Gravity dust collector
This type of dust collector works on the following principle: ? Dust-containing gas passes through the enlarged part of the pipe (gravity settling chamber), the flow rate is greatly reduced, and the larger dust particles settle down under the effect of gravity. In order to avoid the vortex of the airflow to bring up the settled dust particles, the baffle is often added to the settling chamber. Baffles are often added to the settling chamber. Through the settlement chamber of the air velocity shall not be greater than ?3 m / s, the pressure loss is generally 10 ~ 20 mm water column, can capture the dust particles larger than 50 micron particle size. Gravity dust collector has dry and wet type, dry dust removal efficiency of 40 ~ 60%, wet dust removal efficiency of 60 ~ 80%. Gravity dust collector is suitable for pre-purification of dusty gas. In order to improve the dust removal efficiency, can reduce the height of the settling room or set up multi-layer settling room.
Inertial force dust collector
Working principle is:? Dust-containing airflow impacts on the baffle or filter layer,? The airflow turns sharply. The dust particles are separated from the airflow under the effect of inertia force. There are two types of collision type and return type, of which 1 and 2 are collision type, 3 and 4 are return type, 4 is also known as louver type). Inertial force dust collector is suitable for dust particles with particle size above 10 microns, because it is easy to be clogged, and it is not suitable for adhesive and fibrous dust, and its pressure loss varies according to the structure, generally 30-70 mm water column. The dust removal efficiency is 50-70%.
Centrifugal force dust collector
It is the use of airflow in the vortex movement generated by the centrifugal force to remove the dust particles in the airflow of the equipment.? The most commonly used is the cyclone dust collector.? When the cyclone dust collector works, the airflow enters into the dust collector from the upper part along the tangential direction, in which it makes a rotating motion, and the dust particles are thrown to the inner wall of the cylinder part of the dust collector and fall into the dust collection room under the action of centrifugal force. The centrifugal force dust collector was first used in 1885, and has been developed into various types, such as axial introduction of airflow, axial configuration of the dust outlet or peripheral configuration. It is characterized by simple structure, low cost, no moving parts, pressure loss is generally 40 to 150 mm water column, suitable for removing dust particles larger than 5 microns. Protective film dust removal efficiency of about 70 to 90%. Multi-tube cyclone dust collector (referred to as multi-tube dust collector) is a combination of several single-tube cyclone plastisol.
Can be a number of smaller diameter cyclone dust collector connected in parallel, ? It is also possible to connect cyclone dust collectors in series, ? The front stage with a larger diameter cyclone dust collector,? The rear stage uses a smaller diameter cyclone. Parallel multi-tube dust collector can be made into vertical,? Horizontal and tilting types are available. China's finalized production of multi-tube dust collector, the cylinder diameter of 150 and 250 mm two kinds, 9 tube, 12 tube and 16 tube specifications. Multi-tube dust collector can remove dust particles with a particle size of more than 3 microns, with a pressure loss of 50-200 mm water column and a dust removal efficiency of 85-95%.
Scrubber dust collector
Use water to scrub the dusty gas to make the gas purification device. There are the following types: gravity spray dust collector, also known as spray tower or scrubber tower. Dust-containing gas through the droplet space of the spray liquid,? Because of the collision between the dust particles and liquid droplets,? Interception and cohesion and other effects,? The larger dust particles settle down by gravity, and are discharged from the bottom of the tower together with the scrubbing liquid. and the washing liquid together from the bottom of the tower to discharge.? In order to ensure the uniformity of airflow in the tower,? Commonly used porous distribution plate or packed bed. The pressure loss of gravity spray dust collector is less than ?25 mm water column, and it is often used to remove dust particles larger than 50 microns in size. This plastic burning plate has a simple structure, low resistance, easy to operate and so on; but more water consumption, covers a large area, lower efficiency.
