Extraction of ethane from natural gas by adsorption on modified ETS-10

Ethane was extracted from a synthetic natural gas mixture at 298 K and 101.3 kPa using modified ETS-10 as a packed bed adsorbent. Ethane was completely separated from the mixture for a prolonged period until the initial stages of breakthrough. The adsorptive properties of several cation-exchanged forms of ETS-10, a large-pored titanosilicate molecular sieve, were compared. Na-, Ba- and Ba/H-ETS-10 were all found to be selective for ethane over methane. Na-ETS-10 showed the highest Henry's selectivity (α=52) for ethane over methane of the three ETS-10 materials tested. Ideal Adsorbed Solution Theory (IAST) models indicate that significant selectivity should persist at high pressures. Ethane is commonly removed from raw natural gas by energy-intensive cryogenic methods and these results reflect the potential for an alternative and efficient separation process using cation-exchanged ETS-10 as an adsorbent.