Why carbon fiber spinning choose oil-free screw gas compressor
In the field of high-end composite material manufacturing, carbon fiber spinning process has become the core technology of aerospace, new energy vehicles and other industries by converting polyacrylonitrile (PAN) precursor into high-performance carbon fiber. In this process, the compressed gas system is responsible for the key tasks such as precursor drafting, coagulation bath control and fiber surface treatment, and its purity and stability directly affect the mechanical properties of the fiber. Based on international standards and technical specifications, this paper will analyze the irreplaceability of oil-free screw gas compressor in carbon fiber spinning.
Analysis of compressed gas demand for 1. carbon fiber spinning process
the technical requirements of carbon fiber spinning for compressed gas systems focus on the following dimensions:
- zero organic pollution
PAN precursor has a sensitivity of ppb to hydrocarbons, and compressed gas shall meet ISO 8573-1 Class 0 standard (oil content ≤ 0.01 mg/m) and pass ISO 8573-4 oil vapor concentration test (<0.1 mg/m). - Chemical resistance
the coagulation bath contains a strong polar solvent such as dimethyl sulfoxide (DMSO), and the gas path system must meet NACE MR0175 standard. Hastelloy C- 276 or titanium (Gr.2) is used to resist stress corrosion cracking. - pulsation control
fiber drafting requires air pressure fluctuation ≤ 0.3 (ISO 5389:2005) to avoid TSL (tensile strength loss)>15% caused by uneven fiber diameter. - Thermal Energy Management
the discharge temperature of the screw compressor should be stabilized at 80±5 ℃(ISO 1217:2022) to match the temperature control requirements of the precursor pre-oxidation stage.
Key Technical Parameters of 2. Oil-free Screw Gas Compressor
for carbon fiber spinning scenarios, equipment selection needs to verify the following core indicators:
| technical dimension | parameter Requirements | test standard |
|---|---|---|
| gas cleanliness | oil content ≤ 0.005 mg/m ³(Class 0 +) | ISO 8573-1:2010 |
| corrosion resistance | passed ASTM G48 Method C pitting test | ASTM G48-11 |
| pressure stability | pulsation rate <0.2%@ 7bar | ISO 5389:2005 Annex B |
| thermal efficiency | specific power ≤ 5.6kW/(m³/min)@ 10bar | ISO 1217:2022 Annex C |
| material migration control | metal ion precipitation <0.05ppb | ICP-MS Detection (EPA 6020B) |
comparison of 3. oil-free screw type and oil-bearing type
from the perspective of carbon fiber quality control, the performance of the two types of compressors is significantly different:
| contrast Item | oil-free screw gas compressor | oil-bearing screw compressor |
|---|---|---|
| pollution risk | native oil-free design, no adsorption aftertreatment required | relies on activated carbon filtration, residual risk> 0.3ppm |
| operation and maintenance cost | no lubricating oil consumption, maintenance interval> 12,000 hours | replace lubricating oil and filter element every 4,000 hours |
| process interference | stable thermodynamic properties, fiber CV <1.5% | oil mist leads to 2-3 times increase in fiber surface defect rate |
| environmental Compliance | compliance with EPA Method 202 VOC emission limits | additional oil mist recovery device required |
4. technical solutions that comply with industrial verification
the GSR series oil-free screw gas compressor developed by Shanghai granklin Group (Granklin) adopts fully enclosed twin screw design and plasma spraying aluminum coating technology to realize zero oil gas output in the power range of 80-250kW. This model has passed the ASME BPE-2019 Bioprocess Equipment Standard Extension Certification. Its modular heat recovery system can match the energy cycle requirements of carbon fiber production. Process verification has been completed in the T800 grade high-strength carbon fiber production line.
5. Summary
the carbon fiber spinning process puts forward multi-dimensional technical requirements for the cleanliness, thermal stability and corrosion resistance of compressed gas. Choosing an oil-free screw gas compressor certified by ISO 8573-1 Class 0 + can not only eliminate the degradation of fiber performance caused by oil pollution, but also improve the conversion efficiency of the precursor through accurate thermal management. It is recommended to focus on checking the ASTM G48 corrosion test report, ASME BPE gas path integrity certification and specific power index of the equipment to ensure compliance with IATF 16949 automotive-grade material manufacturing specifications. With industry-proven compressed gas solutions, companies can significantly increase the TSI (Tensile Strength Index) of carbon fiber products and strengthen their competitiveness in the high-end composite market.