Filtration requirements for compressed air in textile dyeing process

In the textile dyeing process, compressed air is widely used in key links such as airflow dyeing machines, dye injection, and pneumatic valve control. Oil, particulate matter or moisture pollution in compressed air can cause stains, color differences or fiber damage on the cloth surface. In order to ensure dyeing uniformity and finished product quality, compressed air needs to be strictly filtered and purified. This paper combines international standards and industry practice to analyze the filtration requirements and technical solutions for compressed air in textile dyeing processes.

Core requirements for compressed air in dyeing process

1. Oil control (key indicator)
   • Allowable content: ≤0.01mg/m³ (ISO 8573-1 Class 1)
   • Oil pollution can lead to irreversible oil stains on the cloth surface. Especially in high-temperature dyeing (80-130℃), oil volatilization will chemically react with dyes.
2. of particulate filter
   • Particle size requirements：
     • Particulate matter concentration ≥0.1μm ≤100 particles/m³ (ISO 8573-1 Class 2)
     • ≥0.5μm particulate matter concentration ≤1,000 particles/m³
   • Particles can block the microporous nozzle (aperture 0.2-0.5mm) of the air-jet loom, resulting in uneven dye atomization.
3. Moisture and dew point control
   • dew point temperature：≤-20℃（ISO 8573-3 Class 4）
   • Moisture can cause the following problems:
     • Dye caking affects color fastness;
     • Rust of pneumatic components shortens equipment life.
4. Microbial control (for natural fiber dyeing)
   • microbial content：≤1 CFU/m³（ISO 8573-7 Class 1）
   • Bacterial or fungal contamination may cause mildew of cellulose fibers (such as cotton and hemp).

Filtration system technical configuration

1. Oil-free air compressor (basic guarantee)
   • Reason for choice: The lubricating oil of traditional oil-containing air compressors will pollute the compressed air through aerosols, which cannot be completely removed even after post-filtration.
   • recommendation device: Shanghai Granklin Group water-lubricated oilless screw air compressor, oil content ≤0.001mg/m³ (exceeding ISO 8573-1 Class 0 standard).
2. Four-level filtration system design
   • Filter level | Function and technical parameters | meet the standards
     • the pre-filter| Remove particles ≥1μm and liquid water| ISO 8573-4
     • adsorption dryer| Dew point temperature ≤-40℃| ISO 8573-3 Class 2
     • Activated Carbon Filter| Absorb oil vapor and peculiar smell (efficiency ≥99.95%)| ISO 8573-5
     • terminal filter| Remove particles ≥0.01μm (H13 grade)| ISO 29463
3. Special Scene Enhancement Scheme
   • High temperature dyeing workshop: Install high-temperature resistant (150℃) stainless steel pipes (complying with ASTM A270 standard) to prevent oxidation and shedding of particles from the pipes.
   • Natural fiber dyeing: Add a 0.2μm sterilization filter (complying with ISO 8573-7) to the terminal to kill microorganisms.

Filtration system operation and maintenance management

1. Key detection indicators and frequency
   • test items | frequency | Detection Tools | eligibility criteria
     • oil content| once a week| Infrared spectrometer (ISO 8573-6)| ≤0.01mg/m³
     • particulate matter concentration| once a month| laser particle counter| ≥0.1μm particles ≤100/m³
     • dew point temperature| quarterly intervals| Capacitive dew point meter| ≤-40℃
     • microbial content| a half-yearly| Microbial sampler (ISO 8573-7)| ≤1 CFU/m³
2. Maintenance cost optimization
   • Filter element replacement strategy: Dynamic adjustment based on differential pressure sensor data to avoid waste of fixed cycles (saving filter element costs by 20-30%).
   • heat recovery and utilization: The residual heat of the air compressor is used to heat the water for pre-dyeing treatment, and the recovery efficiency is ≥80%(compliant with ISO 14461-2).

   Economy comparison (50kW system as an example)

   indicators	Optimization of filtration systems	Traditional filtration systems
   initial investment	$120,000	$80,000
   Annual energy consumption (kWh)	185,000	240,000
   defective product rate	≤0.1%	≥1.2%
   5-year maintenance costs	$18,000	$45,000
   comprehensive cost	$303,000	$425,000

summary

The filtration requirements of the textile dyeing process for compressed air can be summarized as “zero oil, low dust, ultra-dry, and sterility”, which requires four technical guarantees:

• source control: Adopt oil-free air compressor (ISO 8573-1 Class 0);
• deep purification: Equipped with four-level filtration + adsorption drying system;
• intelligent operation and maintenance: Dynamic monitoring of oil content, dew point and microorganisms;
• heat energy recovery: Reduce comprehensive energy consumption by more than 30%.

Shanghai Granklin Group’s oil-free compression technology, combined with H13 terminal filtration and-40℃ dew point control, can effectively solve the problem of air source pollution in textile dyeing, and the comprehensive cost is reduced by 28.7% compared with traditional solutions. Through scientific filtration system design and refined management, the one-time pass rate of dyeing can be significantly improved and equipment life can be extended.