Dust removal principle of environmental protection equipment
Bag dust collector
The working principle of the dust collector is as follows: the dust-containing gas enters the filter room from the open flange at the lower part, and the coarse particles directly fall into the ash bin. The dust-containing gas is filtered by the filter bag, and the dust is retained on the surface of the bag. The clean room is exhausted into the atmosphere by a fan. When the dust on the surface of the filter bag continues to increase, the program controller starts to work, and the pulse valve is opened one by one, so that the compressed air is blown through the nozzle to clean the filter bag, so that the filter bag suddenly expands. The dust quickly leaves the filter bag and falls into the ash bin, and the dust is discharged from the ash discharge valve.
The dust collector is mainly composed of an upper box body, a middle box body, an ash hopper, an air inlet equalizing pipe, a support filter bag, an injection device, and an ash discharge device. Dust-containing gas enters the ash hopper of each compartment from the air inlet equalizing pipe of the precipitator, and under the guidance of the ash guide device, the large particles of dust are separated and directly fall into the ash hopper, while the finer dust enters uniformly. The middle box is adsorbed on the outer surface of the filter bag, and the clean gas passes through the filter bag and enters the upper box, and is discharged into the atmosphere through the off-line valves and exhaust pipes. With the progress of the filtering conditions, the dust on the filter bag accumulates more and more. When the equipment resistance reaches a limited resistance value (generally set to 1500Pa), the dust cleaning control device sets the differential pressure or the dust cleaning time. After the set value automatically closes the off-line valve in the first room, the electronically controlled pulse valve is opened according to the set procedure to stop the air blowing. The compressed air is instantly blown to increase the pressure in the filter bag, and the dust on the filter bag is shaken off. (Even if sticky fine dust can be cleaned thoroughly), it will be discharged into the ash bucket by the ash discharge mechanism.
After the bypass of the cyclone dust collector, the working principle is that the dust-containing gas enters tangentially from the inlet. At the same time as the airflow obtains the rotating motion, the airflow is separated up and down to form a double spiral movement. The dust is strongly generated at the boundary of the double spiral. The thicker dust particles are separated to the outer wall by the lower spiral airflow, and some of the dust is drawn out from the central opening of the bypass separation chamber, and the remaining dust is brought to the ash bucket by the downward airflow. The upper spiral airflow has a gathering effect on fine particle dust, thereby improving the dust removal efficiency. This part of the fine dust particles is formed by the upper spiral airflow belt to the upper part, forming a strongly rotating upper dust ring under the top cover, and enters the upper opening of the bypass separation chamber together with the upper spiral airflow, and is introduced into the cone through the return air outlet. Converges with the internal air flow, the purified gas is discharged from the exhaust pipe, and the separated dust enters the hopper.
After the dust-containing gas enters the equipment from the air inlet on the top of the device, it passes through the cyclone separator at high speed, so that the dust-containing gas is adjusted to rotate downwards along the axis, and the centrifugal force is used to remove coarse particles of dust, which effectively controls the initial entry of the electric field. Concentration of dust. Then, the gas enters the electric field to work through the lower ash bucket. Because the lower ash bucket's cross-sectional area is several times larger than the inner pipe's cross-section, according to the principle of constant rotation moment, the radial wind speed and axial wind speed are sharply reduced to produce a zero-speed interface. The heavy particles of dust settle in the lower ash hopper, which reduces the dust concentration entering the electric field. The low-concentration dust-containing gas is condensed on the anode and cathode plate by electric dust collection, and the collected dust is discharged by the air lock after being shaken by dust cleaning. The ash device is transported away. In order to prevent the secondary dust generated in the lower ash hopper after the inner tube whirl and the electric field plate vibrating, an isolation cone is set in the lower ash hopper.
Scope of use: Cement, fertilizer, and other industries, such as various mills, crushing point feed openings, packaging machines and dryers, and various similar dispersing sources.
