There are three kinds of air separation technology: adsorption method, membrane separation method and low temperature method.
Adsorption method: using the selective adsorption performance of molecular sieve for different molecules to achieve the final separation purpose. The process is simple, easy to operate and low cost. However, due to the difficulty in obtaining high purity products and limited equipment capacity, the application scope of this technology is limited.
Membrane separation method: the membrane permeation technology is used to realize the coarse separation of two components by using the different rates of oxygen and nitrogen passing through the membrane. This method is relatively simple, easy to operate, low investment, but the product can only reach 28% - 35% oxygen enriched air, the scale is only suitable for small and medium-sized, only suitable for oxygen enriched combustion and health care applications.
Low temperature method: using the different boiling points of each component in the air, through a series of technological processes, the air is liquefied, and different components are separated by distillation. Compared with the former two methods, this method can realize the complete separation of air components, product purification, large-scale plant and liquid gas dual state, which plays a leading role in the industrialization of production equipment. Compared with the traditional separation methods, the separation of these gases can only be carried out in the low temperature environment below 100k, so it is called low temperature method (or low temperature method).
Low temperature air separation technology is widely used in industry.