Reactive regeneration in novel hybrid solvent: Achieving dual objectives of H2S conversion and absorbent regeneration

Abstract

In this work, we developed a composite solution (FILs/DFP) using ionic liquids (FILs) and 4-formylmorpholine (DFP) for natural gas desulfurization. Among these, [TND-C][Tf2N]/DFP exhibited an impressive H2S uptake of 3.65 mol/mol and H2S/CO2 selectivity of 25 at 30 °C and 1 bar. The 1H NMR, FTIR, and DFT calculations revealed that the dense hydrogen bonding network and the active sites of tertiary amines in FILs/DFP were the main factors for the efficient uptake of H2S. Furthermore, we propose a viable reaction regeneration strategy at room temperature, successfully addressing the challenges of absorber regeneration, the catalytic activity of the FILs remained above 95 % even after six cycles. Overall, this strategy eliminates the high energy losses of H2S desorption and allows for the recycling of FILs with minimal energy consumption. This simultaneously achieving dual objectives of H2S conversion and absorbent regeneration process shows promising applications in natural gas desulphurization.