JPS6224695B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for dry cooling bottom ashes and fly ashes generated from coal boilers.

BACKGROUND ART When pulverized coal is burned in a coal boiler, combustion ash is generated, but its particle size and temperature vary depending on where it is generated. In general, bottom ashes are exposed to high temperatures of over 1,000 degrees Celsius in a boiler, so after being melted once, they re-solidify to form clinker in the form of chunks, but upon discharge, they are crushed by a clinker crusher and broken into coarse particles of approximately 50 mm or less. Become. Temperature is over 200℃, generally 600℃
The temperature is ~1000℃. On the other hand, fly attachment is 3
It is a fine powder of about mm or less, and the temperature is generally 30 to 40.
℃, and at most the temperature is below 200℃.

Conventionally, in the treatment of ash from coal boilers, the bottom ash was treated by a wet process involving water treatment, and the fly ash was treated by a dry process by air transportation and cooling.

Problems to be Solved by the Invention In the conventional treatment method, there are two treatment systems and water treatment equipment is also required, which increases equipment costs and is uneconomical in terms of operation and management.

Also, a method has been proposed in which both assemblies are dry-processed, but this method uses separate cooling devices for each, resulting in two processing systems, which is not an efficient cooling method.

An object of the present invention is to provide a dry cooling method for coal boiler combustion ash, which solves the above-mentioned problems of the prior art.

Means for Solving the Problems In order to achieve this object, the present invention has the following configuration. That is, the bottom ash discharged from the bottom of the boiler and the fly ash discharged from the top of the boiler are collected together by pneumatic transport, and the collected fly ash and bottom ash are separated into coarse ash and an air stream containing fine ash using a cyclone. Ash is fed to the ash cooler, and air containing fine ash is sent to the ash cooler as cooling air for the ash cooler to cool the coarse ash.

Examples Examples of the present invention will be described with reference to the drawings.

The relatively low-temperature fly ash coming out of the top of the boiler and the high-temperature bottom ash coming out of the bottom of the boiler are pneumatically transported together by a transfer blower through an ash recovery pneumatic transportation line, and sent to cyclone 1, which is a classifier. During this time as well, the fly and bottom ashes are cooled. In cyclone 1, it is separated into coarse ash and fine ash. Coarse ash is fed into the ash cooler 2 from the lower part of the cyclone 1, and fine ash is discharged from the upper part of the cyclone with the exhaust stream. This exhaust flow is sucked in by the exhaust fan 3 via an ash cooler or the like. On the way to the ash cooler, the exhaust stream is mixed with the atmospheric air introduced from the atmospheric air intake port 4 and cooled to become cooling air for the ash cooler. The amount of atmospheric air introduced can be adjusted by the atmospheric flow rate regulating valve 5, and thereby the temperature of the cooling air can also be adjusted. The ash cooler 2 consists of a horizontally installed closed trough 6 with a rectangular cross section, which is vibrated by a vibration motor 7. Two vibration motors are installed on the lower center side of the trough. The trough may be tiltable. Inside the trough, a wire mesh 8 is stretched over the entire horizontal surface, and the coarse ash supplied from the coarse ash supply port 9 moves on the wire mesh to the vicinity of the discharge port 10 by vibration.
Enter the ash receiving device 11. By adjusting the mounting angle of the vibration motor, the moving speed, that is, the residence time can be adjusted. While the coarse ash moves on the wire mesh, it is cooled by cooling air blown up from below. Cooling air is introduced from an air supply port 13 provided on the side of the trough via a cooling air flow control valve 12. A uniformly dispersing member such as a punched screen 14 is provided below the wire mesh 8 to uniformly distribute the cooling air. The air used for cooling is sucked through the exhaust port 15, and the pulverized ash is collected by the bag filter 16. The temperature at the bag filter inlet is at most 150°C.
below ℃. When the exhaust from the cyclone is passed through the ash cooler, even if the exhaust contains coarse ash, it will be blocked by the wire mesh in the ash cooler and will not reach the bag filter. Also, if it passes through a wire mesh or is carried toward a bag filter, it will be cooled down by the time it reaches the bag filter, and the bag filter's filter cloth (which can generally withstand temperatures of about 150°C) will not be damaged.

In addition, the shape and size of the cyclone and ash cooler, the type, number and location of the ash cooler tilting device and vibration device,
The number and location of cooling air supply ports and exhaust ports, etc.
Of course, it can be changed as appropriate depending on the processing amount, processing temperature, etc.

Effects of the Invention As described above, according to the present invention, high-temperature, coarse-grained bottom ash and relatively low-temperature, fine-powdered fly ash can be efficiently dry-cooled using a single device, and moreover, only one processing system is required. Therefore, it is possible to dry-cool the combustion ash of a coal boiler economically from the standpoint of equipment and operation management.

[Brief explanation of the drawing]

The drawing shows an embodiment of the method of the invention. 1...Cyclone, 2...Ash cooler, 3...Exhaust fan, 4...Atmospheric intake, 5...Atmospheric flow control valve, 6...Trough, 7...Vibration motor, 8...
Wire mesh, 9... Supply port, 10... Discharge port, 11...
Ash receiving device, 12...Cooling air flow rate control valve, 1
3...Air supply port, 14...Punching net, 15...Exhaust port, 16...Bag filter.

Claims (1)

[Claims] 1. Fly ash and bottom ash are collected together by pneumatic transport, the collected fly ash and bottom ash are separated into coarse ash and an air stream containing fine ash by a cyclone, and the coarse ash is sent to an ash cooler. A method for cooling coal boiler combustion ash, which comprises feeding air containing fine ash to an ash cooler as cooling air for the ash cooler to cool coarse ash. 2. Coal boiler combustion ash according to claim 1, in which a mixture of separated fine ash-containing air and separately introduced atmosphere is used for cooling coarse ash in the ash cooler. Cooling method.