Solutions to Emulsified Steam Turbine Oil
2019/4/21??????view:
Steam turbine oil emulsification seriously threatens the safe and economic operation of the unit and the start-up operation of the turbine. Necessary checks must be done before the start-up. For example, valves, signals, etc. Before starting, we should be familiar with which situations prohibit starting and which situations must be emergency shutdown. Many of these parameters are formulated by the system, and the system will automatically alarm or shutdown. Each system has a specific operating instructions. When starting, it is necessary to check the color change of turbine oil and whether the turbine oil is emulsified or not. If the emulsification of oil is serious, it is recommended to use filtration treatment (Chongqing Zhongjing Vacuum Oil Filter) to achieve the use effect.
Based on the analysis of the reasons for the emulsification of steam turbine oil, the preventive measures are put forward in combination with the operation practice.
1.Reasons for oil emulsification:
Moisture, intense stirring and emulsifier can all cause emulsification of turbine oil, and the existence of moisture and intense stirring are the main reasons for emulsification.
1.1 Due to the insufficient tightness of the steam seal at the end of the turbine, the steam entering into the oil system and the residual moisture in the pipeline purged by the steam during overhaul, the presence of moisture in the turbine oil will accelerate the ageing of the oil and produce emulsification. At the same time, it acts with additives in the oil to promote its decomposition, leading to equipment corrosion. In addition, the exhaust fume exhauster and exhaust pipe on the oil tank and bearing box can not discharge the moisture stored in the tank in time, which will also cause water in the oil.
1.2 The emulsification of steam turbine oil is also related to the performance of additives in the oil. Most of the additives have some surfactant compounds or mixtures. In the molecular structure of these substances, one end is an ice polar group with oil affinity, the other end is a hydrophilic polar group with certain surface activity. Although they are all soluble in oil but not in water, the polar group at a certain speed has affinity to water, which enhances the difficulty of oil-water separation and promotes oil emulsification.
1.3 Intense stirring. When the steam turbine rotates at high speed, oil and water are stirred intensely and sufficiently and become opaque liquid. At this time, the hydrophilic polar groups mentioned above have the opportunity to fully affinity with water. When affinity is strong, they will firmly combine with water. Moreover, because the oil-affinity ice polar groups can dissolve in oil, water and oil can be combined through the action of this substance. Together, water can not be separated from oil at this time, that is, emulsification.
2.Harm of Turbine Oil Emulsification: The role of Turbine Oil System is to provide lubricating oil to turbogenerator bearings and regulate the pressure oil of security system. Therefore, the quality of steam turbine oil directly affects the safety and reliability of steam turbine. The main hazards are as follows:
2.1 As a turbine lubricant, it must have a certain adhesion and viscosity. If the oil is emulsified, the adhesion of the lubricant will be reduced, the adhesion of the oil to the friction surface will not be enough, the oil film will be destroyed, the rotor journal and the bearing bush of the shaft may be dry-abrasion, so that the bearing bush will be burned, the unit will have strong vibration, or even the machine will be damaged.
2.2 The emulsification of turbine oil causes the rust of sliding valves and other parts in the regulation and security system to cause jamming, which reduces the sensitivity of operation. In serious cases, it also causes the refusal of the adjustment and security installation, which leads to the occurrence of unit overspeed accident.
2.3During the operation of steam turbine, sliding friction between rotor journal and bearing produces heat, which needs lubricating oil to take away. If oil emulsification will inevitably affect the smooth flow of oil, insufficient oil supply and heat dissipation, and cause bearing bush burning accident in serious cases.
Chongqing Zhongjing Filtration Equipment Manufacturing Co., Ltd. specializes in manufacturing vacuum oil filters. The solution of steam turbine oil emulsification mainly adopts vacuum separation method to separate water impurities and oil products in emulsified steam turbine oil. Turbine oil vacuum filter specializes in oil-water separation of emulsified oils. The separated oils can be used for moisture detection reports, or equipped with an on-line moisture tester, which can actually monitor the water content in oils.
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