What happens when there is an excess of cooling capacity in the lower tower, but insufficient cooling capacity in the upper tower?

Your statement is incorrect; in a situation like this, an excess of cooling capacity in the tower should result in a decrease in the argon fraction, as insufficient cooling capacity corresponds to a lower reflux ratio

“Decrease in the oxygen purity of Air Liquide leads to a reduction in the evaporation pressure in the upper column, as well as an increase in the argon fraction: A drop in the purity of Air Liquide results in excess cooling capacity in the lower column, an increase in the moisture content of the gas rising from that column, an increase in the reflux ratio, and a decrease in the amount of gas rising from the lower column. The evaporation volume in the main cooler remains unchanged; this manifests as a reduction in the pressure in the upper column, while the argon fraction fluctuates in accordance with the changes in the purity of oxygen and nitrogen in that column

By excess cooling capacity in the lower column, you probably mean a high liquid level in the liquid air separator; this could be caused by an excessive reflux ratio in the lower column. Insufficient cooling capacity in the upper column is manifested by a low level of liquid in the main cooler, reduced evaporation volume, a high reflux ratio, and a shift of the argon-rich zone downward, resulting in a higher proportion of argon in the distillate – but this can easily lead to nitrogen buildup

This post was last edited by victory371 on 2010-11-1 09:41. As a moderator with 525 hours of experience, it seems that your company’s air separation unit belongs to Sichuan Air Separation. What’s your understanding of this statement? ! !

Reply to 4# gader: Dear moderator gader, what exactly does it mean by insufficient cooling capacity in the tower? ! Thank you!

Reply to 6# victory371: Generally speaking, an indicator of the cooling capacity in the upper tower is the level of the main cooling liquid

This post was last edited and replied to by 525h on 2010-11-1 at 13:06. Reply to 5# victory371: Our process is the same as yours, just on a larger scale, haha. Moderator gader is right – there’s an excess of cold fluid in the lower tower; in other words, there’s too much reflux liquid there. This is indicated by a high valve opening for the liquid-air stream going to the upper tower, as well as a low purity of that liquid-air stream. Once it reaches the upper tower, the large volume and low purity of the liquid-air increase the separation burden, reducing efficiency and resulting in less liquid oxygen being produced. Since the amount of oxygen extracted remains constant, the amount of oxygen vapor rising decreases, which is reflected in lower resistance in the upper tower and a lower level of the main cooling fluid. Rising oxygen vapor decreases, the argon-rich region declines, and the argon fraction increases.

Reply to 8# 525h: What is the capacity of the air separation unit at your Chuan Kong facility? We are about to install a unit with an internal compression capacity of 25,000 I was wondering if there are any specific methods or tips for doing this; I hope you would be kind enough to share your knowledge

In fact, the backflow liquid in the retention section increases, causing the argon-enriched zone to move downward! Balance the operations still!

Reply to 3# Bai Ruiguang: How can an increased evaporation rate in the main cooler lead to excessive cooling capacity in the lower tower? It was already said that there is insufficient cooling capacity in the upper tower. What does insufficient cooling capacity mean? Isn’t it simply a reduction in the reflux ratio? So if the reflux ratio in the upper tower decreases, how do you think the argon fraction will change?