Questions regarding the main cooling liquid level and the pressure in the lower column

How does the pressure in the lower column change when the level of liquid oxygen in the main coolant increases, and why? When the level of the main cooling liquid rises (under normal operating conditions, with the heat exchanger fully loaded), the pressure in the lower column increases to a certain extent. This is because an increase in the level of the main cooling liquid leads to an increase in its pressure as well as its temperature, which in turn reduces the temperature difference for heat exchange. What happens to the pressure in the lower column when the purity of the gaseous nitrogen in it decreases? And why? A decrease in the purity of liquid nitrogen in the lower column indicates a reduction in the reflux flow in that column, insufficient cooling capacity in the lower column, an increase in pressure there, and a decrease in the amount of gas supplied

More nitrogen products are extracted and fewer oxygen products. Normally, the main cooler is not fully shut down; when the liquid oxygen level in the main cooler is high, the heat exchange area increases, leading to more liquid nitrogen reflux and a larger volume of inlet gas, as well as a lower pressure in the lower column

LZ, tell everyone the results of the changes

First: As the level of the main cooling liquid rises, when the main cooler is not fully filled and the liquid level is approximately less than 75% of the cooler’s total height, the pressure in the lower tower may decrease as the heat exchange area increases (with the exhaust pressure of the air compressor remaining constant). Conversely, as the pressure in the lower tower increases, and since the exhaust pressure of the air compressor remains constant, any increase or decrease in the pressure of the lower tower is relative ； Second: I don’t know if your question is related to the first one as a consecutive issue ； If so, it may be due to an increase in the main cooling liquid level, a decrease in the heat exchange efficiency of the main cooler, an increase in the pressure in the lower column, and a reduction in the amount of air processed ； And your nitrogen extraction volume remains unchanged, resulting in a decrease in purity ； It can be adjusted by the amount of nitrogen or V3. If your second question is a separate one ； There are many causes and effects.

The liquid oxygen level in the main cooler increases, which leads to an increase in the heat exchange area; as a result, more nitrogen gas is condensed, and the pressure in the lower column decreases (with the compressor exhaust pressure remaining constant). The purity of the nitrogen gas in the lower column declines, and its pressure increases. This is also related to the main cooler, as nitrogen purity is one of the factors that affect the temperature difference in the main cooler