Patent ID: 6610124
Filing Date: 2003-08-26
Classification: B01D,C07C,C10L,Y02C,Y02P

Abstract:
A process for the separation of nitrogen, carbon dioxide or both from a natural gas feed stream, and the recovery of hydrocarbons from said feed stream which comprises:passing said natural gas feed stream to a first pressure swing adsorption unit containing an adsorbent selective for nitrogen, carbon dioxide or both so as to preferentially adsorb nitrogen, carbon dioxide or both from said feed stream and produce a first product stream enriched with methane and a low pressure waste stream having a higher molar concentration of nitrogen, carbon dioxide or both than said feed stream, said waste stream further containing a portion of said hydrocarbons contained in said feed stream and which have been co-adsorbed on said adsorbent; passing said waste stream to a second adsorption unit containing a hydrocarbon-selective adsorbent so as to preferentially adsorb said co-adsorbed hydrocarbons to produce a second product stream enriched with nitrogen, carbon dioxide or both; and directing a methane-containing stream to said second adsorption unit to purge said hydrocarbon-selective adsorbent and produce a combined stream of methane and said co-adsorbed hydrocarbons adsorbed by said hydrocarbon-selective adsorbent.