The argon content at the inlet of the crude argon column is low.
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Let’s discuss the reasons for the low argon content at the inlet of the crude argon column, that is, the issue related to the argon-enriched zone in the main column.
There are two argon-rich zones in the upper column, one in the distillation section and one in the stripping section. Generally, the argon extraction point is located near the lower part of the argon-rich zone in the stripping section; therefore, the level of argon content at the inlet of the crude argon column depends on the argon content in the gas at the extraction point of the main column. The distribution of argon in the upper tower of the main tower varies with changes in the oxygen and nitrogen products and their concentrations. As oxygen production decreases, the oxygen concentration must increase; as a result, the argon-rich zone moves upward. In other words, the argon content in the argon-rich zone of the distillation section increases, while the argon content in that zone of the stripping section decreases. If the nitrogen production decreases, the nitrogen concentration must increase. In this case, the argon-rich zone moves downward; that is, the argon content in the argon-rich zone of the distillation section decreases, while the argon content in the argon-rich zone of the stripping section increases.
Well, what was said upstairs is quite comprehensive and official. I’d like to know the specific reasons why the argon fraction cannot be increased in a certain air separation plant – its oxygen load has already reached the design value. The argon fraction control valve (the valve for the nitrogen gas passing through the oxygen subcooler inside the main cooler) is fully open, the liquid oxygen product valve is also fully open, the nitrogen output is within the design limits, and the liquid nitrogen product valve is fully closed. The possible causes have been ruled out according to the analysis. I think it might be due to the design of the crude argon inlet pipeline. Do anyone have any good ideas?
The last edit to this post was made by jiao*aoli1976 on 2012-12-19 at 14:47. The main measure to adjust the argon fraction is to increase the amount of oxygen removed. It was explained very clearly upstairs.
I’m sorry; I made a fundamental mistake – it should be to increase the oxygen extraction amount. I made a mistake; thanks for the reminder!