What is the impact of increasing the temperature of the air entering the lower tower on air separation?

The nitrogen purity will be poor, and the purity of the argon fraction may be very low.

Reply to 2# you*n*nyou: The nitrogen purity shouldn’t deteriorate

In large-scale fully low-pressure air separation processes, increasing the flow rate through the liquid nitrogen throttle valve V3 reduces the purity of oxygen. Without starting the medium-pressure argon pump, opening valve V116 allows a small amount of hot air to mix with the cooled air after heat exchange, thereby raising the temperature of the air entering the lower column; this improves the purity of oxygen and makes it easier to adjust the parameters compared to before. Personal understanding: An increase in the temperature entering the tower reduces the humidity of the air; as a result, the reflux ratio at the bottom decreases, the purity of the liquid-air mixture improves, and the oxygen purity at the top of the tower also improves. Could the experts think of any other reasons? Or what impact will it have on the entire aircraft’s operational conditions, and what problems might arise over time? Why is it said that increasing the liquid nitrogen throttle valve V3 reduces the purity of oxygen? If the purity of liquid nitrogen meets the requirements for fractional distillation in the upper column, increasing the value of V3 will improve the purity of the liquid-air mixture, which in turn allows the purity of oxygen to increase as well. Of course, V3 cannot be set to an extremely high value either; if it is set too high, the distillation conditions will certainly be disrupted

When the liquid nitrogen throttle valve is opened wider, the backflow ratio to the lower stage increases, which reduces the purity of the liquid air; as a result, the oxygen purity also decreases