Understanding Vaporization in Liquid Oxygen Tanks: Is Self-Evacuation Normal and Within Standards?

We have installed two Liquid Oxygen Tanks, each with a capacity of 5,000 L. We cooled both tanks during the first filling. After the hospital began using them, we observed that consumption was very low. We closed one tank, and the remaining tank has not been depleted in three months. However, we have started experiencing vaporization inside the liquid tank, causing the pressure to increase daily until the vent valve opens and evacuates for safety. Is this normal? If we keep a 5,000 L Liquid Oxygen tank without using it, is there a standard self-evacuation due to vaporization? How much vaporization is considered within standards?

We didn't close both of them. We have closed one full tank as a reserve and are using the other one for consumption.

Your query is not understood. Consumption is need-based. If you mean oxygen flow rate, then that can be checked from the ONLINE gauge. Kindly clarify. Do not keep one tank as a reserve; use the two tanks alternatively. We follow this method.

Thank you for your response. Let me try to explain it like this. We have a LOX 5000L tank that we do not use, resulting in zero consumption. We filled it three months ago, and after this period, we noticed that only 1.5 liters were left. There are no issues with leasing, insulation, or vacuum in the tank.

The manufacturing company explained that even if the tank is isolated, some heat transfer will still occur, leading to vaporization. This constant vaporization causes an increase in pressure inside the tank. Once the pressure reaches a certain level, the tank's safety valve opens to release the vaporized oxygen, resulting in the loss of oxygen from the tank.

Therefore, I wanted to ask if you have encountered a similar situation. Is it normal for unused but full LOX tanks to experience this? I have read online that a vaporization rate of 0.15-3% per day is considered normal in such cases. Have you had any similar experiences?

Thank you for your response. Let me try to explain. We have a LOX 5000-liter tank that we do not use. There is zero consumption as we have kept all the valves closed. The tank was filled 3 months ago, and after this period, we noticed only 1500 liters remaining. There are no leaks, isolation, or vacuum issues with the tank.

The manufacturing company informed me that even when the tank is isolated, there will still be some heat transfer, leading to vaporization. This continuous vaporization increases the pressure inside the tank. Once the pressure reaches a certain level, the tank's safety valve will open to release the vaporized O2, causing the tank to lose O2.

Similar Experiences with LOX Tanks

I wanted to ask if you have encountered a similar situation. Is it normal for unused but full LOX tanks to experience this? I have read online that a daily vaporization rate of 0.15-3% is common in such cases. Have you had any similar experiences?

Yes, loss will be there, even if left unused. We have installed a PSA for our requirement, and LMO and cylinders are for backup. Law in Delhi for PSA Plants We have a law in Delhi that all hospitals are required to have their own PSA plant due to experience gained during the COVID-19 pandemic. That is the reason why we keep LMO as a backup.