The so-called condensation, in layman’s terms, refers to the phenomenon of saturated water precipitation from moist air at a certain pressure and temperature. The temperature point at which water is released is called the dew point.
The higher the gas pressure in a saturated state, the lower the dew point. The higher the moisture content in the air, the higher the dew point temperature. When the moisture content in the air is constant and the temperature of the humid air is lower than the dew point temperature, water will precipitate from the supersaturated air, resulting in condensation; When the air temperature is higher than the dew point, no water will precipitate and condensation will not occur. In addition, if the flue gas contains SO2 components, the higher the SO2 content, the higher the dew point of the flue gas.
Reasons for condensation in pulse bag filters
- Dust collector has air leakage phenomenon
Due to air leakage in the dust collector, a large amount of cold air from the outside is sucked into the dust collector, causing a sharp drop in the local air temperature of the dust collector. Water in the air is analyzed, resulting in condensation.
There are many reasons that can cause air leakage in dust collectors, including welding leakage during the production and installation process of the dust collector shell, inadequate sealing of the discharge device causing air leakage, welding leakage during the installation of non-standard pipelines causing air leakage, and inadequate sealing at the flange connection between the dust collector and non-standard pipelines causing air leakage, etc.
- Excessive moisture content in flue gas
When the moisture content in the processed flue gas is too high and supersaturated water is analyzed, condensation occurs. This phenomenon is particularly prominent in the dust collector at the end of the cement dry process line. Due to the fact that the flue gas at the end of the cement dry process line is generally cooled and tempered using a humidification tower, condensation will occur when the amount of water sprayed is too large, resulting in oversaturation of the moisture in the flue gas.
- Low flue gas temperature
When the temperature of the flue gas processed by the dust collector is close to or below the dew point temperature, condensation will also occur.
- Pulse injection gas temperature too low
The dust collector uses compressed air during the pulse jet cleaning process. When the temperature of the compressed air is not significantly different from the temperature of the flue gas inside the dust collector, condensation generally does not occur. But in winter, when the temperature is usually around minus ten or tens of degrees, the temperature difference between the compressed air sprayed by the pulse and the flue gas inside the dust collector is too large. Due to the saturated compressed air inside the nozzle, the temperature drop after gas injection can cause water to be analyzed in the area and cause condensation.
- The shell of the dust collector lacks insulation measures or has poor effectiveness
The shell of a dust collector generally adopts a steel plate structure, and the thermal conductivity of the steel plate is very high. When there is a large temperature difference between the external air temperature and the internal flue gas temperature of the dust collector, condensation will occur on the shell of the dust collector. If the shell of the dust collector is not insulated, or if insulation measures are taken but the effect is poor, condensation is inevitable in the dust collector.