Synergistic sorbent separation for one-step ethylene purification from a four-component mixture.

Chen, Kai-Jie; Madden, David G; Mukherjee, Soumya; Pham, Tony; Forrest, Katherine A; Kumar, Amrit; Space, Brian; Kong, Jie et al. · Science · 2019

basic_science · Level V

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Abstract

Purification of ethylene (C<sub>2</sub>H<sub>4</sub>), the largest-volume product of the chemical industry, currently involves energy-intensive processes such as chemisorption (CO<sub>2</sub> removal), catalytic hydrogenation (C<sub>2</sub>H<sub>2</sub> conversion), and cryogenic distillation (C<sub>2</sub>H<sub>6</sub> separation). Although advanced physisorbent or membrane separation could lower the energy input, one-step removal of multiple impurities, especially trace impurities, has not been feasible. We introduce a synergistic sorbent separation method for the one-step production of polymer-grade C<sub>2</sub>H<sub>4</sub> from ternary (C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>6</sub>/C<sub>2</sub>H<sub>4</sub>) or quaternary (CO<sub>2</sub>/C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>6</sub>/C<sub>2</sub>H<sub>4</sub>) gas mixtures with a series of physisorbents in a packed-bed geometry. We synthesized ultraselective microporous metal-organic materials that were readily regenerated, including one that was selective for C<sub>2</sub>H<sub>6</sub> over CO<sub>2</sub>, C<sub>2</sub>H<sub>2</sub>, and C<sub>2</sub>H<sub>4</sub>.