As the core component of industrial dust removal systems, filter bags are widely used in industries such as cement, metallurgy, and power. However, frequent incidents of filter bag fires not only cause significant economic losses, but also pose a threat to personnel safety and production continuity. This article will systematically analyze the causes of fires and propose targeted prevention and control strategies.
What is a Filter Bag?
A filter bag is a gas-solid separation device made of multiple layers of fiber materials, which achieves gas purification by intercepting suspended particles. Its performance directly affects the dust removal efficiency and system safety, and special attention should be paid to key indicators such as temperature tolerance and anti-static properties.
Deep analysis of the causes of fire
High temperature triggers
1. Smoke overheating operation
- Typical operating conditions: metallurgical kilns (>300 ℃), cement rotary kilns (250-350 ℃)
- Material limit:
○ Polyester filter material: can withstand 130-150 ℃ continuously
○ Nomex filter material: up to 204 ℃
○ Fiberglass filter material: 260 ℃ (treated with silicone oil)
- Failure mechanism: High temperature causes fiber molecular chains to break, and after a 80% decrease in strength, they are easily ignited by sparks
2. Local overheating phenomenon
- Common triggers:
○ Uneven airflow distribution (measured wind speed difference>30%)
○ Dust cleaning system malfunction (pulse valve failure rate reaches 15%)
○ Poor heat exchange (temperature difference exceeding the design value by 50 ℃)
Combustible Material Accumulation
1.Dust Spontaneous Combustion Characteristics
| Dust Type | Ignition Point (°C) | Minimum Ignition Energy (mJ) |
|---|---|---|
| Coal Dust | 160-180 | 30 |
| Aluminum Powder | 550 | 15 |
| Sulfur | 190 | 1.5 |
2. Consequences of Cleaning System Failure
Oxidation Heat Release Rate Increases by 300% when dust layer thickness exceeds 3mm.
Case Study: At a cement plant, 5mm of dust accumulation on filter bags due to solenoid valve failure triggered spontaneous combustion.
Electrostatic discharge hazards
1. Electricity generation mechanism
- The dust conveying process can generate a static voltage of 10-30kV
- Chemical fiber filter bags are prone to accumulating charges when the surface resistance is greater than 10 ¹³ Ω
2. Discharge ignition conditions
Energy>0.25mJ can ignite most industrial dust
Key prevention measures: Low MIE substances such as carbon black and magnesium powder
Equipment failure risk
1. Mechanical wear and tear
- The damage rate in the pulse blowing area accounts for 60% of the total
- Deviation of the Venturi tube by 5 ° leads to intensified airflow erosion
2. Electrical hazards
- Loose motor wiring can generate 2000 ℃ arc
- When the dust accumulation in the control cabinet reaches 0.5mm, the insulation performance decreases by 50%
Systematic prevention and control plan
Temperature monitoring system
1.Three level warning mechanism:
Level 1 warning (10% over temperature): Sound and light alarm
Level 2 warning (20% over temperature): Interlocking cooling
Level 3 warning (30% over temperature): emergency shutdown
Waste heat recovery technology:
Install GGH heat exchanger, with a cooling range of up to 150 ℃
Optimization strategy for dust cleaning
- Adopting the “pressure time” dual control mode
- Manually check the membrane after every 2000 pulses
Static elimination measures
- Implant stainless steel conductive fibers (content ≥ 5%)
- Set up ion wind static eliminator
Equipment Management Standards
- Daily inspection: Check the action status of the pulse valve
- Monthly inspection: Grounding resistance<4 Ω
- Annual overhaul: replace aging electrical components
Conclusion
By implementing these comprehensive measures, industries can significantly reduce the risk of filter bag fires, ensuring safe and stable operations. Future research should continue to explore new technologies and methods to enhance the fire resistance of filter bags and improve the safety of industrial dust handling.
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