Patent ID: 11874057
Assignee: L'AIR LIQUIDE, SOCIETE ANONYME POUR L'ETUDE ET L'EXPLOITATION DES PROCEDES GEORGES CLAUDE
Field: Chemical engineering (Chemistry)
Classification: CPC F | IPC F

Claim 0:
1. A process for the separation of nitrogen from a feed stream comprising methane and nitrogen, with a methane content between 4 and 12% mol, the process comprising the steps of:
a) separating the feed stream by means of a rubbery-type membrane to produce a permeate enriched in methane at a pressure greater than 2 bara and a non-permeate that is a nitrogen-enriched residue gas at a pressure greater than 2 bara;
b) processing of the high-pressure residue gas in a cryogenic separation unit to produce a methane rich liquid and a nitrogen-enriched gas; and
c) measuring the nitrogen concentration of the nitrogen-enriched gas,
wherein the pressure of the membrane permeate is controlled as a function of the nitrogen concentration in the nitrogen-enriched gas.