After the start-up of the air separation unit, it is not suitable to commission the crude argon column too early when the main column condition has not been established. Because the nitrogen content of argon fraction is very high at this time, it often causes nitrogen blockage in crude argon column. However, in actual operation, the vent valve of crude argon column is often fully opened, which leads to the increase of cold loss and is not conducive to the accumulation of liquid in the main column. The premise of adjusting the working condition of the main column is to ensure the stability of the lower column working condition, especially in the air separation unit with expanded air entering the lower column process.
