Deep cold air separation method

Saturation temperature and saturation pressure are terms in gas-liquid equilibrium. If it is not filled with liquid in a sealed container, part of liquid molecules will enter the upper space, which is called "evaporation ". As the number of vapour molecules in space increases, the pressure of vapour generated by it also increases. At a certain time, the number of vapour molecules in space will not increase any more. At this time, the number of molecules leaving the liquid and the number of molecules returning the liquid from Space reach a dynamic balance, which is also called "saturated state ". At this time, the pressure generated by vapour is called "saturated pressure ". For the same substance, the saturation pressure is related to the temperature. The higher the temperature is, the greater the energy the molecule has, the easier it is to get rid of the liquid and gasification, and the corresponding saturation pressure is also higher. A certain temperature corresponds to a certai...

Why do air separation towers usually use two-stage distillation towers?