High-performance of Mg2+ additive for addressing NH3 escape in inorganic ammonia carbon capture

• Published in: Separation and purification technology 2024-08, Vol.342, p.126883, Article 126883
• Main Authors: Ma, Shuangchen, Fan, Shuaijun, Chen, Liutong, Li, Ying, Liang, Bowen, Chen, Gongda, Zhu, Hongtao, Yang, Lijuan
• Format: Article
• Language: English
• Subjects: Bidirectional mass transfer; Desulfurization wastewater; Kinetics; Mg-NH3 solvation; Mg2+ additive; NH3 escape
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2024.126883

[Display omitted] •Desulfurization wastewater is reused to inhibit NH3 escape.•The kinetics model of NH3 bidirectional mass transfer is established.•NH3 enters the first solvation shell of Mg2+, and reduces the diffusion of NH3.•The pathways for the beneficial effects of each reaction condition are identified.•The overall IACC and co-production of ammonium fertilizer process is designed and simulated. The urgency to reduce the energy consumption of organic amine carbon capture, while the inorganic ammonia carbon capture (IACC) and co-production of ammonium fertilizer eliminates the desorption energy consumption. Inhabiting NH3 escape at the end of IACC process requires a large amount of water consumption, and there is a lack of corresponding process parameters and technical routes. In this paper, Mg2+, one of major components in desulfurization wastewater, was used as an NH3 inhibitor. It’s found that the addition of MgCl2 can increase the total NH3 absorption rate by 13.02 % and reduce the total NH3 escape rate by 87.02 %. Furthermore, the effects of six process parameters in the forward and reverse NH3 mass transfer experiments could be distinctly quantified by the normalization method to determine the differentiation between priority and others. It’s concluded that NH3 can enter the first solvent shell of Mg2+ to replace some H2O based on the first-principles calculations, which is the main cause for the decrease of NH3 diffusion coefficient. Finally, simulation with Aspen Plus was applied to construct the complete process route, and the Arrhenius formula for the Mg(OH)2 nucleation was used to refine the reaction kinetic parameters of the simulation. The heat and water balance of IACC could achieve within this system, and the excellent NH3 inhibition effect of added Mg2+ was verified, which could effectively keep from the NH3 escape within 3 ppm.