Pressure-temperature swing adsorption process for the separation of heavy hydrocarbons from natural gas streams

A process for the separation of C2+ hydrocarbons from a natural gas stream, which process comprises:

• a) subjecting said natural gas stream to an adsorption step by introducing it into the feed input end of an adsorbent bed selective for adsorbing said C2+ hydrocarbons, which adsorbent bed comprises at least one adsorbent material and a feed input end and a product output end, and which adsorbent bed is operated at a first pressure and a first temperature wherein C2+ hydrocarbons are selectively adsorbed by the adsorbent bed and wherein a first C1 product stream having a higher mol % of C1 hydrocarbons than said natural gas stream is retrieved from the product output end of said adsorbent bed;
• b) stopping the introduction of said natural gas stream;
• c) depressurizing said adsorption bed to a second pressure lower than said first pressure;
• d) externally heating said depressurized adsorbent bed to a second temperature greater than said first temperature, thereby causing at least a fraction of the adsorbed C2+ hydrocarbons to desorb from the adsorbent bed;
• e) counter-currently flowing through said heated adsorbent bed a first purge gas stream at a third pressure;
• and
• f) recovering a C2+ product stream comprising C2+ hydrocarbon components and methane,
• wherein a second purge gas stream is passed co-currently through the adsorption bed following depressurization step (c) and prior to heating step (d).