Help: Fluctuations in the inlet pressure at the first stage of the turbine
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Our factory produces methanol from coke oven gas, and it is equipped with centrifugal compressors featuring a three-stage compression structure: one stage for fresh gas and three stages for recycled gas. Recently, as soon as I started working, the inlet pressure would suddenly rise and then drop again, fluctuating back and forth; it would get either closer or further away from the anti-surge cooling line, giving the impression that the system was about to shut down. Related to this are the fluctuations in steam flow, turbine speed, and hydrogen level; I don’t know how to adjust them. . . Do you have any methods to keep stress under control?
““Fluctuations in the inlet pressure of the first stage of the turbine”: Curse: The title is incorrect; it should refer to the compressor. I’m guessing based on what I know about the process. 1. Is the process operating normally? 2. Are the inlet pressure and temperature of the turbine normal? 3. Is the backpressure of the turbine normal? 4. Is the anti-surge valve functioning properly? 5. Is the circulating water in order? 6. Is the anti-surge control system working correctly? By identifying which of these six factors changes first, it will be possible to determine how to address the issue
It is recommended to first reduce the load and give it a try; once stability is achieved, the load can be increased again. If the problem caused by the high load is resolved, then the load can be raised, but it should be kept below the level it was at during the fluctuations. It’s worth giving it a try.
What exactly is going on with the fluctuations in hydrogen? Is it a fluctuation in the content? It might be caused by this
\✅ Yes, thank you for pointing that out. It’s the fluctuations in the inlet pressure on the compressor side; it happens every time there’s a fluctuation. I also look at other indicators; the steam flow rate, the fresh gas flow rate, and the turbine speed are all affected.
In our process, we mainly focus on the hydrogen-to-carbon ratio; more carbon is beneficial for production. Any fluctuation in the hydrogen content, especially an excess thereof, will cause the pressure at the fresh gas inlet to rise, thereby reducing the total volume of purified gas—which is detrimental to production
It’s probably due to fluctuations or imbalances in the hydrogen-to-carbon ratio. In cases of severe imbalance, there may be a sudden and significant increase in hydrogen flow, which could lead to overspeed trip or severe surging.
I’m not very familiar with your process, so I can only make guesses. (If you wish, you can share your technical details at 869270438@qq.com so we can discuss and learn together.*) 1. Is there a problem with the pressure gauge? 2. Has the gas composition changed? 3. Whether the upstream operating conditions have been adjusted. 4. Is the compressor inlet valve functioning properly? 5. Is the first-stage piston of the compressor intact?
The explanation on the 9th floor was very professional; it is recommended to first check whether the pressure is normal and whether there are actual fluctuations in pipeline pressure. Changes in the pressure ratio definitely cause surging; the hydrogen flow rate and rotational speed also change accordingly. Does the valve opening of the second outlet change first, or does the pressure change first? Analyze the sequence through fluctuation analysis. What is the opening degree of the guide vanes at the inlet?