Simulation and Economic Evaluation of the Ammonia Recovery Process Enhanced by Ionic Liquids

The Haber–Bosch (HB) process dominates industrial ammonia (NH3) synthesis by reacting nitrogen (N2) and hydrogen (H2). However, its energy efficiency is significantly constrained by the conventional NH3 condensation step. To further reduce production energy consumption and improve the reactor capacity, we proposed two novel absorption revolution processes enhanced by ionic liquid (IL), using 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([Bim][NTf2]) as the absorbent solvent, referred to as the IL-based vapor NH3 recovery process (ILVR) and the IL-based refrigeration replaced process (ILRR). Both processes integrate IL-based NH3 absorption with the HB synthesis loop. Through thermodynamic models, process simulation, and multiobjective optimization, the energy demands of the NH3 synthesis and IL-based recovery units have been systematically evaluated. Results demonstrate that ILVR, compared to the conventional method, achieves an 18.7% increase in annual production capacity and a 24.4% enhancement in economic efficiency. Simulation results show that both ILVR and ILRR have great market prospects.