Cyclone scrubber dust collector
This dust collector captures dust particles with a particle size of less than ?5 microns, suitable for large gas volume, high dust concentration occasions. Commonly used cyclone water film dust collector,? Cyclone water film dust collector and center spray cyclone dust collector. Cyclone water film dust collector is by the dust collector cylinder nozzle along the tangential direction of the water spray to the wall,? A thin film of flowing water is formed on the wall. Dust-containing gas from the lower part of the cylinder with an inlet flow rate of about 15-22 m / s tangential into the speed, rotating upward, the dust particles by centrifugal force thrown to the wall, adhering to the water film, discharged with the water flow. Airflow pressure loss of 50 ~ 75 mm water column, dust removal efficiency can reach 90 ~ 95%.
Horizontal cyclone water film dust collector
Also known as drum dust collector or rotary cylinder dust collector. The gas stream enters the dust collector and makes a rotating movement along the spiral channel,? Under the action of centrifugal force,? Dust particles are thrown to the wall of the cylinder. The airflow impacts the water surface in the water tank with high speed, and the dust particles fall into the water. The dust particles fall into the water. The water droplets and dust particles stirred up by the airflow impacting the water surface collide, and the dust particles are also captured. Dust particles can also be captured. The airflow carrying the water droplets continues to make rotary motion, the water droplets are thrown to the wall of the apparatus, and the dust particles are captured. The water droplets are thrown to the wall, forming a water film. Forming a water film, the water droplets are thrown towards the wall, forming a water film. The water droplets are thrown towards the wall, forming a water film, which captures the dust particles falling on the wall. The pressure loss in the airflow is 80 to 100 millimeters of water column.
Center spray cyclone dust collector
The center is equipped with a spray porous tube, the dusty airflow from the lower tangent. The dusty airflow is introduced tangentially from the lower part, and the dust particles are thrown to the cyclone by centrifugal force. Dust particles are thrown to the wall by centrifugal force. Due to the collision between water droplets and dust particles and the adhesion of water film on dust particles on the wall, the dust particles are removed. The pressure loss in the airflow is 50 to 200 mm water column. It is suitable for dust particles smaller than 0.5 micron, and the dust removal efficiency is 95-98%.
Diaphragm pump dust collector
Relying on the kinetic energy of the airflow itself, the water is stirred up by impacting the liquid surface. Impact on the surface of the liquid and stir up water droplets and splashes of dust collector. Such as the impact of the water bath type dust collector, dust-containing airflow from the nozzle at high speed,? Impact on the water surface and change the direction,? Large particles of dust are captured by the water. Airflow continues to flow through the water layer, stirring up a large number of water, foam and droplets, dust particles are captured again, dust removal efficiency of up to 80 ~ 95%. The pressure loss is about 100 to 150 millimeters of water column. In addition, there are also made according to the same working principle of the impulse type and double blade impulse type dust removal unit.
Foam dust collector
Also known as foam scrubber, or simply foam tower. There are one or several porous screen plates in the tower, and the washing liquid flows onto the plate, keeping a certain liquid layer height, and the dust-containing gas flow from the lower part of the tower. Dust-containing airflow is introduced from the lower part of the tower, and it passes uniformly through the small holes on the tower plate. The dust-containing gas stream is introduced from the lower part of the tower, and is evenly dispersed in the liquid stream through the small holes on the tower plate. At the same time produce a large number of foam,? Increase the surface area of gas-liquid two-phase contact,? The dust particles are captured by the liquid. The dust removal efficiency mainly depends on the thickness of the foam layer,? When the foam layer is 30 mm thick, the dust removal efficiency is 95-99%; when the foam layer is 120 mm thick, the dust removal efficiency can be more than 99.5%. Airflow pressure loss of 50 ~ 80 mm water column.
