Deep cooling air separation process

After the argon fraction is extracted from the top Tower, it enters into the crude argon tower and conducts the separation of oxygen and argon by the rectification method. Generally, the components of crude argon from the top of the crude argon tower are: argon is more than 98%, nitrogen is less than 0.5%, and oxygen is less than 1.5%. Import Crude argon with purity over 98% into molecular sieve adsorber. There are two adsorbers in each group. One is equipped with 5A Molecular sieve to absorb nitrogen in crude argon; the other is equipped with 4A molecular sieve to absorb oxygen in crude argon. In order to release the adsorbents, two groups of adsorbents need to be set up to switch to use. The adsorber works at the temperature of 90 K. The crude argon enters into 5A Molecular sieve adsorber to remove nitrogen first, and then enters into 4A molecular sieve adsorber to remove oxygen. The process is shown in Figure 18. The gas from a group of molecular sieve adsorbers has a purity of 9...

The reflux liquid in the upper column of the distillation column is throttled by the lower column to the liquid air and liquid nitrogen of the upper column, and the reflux ratio of the upper column is regulated by the liquid nitrogen throttle valve. When the liquid air and liquid nitrogen pass through the throttle valve, the pressure will decrease, and the corresponding saturation temperature will also be reduced. If the supercooling degree of liquid is not enough, some liquid will be vaporized. The higher the gasification rate is, the lower the reflux ratio of the upper column is, and the purity of nitrogen is affected. Therefore, in order to improve the supercooling degree of the liquid nitrogen in the night sky through the throttle valve, a subcooler is generally set up to increase the supercooling degree of the liquid nitrogen in the liquid air.