Reasons for high outlet smoke temperature
Thread Content
During normal operation of the circulating fluidized bed boiler in our factory, it was found that the outlet smoke temperature was 138 degrees, which is about 101 degrees under normal circumstances. The primary air volume is 150,000 cubic meters per hour and the secondary air volume is 18,000 cubic meters per hour. The load is 140 steam tons per hour and the rated load is 240 steam tons. After checking, the thermocouple measuring points are normal. Is it related to the ratio of primary and secondary air volumes? Could you please tell me what the problem is? Thank you!
Check whether there is too much dust accumulated in the tail flue and whether the temperature of the superheater is high. It is best to use a soot blower to blow out the dust to improve the thermal efficiency of the superheater and economizer. Another problem is that the pipe bursts.
Isn’t 138 degrees normal during normal operation? It is normal for the 240 boiler to have a lower exhaust gas temperature at 140 tons. The primary air volume is 150,000, which is a little more than zero, right?
This situation is generally a sign that the heat transfer effect of the tube heat exchanger is poor. Strengthen soot blowing and soot discharge to see if the situation improves. Generally, the superheater, waste heat boiler, and economizer inlet and outlet have temperature and pressure measurements. The host can observe whether the system resistance increases and whether the temperature difference decreases to judge the heat transfer efficiency of each stage. The simplest thing is to compare the current situation with a heat balance estimate under normal circumstances.
The exhaust smoke temperature of 101 degrees feels a bit low. In addition to the boiler design issues and the air distribution factors mentioned by the poster (observe whether the oxygen content of the exhaust gas on the pickaxe meter is normal), it is recommended to track whether the volatile content of the raw coal fluctuates, and if possible, check or track whether the ash return system is normal. The decrease in separator efficiency will also cause the exhaust gas temperature to increase. for reference