Jet scrubber dust collector
The working principle of this dust collector is: water is injected into the injector at high pressure (3.5-7 kgf/cm2 ), and the dusty gas is pumped, so that the dust particles in the gas stream are arrested by colliding with the water droplets. Then the mixture of water droplets and gas enters the settling chamber. The water droplets and dust particles are separated from the gas stream, and the purpose of dust removal is achieved. The purpose of dust removal is achieved. This type of dust collector is suitable for removing dust particles with a particle size of 0.5 micron or more, and the dust removal efficiency is about 90%. Because of the large amount of water, running costs are high, not suitable for a large number of dust-containing gas treatment.
Packed bed scrubber dust collector
Also known as packing tower. After the spray liquid wet packing layer,? It has a large wetting surface. When the dusty gas stream passes through the packing layer, the dust particles are captured and removed when they hit the wet packing surface. This type of dust collector can remove dust particles with a particle size of more than 3 microns, and the dust removal efficiency is about 90%. The airflow pressure loss is 15-50 mm water column. Packed bed scrubber dust collector has vertical and horizontal, single-layer packing and multi-layer packing, fixed bed, moving bed and fluidized bed, flat flow and staggered flow and so on.
Venturi dust collector
Also known as the venturi dust collector, ? consists of a venturi coalescer and a mist eliminator.? The coalescer consists of a shrinkage tube,? The coalescer consists of a contraction tube, a throat and a diffusion tube. Dusty gas into the contraction tube, the flow rate increases, into the throat, the flow rate reaches the maximum. When the scrubbing liquid is added from the contraction tube or throat, the relative flow rate between the gas-liquid two phases is very large, the liquid droplets are atomized under the high-speed airflow, the gas humidity is saturated, and the dust particles are moistened by water. Dust particles and liquid droplets or dust particles and dust particles collide and coalesce. In the diffusion tube, the gas velocity decreases, the pressure rises back to the dust particles for the coagulation nuclei cohesion accelerated, coalescing into a larger particle size dust droplets, and easy to arrest the set.
The venturi dust collector is suitable for removing dust particles of 0.1-100 microns in size, with a dust removal efficiency of 80-95%, and a pressure loss of 300-800 mm water column. If the venturi is equipped with a device for adjusting the throat diameter, the dust removal efficiency will not be reduced when the processed gas flow rate changes. There are many forms of venturi structure, according to the shape of the cross-section is divided into two kinds of round and square; according to the throat structure is divided into two kinds of throat diameter adjustable and throat diameter fixed; according to the liquid atomization can be divided into pre-atomization and non-pre-atomization of the atomization. From the early 70s, some factories use steam and hot water wet dust collector, dust removal efficiency can be increased to 99.9%, and can use the waste heat of the plant.
Bag filter
Filter dust collector. It is a dusty gas flow through the filter material,? Separate the dust,? It is a device to capture the dust. Dust-containing gas is introduced into the cylindrical filter bag from the lower part,? When passing through the gap of filter cloth, the dust particles will be separated by inertia, and the dust particles will be captured by the filter material. Dust particles are intercepted due to inertia, contact and diffusion. Contact and diffusion and other effects are intercepted. If the dust particles and the filter media have opposite charges, the dust particles will be adsorbed on the filter media. then the dust particles are adsorbed on the filter media,? Can improve the dust removal efficiency,? But it is more difficult to clear the dust;? If the dust particles and the filter media have homogeneous charge, the dust particles will be adsorbed on the filter media. then reduce the dust removal efficiency, but easier to clear the dust. Bag filter can remove dust particles with a particle size of 0.1 micron or more, and the dust removal efficiency reaches 99%. The pressure loss of airflow is 100~200 mm water column. Bag material can be natural fiber or synthetic fiber textiles or felt products; purification of high-temperature gases, glass fibers can be used as filter material.
In accordance with the different methods of dust removal from the filter cloth,? Can be divided into three types:? Intermittent cleaning type is to stop working temporarily, with knocking or vibration to remove the dust, can also be used to reverse compressed air blowing; cycle cleaning type is a few groups of bag filter, in order to stop a group of work at certain intervals, and then clean up; continuous cleaning type is to use the continuous movement of the air ring blowing or pulse blowing air method to remove the accumulated dust. The pulse method of removing dust accumulation is called a pulse dust collector. The disadvantage of baghouse dust collector is that it does not have a cooling effect on the passing gas, and it occupies a large area; the advantage is that it is a simple device, with high dust removal efficiency, and the recovered dry dust can be directly utilized.
