【Abstract】In the process of power plant unit operation, the leakage of turbine lubricating oil will occur, which will lead to the increasing
content of particles and moisture in the lubricating oil, and threaten the safety and stable operation of the steam turbine. This paper focuses on
the common faults of the oil purifier and their causes, and puts forward solutions and future improvement measures
【Keywords】 steam turbine; lubricating oil treatment system; lube oil purifier; performance improvement
1 Introduction
Steam turbine lubricating oil is widely used in steam turbine, which can play a role in shock absorption, washing, lubrication and cooling of bearing. At the same time, it can also play an important role in the control of bearing temperature. The quality of steam turbine lubricating oil will have an important impact on the economy and safety of the steam turbine unit, which needs to ensure that the quality, quantity and performance of lubricating oil can be quantified by indicators to avoid the quality of lubricating oil changes. For nuclear power plants, the oil purifier is an important equipment to keep the unit equipment running with high quality. Therefore, improving the performance of this machinery can also have a far-reaching impact.
2 Common fault analysis of steam turbine lubricating oil processing system oil purifier
2.1 principle of the oil purifier
To ensure that the quality of the lubricating oil used by the main engine is guaranteed and qualified, the oil purifier will be set below the main oil tank. oil purifier can be divided into two types: centrifugal and high precision. Among them, the principle of centrifugal oil purifier is to separate the liquid by the difference between the two incompatible substances, and at the same time, the solid particles in the liquid phase. High precision oil purifier is with the capillary role played by the filter element, the impurities and particles in the lubricating oil are absorbed out, to ensure that the lubricating grease has a higher cleanliness. In the case of high precision oil purifier and centrifugal oil purifier cooperate with each other, other impurities and moisture in the lubricating oil can be effectively removed to ensure that the quality of lubricating oil reaches the standard of use, so that the turbine can be used and run more safely.
The working principle followed by the oil purifier is: when the lubricating oil enters the oil purifier, it will form a stable and very thin oil film. Under the action of gravity, the oil will enter the bottom of the container and pull out the air in the container. The air with low relative humidity and polluted oil will produce a large area of oil film wear, because the vapor pressure of water in the oil film is greater than that of water in the air, so the water in the oil will occur obvious gasification phenomenon. The dissolved gas and other gases in the oil overflow into the atmosphere for [3], and then the filtered oil returns to the main tank.
2.2 Handling of common faults in the system
In the specific use process of oil purifier, the most common faults are: ① high liquid level alarm; ② oil intake failure in container; ③ blockage of outlet filter element.
2.3 Cause of the failure occurred
The common fault types include three situations, and the main reasons for these faults are: ① tower liquid level and high liquid level of oil pan. If the vacuum tower is found through the peep hole, it may lead to the emergence of jumping machine problem.② If the-0.45bar.g cannot be reached within 3 minutes in a vacuum environment, then the oil purifier will be automatically shut down, and in the display screen will also make a prompt, that is, “container oil failure”.③ If the outlet of the oil purifier is blocked, when the pressure difference reaches the predetermined value, the differential pressure switch action will prompt an alarm, giving the operator the high pressure difference of the filter.
3 Improvement countermeasures and suggestions for common faults
3.1 Improvement countermeasures for common faults
Through analyzing the common faults of the oil purifier and the causes of these faults, it is necessary to put forward corresponding solutions for the problems to help improve the working efficiency of the steam turbine and improve its working state. First, in view of the problem of high liquid level alarm, the oil can be emptied and then restarted, and the vacuum value can be adjusted appropriately. If it can start successfully, the vacuum value can be raised appropriately. Second, in view of the failure of the container, after the failure of oil intake, the oil purifier should be restarted, and then the vacuum regulating valve is adjusted, so that the vacuum degree in the vacuum tower can be effectively controlled. Another situation is that there are online problems, such as the inlet valve opening range is small or is not opened. In this case, the opening degree of the valve is required to be adjusted. For some imported filters, because there is no differential pressure meter, therefore, there may be a filter element blockage, the solution of this problem only need to timely contact the relevant personnel for repair or replacement. Third, in view of the problem of filter outlet blockage, only need to replace the filter element can be solved. If the filter element is not replaced in time, you can continue to use it for two hours. After the time comes, it will automatically shut down, and the reason will be displayed on the display screen, that is, the outlet filter element is blocked.
