Incident Handling 4: Based on the actual conditions of your plant, how should blockages in the coal feed pipe of the circulating fluidized bed boiler be dealt with?
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1. How to deal with the blockage of the coal drop pipe in the feed pulverizer of the circulating fluidized bed boiler in your plant, based on the actual conditions there? 2. What safety measures to take.
Handling: 1. Once blockage of the coal discharge pipe is detected, the corresponding feeder should be stopped immediately to prevent more coal from accumulating in the pipe, thereby increasing the difficulty of handling the issue. At this time, the coal feeding booster fan should also be started or its output increased, so as to help the coal from other coal feeding pipes enter the furnace more smoothly and prevent blockages in those pipes from causing the incident to escalate. 2. Increase the output of the other coal supply lines to maintain the normal operation of the boiler as much as possible. 3. Treat the coal drop pipe on-site; after clearing it, reinstall it in the coal feeder to restore normal operation ； 4. When handling the coal drop pipe on-site, the operator monitoring the system should pay closer attention to the oxygen content in the flue gases. A rapid decrease in oxygen levels indicates that a large amount of coal accumulated in the coal drop pipe has entered the furnace; in such cases, it is necessary to temporarily reduce the coal supply to prevent overheating and overpressure ； 5. When restarting the coal feeder, it should first operate with a smaller amount of coal, while closely monitoring changes in the oxygen content in the flue gas. Once it is confirmed that the coal feeding is operating properly, the output can be increased as needed. Safety measures include: preventing burns and mechanical injuries, wearing appropriate work clothing and goggles, and being careful during operations.
1. Disable the operation of the feeder via DCS; strive to maintain a certain negative pressure in the furnace to prevent flue gas from flowing back and burning the operators. 2. Use specialized tools for clearing debris (tipped steel pipes for pushing debris, sledgehammers) to clear the obstruction; wear a safety helmet, mask, gloves, and goggles while performing this task. 3. Closely monitor changes in bed temperature and oxygen level, and adjust the furnace negative pressure as appropriate.