Product overview

The equipment that separates the dust from the flue gas is called a dust collector or dust removal equipment. The performance of the dust collector is expressed in terms of the amount of gas that can be processed, the resistance loss when the gas passes through the dust collector, and the dust removal efficiency. At the same time, the price of the dust collector, the cost of operation and maintenance, the length of service life and the difficulty of operation and management are also important factors to consider its performance. Dust collector is a common facility in boiler and industrial production.

Selection basis

The working quality of the dust collector not only directly affects the reliable operation of the dust removal system, but also relates to the normal operation of the production system, the environmental sanitation of the workshop and the surrounding residents, the wear and life of the fan blades, and also involves the economic value of materials. Recycling issues. Therefore, it is necessary to correctly design, select and use the dust collector. When selecting a dust collector, one investment and operating costs must be fully considered, such as dust removal efficiency, pressure loss, reliability, one investment, floor area, maintenance management and other factors. According to the physical and chemical properties, characteristics and production process requirements of soot, targeted Select the dust collector.

Different dust collectors have different dust removal efficiency. For dust removal systems with unstable or volatile operating conditions, attention should be paid to the effect of changes in flue gas treatment capacity on dust removal efficiency. During normal operation, the efficiency of the dust collector is sorted as follows: bag filter, electric dust collector and Venturi dust collector, water film cyclone dust collector, cyclone dust collector, etc.

The working principle of bag dust removal is the process of collecting dust particles by using filter cloth processed by cotton, wool or man-made fiber.

Bag filter has the following advantages:

The dust removal efficiency is high, especially for fine powder also has a high complementary collection efficiency, generally up to 99%;

It can handle different types of particulate pollutants (including high specific resistance dust that is not easy to handle by electrostatic precipitators). According to the processing gas can be designed into a small bag filter, can also be designed into a large bag room;

When the operation elasticity is large and the dust concentration of the inlet gas changes greatly, it has little effect on the dust removal efficiency. In addition, the dust removal efficiency also has a certain stability to the change of airflow velocity;

④ Simple structure, flexible use, easy to recover dry material, there is no sludge treatment.

The application of bag filter is mainly limited by the temperature resistance and corrosion resistance of the filter cloth; the use temperature of the general filter cloth is less than 300 ℃; the bag filter is not suitable for removing dust particles with strong adhesion and hygroscopicity, especially the flue gas temperature cannot be lower than the dew point temperature, otherwise it will frost on the filter cloth, causing the paste bag to be blocked, thus affecting the normal operation of the bag filter.

Technical parameters

Note: The above data are for reference only. Our company reserves the right to amend and can support non-standard customization.

Ash removal method:

The effect of dust removal is an important indicator of the performance of the dust collector. The dust removal methods are mainly divided into mechanical vibration, reverse airflow dust removal and pulse dust removal. In recent years, there have been some new ways of cleaning ash, such as the use of elastic vibration mechanism and the use of sound wave auxiliary cleaning ash and so on.

Mechanical vibration dust removal is to use a mechanical vibration mechanism to drag the filter bag to vibrate in the horizontal direction, or use an eccentric wheel device to vibrate the filter bag frame or regularly lift the filter bag frame for dust removal, or use a special mechanism to twist the filter bag at a certain angle to deform the filter bag and dust removal.

Reverse airflow cleaning is to use the airflow opposite to the filter airflow to deform the filter bag and cause the dust layer to fall off. Including the use of compressed air, clean gas or other gas pulse blowing, rotary blowback and gas ring blowback. On the one hand, the dust cleaning effect is due to the direct impact of the reverse dust cleaning air flow on the dust block, on the other hand, due to the change of the direction of the air flow, the filter bag produces expansion and contraction vibration and the dust block falls off. There are two forms of reverse airflow cleaning dust removal: reverse blowing dust removal and reverse suction dust removal. When dealing with large flow of dust gas, the reverse suction air is often used to clean the dust. Air ring back-blowing dust cleaning is the outer side of the inner filter cylindrical filter bag, a hollow ring is arranged close to the surface of the filter bag, the ring can move up and down, and is connected with high-pressure air or high-pressure fan by hose. The air ring has strong anti-blowing ash cleaning ability and is suitable for felt filter bags. The rotary blowback bag filter adopts the lower air inlet external filter type. The clean air chamber is equipped with a rotatable cantilever pipe. The blowback air flow is sent from the central pipe to the rotary cantilever and blown vertically downward into the filter bag through the blowing hole to make the filter bag bulge and shake off the dust to achieve the purpose of cleaning dust.

