Why the dew exists in filter house? Any solutions?
With the advantages of big air volume, lower resistance, with a excellent purging performance, also can help to desulfidation and defluorination, with a high filter efficiency, so the pulse jet bag filter house is one of the most popular dust collectors in the market.
While many pulse jet bag filter houses exist the dew when operation, if can’t find the solutions, which will corrode the bag filter house, and make the filter bags hydrolyzed or blocked, which will seriously affect the service life of the bag filter houses.
Why the bag filter house exists the dew? Any solutions?
The leakage of the dust collector is big (leak air), which will lead much cold air in from outside, if so, the temperature in bag filter houses will reduce sharply, when the temperature meets the dew points, the water will be separated out from the air.
The leakage higher the main problem is from inferior welding, sealing not well, the air leading pipe not fixed well, etc.
A.Weld the seam according to the standard (China according to JC/T532) when installing.
B.The discharge mouth have to be sealed well. Nowadays mainly use the pneumatic or dynamoelectric air lock valve, if necessary, use them both.
As usual, for the pulse jet bag filter house, we require the air leakage not exceed 3%.
Too much moisture in the air.
When the moisture content is high, the supersaturated water will be separated, so the dew will exist in dust collector. Due to the dust air form the tail of the kiln always cooled by water spraying in dry process cement production, so this problem happened much when the water spray content is too much, which will bring the dew to the bag filter houses and cause much problems.
Control the content of water spraying strictly, use the smallest water volume to meet the cooling requirements.
The temperature in bag filter house is too low.
When the temperature is lower which meet the dew points, the dew will exist.
make the dust air temperature in bag filter house stable.
A.When the temperature is too high, have to reduce the temperature immediately, such as lead the cooler air in, etc.
B.When the temperature is too low, have to increase the temperature immediately, keep the temperature of the dust air at a certain area according to the dew points.
The air temperature from the pulse jet valve is too low. When this happen, the purging area temperature will reduce sharply and make the dew exist, which will mixed with the dust and glued at the surface of the filter bags, make the filter bags blocked.
Reduce the temperature differences of the air between pulse jet valve and the bag filter house.
As usual, the simplest route for the compressed air for pulse jet vales as following:
Compressed air -> compressed air tank -> gas source triplet -> air bag -> pulse jet valves. This route is less investment, simple, but when the temperature of the air source is too low, it may bring the dew at the bag filter houses.
For avoid this happen, we can choose the following design of the compressed air:
Compressed air -> compressed air tank -> air source triplet -> air dryer -> air heater -> air bag (wrapped with heat isolation material) -> pulse jet valve.
The tank of the bag filter house without heat isolation treatment or the treatment not good.
The filter bags dust collector always built by steel board, and the thermal conductivity is high, when the outside temperature is very low, the inside of the tank may exist the dew.
When the temperature difference is very big, so with the heat isolation design for the filter tank, mainly use the rock wool, aluminum silicate, nacre, etc, the thermal conductivity not exceed 0.23W/m.K. The thickness of the isolation material choose according to the located area, temperature differences of year.