What are the signs of damage to air preheater tubes, what are the causes, and how should it be handled?

The last edit to this post was made by Full of dominance on 2011-11-25 at 11:11. Reply 1# rzs20000: 1. The flue gas temperature of the boiler needs to be increased, which results in a decrease in the boiler’s efficiency； 2. The temperatures of the primary air, secondary air, and even tertiary air entering the furnace should be reduced, as this affects the ignition and stable combustion of the fuel ； 3. If the damage is severe, the high temperature of the flue gas entering the dust collector can affect its operation as well as the subsequent desulfurization process ； The higher the temperature of the flue gas entering the desulfurization tower, the lower the desulfurization efficiency. I’m not very familiar with how to handle this; if the situation gets serious, does it need to be removed?

1. Symptoms of damage to the air preheater tubes: (1) A large amount of air mixes into the flue gas, resulting in a significant decrease in the boiler’s load. (2) The exhaust fan load increases, and the flue gas temperature decreases. (3) The air supply volume is severely insufficient, causing sudden changes in the combustion conditions; in some cases, combustion cannot even be maintained. 2. Reasons for damage to the air preheater tubes: (1) The flue gas temperature being below the dew point leads to acidic corrosion of the tube walls. (2) Due to long-term wear by fly ash, the pipe wall gradually thins. (3) Combustible gases or carbon deposits in the flue burn again at the air preheater, or severe ash accumulation in the tubes leads to uneven heating of the tube bundle, resulting in local overheating and damage. (4) Poor material quality, such as weak corrosion and wear resistance. 3. Handling of damaged air preheater tubes (1) If the damage to the tubes is not severe and does not lead to an escalation of the incident, operation can be continued for a short period of time. If there is a bypass flue, it should be activated immediately; thereafter, the flue dampers should be closed. The boiler can then be shut down for maintenance once the backup boiler is put into operation. (2) If the pipes are severely damaged, the furnace temperature is too low, and it is difficult to continue operating, the furnace should be shut down urgently.