Search

AR
RU
ES

Staff members are having a discussion at a desk.

Selection Guide

Home Resources Selection GuideSelection of Filter Material for Dust Collector Filter Bag

Considerations for Selecting Filter Material for Dust Collector Filter Bags

The selection of filter material for dust collector filter bags must be based on a thorough understanding of the operating conditions and the technology of the dust collector. A comprehensive comparison of the performance of various filter materials should be conducted. It should not be assumed that the more expensive the filter material, the better, nor should so-called 'good' filter materials be used to suit all applications.

Selection Principles

Bag type dust collectors generally select filter materials based on the properties of the gas, the properties of the dust, and the cleaning method of the dust collector. The following principles should be followed when selecting:

The performance of the filter material should meet the general conditions and special requirements of the production conditions and dust removal process;
Under the above premise, filter materials with a long service life should be selected as much as possible, because a long service life not only saves operating costs but also meets the requirements for long-term compliance with gas emission standards;
When selecting filter materials, various materials should be ranked and compared comprehensively.

In terms of gas properties, dust properties, and cleaning methods, the main influencing factors should be considered when selecting filter materials, such as high temperature gas and flammable dust.

Various types of dust collector filter bags

By the Properties of Dust-Laden Gas

Gas Temperature

The temperature of dust-laden gas is an important factor in the selection of filter materials. Dust-laden gas with a temperature below 130 °C is usually referred to as normal temperature gas, while gas above 130 °C is considered high temperature gas. Therefore, filter materials can be divided into two categories: normal temperature filter materials below 130 °C and high temperature filter materials above 130 °C. Hence, an appropriate filter material should be selected based on the flue gas temperature.

Gas Humidity

Dust-laden gas is classified into three states based on humidity: it is considered dry gas when the humidity is below 30%; it is in a general state when the humidity falls between 30% and 80%; and it is high humidity gas when the gas humidity is above 80%. For high humidity gas, especially when it is in a high-temperature state and contains SO3 in the dust-laden gas, cooling of the gas can lead to condensation. This not only causes scaling and blockage on the surface of the filter material but also corrodes structural materials, so special attention is required.

Chemical Properties of The Gas

In various furnace flue gases and chemical exhaust gases, there are often multiple chemical components such as acids, alkalis, oxidants, and organic solvents, and they are often influenced by multiple factors such as temperature and humidity. Therefore, comprehensive consideration should be given when selecting filter materials.

By Dust Properties

Table 1: Filter Fabric Selection Based on Dust Properties
Dust Properties	Fiber Material	Filter Material Structure	Post-Treatment
Ultrafine dust	Fine, short fibers, crimped, expanded fibers, irregular cross-sectional shape fibers	Needle felt is superior to fabric. Needle felt should be structured to form a density gradient, with a surface layer of ultrafine fiber batting or a mixed batting layer of coarse and fine fibers; fabric filter materials should use twill weave, weft double, or double-layer structure.	Needle felt surface singeing or hot melt calendering, fabric heat setting or surface raising, fabric and needle felt surface coating
Moist sticky dust	Nylon and glass fiber materials are preferred, with filament fibers being superior to staple fibers.	Needle felt should be heat compounded to form a dense microporous structure; fabric should use satin weave.	Silicon-based fiber treatment for the purpose of aiding dust removal, carbon-fluorine resin fiber treatment for oil and water repellency, needle felt surface singeing or hot melt calendering treatment, fabric and needle felt surface ACRY or PTFE coating, fabric and needle felt surface PTFE film
Abrasive dust	Fine, short fibers, crimped, expanded fibers, synthetic fibers are superior to glass fibers.	Needle felt is superior to fabric. The felt material should be appropriately thickened and relatively soft; the fabric should preferably use satin weave or weft double, double-layer structure.	Silicone oil, graphite, PTFE treatment for glass fibers; felt surface calendering, mirror treatment; fabric surface napping treatment
Flammable, explosive dust	Select fiber materials with a limiting oxygen index greater than 30%, and mix conductive fibers in a proportion of 2%–5% of the main fiber.	Conductive yarn is woven at equal intervals in the warp direction of the base fabric for needle felt, conductive fibers are evenly mixed in the batting of needle felt, and conductive yarn is woven at equal intervals in the warp direction of the fabric	For fiber materials with a limiting oxygen index of less than 30%, treat with a flame retardant; for the purpose of preventing sparks, perform a protective impregnation treatment based on PTFE.

