The special team design and manufacture the plant of 80-65000Nm3/h O2; Fractionation column with oxygen capacity less than 30000m3/h can be preassembled before delivery; Fractionation column with oxygen capacity 30000-65000Nm3/h can be assembled in pieces at the jobsite; Specifically design and manufacture the plant of producing step pressure rating oxygen,nitrogen and argon for coal chemical industry.