Dust disposal - cloth bag filter with pulse filling instrument is more convenient to use. Pulse dust collector is when the dust-containing gas enters the dust collector from the air inlet, first touches the inclined plate and baffle in the middle of the air inlet and outlet, the air flow will turn to flow into the ash hopper, at the same time, the air velocity slows down, due to inertia, so that coarse particles in the gas directly into the ash hopper. As a pre-dust collector, the air flow into the ash hopper is then folded upwards through a filter bag with a metal skeleton inside, and the dust is trapped on the outer surface of the filter bag. The purified gas enters the upper cleaning room of the filter bag chamber, and is collected and discharged to the outlet. The dust-containing gas accumulates in the process of purification through the filter bag with the increase of time. More and more dust on the filter bag, increase the resistance of the filter bag, resulting in a gradual reduction of air handling, for normal work, to control the resistance within a certain range (140-170mm water column), once beyond the range must be carried out on the filter bag ash, ash removal by the pulse controller triggered the sequence of control valves open pulse valve, the pressure in the air bag. Shrinkage air is injected into the corresponding filter bags by Venturi tube through the holes of the injection tube. The filter bags expand rapidly instantaneously, which makes the dust accumulated on the surface of the filter bags fall off and the filter bags return to their original state. The dust falls into the ash hopper and is discharged through the ash disposal system. Thus the dust accumulated on the filter bag is periodically Pulsatively injected to clear the dust, so that the purified gas passes through normally and the operation of the dust removal system is guaranteed.
Analysis of problems in the use of bag filter
(1) control mode of reverse blowing and ash cleaning
The frequency and strength of reverse blowing and ash cleaning are one of the main factors that affect the life of bag filter. Because the load of utility boiler and coal quality fluctuate greatly, the flue gas volume and dust concentration fluctuate greatly. Therefore, several back-blown dust cleaning modes should be set up according to the pressure difference between the upper and lower chambers of the dust collector (the clean gas chamber and the bag chamber) in order to adapt to the change of coal-fired boiler working conditions. The service life of the dust collector is prolonged.
(2) ash fouling
Because the bag dust collector uses water flushing to discharge ash, that is, the ash falling into the ash hopper is discharged into the ash flushing water tank through an electric air lock and then discharged from the trench.
In winter, the ash bucket blocking problem will occur when the boiler is just started or after a long period of shutdown and re-commissioning bag filter. The analysis shows that this is due to the ash hopper condensation and the lack of strict electric lock. Winter outdoor temperature is low, after the dust collector starts, hot smoke into the ash hopper will condensate in the cold wall of the ash hopper, and here is a stagnant zone of flue gas, can not be.
The rapid heating of flue gas makes the ash falling into the ash hopper stick to the wall of the ash hopper and causes ash blockage; at the same time, if the electric gas lock is not tightly sealed, the "water gas" in the ash flushing tank will be sucked into the ash hopper, and the ash trap will be easily blocked by condensation at the ash mouth under the ash hopper. In addition, the power of ash hopper heating device is small and installation position is unreasonable, which is also the cause of ash blockage. Therefore, in the design of the ash bucket, the power and installation position of the ash bucket heating device should be calculated on the basis of fully considering the local temperature and ash discharge form, and the preheating program of the ash bucket should be added to the cloth bag start-up control; at the same time, a safe and reliable gas lock with good sealing performance should be selected, and the temperature protection of the ash bucket should be strengthened.
(3) treatment of smoke from bag filter
Cloth bag filter if smoke or ash, are serious damage, should be dealt with in time. Generally speaking, there are two reasons for smoke, one is due to the bag bag broken cloth dust collector hanging up and down is not tight, the connection between the ceiling and the ceiling is not tight. The other is instantaneous smoke, encountered in this case is actually the dust bag broken but the situation does not disperse is very serious. The efficiency is significantly improved. If the dust bag is seriously damaged, the dust bag can be replaced. Stop the bag filter first, then turn off the dust removal controller, open the entrance door, and remove the bag. When installing new dust bag, clean up the dust on the ceiling.
(4) failure of anti blow ash cleaning system
The main faults of back-blowing ash cleaning system are: back-blowing solenoid valve does not move, compressed air pipeline water and rotary mechanism jam. In addition, the quality of back-blown compressed air (mainly water and dust) and the stability of power supply will affect the normal operation of the solenoid valve. In winter, the outdoor compressed air pipeline is easy to accumulate water or freeze because of the lower outdoor temperature in the north. Therefore, the design of outdoor compressed air pipeline should design the drainage point and thermal insulation measures, especially in cold areas need to increase heat tracing. Because one part of the rotary mechanism operates in high temperature flue gas and the other part operates at ambient temperature, the temperature difference between the two parts is large, which is easy to cause deformation and jam. Therefore, temperature factors should be fully considered in the design