What are the industrial oil dehydration systems?

Industrial oil dehydration systems can be divided into physical separation, chemical adsorption, vacuum treatment, centrifugal separation, coalescence filtration and other technologies according to different principles and application scenarios. The following are common industrial oil dehydration system classifications and their characteristics:

1. Vacuum dehydration system (efficient and widely used)

Principle: Heat the oil in a vacuum environment to reduce the boiling point of water, evaporate the water and discharge it through a vacuum pump.

Applicable oils: transformer oil, lubricating oil, hydraulic oil, turbine oil, etc.

Equipment type:

- Vacuum oil filter (with heating function)

- Thin film evaporation dehydration system (efficient removal of trace water)

Features:

✔ Deep dehydration (down to below 10ppm)

✔ Simultaneous degassing (removal of dissolved air)

✖ High equipment cost

2. Coalescence separation dehydration system (applicable to emulsified water)

Principle: Use coalescence filter elements to merge tiny water droplets into large water droplets, and then discharge them through separators.

Applicable oil products: fuel oil (diesel, aviation kerosene), hydraulic oil, cutting fluid, etc.

Equipment type:

- Coalescing filter + separator (such as Pall, Parker and other brands)

- Online coalescing dehydration device

Features:

✔ Can handle emulsified water (free water + dissolved water)

✔ Suitable for large flow continuous processing

✖ Poor effect on high viscosity oil

3. Centrifugal separation and dehydration (applicable to high water content oil)

Principle: Use centrifugal force to separate water (high density) from oil (low density).

Applicable oil products: waste engine oil, ship fuel, industrial gear oil, etc.

Equipment type:

- Disc centrifuge (such as Alfa Laval, GEA)

- Tubular centrifuge (for laboratory or small flow)

Features:

✔ Can handle high water content (such as more than 10%)

✔ No heating required, suitable for heat-sensitive oils

✖ Unable to remove dissolved water

4. Adsorption dehydration (suitable for trace water treatment)

Principle: Use adsorbents (such as molecular sieves, silica gel, activated alumina) to absorb water in the oil.

Applicable oils: transformer oil, synthetic lubricating oil, precision instrument oil, etc.

Equipment type:

- Adsorption tower/drying tower (offline or online)

- Filter-type adsorption dehydration device

Features:

✔ Can be reduced to below 5ppm (ultra-low moisture)

✔ Suitable for small batches with high precision

✖ Adsorbent needs to be replaced regularly

5. Heating sedimentation dehydration (low cost, suitable for rough dehydration)

Principle: Heating the oil to reduce viscosity, so that free water settles to the bottom and then is discharged.

Applicable oil products: waste oil pretreatment, crude oil, heavy fuel oil, etc.

Equipment type:

- Heating storage tank + sedimentation tank

- Electric heating dehydration tank

Features:

✔ Simple equipment, low cost

✔ Suitable for initial dehydration of high-viscosity oil

✖ Can only remove free water, cannot treat emulsified water

6. Membrane separation dehydration (emerging technology, high precision)

Principle: Use hydrophilic membranes to selectively permeate water molecules to achieve oil-water separation.

Applicable oils: aviation hydraulic oil, precision lubricating oil, etc.

Equipment type:

- Pervaporation membrane dehydration system

- Reverse osmosis (RO) membrane treatment

Features:

✔ Deep dehydration (<5ppm)

✔ No phase change, energy saving

✖ The membrane is easy to pollute and the maintenance cost is high

7. Ultrasonic dehydration (experimental stage, suitable for special oils)

Principle: Use the ultrasonic cavitation effect to destroy oil-in-water emulsion and promote water separation.

Applicable oils: Nano lubricating oil, special synthetic oil, etc.

Features:

✔ No chemical additives, environmentally friendly

✖ Currently less industrialized

Key factors for selecting a dehydration system

| Factors | Recommended technology |

|----------------|--------------------------------|

| High water content | Centrifugal separation → Heating and settling → Vacuum dehydration |

| Trace water | Adsorption dehydration → Vacuum dehydration → Membrane separation |

| Emulsified water | Coalescing separation → Centrifugal separation |

| Online processing | Coalescing filter → Vacuum oil filter |

| Low cost | Heating and settling → Adsorption dehydration (small batch) |

Typical application cases

1. Transformer oil dehydration: Vacuum oil filter (IEC 60422 standard)

2. Aviation fuel dehydration: Coalescing separation + adsorption filtration (ASTM D4306)

3. Waste oil regeneration: Centrifugal separation + Vacuum distillation

4. Hydraulic oil maintenance: Online coalescing dehydration system

Different industrial oils need to be based on Moisture content, viscosity, throughput, cost. Choose the most appropriate dehydration solution.