After all the faults are successfully eliminated, the need to put the switch in the stop position, and then complete the reset of the equipment, until the reset can be started.
3.2 Improvement advice analysis
When the oil purifier fails, it is necessary to choose timely coping methods to deal with it, but to solve the problem, the most fundamental thing is to eliminate the occurrence of these obstacles from the root. Combined on the relevant working experience and knowledge, this paper puts forward some countermeasures and suggestions for improving oil purifier, hoping to provide reference for the solution of related problems in practical work.
First, free water, sediment and pollutants will be deposited at the bottom of the tank, some oil purifier set in the middle of the tank is lower position, which is not from the bottom of the position, the location at the bottom of the distance, cannot to the bottom of the tank and the water content of high oil timely extraction to purify, so should regularly open the drain valve at the bottom of the tank, let impurities and moisture can be discharged from the bottom of the tank.
Second, the oil purifier will directly discharge the gas in the room where the machine is located, which will lead to the lampblack smell in the room is relatively large, the humidity is also relatively large, for personnel and machinery are not suitable for a long time to stay. If workers work in this environment for a long period of time, it will affect their health. If the humidity of the room is relatively large, the operation of the oil purifier will also have adverse effects. The oil purifier will discharge the water in the room, and will be inhaled by the lampblack machine under the action of air evaporation, under the action of long time circulation, the efficiency of the lampblack machine will be reduced. In many current units, the exhaust fan is the main ventilation facilities in the room. In view of this situation, it is suggested to add a row of lampblack machine. In order to increase the air intake in the room, it is necessary to remove the louver in the ventilation fan under the ventilation cover of the external device, so that the ventilation volume can be increased. At the same time, it is also conducive to the ventilation frequency in the room to ensure that the air in the room is always in a relatively clean and clean state.
Third, in the process of the oil purifier, there will be a high jump machine due to the more foam, the occurrence of this situation is closely related to the state of the oil purifier itself. In the process of using the oil pump into the oil, more foam often leads to the false liquid level of the vacuum tower, and thus directly trip. This is also a very common reason for the oil purifier to jump. In order to effectively solve this problem, the vacuum of the vacuum tower can be reduced in the process of oil pump into oil, and then the oil valve is turned down, so as to help solve this problem, but the disadvantage of this solution is that the efficiency of treatment will be significantly reduced.
Fourth, for a part of the imported oil purifier, its own no pressure difference meter, so that there is no way to get the filter pressure difference, and there is no relevant alarm reminder. In the case of poor oil quality, it is easy to jam phenomenon, which leads to the oil purifier jump. Without adding the meter, it is recommended to carry out regular cleaning activities to avoid the blockage phenomenon and reduce the adverse effects on the normal operation of the oil purifier.
Fifth, when the oil purifier fault after the overhaul of the restart process, because the granularity of the lubricating oil did not meet the standards and requirements, the oil purifier failure of the jump machine, resulting in the overhaul time is very tight. The importance of oil purifier is increasingly prominent, so it is recommended to add oil purifier as a backup. The current oil purifier is vacuum oil purifier, filter efficiency is relatively low, but also produce a lot of noise. If you consider adding new oil purifiers, it is recommended to choose the better quality oil purifiers on the market. When selecting the oil purifier, its efficiency and the impact of strong noise on the environment should be taken into account. The oil purifier with good performance in all aspects can avoid various problems caused by the vacuum pressure imbalance. In the case of overhaul and poor oil quality, it can avoid the negative impact on the work efficiency.
4 Conclusion
oil purifier will have a direct impact on the performance of the steam turbine, and its importance is self-evident. In this study, the common faults and causes in the operation of the oil purifier are analyzed, and the corresponding troubleshooting suggestions and improvement suggestions of the oil purifier are given, aiming to lay a solid foundation for the improvement of the working efficiency of the steam turbine.
Post time: Feb-24-2023