Analysis of Common Operation Faults of Pulse Bag Filter

Common faults in operation can usually be classified as dust collector high pressure, excessive dust discharge, and too short operating life of the filter bag.

1. High resistance

The resistance of the precipitator has been determined during the design phase. However, during the operation of the precipitator, if the resistance of the precipitator is suddenly added at a short time, this indicates that the precipitator has encountered problems during the operation and should be repaired and adjusted.

There are two types of factors that have too much resistance:

1.1 Problems with the dust collector immediately after startup

If the resistance of the new dust collector is high, it can be classified as an overall design problem.

1.2 Problems with the dust collector after a period of use

The primary factor is improper operation and problems during the repair process: generally, the filter bag is poor in cleaning, the filter bag is blocked, and the air intake is not evenly distributed.

1.2.1 Improper adjustment of pulse cleaning equipment

Check the quality of the compressed air regularly, whether it contains oil, and whether the water and air supply lines are clear.

It is normal to check whether the pulse solenoid valve is operated at regular intervals, whether the fastening bolt is loose, the diaphragm is not damaged, the electromagnetic coil is not loosened, and the spool is not stuck.

Check whether the setting of the control device meets the requirements and whether it has been changed.

Check if the jet branch pipe or venturi pipe is accurate.

1.2.2 Filter bag obstruction

The primary factors for the obstruction of the filter bag are the excessive filtering speed, the fine dust, the sticky dust, and the filter bags that are poorly cleaned. If the filter speed at which the filter is operated exceeds the planning standard of the filter bag, it is easy to trap the fine dust in the exhaust gas inside the filter bag fiber and then cause the filter bag to become clogged.

It is a good idea to use coated media. For viscous dust, reduce the speed of the filtered air, or increase the pressure of the pulse jet, or use offline pulse cleaning filter bags. The better way is to increase the filter area, in order to facilitate the decline in the filtration speed, extending the life of the filter bag.

1.2.3 Poor filter cleaning

Poor cleaning of the filter bag includes frequent cleaning times and long cleaning time. The frequency of ash cleaning is too frequent to loosen the fiber of the filter bag and then increase the fine dust in the exhaust gas to block the filter bag. Excessive cleaning time will clear the initial powder layer of the filter bag at the same time.

If the cleaning time is too short and the dust on the outer surface of the filter bag is not completely clean and clean, it will be filtered immediately. The dust will gradually accumulate on the outer surface of the filter bag, and then it will become a blockage of the filter bag. When dealing with this kind of problem, several trial runs are required to make adjustments.

1.2.4 Filter bag damp

The filter bag is affected by dampness: the filter housing is not sealed tightly and leaks water and enters the air with moisture. The compressed air used for returning the cleaning dust is not clean (oily, watery), and the compressed air used for cleaning is too cold.

To prevent the filter bag from getting wet, in the cold regions, the compressed air used for cleaning is warmed, deoiled, and removed, and the dust is removed after the dust collector is shut down.

1.3 Avoidance of Excessive Moisture Prevention Measures

Moisture is the biggest factor in the obstruction of the filter bag. The factors that make up the moisture content are usually low temperature episodes of condensation, especially when dealing with incineration or high-temperature smoke. The following options can be used to avoid this condition:

1.3.1 Avoid Improper Startup

1) When the dust collector resistance is large, start up: after the dust collector stops, the filter bag will start again when there is condensed water on the outside. If a lot of dusty air enters at the moment, high humidity will cause the filter bag to muddy. In order to prevent such conditions, dust collector dust inlet air or pre-dust layers should be warmed up.

2) Switch on below the dew point: the dust collector runs below the dew point. If the air is not evenly distributed, it forms the corrosion of the dust collector housing. Therefore, the dust collector should be prevented from running below the dew point.

1.3.2 Air Entry

The air enters the active equipment that often attacks the dust collector flange, repair door or dust collector. If the seal is not strict, the outside air enters the dust collector. When the high temperature exhaust gas is treated, it will attack the low temperature area inside the dust collector, and then cause condensation at a low temperature, which will corrode the dust collector and make the filter bag damp.

1.4 Gas Dispersion

If the inlet gas of the dust remover is unevenly distributed, resistance will be greater when the dust remover is turned on. Therefore, make sure that the air intake of the dust remover is evenly distributed.

