The incredible malfunctions that occurred during operation in those years, Part 1 – The continuously rising temperature of the compressor lubricating oil
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This post was last edited by we11we11 on 2021-7-13 at 21:42. For more details, please refer to these two posts: https://bbs.hcbbs.com/thread-1867582-1-1.html https://bbs.hcbbs.com/thread-1868650-1-1.html. In 2017, a gas power generation project abroad came online; when one of the natural gas centrifugal compressors was started, after the first two startups, the lubricating oil temperature rose from 38°C at the beginning to 65°C, which triggered an shutdown. This indicated a problem with the oil cooler, and this is what led to the creation of the above two posts. At first, it was suspected that the heat exchange tubes of the oil cooler were not tilted, which caused air to accumulate inside and hindered the flow of oil. Later, it was thought that the drainage holes in the partition plates of the oil cooler tube box were too large, resulting in a short circuit within the oil cooler. An external ultrasonic flow meter was then used to measure the flow rate through the oil cooler, but the exact cause could not be identified. In short, it seems that the lubricating oil was bypassing the oil cooler and not flowing through it. Finally, an infrared imaging device was used to examine the flow of oil inside the oil cooler. It turned out that the oil flowed directly past the partition at the tube bank location; it did not pass through the oil cooler at all. Upon inspection using an endoscope, large areas of weld cracks were found at the location of the partition and the vertical walls of the tube bank. The manufacturer’s quality – this fault caused a delay in production of over a month, and troubleshooting it took a great deal of time and effort. The compressor manufacturers are also world-renowned brands. There are so many such incredible malfunctions; I’ll write about a few more when I have time later
Practical experience is priceless. Thanks for sharing
The process of identifying problems is a process of enhancing existing knowledge!
Yes, although the conclusion is simple, the considerable time and effort invested in identifying this fault, along with in-depth study of the system, is indeed a process of improvement
This is a bit unreasonable; the factory inspection for oil coolers is completely absurd
Yeah, it’s produced in Europe – the quality is absolutely unacceptable. Who would have thought that the problem lies here when trying to diagnose it?
For some devices, those imported are not as good as the domestic ones. Moreover, they act in a pretentious manner when providing on-site service and refuse to cooperate. Our domestic engineers are much easier to communicate with
Yes, we all prefer to communicate with engineers from within the country. For equipment manufactured by foreign companies, we always try to arrange for domestic engineers to handle it. foreigners tend to be quite rigid; they need approval from headquarters for anything and cannot handle things flexibly on their own. Additionally, perhaps due to work habits, their way of thinking often doesn’t align with ours
These days, many foreigners who work in China on a long-term basis are extremely cunning; they are the most eager to arrange meals for others, but once the meal is over they turn against those people
Large-scale weld cracks occurred at the positions of the section partitions and the vertical plates of the tube boxes; remember this lesson
This post was last edited by we11we11 on 2024-2-26 at 11:02. At that time, we checked the temperatures at both ends of the oil cooler with our hands; the temperatures at the inlet and outlet sides were higher, while the temperature at the other end was close to room temperature. It was initially assumed that the hot lubricating oil did not pass through the oil cooler. The possible causes for this issue seemed to be the following: 1. The heat dissipation tubes of the oil cooler are horizontal, without any inclination, which may lead to poor flow of oil. There is also a lot of air inside the oil cooler that has not been completely removed. 2. The designed flow rate of the oil cooler does not match that of the auxiliary oil pump; the auxiliary oil pump may be undersized, resulting in the lubricating oil being unable to pass through the tube bundle. 3. If the drain holes on the stage partition are too large, it may cause a short circuit in the oil cooler. (When I opened the oil inlet port at that time, I saw that the drain hole was there; it seemed a bit large, but I didn’t think it would cause a short circuit in the oil cooler. I had no idea that the weld would crack.) ) Mainly, at that time we lacked experience; the foreigners used portable ultrasonic flow meters to check the flow rate in each channel, and it was found that the flow rates were low. If an infrared imaging device had been available at that time to visualize the shape of the oil flow, it would have been possible to quickly determine the location of the fault. This is also a basic requirement for condition monitoring. When bidding, we promised to use such condition monitoring equipment during operation and maintenance to facilitate daily repairs, but in reality we didn’t prepare any of these devices, which shows that there is still a lot to improve in terms of management.