High purity ethane/ethylene separation by gas phase simulated moving bed using ZIF‐8 adsorbent

Growing population and demand for plastics and synthetic fluids in climate friendly environment sets the unprecedented industrial challenge to increase production of clean chemical precursors (e.g., ethylene) with reduced energy consumption and CO2 foot print. The production of polymer‐grade ethylene (>99.9%) from steam cracked gas or oil relies on a cascade of energy intensive distillations of gases. Therefore, in this work two simulated moving bed (SMB) cycles were employed to separate mixtures containing of about 40% of ethane and 60% of ethylene on zeolitic imidazole framework‐8 granulates. The separation cycles were performed with two desorbents with different relative adsorption strength. In the experiment, with carbon dioxide as desorbent, ethylene was obtained with 99.6% purity and 94.2% recovery, while in the experiment using propane as desorbent only 77.1% of ethylene is recovered with a purity of 82.7%. Indeed, it can be concluded that when CO2 is used as desorbent, the obtained productivity is higher. The mathematical SMB model and regions of separation were determined for each desorbent based on experimental data.