Accident Handling 36: What are the symptoms of damage to the water wall in a circulating fluidized bed boiler?
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What are the symptoms of damage to the water wall in a circulating fluidized bed boiler?
1. The drum water level drops rapidly. 2. The water supply flow rate is abnormal. 3. Steam pressure and feedwater pressure drop. 4. There are abnormal noises. 5. The combustion chamber becomes positive pressure. 6. Flue gas temperature decreases. 7. The opening and current of the exhaust fan increase.
(1) Abnormal noises are heard inside the furnace chamber; the negative pressure in the furnace chamber fluctuates toward positive values, and smoke or steam escapes from the areas where there are leaks. (2) The bed temperature at the leakage site drops significantly. (3) Local fluidization of the bed is poor, resulting in inconsistent variations in bed pressure at different points. (4) The drum water level drops rapidly, and the feedwater flow is abnormally higher than the steam flow. (5) The smoke temperature decreases in each section, while the steam pressure and steam temperature show a downward trend.
In the case of external leakage, air will blow out or water will seep downward at the places where the insulation is not tight; this affects the steam system but has no impact on the combustion system. For minor cases, seal the leak under pressure; for severe cases, shut down the furnace immediately.