持液量对乙二醇单乙醚催化精馏的影响及塔板的优化设计

Influence of Liquid Holding Capacity on the Catalytic Distillation of Ethylene Glycol Monoethyl Ether and Optimal Trays Design

提出以环氧乙烷和乙醇为原料、乙醇钠为催化剂,均相催化精馏合成乙二醇单乙醚的工艺。应用Aspen Plus模拟软件和Cup-Tower水力学分析软件,研究了塔板持液量对催化精馏过程的影响,建立了一种基于水力学可行的催化精馏塔板优化设计方法。模拟分析表明,塔板持液量对催化精馏过程有重要影响,过小的持液量将导致原料的转化率降低,而过大持液量将导致目标产物选择性下降,同时持液量受塔结构和塔板水力学条件限制。通过对催化精馏塔的塔径和溢流堰堰高等参数优化,得到优化的持液量数据比常规精馏塔的塔板持液量提高了约2.9倍,对应塔顶EO质量浓度为0.8%,目标产物的选择性为90.4%,可同时达到催化精馏的技术要求和塔水力学条件。

A homogeneous catalytic distillation(CD)process for the synthesis of ethylene glycol monoethyl ether(EGMEE)using ethylene oxide(EO)and ethanol as raw materials and sodium ethoxide as catalyst was proposed.Aspen Plus simulation platform and Cup-Tower hydraulics analysis software were used to study the influence of liquid holding capacity of the tray on the catalytic distillation process.An optimization approach for CD trays based on hydraulics feasibility was established.Simulation analysis showed that liquid holding capacity of the tray had an important influence on the CD process.Too small holding capacity led to the decrease of raw material conversion rate,while excess holding capacity resulted in the decrease of EGMEE selectivity.Moreover,the liquid holding capacity was restricted by the tower structure and the hydraulic conditions of the trays.With optimization of the CD tower diameters and overflow parameters.The optimized liquid holding capacity was almost 2.9 times higher than that of the conventional distillation tower.Under this condition,the corresponding EO mass concentration at the top of the tower was 0.8%and the selectivity of the target EGMEE was 90.4%which can meet the technical requirements of catalytic distillation process and the hydraulic conditions on of the tower.