The performance of the filter bag is directly related to the operation of the filter. At present, there are problems of large dust collector resistance, small processing air volume, and short filter bag life, which not only affects the dust removal effect, but even affects the normal production.
First, running resistance:
Causes: (1) fume condensation dust pocket; (2) electromagnetic pulse valve does not work; (3) poppet valve does not close when pulse valve is working; (4) compressed air pressure is too low; (5) one or more Poppet valve closed.
Remedy: (1) Block air leakage and increase flue gas temperature; (2) Clean or replace; (3) Check poppet valve or PLC controller; (4) Check air line system and air compressor; (5) Check poppet valve Or PLC controller.
Second, the operating resistance is small
Reasons: (1) The process system is not working; (2) the filter bag is damaged; (3) the pressure measuring device fails;
Remedy: (1) Resume work; (2) At this time, it can be seen that the emission concentration increases, and the filter bag should be replaced or repaired; (3) Replace or repair the pressure measuring device.
Third, the dust collector resistance has been determined in the design of the dust collector, but in the operation of the dust collector, if the resistance of the bag filter is found to increase rapidly in a short period of time, it indicates that the dust collector has a problem and should be repaired and adjusted.
The original resistance should be divided into two types:
1. The dust remover occurs immediately after the system is running;
2. The dust collector occurs after working for a period of time;
If the newly installed dust remover is improperly designed, it will easily cause the first phenomenon; the second cause is operational problems and operation and maintenance aspects: the main cause is poor cleaning of the filter bag, clogging of the dust filter bag, and air distribution. Not even. analyse as below:
(1) Poor cleaning device adjustment
1 Check the quality of the compressed air and install the degreasing and water removal.
2 Check the air supply pipe and air bag for free flow, low pressure or leakage.
3 Check if the pulse solenoid valve is working properly, if the fastening bolt is loose, if the diaphragm of the pulse valve is damaged, if the solenoid coil is loose, and if the spring is broken or fallen down.
4 The setting of the sequence controller meets the requirements, whether it is changed or damaged.
5 Whether the injection pipe, injection nozzle, and venturi are designed properly, installed accurately, and can be cleaned effectively.
(2) filter bag clogging
Blockage of filter bags is mainly due to excessively high filtration speed, fine dust, more viscous dust, poor filter bag ash removal, bag filter bags, condensation, and compaction.
If the design speed of the filter speed of the precipitator is higher than that of the filter bag, the fine dust in the flue gas can easily enter the fiber of the filter bag, and the clogging resistance of the filter bag increases. It is a better method to use coated film, coated filter or pre-painted surface on the surface of dust bag. For highly viscous dust, you need to reduce the filtration speed, or increase the pressure of the pulse injection, or use an off-line pulse cleaning filter bag, but a better method is to increase the filtration area, reduce the filtration speed, and extend the filter bag Service life.
Poor cleaning of filter bags mainly includes frequent ash removal and long cleaning time. Frequent cleaning frequency and excessive cleaning pressure make the filter bag fiber loose and increase the fine dust in the smoke to plug the filter bag. If the cleaning time is too long, the initial powder layer on the surface of the filter bag will be washed away, resulting in a decrease in the filtration accuracy of the filter bag.
If the cleaning time is too short, the dust on the surface of the filter bag is not fully cleaned and cleaned immediately. The dust will gradually accumulate on the surface of the filter bag, causing the filter bag to become clogged. This problem can be solved several times. Adjust the injection controller after commissioning.
Reasons for filter bag paste, condensation, and compaction:
The dust collector housing is not tightly sealed, leaks water, leaks air, and enters the air containing moisture. The compressed air used for dust removal is not clean (oily, watery), and the compressed air used for dust removal is too cold.
Gas and water in gas package should be eliminated in time
In order to prevent the filter bag from getting wet, cold air can be used to increase heat preservation, warming, degreasing, and water removal in the cold areas in winter. After the dust collector stops, the dust cleaning system can continue to open the dust removal system 10-20. To ensure that the filter bag surface less dust, reduce the possibility of condensation or compaction of the filter bag.
Water is the biggest cause of filter bag clogging. The cause of water content is usually condensation at low temperatures. When dealing with high temperature smoke, the following methods can be used to prevent this:
1 Avoid improper boot
2 Avoid booting when the dust collector resistance is high; turn it on when it is below the dew point;
When the filter bag is stopped, the condensate on the surface of the filter bag is restarted. In this case, a large amount of dust-laden air is introduced, and the high humidity will cause mud bagging on the surface of the filter bag. In order to prevent this kind of situation, it is necessary to heat the dust at the inlet of the precipitator or to precoat the ash, or to install a bypass device. After the temperature of the flue gas has reached the required level, cut into the precipitator.
3 Boot at below dew point
If the dust collector is operated below the dew point, it is prone to problems. If the intake air is not evenly distributed, local corrosion of the dust collector housing can easily occur. Therefore, the dust collector should be kept below the dew point. If it is unavoidable to start at a low temperature, insulation devices such as steam insulation or electric heating should be used.
4 Air infiltration
Air infiltration often occurs in the dust collector’s flange, access door or dust collector’s mobile device, if the seal is not strict, the outside air into the dust collector, when dealing with high temperature flue gas, it will produce a low temperature zone inside the dust collector, resulting in low temperature Condensation at the place, corrosion of dust collectors, bagging or kinking of filter bags.
(3) Uneven air distribution
If the inlet gas of the dust collector is unevenly distributed, resistance will be high when the dust collector is turned on or the resistance of the dust box is not uniform, and the filter bag will also be damaged by local high speed smoke. Therefore, it should be ensured that the air intake of the dust collector is evenly distributed.
