Ethylene separations using small pore zeolites containing double-six rings and cages

A method for removing impurities from a feed gas stream of ethylene-containing stranded gas including impurities and ethylene, comprising:

• (a) alternating an input of the feed gas stream between an at least two beds of a one or more adsorbent particles made from a homogeneous mixture, wherein the one or more adsorbent particles comprise a zeolite SSZ-98 or a zeolite SSZ-105;
• (b) wherein the feed gas stream contacts one of the at least two beds at a given time by an adsorption step and a product gas stream is simultaneously vented from another of the at least two beds by a desorption step;
• (c) wherein a contacting in the one of the at least two beds occurs at a feed pressure of from about 345 kPa to about 3450 kPa for a sufficient time to preferentially adsorb the ethylene from the feed gas stream and thereby producing a product gas stream during the desorption step containing no greater than about 2 mol % impurities, at least about 98 mol % of the ethylene recovered from the feed gas stream;
• and
• (d) wherein the feed gas stream is input at a feed end of each of the at least two beds, the product gas stream is removed from the feed end of each of the at least two beds during the desorption step, and the impurity-enriched gas stream is produced from the tail gas end of the at least two beds.