FIELD: production of nitrogen gas. SUBSTANCE: cascade method with washing for production of high-purity nitrogen gas with employment of at least two successively arranged membrane blocks consists in delivery of feed mixture to stage N, collection of residual flow of stage N and use of it as feed flow of stage N+1, collection of permeate flow of stage N+1 and delivery of it to permeate flow of stage N by countercurrent flow washing, collection of permeate of the first stage and residual flow of the last stage. Cascade generator, used for production of nitrogen gas, has membranes in the form of hollow fibres. At least one stage of membrane separation has heating or cooling facilities. Generator can be furnished with temperature controllers of the heating and cooling facilities. EFFECT: facilitated procedure. 24 cl, 10 dwg, 2 tbl
