A process for providing nitrogen gas to a customer at a variable flow rate.

摘要

A membrane nitrogen generator adapted to deliver a flow rate of nitrogen gas having a purity better or at least equal to P0, which includes: (a) a source of compressed nitrogen containing gas having a purity lower than P0, the source having a maximum flow rate Fm1; (b) varying means connected to the source of a) which is adapted to vary the flow rate of the source between Fm1 and zero; (c) a nitrogen membrane fed by the source of a) which is capable of delivering a low purity nitrogen gas which is enriched in nitrogen compared to the source and a nitrogen depleted gas which is depleted in nitrogen compared to the source, the low purity nitrogen gas having a purity P1 which increases when the flow rate of the nitrogen containing gas source feeding the membrane decreases, the purity P1 being lower than P0 at the maximum flow rate Fm1; (d) a source of high purity compressed nitrogen gas having a purity which is greater than P0 delivering a high purity nitrogen gas having flow rate control means to control its flow rate from zero to a maximum flow rate value Fm2; (e) mixing means adapted to mix the low purity nitrogen gas and the high purity nitrogen gas and delivering a nitrogen gas mixture; and (f) purity control means adapted to measure the purity of the nitrogen gas mixture and to generate a signal to the flow rate control means to increase the flow rate of the high purity nitrogen gas when the measured purity of said nitrogen gas mixture is smaller than or equal to P0 and to decrease the flow rate of the high purity nitrogen gas when the measured purity of said nitrogen gas mixture is greater than P0.