Large scale air separation plant is an indispensable and important supporting device in coal chemical industry. With the continuous development of equipment manufacturing industry, the actual needs of production demand for it is higher and higher. The design, manufacturing and integrated technology of large-scale air separation plant has become mature day by day, and the stability of the equipment is the key technical index. In recent years, metallurgy, petrochemical, petroleum, chemical fertilizer and other fields have sustained and stable development. Different industries have different demands for large air separation units. Large scale air separation plant is developing in the direction of process diversification, technological innovation and intelligence.