FIELD OF THE INVENTION

The current approach to remove CO2 and heavy hydrocarbons from a natural gas stream involved passing the stream through an amine solvent unit, a dehydration unit to remove the water in the gas stream and then an adsorbent system such as a SeparSIV unit from UOP LLC, Des Plaines, Ill. to remove the heavy hydrocarbons. This approach may lead to high costs for the amine solvent and dehydration units. The high cost tends to squeeze margins and make many opportunities uneconomical to pursue.

SUMMARY OF THE INVENTION

The invention provides a process to purify a gas stream by using an adsorbent bed as well as a secondary device such as a knock-out drum to remove heavy hydrocarbons with a recycle stream then sent first to a vessel containing an amine solvent to remove acid gases including carbon dioxide and hydrogen sulfide (when present) and then sending the treated gas stream to a dehydration unit such as an adsorbent bed or a triethylene glycol absorbent to remove water as well as a knock-out drum or other apparatus to remove condensed liquids. The invention further provides improved integration of the process streams to allow for smaller amine solvent and dehydration units as compared to the prior art.

