When the air separation tower is configured with argon Tower, what are the requirements for the main tower?

In the main tower of the air separation Tower, the distribution of argon varies with the position of the liquid inlet. The position of the liquid inlet increases, and the maximum concentration of argon concentration area in the distillation section also increases. At the same time, the nitrogen content in the distillation can be reduced. However, argon content in the downflow also increases. In order to ensure the oxygen purity, more tower plates are needed below the argon distillation outlet. Therefore, during argon production, the El position of liquid-air feed should be appropriately higher than that without argon production. Some equipments set two positions of the liquid inlet to meet the working conditions of argon production and no argon production respectively.
During argon production, in order to improve the extraction rate of argon, the argon content in oxygen and nitrogen must be reduced. When the argon content in the nitrogen discharge exceeds 0.3% and the argon content in the product oxygen is 0.7%, the extraction rate of argon cannot exceed 60%. Therefore, when allocating argon Tower, the number of tower plates of the main tower is larger than that without argon tower. Increasing the number of tower plates can improve the purity of liquid nitrogen; increasing the number of tower plates in the distillation section can improve the purity of nitrogen discharge, which can reduce the amount of argon taken away by nitrogen and increase the extraction rate of argon. Increasing the fraction to the number of main cold Tower plates is conducive to the separation of argon and oxygen, which can increase the argon content in argon fraction and reduce the argon content in liquid oxygen.