When the amount of treated air increases, the rising steam in the distillation column will increase, and the amount of liquid to be condensed in the main cooler will increase accordingly, so it has no effect on the reflux ratio in the column. The purity of oxygen and nitrogen remained unchanged in a certain range with the increase of gas volume, and the output increased proportionally with the increase of gas volume.
However, with the increase of the amount of condensate in the main cooler, 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 column will increase accordingly. At the same time, with the increase of gas velocity in the column, the amount of downflow liquid increases, and the liquid layer on the tray thickens, which increases the resistance of the tray and the pressure of the upper and lower columns. This will adversely affect the separation of oxygen and nitrogen, and also increase power consumption. When the gas volume is too large, the resistance of the tray and the resistance of the downstream liquid flowing through the overflow funnel will increase greatly, resulting in the rise of the liquid level in the overflow funnel, and even overflow phenomenon, which will destroy the normal working state of the distillation column.
In addition, due to the increase of the rising steam flow rate, it is easy to bring the droplets to the upper tray, which affects the distillation effect, and the purity of nitrogen is reduced, thus reducing the oxygen extraction rate.
Even if the air volume increases about 20%, the general air separation column can work normally without any measures. It is necessary to increase the pore size of the sieve on the tray to reduce the steam velocity when the amount of treated air is too large. Expanding the heat transfer area of the main cooler can reduce the temperature difference between the main coolers and ensure the normal operation of the distillation column.
