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Time：2025-06-23 16:44:52 Reading volume：
The EH Oil Purifier is a key equipment specially used to process fire-resistant fluid (such as phosphate ester high-pressure fire-resistant fluid) of steam turbine generator sets. Its core function is to maintain the cleanliness and physical and chemical properties of the oil and ensure the reliable operation of the regulating system (such as the DEH system). The following is an in-depth analysis of its specific functions:
1. Particle Contamination Control
- Accuracy Requirements:
The servo valve clearance of the fire-resistant oil system is only 3-5μm, and it needs to be filtered to NAS Level 4 (ISO 13/11/8), that is, the proportion of particles ≤1μm is greater than 99%.
- Filter Material Selection:
Use a glass fiber composite filter element with β₅≥200 or a stainless steel sintered filter to intercept metal wear debris, silicate dust, etc.
2. Water Removal
- Hazards:
Water will hydrolyze phosphate oil, produce acidic substances (such as phenols), and corrode metal parts.
- Technical solution:
- Vacuum separation (heat the oil temperature to 60℃+, vacuum degree ≤-95kPa)
- Coagulation and demulsification (hydrophilic/hydrophobic composite filter material layering treatment)
3. Acid value adjustment
- Online regeneration:
Adsorb free acid through an ion exchange resin column to maintain acid value ≤0.15mg KOH/g (GB/T 264 standard).
4. Gas removal
- Eliminate dissolved air in oil (to avoid delayed response of the EH system), gas content needs to be <0.1% (DL/T 571 requirement).
| Module | Key technical parameters | Consequences of failure |
|----------------|------------------------------------|-----------------------------|
| Main filtration system | Filtration accuracy 1μm (β₅≥200) | Servo valve stuck, adjustment system oscillation |
| Vacuum dehydration tower | Working vacuum ≤-98kPa | Oil hydrolysis accelerated, acid value soared |
| Heating temperature control | Constant temperature range 40-65℃ (to prevent local overheating) | Oil oxidation to generate colloid |
| Online monitoring | Particle counter (ISO 4406), moisture sensor | Uncontrolled pollution causes unit protection tripping |
1. Coarse filtration stage:
First, large particles are intercepted by a 100μm stainless steel filter to protect the downstream precision filter element.
2. Fine filtration and dehydration:
- Oil is purified step by step through gradient filter elements (10μm→1μm)
- Vacuum flash evaporation to remove free/dissolved water
3. Deep treatment:
Optional electrostatic adsorber (removes colloidal particles below 0.5μm).
- GB/T 14541-2017:
The particle size of fire-resistant oil during operation must be ≤NAS 6, and the water content must be ≤ 500 ppm.
- IEEE 841:
The oil filter is required to have a bypass self-cleaning function and automatically backwash when the pressure difference is greater than 0.35MPa.
1. Flow matching:
The processing volume is ≥10%/hour of the total system oil volume (e.g. EH oil tank is 5000L, and a 500L/h oil filter is required).
2. Material compatibility:
Seals must be made of fluororubber (resistant to phosphate corrosion), and ordinary nitrile rubber is prohibited.
3. Explosion-proof design:
The heater must comply with ATEX standards (explosion-proof is still required for fire-resistant oil flash point ≥ 240℃).
- Pressure differential surge: filter element blockage (need to check whether the pre-filter is invalid)
- Vacuum ｄｒｏｐ: seal leakage or pump efficiency reduction
- Acid value rebound: resin saturation or oil oxidation deterioration
The fire-resistant oil filter is the "kidney" of the power plant EH system, and its performance directly affects the adjustment accuracy and life of the unit. It is recommended to test the oil PQ index (pollution wear index) once a month and conduct filter element β value verification test regularly.
