Simulation and energetic assessment of the ammonia synthesis loop with ionic liquid-Based ammonia recovery from recycle gas

• Published in: Separation and purification technology 2022-11, Vol.301, p.121951, Article 121951
• Main Authors: Shi, Sensen, Duan, Yuanmeng, Zhan, Guoxiong, Chang, Fei, Zeng, Shaojuan, Ji, Xiaoyan, Liu, Zhichang, Meng, Xianghai, Zhang, Xiangping
• Format: Article
• Language: English
• Subjects: Absorption; Ammonia separation; Energiteknik; Energy Engineering; Ionic liquids; Process assessment; Process simulation
• ISSN: 1383-5866; 1873-3794; 1873-3794
• DOI: 10.1016/j.seppur.2022.121951

[Display omitted] •A novel IL-based ammonia synthesis loop IL-HB is proposed.•The systematic techno-economic methodology of IL-based processes is established.•The entire IL-HB integrating IL-based NH3 recovery from recycle gas is simulated.•IL-HB is superior to the conventional HB in energy consumption and CO2 emissions. Ammonia (NH3) synthesis by Haber-Bosch process is recognized as the most important pathway for NH3 production. However, NH3 recovery from recycle gas using conventional condensation separation is still an energy-intensive process. Ionic liquids (ILs) have been proved to be effective solvents for NH3 separation and recovery due to their unique properties. In this work, a novel IL-based ammonia synthesis loop (IL-HB) was proposed, taking the protic IL [Bim][NTf2] as the absorbent to separate and recover NH3 from recycle gas, aiming to reduce the energy consumption and increase the NH3 production capacity of the synthesis tower. Then, a systematic methodology that considers reliable thermodynamic models as well as process simulation and assessment was established to evaluate the feasibility of the IL-HB. Furthermore, two entire processes (ILa-HB and ILb-HB) that integrate the optimal sections of IL-based NH3 recovery from recycle gas with the ammonia synthesis loop as a whole were simulated, taking the conventional Haber-Bosch ammonia synthesis loop (HB) as the benchmark. The simulation results prove great techno-economic potentials of the proposed ILa-HB and ILb-HB. Compared with the HB, the energy consumption and CO2 emissions of ILb-HB can be reduced by 16.01% and 29.44%, respectively, presenting enormous energy-saving and environment-friendly superiority.