Will the temperature of liquid oxygen increase as the liquid level rises, causing the temperature at the bottom to rise as well?

This post was last edited by victory371 on 2010-10-28 09:16. It’s very professional; looking forward to the replies below. First, I’d like to share my humble opinion: can I assume that as the liquid level rises, the static pressure of the liquid oxygen at the bottom also increases, which in turn raises the boiling point and the vaporization temperature? But it’s not known how the liquid oxygen temperature at the bottom changes

I think the same, but I’m not sure if it’s right. That was the situation yesterday: while driving, the level of the main coolant was very high. After the gas is guided, this happens. The main cooling liquid level first dropped a bit, then stopped dropping and remained stable. The liquid level in the lower tower is still not rising. My feeling is that the main cooler isn’t working. Later, there was no other choice but to lower it using a Tata press. It started working bit by bit.

Reply to 1# mimicong: It will change. If your main cooler isn’t working, does it only reduce the pressure in the upper column? From how much down to how much?

This post was last edited by mimicong on 2010-10-28 at 10:25. For valves that do not condense gas, it is required that they become immobile during debugging. It’s a manual valve. Our tower inlet pressure has dropped from 45 KPA to 40 KPA. But after I got off work, the effect was still not very noticeable. There’s still some air that hasn’t been inhaled. Such a phenomenon has never occurred before; the products have long been qualified. Everything that needed to go into the tank has been put in. Everyone, please help me analyze the reasons why the main cooler is not working. At first, I thought it was due to the high temperature, which prevented nitrogen from condensing, so there was no reflux in the lower column. By the time I finished work, the pressure at the tower had dropped to 37 KPA. But I feel that there is still less liquid returning to the tower.

No, it’s not due to the high temperature; the valves that prevent condensation need to be opened wider. Are you starting the system in a cold condition? If so, drain some of the liquid nitrogen; mainly because the liquid level on the main cooling nitrogen side is too high, resulting in a small heat exchange area

However, it could be the main cooling channel, the Duse, or the non-condensable gas resistance. I hope you can share the final reasons and solutions

Thank you. Our nitrogen is directly returned to the lower column. It is a liquid nitrogen pump that draws liquid nitrogen out from the trays of the lower tower. Let me go check the equipment diagram. I’ll talk to everyone again when I get back. Thank you all.

This temperature will experience some changes, but the variation isn’t significant. However, it has a considerable impact on the evaporation of oxygen. Regarding the issue of the main cooling liquid level not rising, one possibility is that your system has high cooling losses and low expansion volume; additionally, even if the main cooling liquid level doesn’t rise, it might be because the liquid is still being used to establish the liquid level in the tower trays

The temperature will experience some changes, and the purity of liquid oxygen at the bottom will improve over time

Theoretically, this is the case: since it is assumed that the pressure in the upper column remains constant, as the liquid oxygen level rises, the static pressure increases. As a result, the liquid oxygen at the bottom is under greater pressure, which in turn raises its condensation temperature. This leads to a decrease in the temperature difference in the main cooler, and consequently, the pressure in the lower column increases