Abstract: Method and apparatus for a membrane separation system, including process and installation for the separation of air by permeation, using two strategically placed heaters for the production of high purity nitrogen, uniquely designed multi-staged pre-filtration system and a novel method of controlling the nitrogen flow and purity. The system comprises in series an air compressor (1), an air cooler (2) cooled by air or liquid, moisture separator (3), mist removing filter (4), primary heat source (5), coalescing filter (8), carbon tower (9), particle filter (10), secondary heat source (11), membrane separator(s) (14), and control valve (19). The system is to provide and maintain superheated air to the membrane separator(s) using strategically located heaters to eliminate condensation of moisture in the carbon tower or membrane separator(s) eliminating the need for a separate compressed air dryer, or the need for insulation of pipes, vessels and the membrane separator(s).