1. Polyphenylene Sulfide (PPS) – The Most Widely Used High-Temperature Filter Material
Introduction: Polyphenylene sulfide fibers have stable chemical properties, a high melting point (285°C), and excellent heat resistance. They also exhibit outstanding flame resistance, chemical resistance, and stability.
Applications: Mainly used in municipal waste incinerators, utility boilers, coal-fired boilers, hospital incinerators, and cogeneration boilers for pulse-jet bag filters. It is currently the most widely used high-temperature filter material.
2. Polyimide Fiber (P84) – The Best Dust Removal Material for Filtration
Introduction: Polyimide fiber, also known as aromatic polyimide fiber, is a high-performance fiber made by polymerizing pyromellitic dianhydride and aromatic diamine to obtain a polyamide acid prepolymer, which is then spun into fibers through solution spinning.
Applications: Suitable for high-temperature environments such as cement kilns, waste incineration, and power plants.
Characteristics: Polyimide fibers have a unique irregular leaf-shaped cross-section that increases the surface area by 80% compared to ordinary round cross-sections, bringing two major advantages:
Enhanced dust capture ability.
The irregular fiber cross-section, due to uneven internal stress distribution, causes the fibers to naturally curl, giving them strong cohesive entanglement. Therefore, when polyimide fibers are added to fiberglass composite needle felt, the felt layer is less likely to fall off even with increased wind speed.
3. Polytetrafluoroethylene (PTFE) Fiber – The Best Corrosion-Resistant Dust Removal Material
Introduction: PTFE fiber was first developed by DuPont in 1953 and industrialized in 1957. PTFE fiber is a synthetic fiber made from PTFE, either spun or formed into films and then cut or fibrillated.
Applications: Mainly used for high-temperature dust filter bags, filter materials for highly corrosive gases or liquids, pump and valve packing, sealing tapes, self-lubricating bearings, reinforcement materials for perfluorinated ion-exchange membranes used in caustic soda production, and tarps for rocket launch pads.
Characteristics: PTFE fibers inherit the chemical stability, wide operating temperature range, resistance to atmospheric aging, radiation resistance, and low permeability of PTFE. PTFE dust filter bags come in two forms: PTFE fiber membranes laminated onto other filter materials (such as PPS fibers, P84 polyimide fibers, fiberglass, etc.) or both the membrane and substrate made from PTFE fibers, processed into needle felt. 100% PTFE fiber filter bags perform better. However, the high price of PTFE fibers restricts their widespread adoption despite their superior performance.
4. Aramid Fiber – The Most Versatile Dust Removal Material
Introduction: Aramid fiber is a high-performance synthetic fiber first developed by DuPont, characterized by ultra-high strength, high modulus, heat resistance, acid and alkali resistance, lightweight, and flame resistance. Commercially available aramid types include meta-aramid and para-aramid, along with modified products such as Aramid II and Aramid III.
Applications: Meta-aramid is used in high-temperature protective clothing, electrical insulation, and high-temperature filtration due to its heat resistance, flame retardancy, and insulation properties. Para-aramid is used in personal protection, ballistic armor, mechanical rubber products, high-strength ropes, and asbestos replacements due to its high strength and modulus.
Characteristics: High-temperature dust removal is the main consumption market for meta-aramid. Although the cost-performance ratio is not advantageous compared to fiberglass and PPS, aramid fiber filter bags have very low shrinkage rates in high-temperature environments, maintaining a 1% shrinkage rate after 1000 hours at 250°C.
5. Polysulfone (PSO) Fiber – The Best High-Temperature Performance Synthetic Fiber Filter Material
Introduction: Polysulfone belongs to the para-aramid series, known as polyphenylene sulfone terephthalamide fiber, a ternary random copolymer with a sulfone group (-SO2-) in the polymer main chain.
Applications: It is an excellent material for making filter bags for baghouse dust collectors, with good heat resistance, thermal-oxidative aging resistance, hydrolytic stability, low thermal shrinkage, good dimensional stability, and acid resistance, suitable for long-term use in high-temperature environments. Additionally, polysulfone fiber's low friction coefficient makes the filter bags easy to clean. Since polysulfone has high heat resistance, it can be bonded with PTFE (curing temperature 260°C) to create stable, effective filter materials.
6. Fiberglass – The Most Economical High-Temperature Filter Material
Introduction: Fiberglass is a traditional filter material and the most widely used in medium and high-temperature flue gas dust removal. Fiberglass can be categorized into C-glass (medium alkali) and E-glass (non-alkali) based on its composition.
Applications: Fiberglass has excellent high-temperature resistance, capable of operating continuously at 260°C (C-glass) / 280°C (E-glass), with peak temperatures up to 350°C. It has high strength, low elongation, outstanding acid resistance (except hydrofluoric acid), and a smooth surface that reduces filtration resistance and facilitates dust release. Fiberglass does not burn or deform. Various surface treatments give it properties like softness, smoothness, water repellency, anti-condensation, and low shrinkage. Its chemical stability, dimensional stability, high tensile strength, corrosion resistance, smooth surface, hydrophobicity, breathability, and easy cleaning make it a cost-effective option. When user requirements are low, fiberglass is often used in pulse-jet bag filters.
Filter bags are crucial for the efficiency and operating temperature of baghouse dust collectors, and replacing filter bags is a major maintenance expense. Therefore, the service life of filter bags directly affects the operating status and cost of dust collectors.
