Mainly used in situations where pure nitrogen does not contain hydrogen or where users do not have hydrogen. The use of carbon deoxygenation process requires a purity of 99.9% or higher for the primary nitrogen, followed by the use of carbon deoxygenation agent to remove oxygen, and then obtaining high-purity nitrogen through drying and decarbonization processes. The nitrogen purity and oxygen content of this process are less than 3ppm, and the dew point is less than -65 ℃