Fu Hui, Qin Hansong, Wang Yajun, Liu Yibin, Yang Chaohe, Shan Honghong
State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum, Qingdao, Shandong 266580, PR China; Department of Chemistry, College of Science, China University of Petroleum, Qingdao, Shandong 266580, PR China, PR China.
State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum, Qingdao, Shandong 266580, PR China.
J Mol Graph Model. 2018 Mar;80:59-66. doi: 10.1016/j.jmgm.2017.12.003. Epub 2017 Dec 6.
Separation of branched chain hydrocarbons and straight chain hydrocarbons is very important in the isomerization process. Grand canonical ensemble Monte Carlo simulations were used to investigate the adsorption and separation of iso-pentane and n-pentane in four types of zeolites: MWW, BOG, MFI, and LTA. The computation of the pure components indicates that the adsorption capacity is affected by physical properties of zeolite, like pore size and structures, and isosteric heat. In BOG, MFI and LTA, the amount of adsorption of n-pentane is higher than iso-pentane, while the phenomenon is contrary in MWW. For a given zeolite, a stronger adsorption heat corresponds to a higher loading. In the binary mixture simulations, the separation capacity of n-and iso-pentane increases with the elevated pressure and the increasing iso-pentane composition. The adsorption mechanism and competition process have been examined. Preferential adsorption contributions prevail at low pressure, however, the size effect becomes important with the increasing pressure, and the relatively smaller n-pentane gradually competes successfully in binary adsorption. Among these zeolites, MFI has the best separation performance due to its high shape selectivity. This work helps to better understand the adsorption and separation performance of n- and iso-pentane in different zeolites and explain the relationship between zeolite structures and adsorption performance.
在异构化过程中，支链烃和直链烃的分离非常重要。采用巨正则系综蒙特卡罗模拟方法研究了异戊烷和正戊烷在MWW、BOG、MFI和LTA四种类型沸石中的吸附和分离情况。纯组分的计算结果表明，吸附容量受沸石的物理性质（如孔径、结构和等量吸附热）的影响。在BOG、MFI和LTA中，正戊烷的吸附量高于异戊烷，而在MWW中则相反。对于给定的沸石，较强的吸附热对应较高的负载量。在二元混合物模拟中，正戊烷和异戊烷的分离能力随着压力的升高和异戊烷组成的增加而提高。研究了吸附机理和竞争过程。在低压下，优先吸附起主要作用，然而，随着压力的增加，尺寸效应变得重要，相对较小的正戊烷在二元吸附中逐渐成功竞争。在这些沸石中，MFI由于其高形状选择性而具有最佳的分离性能。这项工作有助于更好地理解正戊烷和异戊烷在不同沸石中的吸附和分离性能，并解释沸石结构与吸附性能之间的关系。
