In the main column of the air separation column, the distribution of argon varies with the position of the liquid air inlet. With the increase of liquid air inlet position, the maximum concentration of argon enrichment zone in the stripping section also increases, and the nitrogen content in the distillate can be reduced. However, the argon content in the downstream also increases. In order to ensure the purity of oxygen, more trays are needed under the extraction port of argon fraction. Therefore, in the case of producing argon, the position of liquid air supply E1 should be appropriately increased compared with the case of not producing argon. Some unit is equipped with two liquid air inlet positions to meet the conditions of argon production and non argon production respectively.
In the production of argon, in order to improve the extraction rate of argon, the content of argon in oxygen and nitrogen must be reduced. When the content of argon in exhaust nitrogen is more than 0.3%
The non-power consuming option for liquid air separation plants can be used for full liquid air separation plants,where the produced liquid is sold off. This approach is currently available for most LNG receiving stations. For air separation units with a large cold capacity, the liquid air can be pressurised to 6baA in a vacuum storage tank, and then heat exchanged through a heat exchanger, instead of the air compressor, directly into the cold box for distillation. At the same time in the cold b...