Selection of Filtration Velocity for Pulse Dust Collectors

Selection of Filtration Velocity for Pulse Jet Bag Filters:

1. Selection of Filtration Velocity: Filtration velocity is a key factor in selecting a pulse jet bag filter. It should be determined based on the properties of the flue gas or dust, the application, dust particle size, viscosity, gas temperature, moisture content, dust concentration, and the type of filter media. For fine dust particles, high temperature and humidity, high concentration, and high viscosity, a lower value should be selected, such as ≤1 m/min. Conversely, a lower value can be selected, generally not exceeding 1.5 m/min. For very large dust particles, at room temperature, dry, non-sticky, and with high concentration, 1.5–2 m/min can be selected. When selecting the filtration velocity, the net filtration velocity should be calculated even with a reduction in the filtration area of one chamber (during cleaning) and should not exceed the above values.

2. Filter Media: The selection should be based on the temperature, moisture content, acid/alkali properties of the dust-laden gas, the viscosity, concentration, abrasiveness, and size of the dust. Generally, when the moisture content is low and the gas is non-acidic, the selection is based on the temperature of the dust-laden gas. At room temperature or ≤130°C, 500-550 g/m² polyester needle-punched felt is commonly used. At 250°C, aramid nomex needle-punched felt, 800 g/m² fiberglass needle-punched felt, 800 g/m² double-weft fiberglass fabric, or fluorinated media (FMS) are used (fiberglass materials cannot be used for fluorinated gases). When the moisture content and dust concentration are both high, anti-condensation filter media (or membrane filter media) or coated filter media (the base fabric should be treated needle-punched felt) are preferable. When the dust-laden gas contains acid or alkalinity and the gas temperature is ≤190°C, Ryton (polyphenylene sulfide) needle-punched felt is often used. When the gas temperature is ≤240°C and the performance requirements are not too high, P84 (polyimide) needle-punched felt is used. When the dust-laden gas is flammable and explosive, polyester needle-punched felt should be selected. When the dust-laden gas contains both moisture and is flammable and explosive, (three-proof) polyester needle-punched felt should be selected.

3. Control Instrument: The pulse jet bag filter dust collector's cleaning control uses a PLC microcomputer programmable controller, with three control modes: constant pressure (automatic), timed (automatic), and manual. Constant pressure control: Controlled according to a set pressure difference; if the dust collector's pressure difference exceeds the set value, each chamber automatically cleans itself sequentially. Timed control: According to a set time, each chamber cleans itself sequentially every cleaning cycle. Manual control: Can be manually controlled from the on-site control cabinet for automatic sequential cleaning of each chamber, or individual cleaning of each chamber. The user selects the control mode; if the user has no specific requirements, timed control will be supplied.