The liquid oxygen level in the main condensation evaporator of the air separation unit fluctuates sharply during winter
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Our plant uses an air separation unit with a capacity of 48,000, designed by Hangyang. Every winter, the liquid oxygen level in the main condensation evaporator experiences abnormal fluctuations – for example, it may rise by 300 mm or drop by 300 mm within one minute, and these changes occur over short periods of time in an irregular manner. There are no changes in the expansion volume, resistance, temperature, or the liquid level in the lower tower. We have checked the pressure tapping pipes and transmitters outside the cryogenic box, but we still cannot resolve this issue. Please ask experts to help us solve it!
Have you checked to see if liquid is coming out of the liquid level pressure tap? If liquid appears, there are possible reasons: first, if the environmental temperature in your area is too low during winter, it may lead to incomplete reheating. Second, is the main cooling liquid level in winter the same as that in summer?
The pressure tap was checked and found to be free of liquid; moreover, an electrically heated surface compensator is installed, so the liquid level is slightly lower in winter than in summer
In winter, there is less heat loss and an excess of cooling capacity; could this be due to a high liquid level, or is there liquid in the negative pressure pipe?.....
What about the change in air volume? If process failures are ruled out, it is recommended to check the liquid oxygen extraction valve; we have encountered similar issues here before~~
Whether the electric heating surface compensator is in use. . . . . . . . . .
The fluctuation is 300 per minute; it wouldn’t be that large unless the extraction valve is constantly opened and closed. It is recommended to try using a spare unit, and if that doesn’t work, blow out the instrument tube and check the operation of the electric heating compensator
It is still likely due to incomplete vaporization of the medium being tested.
Have there been any changes in other parameters besides the main cooling liquid level, such as the inlet and outlet temperatures at the expansion end of the expander?
Have there been any changes in other parameters besides the main cooling liquid level, such as the inlet and outlet temperatures at the expansion end of the expander?