Selective removal of nitrogen from natural gas by pressure swing adsorption

摘要

A process for the separation of nitrogen and hydrocarbons from a natural gas stream comprises passing the natural gas stream to a first pressure swing adsorption unit containing a hydrocarbon-selective sorbent so as to preferentially adsorb at least C4+ hydrocarbons to produce a first product stream, comprising methane, nitrogen and a reduced level of the hydrocarbons relative to the natural gas stream The first product stream is then passed to a second pressure swing absorption unit containing a nitrogen-selective sorbent so as to preferentially adsorb nitrogen and produce a second product stream enriched with methane, and a low pressure purge stream having a higher molar concentration of nitrogen than the first product stream.