Investigation on the Interaction Mechanism of the Solvent Extraction for Mercaptan Removal from Liquefied Petroleum Gas
Dexin Sun, Yulong Zhao, Yanjing Cao, Mengqi Liu, Yuxiang Zhang, Liang Zhao, Yuhao Zhang, Jinsen Gao, Chunming Xu, Tianzhen Hao, Jialing Chen, Dewei Ji
Abstract
In order to efficiently obtain the optimum hybrid extraction solvents for mercaptan removal from liquefied petroleum gas, the method of combining molecular dynamics simulation preselection and extraction experiment was carried out. The results show that the selected hybrid solvents all exhibit a better extraction desulfurization performance, and of which, the isopropanol hybrid (IPA) solvent exhibited the best removal efficiency. With the aid of density functional theory calculations, the interaction mechanism was studied and the results show that the weak hydrogen bond plays a crucial role in the n-propylmercaptan (PM) removal process. The strength of the hydrogen bond is attributed to the structure of solvents, such as functional groups as the acceptor of the hydrogen bond and the species, number, and length of side chains attached to functional groups. Based on the above mentioned analysis, IPA exhibits a stronger hydrogen bond interaction with PM, which significantly enhances the extraction capacity and prolongs the service life of the solvent.