In the main column of the air separation column, the distribution of argon varies with the position of the liquid air inlet. With the increase of liquid air inlet position, the maximum concentration of argon enrichment zone in the stripping section also increases, and the nitrogen content in the distillate can be reduced. However, the argon content in the downstream also increases. In order to ensure the purity of oxygen, more trays are needed under the extraction port of argon fraction. Therefore, in the case of producing argon, the position of liquid air supply E1 should be appropriately increased compared with the case of not producing argon. Some unit is equipped with two liquid air inlet positions to meet the conditions of argon production and non argon production respectively.
In the production of argon, in order to improve the extraction rate of argon, the content of argon in oxygen and nitrogen must be reduced. When the content of argon in exhaust nitrogen is more than 0.3% and the product oxygen contains 0.7% argon, the extraction rate of argon can not exceed 60%. Therefore, when equipped with argon column, compared with without argon column, the number of trays in the main column will be more, and increasing the number of lower tray can improve the purity of liquid nitrogen. Increasing the number of trays in the distillation section can increase the purity of nitrogen waste gas, reduce the amount of argon carried by nitrogen and improve the extraction rate of argon. The increase of the number of plates from the fraction to the main cooling is beneficial to the separation of argon and oxygen, and can increase the argon content in the argon fraction and reduce the argon content in the liquid oxygen.
