What factors affect the oxygen extraction rate in air separation units with internal and external compression processes?
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Question for air separation experts: What factors are related to the oxygen recovery rates in internal compression and external compression processes, respectively? Thank you!
From a design perspective, it is related to the number of plates and the efficiency of those plates; from an operational standpoint, it is related to the oxygen content in the contaminated nitrogen gas (that is, reducing the oxygen content in the contaminated nitrogen increases the oxygen extraction rate)
The oxygen extraction rate is expressed as the ratio of the total amount of oxygen in the product oxygen to the total amount of oxygen in the air fed into the tower. That is, ψ = Vo2•yo2/(Vk•yk), where ψ represents the extraction rate of oxygen ； Vo2, Vk--oxygen production and processed air volume, m3/h ； yo2, yk--the volume fraction of oxygen in the product and in air. It can be seen from the above equation that, for a given location, the oxygen content in the air remains essentially constant. When the amount of air entering the tower and the purity of the product oxygen are constant, the level of oxygen extraction depends on the amount of oxygen produced. The amount of oxygen produced, under fixed intake conditions in a fully reduced-pressure oxygen generator, is primarily determined by the oxygen content in the nitrogenous contaminants.