Extraction of ethane from natural gas at high pressure by adsorption on Na-ETS-10

Methane/ethane separation was achieved using Na-ETS-10 as a packed-bed adsorbent over a pressure range of 450–5600 kPa at 298 K. At these pressures, pure methane gas raffinate streams were obtained prior to ethane breakthrough. The extract phase obtained following desorption from the packed-bed column was enriched in ethane. Extract phases containing up to 75% ethane were achieved following separations of a 93/7 methane/ethane feed mixture. Separation performance did not deteriorate as adsorption column pressures increased. Selective adsorption of a synthetic natural gas mixture using an Na-ETS-10 packed-bed column resulted in hydrocarbon outlet compositions ranging from pure methane (up to ∼60 bed volumes at standard temperature and pressure) to ∼93% methane, ∼5% ethane and ∼2% propane (∼150 to ∼850 bed volumes at standard temperature and pressure). In all cases, following desorption, the extract phase was highly enriched in the larger and more valuable hydrocarbons.