There are many types of industrial gases, which can be roughly divided into two categories: general industrial gases and special industrial gases. Compared to these two industrial gases, the production and sales volume of general industrial gases is large, but the requirements for purity are not high; Although the production and sales volume of special gases is small, according to different uses, there are extremely strict requirements for the purity or composition of different special gases, the allowable high content of harmful impurities, and the packaging, storage, and transportation of products. They are high-tech and high value-added products.