P84 (Polyimide) Needle Punched Felt Filter Bag
P84 (Polyimide) needle punched felt filter bags from LYH fit asphalt mixing plants, cement kilns, waste incineration, biomass boilers, and high-temperature dust collection requiring fine particulate capture. Buyers choose P84 filter bags when they need sustained service up to 240 °C, exceptional fine-particle capture from P84’s unique multi-lobal fiber cross-section, and superior emission compliance where Aramid and PPS reach their performance limits.
We supply P84 / Polyimide filter bags from China with custom size discussion, fabric weight options (500–650 GSM), and full surface treatment support. If your project requires a specific bag diameter, length, top/bottom construction, or P84 + PTFE membrane combination for ultra-low emission compliance, we can review the RFQ and pair the right P84 felt to your dust collector.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Material | 100% P84® Polyimide staple fiber, scrim-supported needle felt |
| Fiber Cross-Section | Multi-lobal (trilobal) — unique among baghouse media |
| Continuous Operating Temperature (Dry) | 240 °C / 464 °F |
| Continuous Operating Temperature (Moist) | 195 °C / 383 °F |
| Maximum Short-Term Surge Temperature | 260 °C / 500 °F |
| Specific Density | 1.41 g/cm³ |
| Moisture Regain (20 °C, 65% RH) | 3.0% |
| Standard Fabric Weight | 500 / 550 / 600 / 650 GSM (customizable) |
| Air Permeability | 10–16 m³/m²/min @ 200 Pa |
| Tensile Strength (Warp / Weft) | ≥ 1,000 N / 5×20 cm |
| Filtration Efficiency | ≥ 99.95% (with PTFE membrane: ≥ 99.99%) |
| Combustibility | Self-extinguishing (LOI ≥ 38) |
Material Properties
Unique Multi-Lobal Fiber Cross-Section — Unlike round-cross-section fibers used in polyester, PPS, and aramid, P84 fiber has a trilobal (multi-lobal) cross-section. This dramatically increases fiber surface area per unit volume — by approximately 80% compared to round fibers — giving P84 exceptional fine-particle capture efficiency without sacrificing air permeability. This is P84’s defining advantage in ultra-low emission applications.
Outstanding Fine-Particle Capture — The multi-lobal cross-section captures particles primarily on the bag surface rather than letting them embed deep in the felt. This delivers higher efficiency on fine PM2.5 particulates, lower differential pressure, easier cake release, and longer service life than equivalent round-fiber media.
Excellent High-Temperature Performance — Sustained service up to 240 °C dry / 195 °C moist, with short-term peaks to 260 °C. P84 fits the temperature gap between Aramid (204 °C) and Fiberglass (260 °C), offering needle-felt filtration capability where fiberglass woven cannot match the surface filtration performance.
Self-Extinguishing & Inherently Flame-Resistant — LOI ≥ 38 (one of the highest among synthetic fibers); P84 does not support combustion and provides an additional layer of safety in high-temperature ignition-risk applications.
Good Hydrolysis & Chemical Resistance — P84 maintains performance under moderate humidity and acid dew point conditions far better than aramid, with good resistance to most organic solvents, weak acids, and weak alkalis at elevated temperatures.
Limitations to Note — P84 is vulnerable to SOx attack in coal-fired power plant flue gas with elevated sulfur content, and to strong alkalis at elevated temperatures. For sulfur-rich coal flue gas, choose PPS or PPS+PTFE composite. P84 is also more expensive than PPS or aramid — but the premium is typically justified by superior fine-particle capture and emission compliance.
Available Surface Treatments
| Treatment | Function | Recommended For |
|---|---|---|
| Singeing | Removes loose surface fibers via flame; improves cake release | Standard high-temp dust |
| Calendering / Glazing | Heated rollers densify the surface; enhances surface filtration | Fine-particle capture, low pressure drop |
| Heat Setting | Stabilizes felt dimensions, eliminates shrinkage during operation | All applications |
| PTFE Membrane Lamination | Microporous ePTFE membrane on dust side; emissions ≤ 5 mg/Nm³ | Ultra-low emission compliance, mandatory PM2.5 standards |
| P84 / Aramid Blend | P84 batt on aramid scrim — combines P84 surface filtration with aramid mechanical strength | Cost-balanced premium applications |
| P84 / PPS Blend | P84 batt on PPS scrim — adds acid resistance for moderately sulfur-rich flue gas | Coal flue gas with low-to-moderate SOx |
| Anti-Static | Conductive carbon fiber or stainless-steel filament; surface resistance 10³–10⁸ Ω·cm | Combustible dust in waste incineration, biomass |
| Water & Oil Repellent (WO) | Enhanced moisture and oil rejection finish | Asphalt drum dryers, oily / sticky dust |
Bag Construction
- Top Constructions — Snap band, flange top, ring top, soft cuff, raw edge, strap top
- Bottom Constructions — Disc bottom, flat bottom, reinforced double-bottom, wear-strip bottom
- Sewing — 3-needle chain stitch with PTFE thread (standard for high-temperature P84); overlock or lockstitch on bottoms
- Reinforcement — Optional wear strips, custom skirts, double-bottom reinforcement for abrasive cement and sintering dust
Standard Sizes & Customization
| Dimension | Range |
|---|---|
| Diameter | Φ100 / 120 / 125 / 130 / 150 / 160 / 180 / 250 mm (or custom) |
| Length | 1,000 – 8,000 mm (custom lengths available) |
| Tolerance | Diameter ± 2 mm, Length ± 5 mm |
Non-standard sizes, special top/bottom configurations, and OEM patterns produced from your drawings or sample bag.
