The Core Principles for Selecting Dust Filter Bags 

In the industrial dust removal field, filter bags serve as core filtration components, and their selection directly determines system operation efficiency, emission compliance and whole-life cycle costs. 

To avoid premature filter bag failure, excessive emissions or a sharp surge in operation and maintenance costs caused by improper selection, it is necessary to follow the 

five core principles below and establish a scientific selection logic:

1. Working Condition Priority Principle: Taking Environmental Parameters as the Selection Benchmark

1.1 Temperature Adaptability

High-temperature working conditions (≥240℃): PTFE (Polytetrafluoroethylene) or P84 (Polyimide) filter bags are the first choice, with a temperature resistance limit of up to 260℃ and excellent chemical stability.

Medium-temperature working conditions (120-200℃): Aramid (Nomex) or PPS (Polyphenylene Sulfide) is optional. Note that PPS is prone to oxidation in working conditions with oxygen content ＞8% and requires antioxidant additives.

Normal-temperature working conditions (＜120℃): Polyester (PET) filter bags offer the highest cost performance, but working conditions with water content ＞8% must be avoided to prevent hydrolysis.

1.2 Chemical Corrosiveness

Strong acid/strong alkali environment: PTFE filter bags are the only option, with corrosion resistance far exceeding other materials, but the balance between cost and benefit needs to be evaluated.

Weakly corrosive gas: PPS or polyimide filter bags can have their corrosion resistance improved and service life extended through surface treatment such as membrane coating.

1.3 Humidity and Dew Condensation Risk

High-humidity working conditions (humidity ＞80%): Filter bags with water and oil repellent treatment such as Teflon coating must be selected to avoid a sharp drop in strength of PP (Polypropylene) due to hydrolysis.

Areas with dew condensation risk: Pre-coating devices must be configured or anti-condensation filter bags selected to prevent filter bag clogging caused by dust adhesion.

1.4 Dust Concentration and Particle Size Distribution

High-concentration dust (＞1000g/m³): Thick filter bags (e.g., ≥3mm) or pre-coated filter bags must be selected to reduce filtration resistance and wear risk.

Ultra-fine dust (particle size ＜1μm): Membrane-coated filter bags or ultra-fine fiber filter media such as PTFE microporous membrane are the first choice to ensure emission concentration ≤5mg/m³.

2. Efficiency Matching Principle: Taking Emission Standards as the Selection Boundary

Ultra-low emission requirements (≤10mg/m³)

Membrane-coated filter bags or gradient filter media (e.g., PTFE microporous membrane on the surface and PPS needle-punched felt as the substrate) must be selected to achieve a surface filtration mechanism 

and reduce dust penetration rate.

Ordinary needle-punched felt filter bags should be avoided, as their deep filtration characteristics are prone to emission fluctuations.

Normal emission requirements (10-50mg/m³)

Conventional needle-punched felt filter bags such as polyester and PPS can be selected, but post-treatments such as singeing and calendering need to be added according to working conditions to improve ash cleaning performance.

3. Cost Balance Principle: Optimal Whole-Life Cycle Cost

3.1 Balance between Material Cost and Performance

Non-extreme working conditions: Blind selection of high-priced materials such as PTFE should be avoided. For example, in medium-temperature and non-corrosive working conditions, 

the initial cost of aramid filter bags is only 1/3 of that of PTFE with a comparable service life.

Life cost analysis: Low-priced filter bags may lead to a much higher total cost due to increased downtime losses, labor costs and waste disposal fees caused by frequent replacement, compared with high-performance filter bags. 

Quantitative evaluation through the LCC (Whole-Life Cycle Cost) model is required.

3.2 Operation and Maintenance Cost Consideration

High-resistance filter bags such as uncoated needle-punched felt require more frequent ash cleaning, increasing compressed air consumption and pulse valve wear, which must be included in cost calculation.