By the Cleaning Method of Dust Collector

The cleaning method of the bag type dust collector is another important factor in selecting the structure and type of filter material. Due to differences in cleaning energy and filter bag deformation characteristics, different cleaning methods of bag type dust collectors are suitable for different structural types of filter materials.

Table 2: Pulse Cleaning (Generally Prioritize Selecting Needle Felt Type Filter Materials)
Type of Filter Material	Operating Temperature/°C	Mass Per Unit area/(g/m²)	Basic Characteristics of Filter Material	Application Limitations
Polypropylene (PP) needle felt	90	Approximately 500	Excellent acid and alkali resistance	Only suitable for low temperatures
Polyester needle felt	132	440–610	General acid and alkali resistance, a more economical choice	Only suitable for medium to low temperatures, not resistant to hydrolysis, especially in acidic environments
Antistatic polyester needle felt	130	475–540	Suitable for handling highly fluid dust, such as toner, coal dust, and dust prone to static electricity	Only suitable for medium to low temperatures, not resistant to hydrolysis, especially in acidic environments
Homopolymer acrylic (acrylic) needle felt	126	Approximately 500	Excellent acid and alkali performance	Only suitable for medium to low temperatures
Aromatic polyamide needle felt	202	Approximately 475	Suitable for high-temperature operation, good alkali resistance	Poor acid resistance
Polyphenylene sulfide needle felt	190	Approximately 540	Excellent acid resistance (except for nitric acid and bromides)	Sensitive to the oxygen content in flue gas, it is recommended that the oxygen content in flue gas be less than 10%
Polyimide needle felt	240	Approximately 475	Flame retardant, high temperature resistance	Under high temperature, humid, and acidic conditions, hydrolysis may occur.
Teflon B fiberglass woven fabric	260	540–745	Flame retardant, high temperature resistance, excellent acid and alkali resistance (except hydrofluoric acid)	The fit between the filter bag and the filter bag frame is quite sensitive and critical.
Acid-resistant glass fiber woven fabric	260	540–745	Flame retardant, high temperature resistance, excellent acid and alkali resistance (except hydrofluoric acid)	The fit between the filter bag and the filter bag frame is quite sensitive.
Polytetrafluoroethylene (PTFE) needle felt	260	Approximately 680	Excellent acid and alkali performance	High cost

Table 3: Back Flushing & Shaking Cleaning (Generally, Woven Fabric Filter Materials Are Preferred)
Type of Filter Material	Operating Temperature/°C	Mass Per Unit area/(g/m²)	Basic Characteristics of Filter Material	Application Limitations
Polyester woven fabric	132	305–340	General acid and alkali resistance, a more economical choice, especially suitable for shaking cleaning dust collectors	Only suitable for medium to low temperatures, not resistant to hydrolysis, especially in acidic environments
Polyphenylene sulfide fiber woven fabric	190	Approximately 305	Good acid resistance (except for nitric acid and bromides)	Sensitive to the oxygen content in flue gas, it is recommended that the oxygen content in flue gas be less than 10%
Aromatic polyamide fiber woven fabric	202	Approximately 305	Suitable for high-temperature operation, good alkali resistance	Poor acid resistance
Polyimide woven fabric	240	Approximately 305	Flame retardant, high temperature resistance	Under high temperature, humid, and acidic conditions, hydrolysis may occur.
Teflon B glass fiber woven fabric	260	340–475	Flame retardant, high temperature resistance, excellent acid and alkali resistance (except hydrofluoric acid)	Not suitable for shaking cleaning dust collectors
Acid-resistant glass fiber woven fabric	260	340–475	Flame retardant, high temperature resistance, excellent acid and alkali resistance (except hydrofluoric acid), more durable than Teflon B woven fabric	Not suitable for shaking cleaning dust collectors
Polytetrafluoroethylene (PTFE) woven fabric	260	Approximately 305	Excellent acid and alkali resistance, suitable for shaking cleaning dust collectors	High cost

By the Operating System

The operating system of a bag type dust collector is determined by the production process. Many production processes do not operate continuously 24 hours a day. In such cases, the quality requirements for the dust collector filter material can be appropriately reduced, and it is not necessary to choose particularly expensive filter materials. Over time, filter materials also undergo aging. The aging issue should be considered when selecting filter materials.

