复合萃取精馏分离乙酸乙酯-乙醇-水混合体系的研究

摘  要

    本文综述分析了国内外有关乙酸乙酯一乙醇一水体系分离现状，提出了复合萃取精馏工艺流程，选择水为分离乙酸乙酯和乙醇的萃取剂，甘油为分离乙酸乙酯和水的萃取剂。

采用气相色谱法测定乙酸乙酯、乙醇、水在甘油中的无限稀释活度系数，用单参数法关联乙酸乙酯-甘油、乙醇-甘油、水-甘油二元体系的模型参数。设计单级循环式汽液平衡釜，系统的测定了乙酸乙-乙醇、乙醇-水、乙酸乙酯-乙醇-水、乙酸乙酯-乙醇-甘油、乙醇-水-甘油及乙酸乙酯-乙醇-水-甘油体系的VLE，采用最小方差法关联Wilson, UNIQUAC， NRTL， Margules，Van Laar模型中该体系的相互作用参数。

模拟结果表明：Wilson模型关联误差最小，同时建立了二元、三元、四元模拟框图并用NEWTON-RAPSON法关联二元、三元、四元汽液平衡数据，并与实测数据进行比较。为复合萃取精馏模拟计算及进一步实验研究提供了理论依据和基础数据。

关键词：萃取剂，复合萃取精馏，甘油，汽液平衡，模型参数

Abstract

    The recent processes of separation ethyl acetate-ethanol-water mixture were reviewed in this paper. Azeotropic distillation，membrane separation，liquid-liquid extraction, extractive distillation processes were studied and discussed. On the basis of predecessors，the composite extractive distillation was put forward first by which high purity ethyl acetate can be obtained one time.

The interaction of solvents，ethyl acetate，ethanol and water were studied in detail, relative volatility of ethyl acetate/ethanol and ethyl acetate/water were tested under different solvents. Combined with other influencing factors，water was selected as extractive agent for ethyl acetate-ethanol system and glycerol for ethyl acetate-water system. VLE  data  of  ethanol-water, ethyl acetate-ethanol and ethanol-ethyl acetate-water, ethanol-water-glycerol, ethyl acetate-ethanol-glycerol and ethanol-ethyl acetate-water-glycerol were tested by the simple single equilibrium caldron .The interactive parameters of Wilson, UNIQUAC, NRTL, Margules. Van Laar equation were correlated by the method of  Minimum Variance .The results showed that Wilson equation had the minor absolute error. Diagram of two phases system simulation calculation, Diagram of three phases system simulation calculation and Diagram of four phases system simulation calculation were given，the binary，ternary and quaternary VLE data were simulated according to interactive parameters. The results of calculation data were coincided with experiment data, and providedbasic data for the separation calculation of ethyl acetate-ethanol-water.

The paper can provide theoretical basis and industrial produce for the simulation and calculation of composite extractive distillation and further studies on experiments.

Keywords: Extraction agent；Composite extractive distillation；Glycerol；VLE；Model parameter

目   录

1 概述 1

1.1  前言 1

1.2  国内外研究现状及趋势 4

2  复合萃取溶剂的筛选 11

2. 1  国内外萃取剂筛选现状 11

2. 2  复合萃取剂筛选 13

2. 3  实验部分 15

3  汽液平衡数据的测定及关联 19

3. 1  概述 19

3. 2  实验方案筛选 19

3. 3  无限稀释活度系数的测定 20

3. 4  汽液平衡数据的测定 22

3. 5  小结 35

结论 36

参考文献 37

致谢 40