CFB boiler ash handling system composition
CFB boiler ash handling system equipment is mainly composed of: rotary ash cooler, en-masse conveyor, chain bucket conveyor, bucket elevator, slag bin, double-shaft humidifying mixer, bulkloader, screw conveyor, electric air lock feeder, electric and manual gate valve, triple valve, and fabric filter, etc.
There are mainly two types ofprocess of CFB boiler ash handling system:
- RAC is the cooling equipment for high temperature ash of CFB. Sizhou has various types RAC to
meet the output and spatial arrangement of units with different capacity, and the maximum
output can reach 20t/h. The ash discharging pipes and spiral blades contacting with high temp.
ash are both applied high temperature resistant stainless steel, the cylinder internal is applied
the type of spiral blades conveying, which is not easy for coking, and the cylinder has long life.
The whole equipment is equipped with such safe measures as alarm for overpressure, overtemperature, and
water-break. - Working Principle
Roller assembly is composed of internal and external rollers. Helical pieces are welded on the inside
wall of internal roller. Longitudinal plates are arranged between the helical pieces. When the drive unit
takes the roller turn, slag will be rolled forward freely with the help of helical pieces without extrusion
pressure, so there is little wear conditions. Longitudinal plates, on one hand, can raise the slag to a high
elevation, which both prolongs the cooling time and increases the heat exchanging area; on the other
hand, can reduce the displacement of slag and roller, and thus lighten abrasion wear and extend the
lifespan of slag inlet part considerably.
•Structure Features and Service Conditions of Roller Type
- There is no coking in the slag cooler because it is of helical conveying type, without fluidizing air.
- It can adjust to different kinds of coal well. The difference lies in the slag output of equipment for
the roller slag cooler, so there is little requirement for the coal if it is within the output/capability. - It can operate safely and reliably. Simple structure of the roller enables the slag to come out freely
and smoothly without striking or pushing activities, which ensures a good condition for operation. - Less power consumption and operation cost.
- Less investment and maintenance charges are required.
- This is applicable on conditions that the slag volume is less than 20tons per hour and field length
more than 10meters.
•Structure of Roller Slag Cooler
•Common Feature of All Types Slag Coolers
Height adjustable device of double-helical crew supporting wheel has been provided which can
adjust the height of roller when the machine is in service if abrasion happens to the supporting
wheel after being operating for a period, so it can make the center of roller in place
•Common Feature of All Types Slag Coolers
Device with helical seal and fine ash return-flow together has been designed at the movement interface of roller and
slag inlet parts. Slag flowed out will be returned to roller by the helix which is in the same direction of roller rotation, so
a little ash can rotate with roller/shell by return device back to roller/shell to avoid the ash/slag overflowing.
•Common Feature of All Types Slag Coolers
Many alarms such as water interruption inspection, pressure and water temperature measuring and interlock control have
been provided to ensure the equipment operates safely. Details are shown in the attached drawing.
•En-mass conveyer is the conveying equipment for dry ash, coal and other similar
material. Its dragging chains are concave teeth type with the advantages as big
loading capability, long life and high adaptability to chains and without the
disadvantage of chains falling. It is lined the basalt cast stone line plate at the bottom
which is wear resistance and with small friction. The conveying range is from 0 to 100
t/h.
•Chain bucket conveyer is the equipment for horizontally or slantwise conveying material. The pulling chain is plate type chain with high
strength and long lifespan. It is equipped with spring spiral take-up device which can make the tension of the pulling chain adjust automatically. The hopper is made of high temperature resistant material that is suitable to convey the material with high temperature. The width B of hopper is with such types as 350、450、630、800、1000、1200, etc, and the maximum output is 120t/h.
•Bucket elevator is the lifting equipment for
vertically conveying the powder, particle and small block material. The chains are heavy plate type, and hoppers are made of wear resistant steel
plates with high strength. The master wheel is applied friction drive to avoid chains falling, and the splitting structure can be easily installed. The
output can reach 150m 3 /h, and the lifting height can reach 50m.
Double-shafts humidification mixer: It is used for mixing evenly and conveying material with two pieces turning shafts synchronously.The material will be humidified fully through the SS atomizing nozzle, and the humidification rate can be adjusted manually by the user. The blades are made of iron-based wear resistant alloy and the compound ceramic that can improve the life of blades. The output range is from 10 to 200 t/h.
Bulk loader: Ash and coal powder material will be trucked centralizedly. It is equipped with telescopic discharging pipes which is easy to discharge, with level meter to make the entrucking be automatic, and with dust exhaust fan or bag filter to decrease the dust. The output range is from 60 to 150t/h.
