The scope of turbine oils is quite wide. This lubrication of bearings and gearboxes of steam and hydraulic turbines, work in the brake system, compressors, fans and other mechanisms. Most often, turbine oil purification consists of a base paraffin oil, obtained by deep cleaning, and a combination of various additives. But sooner or later, the properties of the oil during operation are lost and it turns into waste turbine oil.
The following requirements are imposed on turbine oils:
- compliance with the degree of viscosity of the operating temperature;
- good antioxidant properties and resistance to oxidation when exposed to high temperatures;
- high anti-corrosion properties;
- high demulsifying ability;
- high antiwear properties;
- high anti-foam properties.
Such factors as high temperature, contact with air oxygen, water and metal particles, as well as the presence of impurities, have a serious impact on turbine oils.
The process of decomposition of turbine oils is not instantaneous, usually it occurs gradually. Its course can be seen by changing the color of the oil from red to red-brown, and at the final stage to black. The aging of turbine oils is accompanied by an increase in their acid number, the formation of sludge, a decrease in anti-corrosion, demulsifying and anti-foam properties.
The process of decomposition can be controlled by competent maintenance of the lubrication system of the turbine. Great attention should be paid to the oil cooler, the presence of foreign matter in the lubrication system and ventilation.
The service life and performance of transformer oils depend on technical factors and the type of turbine in which they are used.
To date, there are no clear recommendations regarding the timing of the replacement of turbine oils. It is usually recommended to follow the critical values of the following parameters:
- viscosity (should not exceed the recommended value by more than 20%);
- acid number (should not be greater than or equal to 0.5 mg KOH / g);
- surface tension force (replacement is recommended at a value of 15 dyn / cm or at 1/2 of the rate of fresh oil).
Waste oils of absolutely any origin are fairly hazardous waste, therefore, their discharge into water bodies or discharge into the soil is unacceptable. The need for recycling mining today is beyond doubt, which is associated with problems arising from the burial and destruction of waste. For example, when burning oils in order to produce energy, many harmful substances are released into the atmosphere.