Diagnosis of smoke crossover issue in boiler air preheater
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This post was last edited by ZhiNeng on 2018-11-8 at 19:38. The temperature of the hot air in the air preheater is too high; it is suspected that smoke is leaking in. An opening was created, but no problem was detected. Experts are requested to help diagnose this issue. Are there any methods or experiences to determine where the leak is?
Check whether the air volume is normal. Collect air samples for heating to analyze for the presence of flue gas components: Absent: Check whether the flue gas temperature is fluctuating or whether the air flow rate is normal. Present: Preheater leakage
Generally, the air preheater is at positive pressure, while the boiler flue gas outlet is at negative pressure. The pressure of cold air is high; even if there is cross-ventilation, it’s the cold air that mixes with the flue gas, right? If the temperature of the hot air is too high, check whether the temperature at the flue gas outlet, as well as the temperature at the outlet of the economizer located above the air preheater, are within normal ranges
The exhaust gas temperature is lower than that of the hot air; if the tubes carrying the dust are corroded, cold air and dust exchange with each other, which results in abnormal hot air. This is the only explanation for the low exhaust gas temperature – I really can think of no other reason. The boiler has only an air preheater; it lacks a economizer
To be completely honest, there’s nothing that advanced; it all relies on experience and common sense