【作者】 张亮；

【导师】 曾爱武；

【作者基本信息】 天津大学 ， 化学工程， 2007， 硕士

【摘要】 随着焦化工业的发展,焦化苯已经成为苯的一个重要来源。但是,其中含有的多种烷烃、烯烃能够与苯形成共沸物,传统的分离方法不适应当今绿色化工的发展要求。本文利用萃取精馏新工艺精制纯苯,回收噻吩。萃取精馏的关键在于溶剂的选取。本文利用UNIFAC方程以及其两种主要的修正形式对文献中报道过的溶剂:N-甲基吡咯烷酮(NMP)、二甲基亚砜(DMSO)、N,N-二甲基甲酰胺、吗啉、苯胺、二苯基甲烷、乙二醇、二甘醇、四甘醇(TEG)、环丁砜等进行了筛选,并且选择己烯、环己烷、甲基环己烷、正庚烷作为烷烃、烯烃的代表。从萃取效果方面考虑,环丁砜、二甲基亚砜、四甘醇、N-甲基吡咯烷酮、N,N-二甲基甲酰胺都是优良的溶剂,但考虑到沸点、毒性等因素,选择NMP作为萃取精馏实验的溶剂。萃取精馏实验分为三个阶段:除烷烃与烯烃阶段、苯精制阶段以及噻吩回收阶段。第一阶段,通过一次萃取精馏成功的除去了烷烃、烯烃,并且最大限度的保留了噻吩,为后续的步骤打下了基础;第二阶段,制取了纯苯,色谱分析噻吩杂质基本不出峰;在第三阶段,噻吩得以回收,并且浓缩其浓度至99%(质量百分数)。实验过程中,采用不同的回流比和溶剂比,分析了操作参数对萃取精馏的影响。最后,对整个萃取精馏实验过程进行了模拟计算,得到最佳的操作参数;分析了在三个阶段不同的组分在不同的物流中的质量分率,计算了在没有物料浪费、操作在理想的条件下进行所能达到的最大收率;同时分析了萃取精馏塔、溶剂回收塔内部的浓度和温度分布。更多还原

【Abstract】 With the development of the coking industry, coking benzene is becoming an important source of benzene, but it always contains alkanes and alkenes, which could form azeotropic mixture with benzene. The traditional separation method could not fit the development of the environmentally friendly chemistry. This paper refines the benzene and recovers the thiophene through extractive distillation technology.The key of the extractive distillation is the choice of solvent. In the paper it evaluates solvents that had been reported with UNIFAC model: N-methylprolinodone (NMP), Dimethyl sulfoxide (DMSO), Dimethyl formamide, Morpholine, Aniline, Diphenyl methane, Ethanediol, Diglycol, Tetraethylene glycol (TEG), Sulfolane. And hexane, cyclohexane, methyl cyclohexane and 1-heptane are selected as the representative of alkanes and alkenes. It is proved that Sulfolane, DMSO, TEG, NMP and Dimethyl formamide are effective solvents. However, considering for the BP and toxicity, NMP is selected as solvent in the extractive distillation experiment.The experiment is composed of three parts: the process of removing alkanes and alkenes, the process of refining benzene and the process of purifying thiophene. In the first stage, alkanes and alkenes are removed mostly by once extractive distillation, and the thiophene is maximumly preserved, so it lays the foudation for the follwing stage. The high quality benzene is obtained in the second stage, and the thiophene could not be detected through GC. In the end, high concentration thiophene up to 99% (in mass) was recovered successfully. Different reflux and solvent ratio are adopted in the experiment process, and the effect of the operation parameters is discussed.At last, the extractive distillation process is simulated, and the optimal operation parameter is obtained. Different component split in different product steams is analyzed during three different stages, and the greatest yield is calculated in an ideal operating condition without any waste. At the same time, the temperature profile and concentration profile are analyzed along the extractive distillation column and solvent recyling column.更多还原