4 major factors affecting dust collection effect of dust collection bag filters
Pulse bag filter is a dry dust filter device. It is suitable for collecting fine, dry, non – fibrous dust. In the practical operation of dust collector, there will be some problems such as poor purification effect or ash emission, low dust collection efficiency or excessive discharge.
In this paper, four main aspects affecting dust collection efficiency of pulse bag filter are shared, and corresponding solutions and optimization measures are put forward.
01 The filter bag
1.1 Filter bag material
The material of the pulse bag filter plays a decisive role in dust collection efficiency. The performance and use of precipitate are very high in many enterprises with 24 hours non-stop production.
Therefore, the dust filter bag material should have enough strength to withstand multiple frequency and high pressure spraying, good air permeability, good filtration effect, long service life and high cost performance.
1.2 Filter bag damaged
The diameter difference between filter bag and keel is very important. When the clearance is too small, the expansion and contraction of the filter bag can not meet the requirements, which will cause poor cleaning effect; When the fitting gap is too large, the filter bag will increase friction with the keel, resulting in accelerated wear of the filter bag. Generally, the filter bag and the keel are closely matched, but there is a certain gap. Usually, the filter bag circumference is 10 mm to 20 mm larger than the keel, and the length remains the same.
Another keel fracture, deformation or welding burr, will also cause accelerated wear of the filter bag. In addition, the filter bag should be made of cloth bag with elastic ring, so that the flower plate and the filter bag are tightly sealed, reducing the wear at the top of the filter bag deconvolution.
When assembling, make sure that the spray tube is aligned with the filter bag, and prevent damage to the filter bag caused by mechanical friction in the upper part of the filter bag caused by the improper position of the spray tube.
1.3 Filter bag blockage
The main reason for the blockage of the filter bag is that the dust is damp or sticky, the filter bag is poor and the filter bag is damp.
(1) The dust is moistened or sticky, which leads to the blockage of the outer surface of the filter bag. The resistance of the filter bag increases, which affects the dust removal efficiency. Generally, the dust is sprayed for 10-20min after shutdown.
(2) The reasons for the poor cleaning of filter bag mainly include too many cleaning times and too long cleaning time. The cleaning frequency is too frequent to make the fiber organization of the filter bag loose and increase the fine dust in the gas to plug the filter bag. The cleaning time is too long and the initial powder layer on the surface of the filter bag will be cleaned off.
(3) The filter bag is damp: the main reason is that the dust collector shell seal leakage, into the wet air, compressed air for spraying dust contains water. In order to prevent the filter bag from being damp, the compressed air tank used for dust cleaning can be insulated and dewatered. The air source trilink of the compressed air pipeline can be drained and refuelled in time, and the dust cleaning can continue for 10-20min after the dust collector stops.
02 Filtering wind speed
When the dust particle size is fine, temperature, humidity is high, concentration is large, viscosity is large, the filter wind speed should be lower, on the contrary, the high value can be selected.
2.1 induced draft fan
The induced draft fan motor power meets the requirements, too low power will lead to insufficient wind pressure, low wind speed, dust can not be effectively purified and filtered.
High power will lead to excessive filter wind speed, will increase the filter bag load, resulting in short service life of the filter bag, low efficiency. Regularly check the induced draft fan impeller, check whether the impeller has deformation, damage, timely adjustment or replacement processing.
2.2 Pipeline branches are too long and excessive
According to the power of each dust collector, the number of dust collector is reasonably equipped, and the dust collecting equipment corresponding to each dust collector is reasonably calculated and matched, so as to ensure that it can not only meet the needs of on-site purification, but also maximize the use of dust collector.
03 Air leakage
The air leakage of pulse dust collection bag filters directly affects the dust collecting effect of the dust collector, and the air leakage rate is generally less than 3%.
3.1 Pipe Damage
The compressed air pressure used by pulse bag type dust collector is generally 0.02-0.8mpa. The compressed air pipe or spray pipe is damaged, air leakage will cause under pressure, and the pressure of the air chamber spray pipe is insufficient, resulting in the shrinkage and expansion of the bag, and the powder material on the bag is not easy to be completely clean. Check regularly whether the blowpipe is aligned with the filter bag.
3.2 Electromagnetic pulse valve, can instantly open and close high pressure air source pulse
Controlled by the output signal of the pulse controller, the filter bag is sprayed and cleaned room by room, so that the resistance of the dust collector is kept within the set range, so as to ensure the dust removal capacity and dust collection efficiency of the dust collector.
Daily check whether the electromagnetic pulse valve is working normally, fastening bolts are loose, open the electromagnetic pulse valve to check whether the size of the diaphragm is damaged, whether the diaphragm hole is positive, whether the electromagnetic coil is loose; Whether the spool is stuck, pay special attention to the compressed air line valve must be closed during the electromagnetic pulse valve inspection.
3.3 Gas chamber valve
The valve plate of the air chamber valve is kept in the recycling state before the air chamber is sprayed and cleaned. When the cylinder is opened, the valve plate installed on the top of the cylinder is closed to the air outlet of the air chamber, and the negative pressure of the pipeline of the induced draft fan is cut off. Then, under the control of the electromagnetic pulse valve, the bag is sprayed and cleaned.
The shedding of the valve plate of the air chamber valve will lead to the outlet air flow of the air chamber can not be closed. The negative pressure of the induced draft fan operation and the positive pressure of the pulse solenoid valve through the blowpipe to the filter bag are offset, leading to the expansion and contraction of the filter bag can not meet the requirements, and the dust cleaning of the filter bag is not clean and the dust cleaning effect is poor.
To regularly open the upper cover of the gas chamber, check the valve plate of the gas chamber valve, check whether the valve plate is welded and deformed, check whether the fastening nut of the valve plate falls off, and tighten it in time.
04 Heat preservation
Heat preservation is to keep the gas dry, avoid the gas moisture, so as not to cause the knot of the powder and form the paste bag. Most filter bags appear daub, blocked paste bag phenomenon, is because of low dust temperature, compressed air humidity and other factors caused.
In the autumn and winter season in the north, the bottom of the air storage tank for wind can be wrapped with cotton cloth or wrapped with electricity, and the bottom of the regular drainage treatment. Regularly drain and refuel the air source triplet of the compressed air pipeline of the dust collector.
Do a good job of the operation and maintenance of the dust collector, improve the efficiency of dust removal, can effectively reduce the loss of air volume system, reduce energy consumption, but also can reduce the number of pollutants discharged, reduce the pollution to the environment, so that enterprises to achieve green production.