Analyze the causes of powder leakage from dust collection bags.

Causes of dust‑bag surface powdering: flue gas temperature is too low. When the flue gas handled by the dust collector has a temperature close to or below its dew point, condensation can occur. The pulse‑jet blow‑off air temperature is also too low. If the compressed‑air temperature differs only slightly from the dust collector’s internal flue‑gas temperature, condensation typically does not occur.

However, in northern regions, when temperatures drop to well below freezing—often ranging from minus ten to minus several tens of degrees Celsius—the temperature difference between the pulsed compressed air and the flue gas inside the dust collector becomes excessively large. As a result, the sudden injection of compressed air into the filter bags causes a sharp drop in bag‑surface temperature, typically leading to condensation. Additionally, the moisture content of the flue gas may be too high, or the material entering the baghouse may contain excessive moisture.

High temperatures generate substantial steam, which can cause the dust‑collection bags to become clogged and condense. For example, when clinker entering a cement mill is at a high temperature and the slag has a high moisture content, the combination produces copious water vapor that adheres to the pores around the filter bags, blocking them completely. After a period of operation, the dust‑collection efficiency declines significantly.

Dust collectors exhibit air leakage. When air leaks into the dust collector, it draws in large amounts of cold ambient air, causing a sharp drop in local air temperature and leading to condensation as moisture in the air precipitates. Additionally, the shell insulation of pulse-jet baghouse dust collectors is inadequate. The dust collector’s shell is constructed of steel plates without thermal insulation; consequently, when cold outside air enters the unit, the flue gas temperature approaches the dew point, resulting in a significant temperature decline and triggering condensation within the baghouse.