Author: Vanessa 9 Apr. 2025 Category: Applications
Ⅰ. Formation and harm of oil mist
Oil mist is a tiny oil droplet suspension generated by mechanical processing, lubrication system or industrial process, with a particle size usually between 0.1~10 μm. The main sources include:
- Mechanical processing: lathes, milling machines, grinders, etc. produce oil mist when using cutting fluid or lubricating oil;
- Compressed air system: air compressor exhaust produces micron-level oil bubbles, carrying lubricating oil atomized particles;
- Food processing: grease aerosols produced by processes such as frying and spray drying;
- Flash evaporation effect: high temperature surface (>150℃) causes instantaneous vaporization and condensation of oil film
According to the WHO Occupational Exposure Limit Guidelines, oil mist exposure causes:
- Respiratory system damage: particles below 0.5 μm can directly reach the alveoli (the content of carcinogen PAHs reaches 3.8 μg/m³);
- Cardiovascular disease: long-term exposure increases the incidence rate by 27% (US NIOSH data);
- Transnational pollution: the cross-border transmission distance of atmospheric oil mist particles can reach 800 km (EU Environment Agency monitoring data), and oil mist deposition may pollute water bodies and soil.
- Equipment loss: Oil mist adheres to electrical equipment, reducing heat dissipation efficiency and increasing fire risks.
- Therefore, efficient oil mist separation technology is crucial to industrial clean production and occupational health.
II. Main mechanisms of oil mist separation
The core of oil mist separation is to separate oil droplets from the gas through physical or chemical methods. The main mechanisms include:
(1) Inertial collision and interception
- Principle: When the oil mist-containing airflow passes through the fiber or metal filter, the oil droplets hit the filter surface due to inertia and are captured.
- Applicable particle size: larger oil droplets >1 μm.
- Typical equipment: wire mesh filter, cyclone separator.
(2) Centrifugal separation (cyclone separation)
- Principle: The airflow rotates at high speed in the cyclone separator, and the oil droplets are thrown to the wall due to centrifugal force and gathered into droplets for discharge.
- Applicable particle size: oil droplets >5 μm.
- Advantages: no filter material loss, low maintenance cost.
(3) Electrostatic adsorption (ESP)
- Principle: When the oil mist passes through the high-voltage electrostatic field, it is charged and adsorbed and collected by the opposite electrode.
- Applicable particle size: ultra-fine oil mist (such as oil smoke) of 0.01~1 μm.
- Typical applications: kitchen oil fume purification, precision electronics industry.
(4) Filtration and coalescence
- Principle: When the oil mist passes through the special fiber filter material, the tiny oil droplets coalesce into large droplets, and finally separate due to gravity sedimentation.
- Applicable particle size: 0.1~10 μm, especially suitable for emulsified oil mist.
- Typical equipment: Trenntech coalescing filter element, glass fiber filter.
(5) Condensation method
- Principle: The oil mist is condensed into liquid by cooling, and then separated by gravity or centrifugal force.
- Applicable scenarios: high temperature and high humidity gas (such as food processing steam).
Ⅲ. Application cases of separation technology combination
In actual industrial applications, various oil mist separation mechanisms are often used in combination to ensure the filtering effect. The following are common separation technology combinations and application scenarios:
| Industry | Oil mist type | Applicable separation technology |
| Machining Cutting | fluid oil mist | Centrifugal separation + coalescence filtration |
| Air compressor system | Lubricating oil mist | Electrostatic adsorption + high efficiency filter |
| Food industry | Vegetable oil mist | Condensation + cyclone separation |
| Chemical industry | Organic solvent mist | Activated carbon adsorption + electrostatic dust removal |
Ⅳ. Future development trend – affinity coalescence method
Affinity coalescence is an oil mist separation technology based on surface affinity. It achieves efficient separation of tiny oil droplets through the selective adsorption and coalescence of special materials on oil droplets. Compared with traditional mechanical filtration, this method has higher separation efficiency and lower energy consumption.
Technical and economic analysis, cost comparison (processing capacity 1000m³/h):
| Parameters | Traditional ESP | Affinity Coalescing |
| Initial investment | $28,000 | $35,000 |
| Annual consumables | $6,500 | $1,200 |
| Energy consumption | 8.5kW | 3.2kW |
| ROI cycle | 3.2 years | 1.8 years |
The affinity coalescence method has achieved a qualitative leap in oil mist separation technology through precise surface energy regulation and structural design. With the development of new functional materials and intelligent monitoring technology, this technology is rapidly evolving towards high efficiency, intelligence and sustainability. In the next five years, the global affinity coalescence equipment market is expected to continue to expand at an annual growth rate of 12.8%. Trenntech Filtration has been deeply involved in the oil mist separation sector and has achieved dual breakthroughs in material innovation and production technology in the field of affinity coalescence. Welcome to contact the Trenntech team to provide you with more effective and economical design solutions for oil mist filtration.