Cartridge dust collector
Under the function of the main fan of the system, the dust-containing gas enters the air box at the bottom of the dust collector from the air inlet at the lower part of the dust collector for pre-treatment of the dust-containing gas, and then enters into the dust removal chambers of the upper box from the bottom; dust adsorption On the outer surface of the filter cartridge, the filtered clean gas passes through the filter cartridge and enters the clean air cavity of the upper case and is collected at the air outlet for discharge.
As the filtration conditions continue, the dust accumulated on the outer surface of the filter cartridge will accumulate more and more, and the operating resistance of the equipment will increase accordingly. In order to ensure the normal operation of the system, the upper limit of the resistance of the dust collector should be maintained in the range of 1400 ~ 1600Pa Within this limit, the PLC pulse automatic controller should issue a command through fixed resistance or timing to perform three-state cleaning.
The dust removal process of the cartridge type dust collector is to first cut off the clean air outlet channel of a certain room, make the room in a static state of the air flow, and then perform compressed air pulse to blow back the dust. After the dust is removed, it takes several seconds. After natural settling, the clean air outlet channel of the chamber is opened, which not only completely cleans the ash, but also avoids the secondary adsorption of dust generated by blowing the ash, thus circulating the ash cleaning from room to room.
Multi-tube dust collector
The dust-containing gas enters the gas distribution chamber from the main intake pipe, and then enters the annular gap between the ceramic cyclone body and the deflector. The deflector changes the gas from linear motion to circular motion. Most of the rotating airflow spirals downward from the cylinder along the cyclone and flows toward the cone. The dust-containing gas generates centrifugal force during the rotation process, and the density is greater than The dust particles of the gas are thrown towards the wall of the cylinder. When the dust particles are in contact with the cylinder wall, they lose their inertia and rely on the momentum of the inlet speed and downward gravity to fall along the wall surface into the ash discharge port and enter the total ash hopper. When the rotating descending external swirling air reaches the lower end of the cone, the cone rotates in the same direction of rotation as the spiral tube axis from the bottom to the top to continue the spiral flow (clean air), passing through the ceramic cyclone exhaust pipe. Enter the exhaust chamber and exit through the main exhaust port.
The electric precipitator is based on the electric precipitator and the control method of the dust source. It is a new way to solve the dust removal of small scattered dust spots. It uses the exhaust pipe or airtight cover of the production equipment as the electrode plate, sets an electrode in the cover or tube, and connects it with a high voltage power source to form an electric field. When the dust-containing gas passes through the electric field, the dust is collected on the cover or the tube wall under the force of the electric field, and the purified gas is discharged through the exhaust pipe. The dust is removed by artificial vibration or by weight. It is especially suitable for dispersing dust spots such as crushing, screening workshops and sintered conveyor belts, as well as purification of dust in mine tunnels and small boilers. Although there are many types of simple electrostatic precipitators, they can be summarized into three types: hood type, tube type and open type.
Dust removal device
The hood type dust removal device controls the local dust source point in a closed hood, and suppresses or traps dust by a high-voltage electric field. Typical hood-type dust removal devices are used in the process of crushing, transporting and sieving raw materials, such as belt conveyors, vibrating screens, warehouse roofs, and dust points with falling material levels.
Explosion-proof dust collector
Because the explosive dust of aluminum powder is in a certain concentration, it is likely to explode or burn when it encounters sparks or static electricity.