For harsh operating conditions and continuous production processes, bag type dust collectors must use high-quality filter materials. Otherwise, the filter material's lifespan will be too short, and the frequent replacement of filter bags will affect normal production and increase operating costs.

Various types of filter bags on a gray background

By Special Working Conditions

Special working conditions mainly refer to the following situations: high-concentration dust process collection; high-humidity process collection; intermittent process collection with large temperature changes; processes containing combustible gases; occasions with strict emission standards and special purification requirements; occasions requiring low-resistance operation; and the treatment of gases containing oil mist and other sticky fine dust. When handling gases in the above special processes and occasions, the design of the dust removal system, the selection of dust removal equipment, and the selection of filter materials must all be comprehensively considered and treated differently.

Blue bag type dust collector in a factory

Table 4: Special Flue Gas Treatment Methods and Filter Material Selection
Special Dust Removal Conditions	Dust Removal System Design	Dust Removal Equipment	Filter Bag Material
High concentration	Use a lower filtration air velocity. If hard coarse particles are present, a coarse particle separator can be used at the preceding stage.	Use an external filter pulse dust collector; The spacing between filter bags should be wide for smooth dust fall; A large ash hopper should be designed to ensure reasonable airflow distribution and take measures to prevent filter bag abrasion; The dust cleaning device should operate continuously and reliably.	The filter bag should have minimal deformation and be thick; The surface of the filter bag should be calendered or treated with oil impregnation for hydrophobicity and additives; It is best to choose PTFE composite material.
High humidity conditions vary greatly	Insulate and drain the system pipeline; Insulate or heat the dust collector; Control the operating temperature of process equipment.	Use boat-shaped ash hoppers and air cannons to prevent ash blockage in the hopper; The compressed air for blowing should be dry and heated to prevent condensation; Set up a drying, hot air delivery system; Use sintered plate dust removal equipment; (5) Increase the pressure of the blowing system.	Use PTFE composite material; To ensure the filter material does not condense, use filter material with good hydrophobic and oleophobic properties and a smooth surface treatment.
Large temperature variations, intermittent process	Extend the dust removal pipeline to prevent excessive temperature; Add a regenerative cooler to reduce temperature fluctuations; Add a cold air valve for blending cold air to prevent excessive temperature.	If condensation occurs when the temperature drops, consider insulation and heat tracing for the dust removal equipment; The compressed air for blowing should be dry.	Use temperature-resistant filter materials; When humidity is high, hydrophobic filter materials are required.
Ultra-low emission requirements are high or there are special purification requirements	The filtration air velocity should be conventional (1/2)–(2/3); Avoid insufficient or excessive cleaning, effectively control the pressure, amplitude, and cycle of cleaning.	Ensure good sealing of dust removal equipment; Use electrostatic-bag composite dust collectors; Increase the filtration area.	Use MPS filter material with special technology, coated with an effective active filter layer, which has a good filtering effect on dust smaller than 5 μm; Use PTFE membrane filter material; Use ultra-fine fiber filter material.
Stable low-resistance operation	Reduce the resistance at the air inlet and outlet; Reduce the internal resistance of the equipment.	Effective dust cleaning mechanism; Shorten dust cleaning cycle; Adopt fixed-resistance dust cleaning control; Lower filtration speed.	Use conventional filter material post-treatment processes such as impregnation, coating, and calendering; Implement surface filtration to prevent increased resistance of the filter material during operation.
Dust removal containing oil mist	The process may be combined with other dust removal methods to absorb oil mist; Pre-spray and continuously add an appropriate amount of adsorptive dust inside the pipeline; There is a possibility of sparks and combustion explosion, add a flame arrester.	Use a pulse dust collector to improve cleaning ability; Insulate and heat the dust collector to prevent oil mist and water vapor condensation; Implement explosion-proof measures for the equipment.	Select filter material treated with oil and water repellency; Use PTFE membrane filter material; Use corrugated sintered plates;