均相/非均相催化精馏合成乙二醇单丁醚控制分析与比较

以环氧乙烷和正丁醇合成乙二醇单丁醚为例，开展了均相和非均相两种催化精馏工艺的稳态模拟、动态行为和控制研究，比较分析了两种工艺的特点。在Aspen Plus模拟平台上取得精馏塔稳态模拟数据，采用相对增益矩阵（RGA）对均相和非均相催化精馏塔进行分析，确定了双温度控制回路。在Aspen Dynamics中建立了控制方案，在添加正丁醇进料摩尔分数±10%的阶跃扰动下，考察了催化精馏塔的动态响应及控制效果。研究结果表明，均相和非均相催化精馏工艺均能达到控制要求，但非均相反应体系控制方案有更快的动态响应、更小的扰动变化量，并能更早恢复到设定值，其原因在于非均相工艺不存在催化剂浓度变化因素。

Control, Analysis and Comparison of Homogeneous and Heterogeneous Catalytic Distillation for the Synthesis of Ethylene Glycol Monobutyl Ether

Catalytic distillation (CD) is a typical intensification technology of chemical process via coupling catalytic reaction and product separation into one operation unit and has been widely used in the industrial field. In a CD column, some chemical reaction systems can adopt either homogeneous catalyst or heterogeneous catalyst, although the corresponding operation processes and control structures may not be the same. However, there have been few works focusing on the comparison between the homogeneous and heterogeneous CD processes for a sequential-competitive reaction system aiming at selectivity, especially from the aspect of dynamic control performance. In this paper, the synthesis of ethylene glycol monobutyl ether (EGMBE) using ethylene oxide and n-butanol is taken as an example to illustrate the differences between the homogeneous and heterogeneous CD processes. The steady state performance, the control structure design, and dynamic characteristics are analyzed and compared. Moreover, the homogeneous and heterogeneous EGMBE production processes are firstly set up in the Aspen Plus platform and designed with the same feed flowrates, conversion and selectivity objectives and product purity targets. Steady state simulations are carried out to obtain the basic operating conditions and equipment sizing parameters. The relative gain array (RGA) matrix is used to analyze the homogeneous and heterogeneous CD processes, based on which a two-temperature control loop is determined for both processes. The control structures are then designed and set up in Aspen Dynamics, in which dynamic simulations are carried out. By adding a ±10% disturbance of n-butanol feed flow rate in both processes, the dynamic response and control effect are investigated. The results show that the proposed control structures of both homogeneous and heterogeneous CD processes can provide effective control and meet the control requirements. Moreover, the control structure of the heterogeneous CD process has faster closed-loop response, lower steady-state offset and faster recovery to the set point than that of the homogeneous CD process. Besides, there is no variation in catalyst concentration along the heterogeneous CD column.