When the amount of processing air increases, the rising steam in the distillation tower will increase, and the amount of liquid required to condense in the main cooler will also increase accordingly, so the reflux ratio in the tower will not be affected. The purity of oxygen and nitrogen can remain basically unchanged within a certain range of increased air volume, while the output will increase proportionally with the increase of air volume.
However, as the amount of condensed liquid in the main cooler increases, the heat load of the main cooler increases. When the heat transfer area is insufficient, the temperature difference of the main cooler will inevitably expand, and the pressure of the lower tower will increase accordingly. At the same time, due to the increase of air flow velocity in the tower, the amount of downflow liquid increases, and the thickening of the liquid layer on the tray increases the resistance of the tray, and the pressure of the upper and lower columns will also increase accordingly. This will have a negative impact on the separation of oxygen and nitrogen, and also increase the power consumption. When the gas volume is too large, the resistance of the tray and the resistance of the downflow liquid flowing through the overflow bucket will increase a lot, causing the liquid level in the overflow bucket to rise, and even the liquid flooding phenomenon that the liquid cannot flow down will occur, which will destroy the normal working conditions of the distillation tower.
In addition, due to the increase of the rising steam flow rate, it is easy to bring the liquid drop to the previous tray, which affects the distillation effect, and the nitrogen purity decreases, thus reducing the oxygen extraction rate.
The general air separation tower can work normally by increasing the air volume by about 20%, and no measures need to be taken. When the processing air volume is too large, it is necessary to increase the aperture of the sieve hole on the tray to reduce the steam speed. Increase the heat transfer area of the main cooler to reduce the temperature difference of the main cooler and ensure the normal operation of the distillation tower.
