The use and maintenance of pulse cleaning bag type dust collector
General problems and matters needing attention in the use and maintenance of bag type dust collector:
The use of bag type dust collector general maintenance problems and matters needing attention can be divided into dust emissions exceed the standard, the pressure of the dust collector is higher than normal, and the service life of the filter bag is too short in three aspects, there is a clear link between the three, as follows:
One, excessive dust emissions
The basic reasons for excessive dust emission
1 of the initial layer is not the surface of the filter bag;
2 bag breakage;
3 bad bag assembly;
Respectively described as follows:
1, the initial layer is not the surface of the filter bag
In the dust collector operation, if the emissions exceed the standard and operating pressure filter design is too low, is likely to be the initial lack of surface powder layer bag, the reason may be the cleaning cycle filtration rate is too high, the bag bag is too short, blowing compressed air pressure is too high, the dust load decreased etc..
The filtration rate is too high, the dust removal rate will increase, high filtration velocity, the initial dust layer is broken, and the impact caused by the excessive wear dust bag, if this number is too high can easily lead to clean the filter bag bag fabric loose, which will cause the dust emissions exceed the standard.
In periods of collector pulse cleaning, to ensure the pulse cleaning cycle time filter working set under stable pressure, the longest pulse cleaning time as well, to ensure the initial dust does not fall off, set the shortest time cleaning as well, if the initial dust layer, can be used to prolong the cleaning period compensation, if the use of differential pressure control, improve the stability of precipitator inlet and outlet pressure can be set.
If the dust emission exceed the standard is only in the bag after cleaning, you only need to check the pulse cleaning of the compressed air pressure is too large.
The dust load is reduced from may reduce productivity, or maintenance, is the control system of dust collector due to the adjustment, the solution method: the method can be used with a light load slowly began to rise by pre load or dust cover to solve.
2, the filter bag damage (wear, burn, corrosion)
The use of bag precipitator maintenance costs accounted for the largest, up to 70% of the cost of maintenance. The basic situation is wear, burn, corrosion and so on, the method can be used in the following ways:
1 wear
High filtration velocity, resulting in shock, wear dust bag, also make the fabric fiber tension bag is damaged, the solution: adjust the flow of waste gas, dust collector, when the flow changes are expected to greatly, can increase the flow of automatic control system to ensure the filter working in a stable gas.
Gas distribution of dust collector are easy to make a direct impact on the local exhaust dust bag containing high content, easy to exhaust gas inlet part of the bag perforation, use cycle is too short, the solution: in the precipitator inlet conduit is installed at the inlet guide for distribution, or often wear parts of the bag to replace the wear resistance the bag.
The bag is too small, the distance between the keel and so easy to wear and tear caused by the bending bag between the keel should be adjusted and firmly installed the bag and replace bent.
The difference between the keel and the diameter of the filter bag is too small, poor cleaning effect, should improve the cleaning cycle and improve the blowing air pressure, friction with the keel of the bag is too large, will accelerate the wear, with better than 10~20mm for the bag perimeter of the keel, the length should be consistent, some characteristics of the filter changes greatly with temperature and the elongation, the need to pay special attention to.
Keel place of welding holes or burrs, rough surface or caused by corrosion, will accelerate the wear of the filter bag. The filter bag and the porous plate sealing, will cause the bag top fold wear, with good elastic ring. Venturi or pulse tube bag is relatively easy to align, the upper bag produces mechanical friction, should be adjusted. The bag too frequent cleaning, accelerates wear bag, should be adjusted. More than design standards for dust emissions, will also enable the bag to accelerated wear. The dust collector dust ash storage too much, will accelerate the wear of the bag.
All the above reasons will cause the dust collector to exceed the standard, and it will also reduce the service life of the dust collector.
2 burned
The reason caused by burning dust bag, mainly to the high temperature of exhaust gas. If the temperature of exhaust gas dust remover long handled more than bag working conditions, easy to make the bag hardening shrinkage, or melt to produce holes, is particularly important in the choice of when to replace the bag.
