四氢萘-正癸烷-二甲基亚砜液-液平衡数据的测定与关联

摘要

煤直接液化中油中含有50%~70%的芳烃，其中80%左右为重芳烃，利用二甲基亚砜(DMSO)对液化油中芳烃萃取分离是对煤液化油进行改质的有效途径。相应体系液液平衡的测定是煤直接液化中油芳烃萃取过程研究开发的理论基础。研究测定了常压下四氢萘-正癸烷-DMSO三元体系在303.15、313.15、323.15 K 时的液-液平衡数据，得到了该体系三元相图，并用Othmer-Tobias方程与NRTL方程进行了关联。体系中四氢萘对正癸烷选择性系数为3.2~17.7，表明用DMSO萃取分离四氢萘和正癸烷具有很好的性能。通过体系液-液平衡数据关联获得了NRTL方程模型参数，利用NRTL模型对该体系进行计算，计算值与实验值的平均偏差较小，说明NRTL模型适用于该体系的液-液平衡。%Coal direct liquefaction oil contains 50%~70% aromatics, in which heavy aromatics accounts for about 80%. Dimethyl sulfoxide (DMSO) is a desired solvent for heavy aromatics extraction, and the quality of liquefaction oil can be improved by extraction with DMSO. Tetranap was selected as a model aromatics compound based on the composition of liquefaction oil, and n-decane was selected to represent the rest part of liquefaction oil. The liquid-liquid equilibrium (LLE) of the tetranap-n-decane-DMSO ternary system under atmospheric pressure was measured at 303.15, 313.15, 323.15 K, respectively, and the phase diagram of this ternary system was obtained. The results were correlated with the Othmer-Tobias and NRTL models to obtain binary interaction parameters, which show that both the Othmer-Tobias and the NRTL models can correlated the equilibrium composition satisfactorily, the selectivity coefficients of tetranap to n-decane are 3.2~17.7. The results show that DMSO is a suitable extraction solvent to separate tetranap and n-decane.