Application of oil-free air in air separation industry

Specification for technical application of oil-free air in air separation industry

as a core area of industrial gas supply, the air separation industry has strict requirements on the quality of compressed air. Oil-free air technology provides key support for the stable operation of air separation equipment and the guarantee of gas purity by eliminating oil pollution in compressed air. The technical application specifications of oil-free air in the air separation industry are described as follows:

definition and Implementation Path of 1. Oil-free Air Technology

1. Technical definition

oil-free air refers to the compressed air oil content is very low (≤ 0.01 mg/m3) clean gas source, in line with ISO 8573-1 international standard 0 requirements. This technology ensures that the compressed air does not carry lubricating oil components by means of physical isolation or chemical conversion.

2. Implementation mode

• oil-free air compressor: Using water-lubricated bearings, ceramic seals and other technologies to prevent oil pollution from the source.
• Oil injection machine + oil-free converter: The oil is decomposed into water and carbon dioxide through a catalytic oxidation device to achieve deep oil removal (residual oil amount <0.0025 mg/m3).

Core demand for oil-free air in 2. air separation industry

1. Process stability requirements

• molecular sieve protection: Air separation equipment relies on molecular sieves to absorb moisture and carbon dioxide in the air. Oil pollution will cause blockage of molecular sieve pores and shorten the life of the adsorbent.
• distillation column efficiency: Oil is easy to condense in low temperature environment and adhere to the surface of the heat exchanger, reducing the heat exchange efficiency and increasing the energy consumption of the equipment.

2. Product quality control

• high purity gas production electronics, medical and other fields require nitrogen purity ≥ 99.9995 and oxygen purity ≥ 99.999. Oil pollution will directly lead to unqualified products.
• System cleanliness: The air separation equipment needs to operate stably for a long time, and oil accumulation will cause pipeline corrosion, valve sticking and other faults.

Key application scenarios of 3. oil-free air in air separation industry

1. Process gas supply

• pneumatic instrument drive: Oil-free air provides power for precision instruments such as pressure sensors and flow meters to avoid measurement errors caused by oil blockage.
• Molecular sieve regeneration purge: In the molecular sieve regeneration cycle, oil-free air is used for reverse purging to completely remove impurities on the surface of the adsorbent.

2. Equipment protection and energy efficiency optimization

• heat exchanger protection oil-free air reduces oil deposition on the heat exchange tube wall, maintains heat exchange efficiency and reduces energy consumption of equipment operation.
• Compressor Lubrication: In the oil-injected compressor system, oil-free air is used as sealing gas or cooling gas to prevent oil from entering the main compression process.

3. Special process support

• rare gas extraction: The separation of rare gases such as neon and xenon requires ultra-pure gas source. Oil-free air can reduce impurity interference and improve extraction efficiency.
• liquid gas production: In the preparation process of liquid oxygen and liquid nitrogen, oil-free air ensures the cleanliness of the cryogenic container and reduces evaporation loss.

4. technical implementation specifications and operation and maintenance requirements

1. System Design Criteria

• pre-filtering: Configure multi-stage filters (such as 5 micron and 1 micron filter elements) to intercept particulate matter and residual oil.
• Drying device: Integrated refrigeration dryer or adsorption dryer, the dew point temperature of compressed air to -40 ℃ below, to prevent the formation of condensed water and oil emulsion.

2. Operation monitoring indicators

• oil content detection: On-line oil detector shall be set at the outlet of the air compressor and the gas consumption point, and the real-time monitoring data shall be ≤ 0.01 mg/m3.
• Pressure dew point monitoring: Ensure the dryness of compressed air through the dew point meter to avoid the synergistic corrosion of moisture and oil.

3. Maintenance management points

• filter element replacement cycle: The precision filter element needs to check the pressure difference every 3 months, and replace it immediately when it exceeds 0.1MPa.
• Maintenance of catalytic oxidation unit: Regularly clean the carbon on the catalyst surface, and replace the catalyst module every 2 years to ensure that the oil removal efficiency is ≥ 99.9.

5. Industry Application Cases

1. Semiconductor manufacturing field

A fab uses an oil-free air system to drive a pneumatic manipulator to achieve zero pollution of silicon wafer transmission in a clean room environment and increase product yield by 1.2.

2. Medical Gas Supply

an oil-free air compressor is deployed in an oxygen station of a hospital to ensure that the oil content of medical oxygen is less than 0.003 mg/m3, which is in line with the standard of Chinese Pharmacopoeia.

3. Food grade nitrogen production

A food packaging enterprise through oil-free air technology, the nitrogen purity to 99.999%, extend the shelf life of food more than 30%.

6. Supplementary Provisions

this specification is applicable to new projects and technological transformation in the air separation industry. When it comes to the separation of special gases (such as helium and hydrogen), special purification devices shall be additionally configured in combination with gas characteristics.

Through the implementation of oil-free air technology, the air separation industry can significantly improve the operational stability of equipment, gas purity and production energy efficiency, to meet the high-end manufacturing field of clean air demand.