Application of Boiler Bag Dust Collector
The bag filter of 9 boilers in this project has been operated for 2 heating periods, and all indicators have reached the design requirements. The measured outlet dust concentration is below 50mg/m³. The operation of the boiler has never been affected by the dust collector problem during operation, and the emission standards are stable. The PLC automatic control system runs normally and runs according to the pre-set program. As long as a certain parameter exceeds the specified range, the PLC system can promptly alarm and activate the bypass flue and bag. Application precautions are as follows: (1) Pre-sprayed bag filter of the bag filter is pre-sprayed on the bag before it is put into operation and stopped for a long time, that is, a protective layer is sprayed on the outer surface of the bag in advance to prevent Very fine dust enters the filter cloth to block the pores and is extremely difficult to clear out. At the same time, it prevents the tar substance in the oil fume from blocking the filter bag when the boiler is ignited with oil.
Shutdown maintenance of the bag filter. If the air box pulse filter is out of service for a long time, take maintenance measures to prevent the bag from being damp, compacted and corroded. Close all the inlet and outlet valves of the dust collector. During the shutdown, open the inlet and outlet valves at regular intervals, use the chimney for natural ventilation for 4 hours, or turn on the electric heater for 8 hours to drive away the moisture in the dust collector and keep it dry.
Selection of bag filter ①Pay attention to the requirements of temperature resistance, acid resistance and alkali resistance of the filter material. At present, the optional filter material of bag filter used in boilers includes Leyden, glass fiber laminating and so on.
Pulse blowback is used, and a larger air-to-cloth ratio can be used to reduce the number of filter materials and reduce the size of the dust collector.
According to the pressure of compressed air, the bag filter is divided into high pressure pulse type (0.5～0.8MPa), medium pressure pulse type (0.2～0.4MPa) and low pressure pulse type (0.06～0.10MPa). The three forms cause great differences in the structure of the dust collector, but the dust removal effect is very good, which should be determined according to the specific situation.
The bypass flue of the bag filter, PLC control device and automatic ash hopper heating device are all available. Whether to install water spray or cold air cooling measures before the dust collector, it needs specific analysis.
How to discharge, store and transport the fine ash separated by the bag filter must also be handled well, otherwise it will cause secondary pollution.
The pulse bag filter is a dry filter device. It is suitable for capturing fine, dry, non-fibrous dust. When the dust-containing gas enters the pulse bag filter under the negative pressure of the induced draft fan, due to the action of gravity, part of the dust particles settle down and fall into the hopper, and part of the dust particles are blocked when the gas passes through the filter bag , Adsorbed on the filter cloth bag, after the cycle time, the air chamber valve plate of the air chamber of the dust collector is closed, and then the pulse valve is opened, and the compressed air enters from the top-down direction from the opening of the filter cloth bag through the blowing pipe, and passes through the filter bag instantly After shrinking, expanding and shrinking, the dust adsorbed on the outside of the filter bag is cleaned to the hopper, and then the powder is discharged through the screw conveyor and then discharged through the star dis-charger, so that the powder is concentrated and recovered, and the gas is purified.