The reason why there are two argon enrichment zones in the twin-tower process is not only due to dilution of air, but also because the upper tower of the twin-tower process is the nitrogen-argon-oxygen air separation tower. In addition, the effect of oxygen-rich liquid air is also a major factor. Argon content in the oxygen-rich liquid air is about 2% and its quantity is very large, which has a great influence on the distribution of argon in the upper tower.It is the key factor for the formation of two argon enrichment zones in the upper column of the two-column process.
The air in the new single column process enters from the middle of the distillation column with argon content of 1. At the same time, the air separation column in the new single column process is a nitrogen-oxygen-argon distillation column. Even if the argon content of the rising gas is high, the argon content of the mixed gas can not reach 2%, while the air inlet is above the distillation section. Under the condition of argon extraction, the argon content in the distillation section can only decrease continuously.Of course, it is impossible to form another argon enrichment zone.