Sonic dust collector
Dusty gas in the acoustic vibration,? cause dust particles **** vibration, dust particles collide with each other, and then cohesion. The acoustic wave dust collector consists of acoustic wave generator, coalescence tower and acoustic wave generator. Coagulation tower,? Dust collector and other components,? And often used in series with centrifugal force dust collector. The acoustic wave source is located in the upper part of the coalescing tower. In the coalescence tower to produce intensity of about 150 dB of sound waves, so that the dust particles collision and cohesion. The dust particles are trapped in the tower, which has an effective height of 10 to 20 meters, for a few seconds to ten seconds before being collected by a dust collector. Acoustic dust collector can deal with dust particles of 0.1-100 micron particle size, pressure loss of 60-100 mm water column, dust removal efficiency of 80-95%. It is characterized by great adaptability, can handle high temperature and high concentration of dusty gas, can also be used in the wet state, but there is noise. Electrostatic precipitator was first developed by F.G. Cottrell in 1906, so it is also called Cottrell electrostatic precipitator. It is the use of a strong electric field
The gas ionization, the dust in the gas also has an electric charge, and under the action of the electric field and gas separation.
The electrode form of dust collector has two kinds of flat plate and tube type, ? Usually the negative electrode is called discharge electrode,? The positive electrode is called the dust collection electrode (or settling electrode). Such as tube-type electrostatic precipitator to 220 volts (or 380 volts) of alternating current through the boost rectifier, into 3 ~ 60,000 volts of high-voltage direct current, insulated into the corona wire, the cylinder wall for the dust collection pole, by the conductor ground, corona wire and the cylinder wall to form an electrostatic field between the corona wire and the air around the line to produce ionization, the formation of a large number of negative ions and electrons, the movement of dust to the dust collection pole. The dusty gas enters into the dust collector from the inlet of the dust collector, the uncharged dust particles combine with the negative ions and become negatively charged, and then lose their charge and become neutral when they move to the dust collecting pole, and then fall into the dust hopper along the dust collecting pole through vibration, etc. The cleaned gas enters into the dust collector from the inlet of the dust collector. The purified gas is discharged from the outlet of the dust collector. Electrostatic precipitator consumes less energy than other dust collectors, the pressure loss of airflow is generally 10-50 mm water column, the dust removal efficiency is as high as 90-99.9%, suitable for removing dust particles with particle size of 0.05-50 microns, and it can be used in high temperature and high pressure occasions, and it can be operated continuously. The disadvantage is that the equipment is huge, high investment.
Other types of dust collectors
In addition to the above has been finalized production of a variety of dust collectors,? There are also high gradient magnetic dust collector, ? Electrostatic wet dust collector,? Ceramic filter dust collector, etc. Iron and steel industry dust particles in the exhaust gas about 70% of more than a strong magnetic, so you can use high gradient magnetic filter. Such as converter dust, mainly strong magnetic particles, with a magnetic filter to capture dust particles with a particle size of 0.8 microns or more, the efficiency of 99%, the pressure loss of 170 mm water column.
The electrostatic wet dust collector is equipped with a high-voltage ionizer. The dust particles in the gas stream are charged before entering the scrubbing area with packing material. The charged dust particles are then attracted by the packing and washed away by the water. This type of dust collector can remove dust particles with a particle size of 0.1 micron with an efficiency of up to 90%. Ceramic filter dust collectors use microporous ceramics as the filter media, which can be used to remove dust from high temperature gases. The microporous filter media can be made into different pore sizes. If the pore size is 1 micron, the dust above 1 micron can be captured. According to the test, when the pore size is 0.85 micron, dust particles with particle size larger than 0.1 micron can also be captured.