2. The basic factors of excessive dust emission

2.1 The initial layer of the outer surface of the filter bag is not

In the operation of the pulse dust collector, if the discharge exceeds the standard and the operating pressure of the dust collector is lower than the designed value, it is very likely that the initial powder layer of the filter bag is lacking. The factor may be that the filtration speed of the filter bag is too high, and the filter bag is The cleaning cycle is too short, the pressure for blowing compressed air is too high, and the adhesion of dust is reduced.

2.2 Damage to filter bag (wear, burn, corrosion)

Replacement of the filter bag accounts for the largest proportion of the maintenance cost of the dust collector, up to more than 70% of the maintenance cost. Its fundamental condition is wear, burning, corrosion, etc.

2.2.1 Wear

1) Excessive filtration speed: Excessively high filtration rate causes dust to impact and abrade the filter bag, and also impairs fabric fiber tension in the filter bag. Treatment method: adjust the inlet flow of the dust collector.

2) Uneven distribution of air intake: the uneven air intake of the dust collector makes the high-content large-particle dust directly impact some filter bags. It is easy to perforate some filter bags at the inlet of the waste gas and the application cycle is too short.

Treatment method: inlet diffuser guide plate is used at the air inlet duct of the dust collector to replace the filter bag, which is frequently worn, with a wear-resistant filter bag.

3) The interval between the filter bags is too small: the interval between the filter bags is too small, and the dust skeleton twists and turns to form the wear between the filter bags. If the glass fibers are sensitive to each other, they should be adjusted, the equipment must be strong and the tortuous skeleton should be replaced.

4) The diameter of the filter bag and the frame do not match: if the cleaning is too small, the cleaning effect is not good. The cleaning cycle should be increased and the air pressure should be increased. When the filter bag is too big, the collision between the filter bag and the skeleton will accelerate the wear. The better fit is that the filter bag is 10-20mm longer than the perimeter of the frame, the length should be the same, and some filter cloths will change with temperature and have elongation. The special features require special attention.

5) Miscellaneous: when the frame of the dragon has a hole or burr at the weld, or the rough appearance due to corrosion, it will also accelerate the wear of the filter bag. Poor sealing between the filter bag and the perforated plate will cause wear on the top of the filter bag at the back pleats. It is better to use a flexible ring instead.

Venturi tube or pulse tube is not properly aligned with the filter bag, causing mechanical conflict in the upper filter bag and should be adjusted.

The filter bags are cleaned too frequently, the dust contained in the exhaust gas exceeds the planning standards, and the dust stored in the dust collectors is too much dust, which will accelerate the wear of the filter bags.

2.2.2 Incineration

The factors that constitute the incineration of the filter bag of the dust collector are mainly the temperature of the dust.

2.2.3 Corrosion

The primary factor of corrosion is that the dust is rich in acid and alkaline components, and the dew point is changed as the concentration of these chemical gases changes. If the dust remover is turned on or shut down below the dew point, the SO2 in the exhaust gas will constitute H2SO2.

Constitute the filter bag fiber deformation and lose strength, to avoid the approach is to use acid and alkali filter bags, the dust collector inlet pipe, shell insulation, conditional conditions can give dust collector heating.

Condensation water in the exhaust gas also constitutes the obstruction of the filter bag. When the initial dust layer on the outside of the filter bag is due to moisture, the dry dust will cause the dust to condense and compact, and then cause the filter bag type to be elastic.

If the filter bag is pulsed under this condition, the filter bag will be damaged. The dust filter is used to stop the pulse and clean the filter bag several times, which is advantageous for maintaining the filter bag.

3. The filter bag is too short

The factors affecting the service life of the filter bag are as follows: improper selection of filter bag raw materials, filtration speed, dust adhesion, dust composition, dust characteristics, cleaning methods, cleaning frequency, system startup, and shutdown times. When identifying the useful life of filter bags, you should consider whether it is improper to use them and carefully check and record the status of the dust collector. Does the dust collector often turn on and off at the dew point and the pulse cleaning cycle and cleaning time are not reasonable? . Equipment differential pressure gauges and thermometers are prerequisites for ensuring records, and they are also one of the ways to ensure the normal operation of the dust collector.