With the continuous progress of my country’s modern industrial technology, the level of my country’s industrial production facilities has been greatly improved, and industrial productivity has been comprehensively improved. As an important basic device in industrial production, centrifugal compressors will have certain faults during their operation. Among them, the temperature rise of bearing bushes is more common, which will affect the overall operation of centrifugal compressors, and in severe cases will cause major problems. failure, resulting in reduced production efficiency. For this reason, this paper conducts in-depth research and analysis on the reasons for the temperature rise of the centrifugal compressor bearing bush, and puts forward a variety of reasonable opinions and countermeasures, aiming at further promoting the performance improvement of the centrifugal compressor and solving the current problem of bearing bush temperature rise. High security risk.
Key words: centrifugal compressor; bearing bush; temperature rise; main reason; effective countermeasures
In order to explore the specific reasons for the temperature rise of the centrifugal compressor bearing bush, this paper chooses the centrifugal compressor of L enterprise as the research object. The centrifugal compressor is a 100,000 m³/h air separation unit air centrifugal compressor, mainly The air is compressed, and the imported air of 0.5MPa can be compressed to 5.02MPa, separated and then transported to other systems for use. During the production process of L enterprise, the centrifugal compressor experienced several times of temperature rise of the bearing bush, and each time the temperature rise was different, which affected the normal and safe operation of the centrifugal compressor. In order to solve this problem, it is necessary to detect the centrifugal compressor, so as to determine the cause and formulate a scientific countermeasure.
1 centrifugal compressor equipment indirect
L company’s 100,000 m³/h air separation unit air centrifugal compressor is a common type of compressor in the current market, the model is EBZ45-2+2+2, and the shaft diameter is 120mm. The centrifugal compressor is composed of a steam turbine, a speed-up box and a compressor. The shaft connection between the compressor, the speed-up box and the steam turbine is a diaphragm connection, and the bearing of the air centrifugal compressor is a sliding bearing, and there are 5 bearing bushes in total. .
The centrifugal compressor uses an independent oil supply system. The type of compressor lubricating oil is N46 lubricating oil. The lubricating oil can enter between the shaft diameter and the bearing through the rotating force of the shaft diameter itself.
2 Problems in the operation of centrifugal compressors
2.1 There are major problems
After a comprehensive overhaul in 2019, the air centrifugal compressor of the air separation unit operated relatively smoothly within one year, with no major failures and fewer minor failures. However, in October 2020, the temperature of the main supporting bearing bush of the centrifugal compressor experienced an abnormal rise. The temperature reached a maximum of 82.1 degrees Celsius, then slowly fell back after rising, and stabilized at around 75 degrees Celsius. The centrifugal compressor experienced abnormal temperature rises many times, and the temperature rises varied each time, basically around 80 degrees Celsius.
2.2 Body inspection
In response to the problem of abnormal temperature rise of the centrifugal compressor, in order to ensure the safe operation of the centrifugal compressor, L company disassembled and inspected the centrifugal compressor body in December, and it can be clearly observed that there is lubrication in the main supporting tile area Oil high temperature sintering carbon deposition phenomenon. During the external inspection of the centrifugal compressor, a total of two bearing pads were found to have carbon deposits, and one of the bearing pads had a sunken pit of about 10mmX15mm, and the deepest pit was about 0.4mm.
3. Analysis of the reasons for the abnormal temperature rise of the centrifugal compressor bearing bush
According to the analysis of technicians, the main reasons for the abnormal temperature rise of the centrifugal compressor bearing bush are as follows: (1) The quality of the oil. When the centrifugal compressor is running at high speed, the high temperature and high pressure conditions will cause the aging of the lubricating oil, which will have an adverse effect on the lubrication effect of the centrifugal compressor. According to the calculations of technicians, every time the temperature rises by 10 degrees Celsius, the aging speed of the lubricating oil will be doubled, so if the performance of the lubricating oil is poor, the aging speed will be significantly accelerated under high temperature conditions. The performance inspection of lubricating oil found that many of the indicators did not meet the standard requirements [1] (2) The amount of oil used. If too much lubricating oil is added, it will cause carbon deposition in the excess lubricating oil under high temperature conditions, because too much lubricating oil will lead to insufficient oil return, and the oil mixture that is difficult to volatilize and has a high viscosity will stay near the bearing bush , resulting in a reduction in the bearing clearance, increasing the wear and load of the bearing pad, which will lead to an abnormal increase in the temperature of the bearing pad due to high friction. (3) Abnormal shutdown. According to the investigation of the technicians, a week before the abnormal temperature rise of the bearing bush of the centrifugal compressor, there was a large-scale steam shutdown problem in the plant, which led to the abnormal shutdown of the centrifugal compressor. The abnormal shutdown would cause the axial Force and unbalanced centrifugal force increase instantaneously, thereby increasing the operating load of the bearing bush, resulting in an increase in the temperature of the lubricating oil.
4 Effective countermeasures for the temperature rise of the centrifugal compressor bearing bush
First of all, it is necessary to improve the quality of lubricating oil to ensure that the parameters of the lubricating oil can meet the basic operating conditions of the centrifugal compressor. The lubricating oil can be improved by adding antioxidants, anti-friction agents and anti-foaming agents to the lubricating oil. Performance, can achieve good results, reduce the aging speed of lubricating oil, so as to prevent the lubricating effect of centrifugal compressor bearing pads from decreasing due to too fast aging speed of lubricating oil, and can well solve the problem of abnormal temperature rise of bearing pads [2].
Secondly, the amount of lubricating oil used needs to be strictly controlled. According to the specific operating conditions of the centrifugal compressor, the amount of lubricating oil added should be controlled within a reasonable range. Too much or too little lubricating oil will cause the centrifugal compressor to malfunction. Therefore, it is necessary to accurately calculate the lubricating oil consumption rate of the centrifugal compressor and replenish enough lubricating oil in time.
Furthermore, because the support surface of the support bearing of the centrifugal compressor is made of hard alloy material, the wear speed is relatively slow, so the carbon deposit on the thrust pad can be cleaned with kerosene to deal with the carbon deposit problem, thereby recovering The surface finish of the thrust pad can achieve good results after treatment. In addition, in view of the problem of insufficient oil drain holes in the bearing ring, the oil return volume will be reduced, which will affect the oil return effect. The method of stress concentration at the opening of the bearing ring is adopted, and the technician recalculates the opening position The pressure, and communicated with the manufacturer, increased the wedge, so that the lubricating oil can better enter the surface of the bearing bush to form an oil film.
Finally, in order to solve this problem, the two lower pads in the new bearing pad are used to scrape the oil wedge, increase the oil bag, increase the lubricating oil retention during the operation of the pad, and make the contact between the bearing pad and the shaft diameter more uniform. , to ensure that the contact point between the bearing bush and the shaft diameter can meet the quality requirements. At the same time, the scraping method is adopted to scrape off all the existing stains to ensure the quality is qualified [3].
After taking the above countermeasures, the problem of abnormal temperature rise of the centrifugal compressor has been well resolved. After a week of testing and testing, the temperature of the bearing bush can be controlled between 50-60 degrees Celsius, and the vibration value is within the specified range. Inside, the transformation effect is obvious.
conclusion
To sum up, this article comprehensively analyzes the reasons for the temperature rise of centrifugal compressor bearing bushes, and puts forward effective countermeasures, hoping to play a certain role in reference and help for my country’s industrial production.