Membrane process and system for nitrogen production

Claim 1

An on-site system for the production of high purity nitrogen gas from air comprising: (a) a first membrane or pressure swing adsorption separation system capable of separating air into a partially purified nitrogen stream containing residual oxygen and an oxygen rich discharge stream; (b) means for supplying feed air to said first membrane or pressure swing adsorption separation system for separation therein; (c) a second membrane, pressure swing adsorption or cryogenic separation system capable of separating relatively pure hydrogen from an impure hydrogen stream containing a relatively high level of impurities, so as to produce a purified hydrogen stream having a desirably low level of said impurities; (d) means for supplying impure hydrogen feed gas available on-site to said second membrane, pressure swing adsorption or cryogenic separation system for purification therein; (e) a catalytic combustion system adapted for the reaction of said purified hydrogen stream with residual oxygen present in the partially purified nitrogen stream; (f) means for passing the partially purified nitrogen and purified hydrogen from said first and second separation systems to said catalytic combustion system; and (g) means for recovering a high purity nitrogen gas stream from said catalytic combustion system, said high purity nitrogen having a desirably low residual oxygen content, whereby high purity nitrogen can advantageously be produced on-site by the convenient purification of low cost, impure hydrogen available on-site and the economical use thereof in the final purification of the partially purified nitrogen stream.