace, for example, about 4 to 8, are arranged at equal intervals in the circumferential direction. At the center of the lower table 1a of the blowing hopper 1, a stirrer 3 is arranged in which a plurality of scrapers 3a are rotated by a motor 3b to prevent shelves.

    The supply device 2 includes a supply board 2b that is rotated on the lower table 1a of the blowing hopper 1 by a motor 2a. A dust receiver 2c is provided in an annular shape.

    The lower table 1a is provided with a combustible dust discharge port 1b, and air conveyance pipes 1c are arranged above and below the discharge port 1b. The air conveyance pipe 1c is branched into a plurality of blow blowers 4 provided for conveying air supply, and is connected to a discharge port 1b and tuyere through a flow meter 5, respectively. When the combustible dust receiver 2c filled with the combustible dust coincides with the discharge port 1b, the combustible dust in the combustible dust receiver 2c passes through the discharge port 1b due to the pressure of air in the air transport tube 1c. Enters and is transported to the tuyere.

    FIG. 3 shows the change in the blowing flow rate and the operating state. In the present invention, the blockage of the combustible dust blowing pipe is detected by the blowing flow rate measured by the flow meter 5. The normal blow-in flow rate is set to 12 m / s with a margin of slight decrease from the critical flow velocity leading to the blockage, and the determination value for the lower blow-flow rate lower limit is set to the end limit of 8 m / s. .

    When the blowing flow rate is lower than the determination value (8 m / s), the motor 2a of the corresponding supply device 2 is stopped while the carrier air is kept flowing. As a result, although the inside of the piping has been gradually closed, the supply of new powder is stopped, so that portion is gradually blown by the carrier air. Thereafter, after the amount of transported air exceeds the determination value of the blow-in flow rate lower limit, the motor 2a is driven after a certain timer to resume cutting. As a result, since the blow-in pipe can be automatically purged before the transfer pipe is completely blocked, the transfer can be carried out at a low flow rate near the terminal speed, and the wear of the pipe can be prevented at a low level.

It is the schematic of the blowing apparatus of this invention. The principal part of the blowing apparatus of this invention is shown, (a) is a longitudinal cross-sectional view, (b) is a top view. It is a figure which shows the change of an inflow flow rate, and an operation state. It is a graph of the piping abrasion test which shows the relationship between the conveyance flow rate of 5 mm or less combustible dust, and an abrasion loss. It is a graph which shows the relationship between the conveyance flow rate of 5 mm or less combustible dust, and the obstruction | occlusion frequency. It is a schematic diagram of a combustible gas blowing line.

Explanation of symbols

1: Blowing hopper 1a: Lower table 1b: Discharge port 1c: Air conveyance pipe 2: Supply device 2a: Motor 2b: Supply board 2c: Combustible dust receiver 3: Stirrer 3a: Scraper 3b: Motor 4: Blow blower 5 : Flow meter 10: Combustible dust hopper 11: Dust remover 12: Damper 13: Intermediate hopper 13a: Upper damper 13b: Lower damper 14: Screw conveyor 15: Water-cooled screw conveyor 16: Sieve device 17: Tuyere

Claims (2)

In a combustible dust blowing device that collects combustible dust from a waste melting furnace and connects the collected combustible dust to each of the tuyere formed in the circumferential direction of the furnace with a blow pipe. ,
The drive source of each blowing device is an independent drive system, and a flow meter is provided for each blowing pipe. When the blowing flow rate decreases, only the driving source of the closed combustible dust blowing device is temporarily stopped. A combustible dust blowing device characterized in that means for stopping cutting and providing means for continuously supplying carrier air and blowing with clean air is provided. Combustible dust that collects combustible dust from a waste melting furnace and blows the collected combustible dust into each of the tuyere that is formed in the circumferential direction of the furnace and is connected to the plumbing pipe. In the dust blowing device,
A sieving device is arranged on the upstream side of the blowing device, a blowing hopper for storing the flammable dust under the sieving is arranged, and a supply device corresponding to the number of tuyere is provided below the blowing hopper. The supply device is provided with a supply panel that rotates on the lower table of the blowing hopper, and the periphery of the supply panel is partitioned into a plurality of parts and is opened up and down, and is combustible. Combustible, characterized in that a dust receiver is provided in an annular shape, while a discharge port for discharging flammable dust is provided in the lower table, a blow pipe is arranged above and below the drain, and a flow meter is provided in each blow pipe. Dust blowing device.

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