Composition and working principle of bag filter

The composition and working principle of the bag filter the structure of the bag filter consists of: dust hopper, air inlet and exhaust duct, filter chamber (middle and lower box), cleaning chamber, filter bag and frame (bag cage bone), manual air inlet valve, pneumatic butterfly valve, pulse ash cleaning mechanism, etc Working principle of bag filter: bag filter is a filter type dust removal equipment based on the filtering principle It uses organic fiber or inorganic fiber filter cloth to filter out the dust in the gas Dust removal process: the dust containing gas enters the middle box from the air inlet, enters the cloth bag from the outside of the filter bag, the dust is blocked on the surface outside the filter bag, the purified air enters the bag, then enters the upper box from the upper part of the cloth bag, and Zui is discharged from the exhaust pipe 1、 Working principle of bag filter: after the dust containing gas enters from the air inlet at the upper part of the ash hopper, under the action of the wind shield, the air flow flows upward and the flow rate decreases Some large particles of dust are separated and fall into the ash hopper due to the inertial force The dust containing gas enters the middle box and is filtered and purified by the filter bag The dust is blocked on the outer surface of the filter bag The purified gas enters the upper box through the filter bag mouth and is discharged by the air outlet With the increasing dust on the surface of the filter bag, the pressure difference between the inlet and outlet of the precipitator also rises When the resistance of the precipitator reaches the set value, the control system sends out the dust removal instruction, and the dust removal system starts to work First, the solenoid valve is opened immediately after receiving the signal to make the small diaphragm The compressed air in the upper air chamber is discharged Due to the change of the force on both ends of the small diaphragm, the exhaust channel closed by the small diaphragm is opened The compressed air in the upper air chamber of the large diaphragm is discharged from this channel The force on both ends of the large diaphragm is changed, making the large diaphragm act, opening the closed output port, and the compressed air in the air bag is injected into the bag through the output pipe and the spray pipe to realize ash cleaning When the control signal stops, the solenoid valve is closed, the small diaphragm and the large diaphragm are reset one after another, and the injection stops Pulse valve is the key part of pulse bag filter, and its service life is the concern of user Zui The company can provide imported filter bags and pulse valves according to the needs of users 2、 The cleaning method of bag filter is an important factor to determine the performance of bag filter The basic types of bag type dust remover are: mechanical vibration cleaning, back blowing cleaning, combined vibration cleaning, pulse back blowing cleaning and pulse jet cleaning The low-pressure pulse bag filter belongs to the pulse jet cleaning mode 3、 Technical features of bag filter (1) the submerged pulse valve is adopted, which can open and close quickly and has small resistance For 6-8 meter long filter bag, the injection pressure is only 0.15-0.3mpa, which can obtain good dust removal effect (2) strong ash removal ability The acceleration obtained on the surface of the filter bag is far greater than that of other types of bag type dust remover, which is uniform in dust removal and has good effect (3) high filtering load Because of the guarantee of strong dust removal, the resistance of the dust collector will not be too high even if it operates at a high filtering wind speed, generally 1200-1500pa Compared with the counter blowing dust collector, the pulse bag dust collector has a larger processing air volume with the same filtering area (4) it is convenient to check and replace the filter bag The filter bag is easy to install and change, without binding The operator does not need to enter the box, and the operation environment is good (5) low equipment cost Due to the high filtering load, the filtering area required for the treatment of the same flue gas volume is smaller than that of the back blow bag filter, so the equipment is compact and the floor area is small (6) advanced control technology The control system based on PLC can control the operation parameters of dust remover, inlet flue gas temperature and dust removal pressure in real time, which has complete functions, stability and reliability 4、 Technical performance: the technical performance of the low-pressure pulse bag filter is mainly reflected in the processing air volume, dust concentration at the outlet, equipment resistance and the service life of the filter bag (1) air volume treatment: the low-pressure pulse bag filter can deal with the dust with large air volume so as to reduce the filtering area, miniaturize the equipment and save investment Under the condition of satisfying the object of dust removal, the appropriate filtering wind speed can be determined according to the way of dust removal, the nature of dust, the material of filter bag, etc (2) the dust concentration at the outlet of the low-pressure pulse bag filter has a high dust removal efficiency, and the dust concentration at the outlet can meet the national emission standards, even up to 10mg / M 3 (3) equipment resistance the resistance Δ P of the dust collector is directly proportional to the power of the fan, which is an index directly related to the energy consumption of the fan and involves the operation cost of the dust removal system The resistance of the precipitator is related to many factors, such as the structure of the device, the type of filter material, the nature of dust, the way of cleaning dust, the filtering wind speed, the temperature and humidity of the gas The low pressure pulse bag filter can control the resistance of the filter within the range of 1200-1500 PA Ensure that the deposited dust can be removed quickly and evenly from the filter cloth without damaging the filter bag and consuming less power The resistance of dust collector is composed of three parts: Δ P = Δ p 1 + Δ p 2 + Δ p 3, among which Δ p 1 - mechanical resistance Δ p 2 - resistance of filter cloth Δ p 3 - resistance of dust layer (4) service life of filter bag The service life of the filter bag is related to its material, flue gas temperature, composition, acid dew point, dust property and other factors At the same time, it is also affected by the filtering wind speed, inlet dust concentration, ash cleaning frequency and management and maintenance Therefore, for a dedusting equipment, it is necessary to correctly select important parameters such as filtering wind speed, filter bag material, and ash cleaning method to ensure the service life of filter bag