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Time：2025-04-18 11:37:13 Reading volume：
The transformer oil vacuum dehydration purification system is mainly used to remove moisture, gas (such as oxygen, nitrogen) and solid particles in the oil, and restore the insulation performance and chemical stability of the oil. Its core principle is vacuum evaporation + mechanical filtration, and the main processes include heating, vacuum degassing, precision filtration and other links.
A typical vacuum dehydration oil purification system includes the following key components:
1. Oil feed pump: extracts the transformer oil to be treated.
2. Heater: increase the oil temperature (usually 50~65℃), reduce the boiling point of water, and promote evaporation.
3. Vacuum separation tank (degassing tower): core component, where the oil is atomized or forms a film, and moisture and gas evaporate in a vacuum environment.
4. Vacuum pump: maintain a high vacuum degree (usually <1kPa) and extract water vapor and gas.
5. Condenser: condense and collect the extracted water vapor to prevent backflow.
6. Precision filter: remove solid particles in the oil (such as metal chips, fibers).
7. Oil outlet pump: transports the purified oil back to the transformer or oil storage tank.
(1) Heating stage
- The oil is heated to 50~65℃ (avoid exceeding 70℃ to prevent oil oxidation).
- After heating, the saturated vapor pressure of water in the oil increases, making it easier to evaporate.
(2) Vacuum degassing and dehydration
- The oil enters the vacuum separation tank and forms fine oil droplets or oil films through a spray nozzle or a thin film evaporator to increase the evaporation area.
- In a high vacuum (<1kPa) environment:
- The boiling point of water decreases (for example, at 1kPa, water can boil at about 7℃).
- Dissolved gases (O₂, N₂, etc.) precipitate and are pumped out by the vacuum pump.
- The oil stays in the tank for a sufficient time (usually several minutes to several hours, depending on the degree of contamination) to ensure that moisture and gas are fully removed.
(3) Condensation and exhaust
- The evaporated water vapor and gas are pumped to the condenser by the vacuum pump, and the water vapor is condensed into liquid water and then collected and discharged.
- Non-condensable gases (such as O₂, N₂) are discharged to the atmosphere through the vacuum pump.
(4) Precision filtration
- The degassed and dehydrated oil passes through a 1~5μm precision filter element to remove residual particles and ensure the cleanliness of the oil (such as NAS 1638 level 6 or higher).
(5) Oil return
- The purified oil (water content ≤ 10 ppm, gas content ≤0.1%) is transported back to the transformer or oil storage tank by the oil discharge pump.
| Parameter | Typical value | Description |
|-------------------|--------------------------|-----------------------------|
| Vacuum degree | 0.5~1kPa (absolute pressure) | The lower the vacuum degree, the higher the dehydration efficiency |
| Oil temperature | 50~65℃ | Too high will cause oil oxidation |
| Processing flow | 1,000~12,000 L/h | Depends on the equipment model |
| Final water content | ≤10ppm | After reaching the standard, it can meet the insulation requirements |
| Final gas content | ≤0.1% | Prevent oil deterioration and bubble discharge |
| Filtration accuracy | 1~5μm | Ensure no solid impurities |
✅ Efficient dehydration: It can process free water and dissolved water to reduce the water content in the oil to below 10ppm.
✅ Deep degassing: Remove gases such as O₂ and N₂ to reduce the risk of oil oxidation.
✅ Integrated purification: Filter particulate matter at the same time to improve oil insulation strength (≥50kV/2.5mm).
✅ Automated control: Modern systems are equipped with Pa LC to automatically adjust temperature, vacuum, and flow.
- New oil treatment: Dehydrate and degas before injecting into the transformer.
- Operating oil maintenance: Regular purification to extend oil service life.
- Post-fault processing: Regeneration of damp or contaminated oil (such as water ingress, mild overheating).
- Transformer maintenance: Oil purification before vacuuming and oil filling.
⚠ Avoid overheating: Oil temperature >70℃ will accelerate oxidation and reduce oil life.
⚠ Prevent oil return contamination: Turn off heating before shutdown, continue vacuuming for 5~10 minutes to avoid condensate backflow.
⚠ Regular maintenance:
- Check vacuum pump oil (to prevent emulsification).
- ｒｅｐｌａｃｅ filter element (ｒｅｐｌａｃｅ immediately when the differential pressure alarm sounds).
- Calibrate the vacuum sensor and temperature controller.
The vacuum dehydration oil purification system efficiently removes moisture, gas and impurities in transformer oil through heating + high vacuum + precision filtration, and restores the insulation performance of the oil. Its core is to increase the contact area between oil and vacuum (spray/thin film evaporation), so that moisture and gas evaporate quickly under low pressure, which is suitable for the regeneration of insulating oil in power transformers, reactors, mutual inductors, etc.
