Dual-PSA process with recycling packed with MOF MIL-100(Fe) for the separation of H2, CH4, and C2H6 from a CH4 decomposition non-thermal plasma reactor

The purification of hydrogen and the recovery of methane with low C 2 -hydrocarbon levels from the outlet gas stream of the atmospheric non-thermal plasma (NTP) methane decomposition process, which directly produces hydrogen from methane without emitting carbon dioxide, are fundamental from both economic and environmental perspectives. In this work, a two-stage pressure swing adsorption (dual-PSA) process with a recycling stream was studied to carry out this separation, using MIL-100(Fe) as the adsorbent and considering two different fresh feed compositions (27.8 % H 2 , 63.4 % CH 4 , 8.8 % C 2 H 6 and 57.1 % H 2 , 31.1 % CH 4 , 11.8 % C 2 H 6 ). The adsorption capacity of these compounds on MIL-100(Fe) was evaluated at three different temperatures (303, 313, and 333 K) and pressures up to 5 bar, with the order from highest to lowest being C 2 H 6 > CH 4 > H 2 . Single and multicomponent breakthrough curves were experimentally measured and simulated to validate the proposed predictive model. A dual-PSA process was designed and simulated using the validated model. The best simulation results with the low-hydrogen-content fresh feed showed that it is possible to increase the hydrogen concentration to 99.991 % with a hydrogen recovery of 87.1 % and an energy consumption of 105.9 W h mol H2 −1 . Alternatively, if the high-hydrogen-content fresh feed is employed, a rise in the concentration to 99.991 % hydrogen can be achieved with a higher hydrogen recovery (96.8 %) and lower energy consumption (46.8 W h mol H2 −1 ).