The bag filter for pulse jet cleaning relies on compressed gas to eject high-speed airflow (called primary gas) through the pulse valve through the small hole of the nozzle. The primary gas induces several times the surrounding gas (called secondary gas) into the filter bag through the inducer to form gas waves, causing the filter material to expand and vibrate rapidly, thus realizing dust cleaning. According to the different injection pressure can be divided into high pressure pulse and low pressure pulse two categories. The injection pressure of the air source provided by the high-pressure pulse is 0.4~0.7MPa. High-pressure pulse injection due to the high injection pressure, affecting the service life of the bag, and the gas source configuration equipment is more, the injection system is complex, one-time investment is large, vulnerable parts are many, so the high-pressure pulse to the low-pressure pulse development trend. The low-pressure pulse is based on the high-pressure pulse, and an air storage box is added to output the low-pressure air supply. The injection valve is fixed at the bottom of the air storage box. When the valve is closed, the valve port is pressed. When the valve is opened, the low-pressure air flow of the air storage box enters the cloth bag to clean the dust. This cleaning method has the characteristics of strong cleaning ability and good cleaning effect, and is widely used in many industries.

Cartridge dust collector

The filter cartridge dust collector is composed of filter cartridges as filter elements or a dust collector using pulse blowing. According to the installation method, the filter cartridge dust collector can be divided into oblique insertion type, side mounting type, lifting type and top mounting type. According to the filter cartridge material, the filter cartridge dust collector can be divided into long fiber polyester filter cartridge dust collector, composite fiber filter cartridge dust collector, antistatic filter cartridge dust collector, flame retardant filter cartridge dust collector, coated filter cartridge dust collector, nano filter cartridge dust collector, etc.

The structure of the filter cartridge dust collector is composed of an air inlet pipe, an exhaust pipe, a box body, an ash hopper, an ash cleaning device, a diversion device, an airflow distribution plate, a filter cartridge and an electric control device, similar to the air box pulse bag dust removal structure.

The arrangement of the filter cartridge in the dust collector is very important. It can be arranged vertically on the plate of the box body or inclined on the plate. From the point of view of the cleaning effect, the vertical arrangement is more reasonable. The lower part of the flower plate is the filter chamber, and the upper part is the gas box pulse chamber. An airflow distribution plate is installed at the inlet of the dust collector.

After the dust-containing gas enters the dust hopper of the dust collector, due to the sudden expansion of the air flow section and the action of the air flow distribution plate, some coarse particles in the air flow settle in the ash hopper under the action of dynamic and inertial forces. After the dust particles with fine particle size and small density enter the dust filter chamber, the dust is deposited on the surface of the filter material through the combined effects of Brown diffusion and sieve filtration, and the purified gas enters the exhaust chamber and is discharged through the fan.

The resistance of the filter cartridge filter increases with the increase of the thickness of the dust layer on the surface of the filter material. When the resistance reaches a specified value, the dust shall be cleaned. At this time, the PLC program controls the opening and closing of the pulse valve. First, the lifting valve of a sub-chamber is closed to cut off the filtered air flow. Then the electromagnetic pulse valve is opened. The compressed air expands rapidly in the upper box body and flows into the filter cartridge in a short time, causing the filter cartridge to expand and deform to generate vibration. Under the action of reverse air flow, the dust attached to the outer surface of the filter bag is stripped and falls into the ash hopper. After the dust cleaning is completed, the electromagnetic pulse valve is closed, the poppet valve is opened, and the filtration state of the chamber is restored. Ash cleaning is carried out in turn in each chamber, and the ash cleaning cycle is from the first chamber to the next ash cleaning. The shedding dust falls into the ash hopper and is discharged through the ash unloading valve.

In this process, the filter cartridge must be replaced and cleaned regularly to ensure the filtering effect and accuracy, because in the filtering process, in addition to being blocked, some dust will be deposited on the surface of the filter material, increasing the resistance, so the general correct replacement time is three to five months.

Dust removal device:

The traditional filter cartridge dust collector has two kinds of dust cleaning methods, one is high-pressure airflow back blowing, one is pulse airflow blowing, practice shows that the advantage of the former is uniform airflow, the disadvantage is large gas consumption; the latter has the advantage of small gas consumption, the disadvantage is weak airflow. To this end, two improvements can be made: on the one hand, a diversion device is added to the pulse blowing pipe to strengthen the airflow induction effect, and on the other hand, the upper diversion duct of the filter cartridge is canceled to make the pulse airflow and the induced airflow fully enter the filter cartridge at the same time. After the improvement, the air consumption is less, the air flow is uniform, and the cleaning effect is good. According to the calculation, the flow rate of the cleaning air flow after the technical improvement is 3-5 times of the pulse gas volume.

Gas distribution plate:

The air flow distribution of the filter cartridge dust collector is very important, and it must be considered how to avoid the high wear area of the filter material at the equipment inlet due to the high wind speed. The airflow distribution plate has unique requirements for the filter cartridge dust collector, and the airflow distribution must be very stable and uniform. It is beneficial to the rise of airflow and the decline of dust, and the opening rate of the airflow distribution plate is 35%. According to the calculation, the resistance coefficient is <2, which shows that the porous airflow distribution plate can meet the requirements of the filter cartridge dust collector when the airflow velocity is <0.8 m/s.