Industry Applications
- Asphalt Mixing Plants — premium drum dryer baghouses requiring extended service life and fine-particle capture
- Cement Plants — kiln tail, raw mill, alternative fuel co-processing with elevated chlorine content
- Waste Incineration — municipal solid waste (MSW) and hazardous waste exhaust requiring fine PM capture
- Biomass Power Generation — wood, bagasse, agricultural residue combustion with stringent emission targets
- Steel Sintering — sinter plant secondary dedusting, blast furnace gas cleaning
- Iron & Steel — EAF, ladle refining, hot-metal dedusting at elevated temperature
- Carbon Black Production — process tail gas dedusting requiring fine particulate compliance
- Lime & Gypsum Plants — kiln exhaust at elevated temperature with stringent emission control
- Power Plants — biomass and waste-to-energy boilers (not recommended for high-sulfur coal)
- Ultra-Low Emission Compliance — high-temperature applications mandating ≤ 10 mg/Nm³ or ≤ 5 mg/Nm³
Why Choose LYH P84 Filter Bags
- Genuine Evonik P84® polyimide fiber — sourced from the original P84 manufacturer; no substitute fibers
- Multi-lobal fiber advantage preserved — proper needle-punching technique maintains the unique cross-section that gives P84 its filtration edge
- Strict QC on fabric weight, air permeability, tensile strength, fiber cross-section integrity
- Full customization — any size, any top/bottom, any treatment combination
- Engineered for premium duty — proven configurations for asphalt, cement alternative fuel, waste-to-energy, and ultra-low emission applications
- High-temperature sewing — all seams use PTFE thread for thermal compatibility
- Fast lead time — standard sizes ship in 10–20 days
- Engineering support — application engineers help match P84 grade and treatment to your gas chemistry, temperature, and emission target
- Reliable logistics — individually wrapped, ring-up packing, sea / air / courier shipment worldwide
FAQ
Q1: What is the maximum operating temperature of P84 filter bags? P84 (Polyimide) filter bags operate continuously at up to 240 °C (464 °F) in dry conditions and 195 °C in moist conditions, with short-term peaks up to 260 °C. For sustained operation above 240 °C, consider Fiberglass, FMS composite, or PTFE alternatives.
Q2: What makes P84’s multi-lobal fiber cross-section different? Standard filter fibers (polyester, PPS, aramid) have a round cross-section. P84 fiber has a trilobal (multi-lobal) cross-section that increases fiber surface area by approximately 80% compared to round fibers. This dramatically improves fine-particle capture, surface filtration, cake release, and air permeability — especially important for ultra-low emission compliance.
Q3: Why choose P84 over Aramid (Nomex)? P84 offers higher temperature tolerance (240 °C vs Aramid 204 °C), superior fine-particle capture due to multi-lobal cross-section, and better hydrolysis resistance. P84 is preferred for premium asphalt drum dryers, alternative fuel cement kilns, and any application with stringent emission targets. Aramid is more cost-effective for standard dry hot-gas applications without strict emission requirements.
Q4: How does P84 compare to PPS? PPS offers better resistance to sulfur and acid (preferred for coal-fired power), at lower cost. P84 offers higher temperature tolerance (240 °C vs PPS 190 °C) and superior fine-particle capture, but is sensitive to SOx. Many premium installations use P84/PPS blend — P84 batt on PPS scrim — to combine the strengths of both fibers.
Q5: Is P84 suitable for coal-fired power plants? Generally no for high-sulfur coal flue gas — P84 is vulnerable to SOx attack at elevated temperature. For coal-fired power, choose PPS or PPS+PTFE composite. P84 is suitable for biomass-fired and waste-to-energy applications where sulfur content is low and fine-particle capture is the primary requirement.
Q6: When should I specify PTFE membrane on P84 bags? PTFE membrane lamination is recommended when emission targets are below 10 mg/Nm³, when very fine PM2.5 capture is required, or when the dust is sticky/condensable. P84’s multi-lobal structure already provides excellent surface filtration, so P84 + PTFE membrane delivers among the highest filtration efficiencies achievable in the industry.
Q7: What is the typical service life of P84 filter bags? In typical asphalt and waste incineration applications, P84 filter bags deliver 3–5 years of service life. With PTFE membrane lamination and proper application matching, service life can extend to 5–7 years.
Q8: Why is P84 more expensive than other filter media? P84 polyimide fiber is produced by a single global manufacturer (Evonik) using a complex high-cost process. The fiber’s unique multi-lobal cross-section requires specialized manufacturing equipment. However, P84 typically delivers 2–3× longer service life than aramid in equivalent applications, lower emissions, and lower differential pressure — yielding favorable total lifecycle cost in premium applications.
Q9: What information do I need to provide for a quote? (1) bag dimensions, (2) top/bottom construction, (3) operating temperature & humidity, (4) flue gas composition (SOx, NOx, halogens, alkali), (5) dust type & concentration, (6) emission requirement, (7) quantity. A drawing or sample bag is even better.
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