Why is the water wall tube damaged when the circulating fluidized bed boiler operates?

(Question Details) Specific Performance:

(1) There are blasting sounds in the furnace, and the furnace chamber is under positive pressure. There is smoke emitted from the combustion chamber in a leakage. In severe cases, the explosion-proof door of the boiler body opens.

(2) Drum water level drops rapidly and the feedwater flow rate is not abnormally larger than steam flow. MFT acts when the water level is below -280mm.

(3) Drum pressure, steam flow rate, exhaust temperature decrease, smoke temperature difference increases on both sides.

(4) The negative pressure at the inlet of the flue and suction fan becomes smaller and the temperature difference between the two sides increased.

(5) Smoke temperature decreases at the inlet and outlet of the cyclone separator, and the temperature of the material returned is low.

(6) Bed pressure increases, bed materials clean, fluidization poof, bed temperature distributes unevenly and bottom slag discharge difficultly.

Answer：cause of failure:

(1) Fly ash wear thins the pipe wall.

(2) Defective membrane water wall.

Troubleshooting:

(1) If the water wall tube is not badly damaged and can maintain the normal position and the failure will not be expanded, the load can be appropriately reduced and the maintenance time can be shortened to run until the standby furnace is put into operation. If the standby furnace can’t be put into operation for a long time and the damage of the malfunctioning furnace is intensified, the furnace should be stopped immediately.

(2) If the normal water level cannot be maintained, stop the furnace immediately, stop the bottom material and circulating ash, keep the induced draft fan running, and stop the induced draft fan after the steam leakage is eliminated.

We are strictly in accordance with the provisions of the use of advanced automatic robot and welding machine to complete the manufacture of elbows and the welding between the elbow and flat steel, fully automated to ensure the accuracy of the distance between the two.