Because aluminum powder explosion, the most critical factor is the concentration of aluminum powder. The most effective way to control the explosion of aluminum powder is to control the concentration of aluminum powder. The tool for controlling the concentration of aluminum powder in this equipment is a dust collector. As long as the working condition of the blasting machine dust collector is good and the dust removal effect is good, the concentration of aluminum powder in the entire blast cleaning machine equipment will not increase. Therefore, ensuring the good dust removal effect of the dust removal device is the key to the normal operation of the equipment. The quality of the dust removal effect is mainly determined by the filter material. When the filter material is blocked, the dust removal effect will be greatly reduced. When the filter material is well ventilated and filtered, the pressure difference between the static pressure chamber and the dynamic pressure chamber of the dust collector will be stable within a fixed range. Therefore, controlling the pressure difference of the dust collector is the most effective way to control the working status of the dust collector. Method. Based on this, DISA has invented an explosion-proof dust collector. The main method is to install a pressure difference controller in the place where there is no vibration near the dust collector of the shot blasting machine. The pressure difference value detected by the instrument will change. When the detection value exceeds the set upper and lower limits, the pressure difference controller will control the cleaning mechanism of the filter bag of the dust collector, such as the shock or backflush mechanism to filter the dust filter material. Surface dust is removed to ensure that the dust collector has a good working condition. When the automatic cleaning still fails to meet the requirements, the differential pressure controller will control the alarm and control the equipment to automatically shut down to prevent accidents.
In order to ensure safe operation, we have also installed gravity automatic blast vents in key parts of the blasting machine dust collector. This device is generally designed on the top of the shot blasting chamber body and the dust removal pipe. The dust-intensive part has been precisely It is calculated that the door can be automatically opened immediately after the explosion, and the pressure of the explosion can be released to avoid injury to equipment and personnel. After pressure is released, the door closes automatically by gravity.
This shot blasting machine adopts FEF210 backflushing bag-type dust collector, with a dust removal efficiency of more than 99%, exhaust gas emission ≤90mg / m3, in line with GBJ4-73 industrial "three waste" emission standards, the main fan power is 30kw, The electrostatic function needle felt industrial filter cloth is precisely sewn. The bag can be easily removed for cleaning and reuse. And the filter bag is reliably grounded during the installation process, which can effectively avoid the possibility of aluminum powder explosion due to static electricity.
Pulse bag type dust collector
Since the introduction of the pulse bag type dust collector in the 1950s, it has been widely used at home and abroad and has been continuously improved. It has made great progress in purifying dust-containing gas. Due to the advanced ash cleaning technology and the air-to-cloth ratio, it has a large amount of air volume. Large, small footprint, high purification efficiency, reliable work, simple structure, small maintenance and so on. Dust removal efficiency can reach more than 99%. Is a mature and relatively complete high-efficiency dust removal equipment . 
1. This dust collector adopts the technology of divided-chamber air-stop pulse injection dust removal technology, which overcomes the shortcomings of conventional pulsed dust collector and divided-chamber reverse blow dust collector. It has strong dust removal ability, high dust removal efficiency, low emission concentration, low air leakage rate and energy consumption Less steel consumption, less steel consumption, less floor space, stable and reliable operation, and good economic benefits. Suitable for metallurgical, building materials, cement, machinery, chemical industry, electric power, light industry industries, dust-containing gas purification and material recovery.
2. As the ash cleaning pulse is used to separate the air from the room, the ash can be completely cleaned in one shot, so the ash cleaning cycle is extended, the ash cleaning energy is reduced, and the compressed air consumption can be greatly reduced. At the same time, the fatigue of the filter bag and the pulse valve is correspondingly reduced, thereby doubling the life of the filter bag and the valve plate.
3, bag replacement can be carried out in non-stop system fan, the system under normal operating conditions. The mouth of the filter bag adopts an elastic expansion ring, which has good sealing performance and is firm and reliable. The filter bag keel adopts a polygonal shape, which reduces the friction between the bag and the keel, prolongs the life of the bag, and facilitates the unloading of the bag.
4. The upper bag extraction method is adopted. After the skeleton is pulled out during bag replacement, the dirty bag is put into the ash bucket at the lower part of the box and taken out from the manhole, which improves the bag changing operation conditions.
5. The box body adopts air-tight design, good sealing performance, excellent sealing materials for inspection doors, kerosene leak detection during the production process, and the air leakage rate is very low.
6. The inlet and outlet air ducts are compactly arranged and the airflow resistance is small.