A small issue with low-pressure hydrogen-free argon treatment
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I would like to ask the experts here: Why is the temperature of the night sky gas exiting the crude argon secondary tower condenser -188 degrees, when the temperature after it passes through the heat exchanger in the main tower and exchanges heat with nitrogen and contaminated nitrogen is -179 degrees? Part of this gas goes into the upper tower, while another part goes into the crude argon condenser; so what’s the reason for this difference in temperature? I know there is a pneumatic valve in between to control the liquid level in the coarse argon condenser; could it be the throttling effect of this valve? Who knows? Could you explain it? Thank you, I’m a complete beginner~~
Throttle valve, so the temperature drops
The liquid coming from the main tower is at 500 KPA; it is throttled to 50 KPA upon reaching the crude argon condenser. When the pressure drops, the temperature naturally drops as well.
Perhaps the nitrogen content in the liquid air is high; this can be analyzed. At a pressure of 50 Kpa, the temperature of the liquid air does not drop to -188 degrees
But after passing through the device, and after going through the throttle valve, it reaches roughly this temperature
The pressure of the condenser is primarily controlled by the throttle valve located at the top of the condenser and upstream of it; the throttle valve serves only to supply liquid air to the condenser (used to control the level of liquid air). To reduce the gasification rate after throttling, the liquid air before the throttle valve is a subcooled liquid.
The night air is drawn out from the bottom of the lower tower, passes through a subcooler, and then is throttled to enter the upper tower; therefore, it is not called a heat exchanger but rather a subcooler. The pressure of the gas entering the condenser of the crude argon column at night is 5 kilograms, and this pressure drops to 50–60 kilopascals; as a result, the throttling cooling effect is reduced
Another possible reason for the lower temperature in your crude argon column’s night sky section is that the operating pressure of the condenser in that column is too low, or perhaps the purity of the gas in that section is low. It is advisable to maintain the operating pressure of the crude argon column at around 50KPa–60KPa. Furthermore, your low temperature may cause the crude argon column to freeze