3 corrosion
The condensed water in the air will cause clogging of the filter bag dust filter bag, when the initial surface layer due to moisture, dry dust will cause condensation, compaction, which leads to the elastic bag, if under the condition of pulse cleaning bag, the bag will accelerate the damage.
The dust collector shutdown and then pulse cleaning bag several times, is beneficial to the protection of the bag.
Two, the resistance is too high
Collector resistance has been determined in the design of dust collector, but in running, if it is found that the dust resistance increased dramatically in a short period of time, said the problem of dust collector, should carry out repair and adjustment.
1 cleaning device adjustment poor
Check the quality of the compressed air, whether it contains oil and water; check the gas supply pipe is smooth; check the pulse electromagnetic valve is working properly, the fastening bolts are loose, the diaphragm is damaged, the electromagnetic coil is loose; the spool is jammed; whether the sequence control instrument set in accordance with the requirements, whether the change; jet pipes, venturi tube is installed accurate;
2 bag jam
The main reason is the filter bag jam speed is too large, too small, sticky dust, dust bag, bag with poor cleaning.
If the gas filter dust collector runs faster than the bag design standard, could easily lead to fine dust in the air in the bag stuck inside the fiber. To plug the filter bag. The coated filter material on the surface or pre coating protective powder layer bag, is a good method.
For dust with large viscosity, is the need to reduce or increase the filtration velocity, pulse pressure injection, or the use of off-line pulse cleaning bag, but a better approach is to increase the filtering area, in order to reduce the filtration velocity, prolong the service life of the filter bag.
Bag cleaning bad mainly includes the frequency of cleaning, frequent cleaning time. The frequency of cleaning frequency is easy to loose fibrous tissue bag thereby increasing the fine dust exhaust clogging in the bag, cleaning time is too long will be the initial powder layer bag surface together with the cleaning.
If the cleaning time is too short, the surface of the dust filter bag is not completely clean, then began to filter dust, gradually accumulated in the bag surface, resulting in clogging of the filter bag, to solve this problem, can be adjusted through several test run.
Reason: for cleaning damp bag of compressed air is too cold. In order to prevent the bag in the damp, cold areas, can be used for cleaning the compressed air ash increase insulation, heating, oil, water, dust in the shutdown and then continue cleaning 10~20. Water is the biggest reason for the cause of blockage of the filter bag, containing water is usually low temperature condensation occurs, especially in the treatment of burn or high temperature flue gas, such a situation can be used the following methods to prevent:
Avoid improper boot
Avoid the dust collector resistance when the boot;
Boot at less than dew point;
Reboot after shutdown in the dust collector bag surface condensation water, so when entering a lot of dust air, with high humidity will cause the surface of muddy bag.
In order to prevent and cure this kind of situation, we should preheat the dust collector to import the dust laden air, or pre covering the dust layer.
At less than the dew point
The dust collector below the dew point operation, prone to problems, if the gas distribution is not uniform, easy to cause corrosion, local dust precipitator therefore should avoid dust remover in coagulation below dew point, the thermal insulation device should be used.
The air infiltration
Air infiltration often occurs in the dust of the flange, access door or dust filter of the active device, if the seal is not strict, the external air into the dust collector,
When dealing with the high temperature exhaust gas, will produce a low temperature zone in the precipitator internal, resulting in low temperature condensation, corrosion caused by damp dust collector, filter bag.
3 improper gas distribution
If the inlet gas distribution of the dust collector is not uniform, the resistance is bigger when the dust collector starts, so the air inlet distribution of the dust collector is uniform.
Three, the life of the filter is too short
The following factors affecting the service life of the filter bag:
The improper use of the filter bag filter bag variety; quality; filtration velocity; dust dust dust load; components; properties; cleaning method; cleaning frequency; system startup, shutdown times and maintenance work.
In the evaluation of the service life of the filter bag, should consider whether the use of improper, carefully check and record collector working conditions, dust collector are often below the dew point startup, shutdown, and pulse cleaning cycle, the cleaning time is reasonable, installation of differential pressure gauge, thermometer is a prerequisite to ensure the record. Is to ensure the normal operation of the dust collector.
