The hazards of large expansion volume in the upper tower of air separation
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1. Is it excessive cooling that causes the tower to cool down, leading to a decrease in oxygen purity? However, the purity of the contaminated nitrogen will increase
Introducing too much expanded air into the upper tower will lead to a decrease in nitrogen purity (the average nitrogen purity drops, and of course the oxygen content in the impure nitrogen increases), as well as a reduction in the oxygen extraction rate (a decrease in oxygen production). Therefore, it is better to follow the design parameters provided by the manufacturer and maintain a certain amount of bypass flow in order to achieve the highest possible oxygen extraction rate. Further adjustments can be made later to see if it is possible to recycle some of the bypass air~~
The introduction of an increased volume of gas into the upper column is aimed at tapping into its distillation potential; however, feeding too much gas into this column will reduce its distillation efficiency. For example, if a column is capable of distilling 10,000 cubic meters of gas, supplying 11,000 cubic meters will inevitably result in a poorer separation effect. Therefore, when the expansion volume is large, a portion of the flow must be diverted through a bypass and not all of it can be sent to the upper tower.
I think it’s mainly necessary to look at your air separation load; if the load is lower, less expanded air will enter the upper tower. If the load is high, you can try reducing the bypass flow. Adjust slowly when making adjustments. Each air separation unit has its own characteristics, and it takes time to figure out the patterns.