Maintenance of High Temperature Dust Filter Bags
When dealing with higher flue gas temperatures, it is important to prioritize the maintenance and usage of dust filter bags. Here are some suggested measures:
Water mist cooling: To prevent issues like air preheater blockage or combustion failure due to a sudden increase in flue gas temperature, it is recommended to implement water mist cooling before the dust collector. This can be achieved by installing atomization nozzles in front of the inlet baffle of the dust collector. The nozzles are connected to a pipeline with an automatic solenoid valve, which is linked to a pressure source. Under normal conditions, the solenoid valve remains closed. However, when abnormal conditions arise (such as the smoke temperature exceeding the bag's temperature limit), the solenoid valve opens automatically. The pressurized water is atomized by the nozzles and mixed with the smoke, resulting in vaporization and endothermic cooling of the smoke, thereby protecting the filter bag's lifespan.
Pre-dusting of the bag filter: Before starting the unit or during low load stable fuel operations, it is important to pre-coat the dust collector with powder to prevent dust collector bag clogging. This pre-coating process can involve various measures such as using an ash storage tank, a dust collector on top of the warehouse, a feeder, a suction fan, etc.
Preventing filter bag clogging: The primary cause of filter bag clogging is the infiltration of water or oil into the powder layer of the filter bag. To avoid this issue, a dust spray device can be installed in front of the dust collector. This device can spray calcium oxide powder, which will mix with the soot and wrap around the dust particles. It also contributes to the desulfurization and dechlorination process. If the boiler experiences a burst pipe or if the dust moisture content exceeds a certain threshold, the dust collector's PLC system can control the activation of a bypass mechanism to divert the dust. In cases where the smoke temperature is too low, the bypass can also be opened. It is important to thoroughly clean the dust collector after a shutdown to ensure effective prevention of such issues.
By implementing these measures, the occurrence of undesired phenomena can be effectively prevented in high-temperature dust filter bags.
