Rigorous modelling and optimization of hybrid absorption-adsorption separation process of H2/CH4 using ZIF-8/glycol/water slurry

Efficient separation of H2/CH4 is vitally important for the hydrogen energy system. To guide the scale-up of the separation technique using the ZIF slurry, the rigorous modelling and optimization of the separation process of H2/CH4 using ZIF-8/glycol/water slurry is conducted. A rigorous phase equilibrium model is proposed to describe the hybrid absorption-adsorption with liquid film permeation. Next, the MESH (Material balance, phase Equilibrium, Summation, Heat balance) equations for mass transfer units, modelling and multi-objective optimization of the full separation process are established. The effect of operation pressure and gas-slurry volume ratio on product purity, recovery ratio and unit energy consumption are investigated. Results show that the calculated solubilities of pure/binary components are in good agreement with the experiment data. The feed gas (H2/CH4: 70: 30) can be enriched to be (H2/CH4: 99: 1) with the H2 recovery ratio of 99.5 % and the total unit energy consumption reaches 0.2492 kW·h/Nm3 (feed gas).