Selection of bag filter 11 factors

The main working principle of the bag filter is that the bag captures a dust collector that filters the dust particles that are collided by inertia to achieve the filtering effect. Bag filter should pay attention to many factors when choosing. Below we will introduce you how to judge the quality of the bag filter.
The main working principle of the bag filter is that the bag captures a dust collector that filters the dust particles that are collided by inertia to achieve the filtering effect. Bag filter should pay attention to many factors when choosing. Below we will introduce you how to judge the quality of the bag filter.
I. Airflow rising speed The airflow rising speed has an important influence on the dusty gas filtered by the filter bag and the dust that has left the filter bag due to pulse cleaning and returning to the surface of the dust bag with the airflow. In the interior of the precipitator, the actual speed at which the dust-containing gas at the lower end of the filter bag can rise is the rate at which the airflow rises.
2. Method of cleaning ash (1) Tube-type blowing and box-type spraying For the large-scale long-bag pulse dust collector, the tubular injection structure is much better than the box-type blowing, and the injection apertures are different, so as to ensure that each filter bag is clear. The ash strength is uniform. The tubular blowing method is to provide a blowing pipe above each filter bag, which is an orderly blowing, that is, a cleaning air flow is sprayed into each filter bag through the nozzle on the pipe.
(2) Online cleaning and offline cleaning.
On-line cleaning and filtration, the impact on system fluctuations is small, but the cleaning is not thorough and cannot be repaired online. Online cleaning means that the filter bag is still filtered by dusty gas during pulse injection. Pulse bag dust collector can be used in online cleaning and off-line cleaning. III. Dust cleaning pressure is an important parameter for bag filter design. Pulse valve is divided into high pressure valve (right angle valve) and low pressure according to the pressure inside the air bag. Valve (submerged valve), low pressure (0.2 ~ 0.35MPa) and ultra low pressure (0.2MPa or less), medium pressure (0.35 ~ 0.5MPa), high pressure (0.5-0.7MPa). Different cleaning pressures will directly affect the equipment cleaning performance.
4. The pressure resistance of the equipment adopts the negative pressure type air conveying device powered by Roots blower. The design pressure of the dust collector is 15~50kPa, and for the long bag pulse dust collector, it is generally 6000~8000Pa, which is used as a general purpose bag filter. The equipment withstand voltage is 4000~5000Pa. The design pressure tolerance of the equipment must be determined in accordance with the normal pressure of the bag filter. The pressure resistance of the bag filter is determined according to the process requirements and the static pressure of the fan.
V. Equipment resistance When designing, the equipment resistance variation margin should be considered to determine the selection of the fan. The pressure loss allowed in the operation of the equipment has a certain range of variation. Equipment resistance is the main basis for fan selection. Pulse bag dust collector pressure loss is usually less than 1500Pa. The pressure loss of the bag filter is usually between 1000 and 2000 Pa. The so-called equipment resistance refers to the total pressure difference between the inlet and outlet of the precipitator in the operating state.
6. Dust concentration of export According to different purposes and process characteristics, different bag filter structure and filter material are selected. In the case of hazardous substances such as lead and cadmium, the outlet concentration is required to be particularly low. Depending on the structure of the dust collector, the type of filter material, and the nature of the dust, it is generally between 1 and 50 mg/m3, and the dust concentration at the outlet of the bag filter. The concentration of dust in the outlet must be lower than the specified values of environmental protection regulations and national health standards.
7. Impurity concentration at the inlet The dust concentration at the inlet is often expressed in the dust content of the standard volume. The dust concentration at the inlet of the bag filter should be considered as follows.
(1) Ash discharge device (2) Pre-duster and filter wind speed.
(3) Wear of filter materials and cabinets (4) Equipment resistance and cleaning cycle 8. Dust properties From the design of the bag filter, the dust should be considered, and the special properties of dust should have special requirements for the bag filter. .
(1) Electrostatic properties.
(2) Hygroscopicity and deliquescence.
(3) The density of the particles.
(4) Particle shape.
(5) Particle size (6) Adhesion and cohesiveness.
IX. Gas composition The composition of the gas is considered only when the parameters such as density, viscosity, mass heat capacity are related to the calculation of the dynamic performance of the fan and the resistance of the pipe and the design of the cooling device. The design of the baghouse is usually calculated as the process air. Except for special circumstances, the gas handled by the bag filter is mostly ambient air or kiln flue gas.
X. Use temperature To prevent condensation, the gas temperature must be kept above the dew point of 20 °C. The maximum allowable temperature (instantaneous allowable temperature and long-term operating temperature) allowed by different filter materials is strictly limited. The deviation between the operating temperature and the design temperature can have serious consequences because the temperature is restricted by the following two conditions. The use temperature of the bag filter is an important basis for the design.
XI. Handling air volume The air volume should also be considered to increase the amount of diluted air. If the flue gas treatment temperature of the bag filter has been determined, and the gas is cooled by the dilution method. When designing, we must pay attention to the location of the dust collector and the temperature of the flue gas. The air volume of the treatment determines the size of the bag filter. Generally, the air volume is used for the air volume.