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Time：2025-04-12 10:54:34 Reading volume：
Filtering ethyl (C2H2) in transformer oil requires a combination of physical, chemical, or adsorption methods, because ethyl is dissolved in the gas in the oil and cannot be directly removed by conventional mechanical filtration. The following is a systematic treatment plan:
Ethyl is an important indicator of fault gas in transformer oil, usually caused by current arc discharge or high temperature fault. Its presence may indicate that there is a serious problem inside the equipment (such as current, overheating), and the source of the fault must be eliminated before the oil is treated.
(1) Detection and diagnosis
- Gas chromatography analysis (DGA): quantitatively detects the concentration of ethyl discharge and determines the type of fault (such as current discharge, local overheating).
- Equipment inspection: confirm that there is no continuous display or overheating inside the transformer; otherwise, the equipment must be shut down first.
(2) Degassing treatment
- Vacuum degassing method:
- Heat the oil to 50-60℃ (to increase gas solubility recovery).
- Draw to a high vacuum (such as <1 mbar) in the vacuum tank and precipitate the dissolved gas (including ethyl) through negative pressure.
- Need to be recycled multiple times; the efficiency depends on the vacuum degree and oil temperature.
- Membrane separation technology: uses a sparse permeable membrane to separate gas from oil (suitable for large systems).
(3) Adsorption treatment
- Activation or adsorption: can adsorb small molecular hydrocarbon gases, but the selectivity for acetaldehyde is low.
- Special adsorbent:
- Molecular sieve (such as 4A or 5A): preferentially adsorbs small molecular gases such as acetaldehyde.
- Activated carbon fiber: relatively ineffective, better adsorption effect on acetaldehyde.
- Hydrophobic adsorbents, such as copper or silver adsorption, can enhance the chemical adsorption of acetaldehyde.
- Operation method:
- Connect the adsorbent to the oil filter circulation pipeline, and the oil flows through the adsorption bed (the flow rate needs to be controlled to avoid short flow).
- After adsorption, it needs to be replaced or regenerated (such as high-temperature desorption).
(4) Chemical treatment
- Oxidation method: use a killer or peroxide to oxidize acetaldehyde to amino or CO2, and then achieve it through alkaline washing or filtration (need anions, which may affect the oil quality).
- Catalytic hydrogenation: convert ethane into styrene or ethane under the action of a catalyst (specialized equipment is required and will be available on site soon).
(5) Oil regeneration or replacement
- If the concentration of ethane in the oil is as high as 1% or other quality products (such as carbon particles and acid value increase) are present at the same time, it is recommended to use:
- White clay regeneration: adsorbs gas and causes losses.
- Full oil replacement: directly ｒｅｐｌａｃｅ new oil when economical.
- Safety protection: Ethane is flammable and explosive. Explosion-proof equipment is required during treatment to avoid fire sources.
- Adsorbent selection: The effect of the preferred adsorbent on the performance of transformer oil (such as degassing and acid value).
- Efficiency verification: DGA detection is required again after treatment to confirm that the starting concentration has dropped to a safe range (usually <1 ppm).
- Preventive measures: Install an online DGA monitoring system to track the gas content in real time.
- Regularly monitor the gas content in the oil.
- Maintain the tightness of the transformer to prevent air from entering and accelerating oil deterioration.
The above methods can effectively reduce the acetaldehyde content, but the appropriate solution must be selected in combination with the equipment status and economic efficiency. If the problem persists, it is recommended to consult a professional oil treatment company (such as Pall, Hypro, etc.).
