Cryogenic air separation nitrogen production is a traditional and technically mature industrial nitrogen production method. The core principle is based on the difference of boiling points of air components, and nitrogen purification is realized through deep freezing and rectification separation. The process mainly includes four links: air compression, purification, liquefaction and rectification: firstly, air is compressed to a certain pressure to remove impurities such as water and carbon dioxide to prevent blocking at low temperature, and then air is cooled to about - 196 ℃ through heat exchange to make it liquefied. Finally, the boiling point difference between liquid nitrogen (- 196 ℃) and liquid oxygen (- 183 ℃) is used to exchange gas and liquid repeatedly in the rectification column to enrich nitrogen on the top of the column, so as to obtain high purity nitrogen.
The core characteristics of this technology are outstanding, and the advantages are obvious: the purity of nitrogen is very high, reaching more than 99.999%, which can meet the demands of high-end industry; With large single-unit capacity, it can realize continuous gas supply of thousands to tens of thousands of cubic meters per hour, adapt to large-scale production scenes, and synchronously produce liquid nitrogen, liquid oxygen and other by-products, with high comprehensive benefits.
Its limitation is also obvious: complex equipment structure, large floor area, high capital construction and equipment investment cost; Long startup time and high energy consumption; Strict maintenance requirements, accurate control of temperature, pressure and other parameters.
Cryogenic air separation nitrogen production is more suitable for large-scale industrial scenes with high requirements on nitrogen purity and output and stable gas consumption, such as steel smelting, petrochemical industry, etc.
