When the amount of processing air is reduced, the rising steam and reflux liquid in the upper column will be reduced, but the reflux ratio will not change. Therefore, the reduction of processing air in a small range will not affect the purity of oxygen and nitrogen, and the reduction of processing air volume will help to reduce the pressure of the upper and lower columns. However, according to the material balance, the production of oxygen and nitrogen will naturally decrease when the amount of processing air is reduced. If the amount of processing air is too small, there will be leakage on the tray. If the heat and mass exchange of the leaked liquid is not sufficient, the purity of oxygen and nitrogen will be greatly affected, and even the normal production can not be realized. Therefore, the minimum allowable load of distillation column is generally specified.
