Power Plant Requirements for Oil Content of Compressed Air

Power plants have strict requirements on the oil content of compressed air, generally, the oil content is not more than 0.1 mg/m & sup3;(ISO 8573-1 grade 2) or lower, and some key systems even require ≤ 0.01 mg/m & sup3;(grade 1). Specific requirements vary by system use and industry standards, the following is a detailed description:

1. oil content requirements for different systems

1. compressed air system for instrument
   • core Requirements: Oil content ≤ 0.1 mg/m & sup3;(ISO 8573-1 Level 2), some high-standard scenarios may require ≤ 0.01 mg/m & sup3;(Level 1).
   • Reason the instrument gas is directly involved in the precise operation of the control system, and the oil content may cause the instrument jamming, misoperation or corrosion, which will affect the safe operation of the power plant.
2. Plant miscellaneous compressed air system
   • core Requirements: Oil content is usually ≤ 1 mg/m & sup3;(ISO 8573-1 Class 3), but it needs to be adjusted according to specific applications.
   • Reason the miscellaneous system is used in non-precision scenes such as pneumatic tools and purging. It is less sensitive to oil, but it is necessary to avoid oil pollution to equipment or environment.
3. Compressed air system for ash removal
   • core Requirements: oil content ≤ 1 mg/m & sup3;(grade 3), powder material transportation may require ≤ 0.1 mg/m & sup3;(grade 2).
   • Reason: Oil may adhere to the surface of ash particles, affecting the ash removal efficiency or blocking the pipeline, and the transportation of powdery materials needs higher cleanliness.

2. industry standards and specifications

1. international Standard (ISO 8573-1)
   • grade 0: Residual oil content as defined by the equipment user or supplier (better than Grade 1).
   • Grade 1:≤ 0.01 mg/m & sup3;(applicable to respiratory gas, electronic industry, pharmaceutical industry, etc.).
   • Level 2:≤ 0.1 mg/m & sup3;(applicable to instrument gas, food and beverage industry, etc.).
   • Grade 3:≤ 1 mg/m & sup3;(applicable to general industrial gas).
2. Domestic Standards (GB/T 13277.1-2008)
   • corresponding to ISO 8573-1, defines the purification level of compressed air pollutants, including oil content, water content and particulate matter requirements.
3. SPECIAL SPECIFICATION FOR POWER PLANT
   • technical Guidelines for Design of Instrument and Plant Compressed Air Systems in Thermal Power Plants: The oil content of instrument gas is specified to be ≤ 0.1 mg/m & sup3;, refer to ISO or GB standard for plant gas according to its use.
   • Power Engineering Design Manual-Ash Removal Design of Thermal Power Plant: Clarify the oil content requirements of the ash removal system, and the conveying of powdery materials shall be ≤ 0.1 mg/m & sup3;.

3. oil content control measures

1. selection of air compressor
   • oil-free air compressor: Directly produce oil-free compressed air, suitable for oil-sensitive scenarios (such as instrument gas, pharmaceutical).
   • Oil-injected screw air compressor: Multi-stage filtration (e. g. coalescing filter, activated carbon adsorption tank) is required to reduce the oil content to ≤ 0.1 mg/m & sup3;.
2. Post-processing equipment
   • coalescing filter: Removing liquid oil and oil aerosols can reduce the oil content to ≤ 1 mg/m & sup3;.
   • Activated carbon adsorption tank: Further remove oil vapor and meet the requirements of level 1 (≤ 0.01 mg/m & sup3;).
   • BEKOKAT oil-free catalytic machine: Complete decomposition of oil through catalytic oxidation technology to ensure zero oil pollution.
3. Regular inspection and maintenance
   • use a compressed air quality detector (with oil cartridge and water vapor detection tube) to regularly check for oil content, water content and particulate matter.
   • Visually check the spread of oil spots after compressed air is introduced into purified water, or check the blue fluorescence on the filter paper by ultraviolet lamp.