乙酸乙酯生产废水中酯的回收工艺研究及模拟计算
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摘要
乙酸乙酯是性能优良的溶剂、萃取剂和重要的化工原料。在乙酸乙酯生产过程中，由于产品的分离、精制及生产品种的转换，将排放出轻、中、重三种不同组成的废水，这些废水中含有大量具有回收价值的乙酸乙酯。这些废水通常作为低值产品出售，或作为废物烧掉，甚至直接排放造成环境污染。为有效地分离回收废水中的乙酸乙酯，本论文针对为轻、中、重三种组分废水进行了系统的分离回收工艺研究。
根据废水组成的不同及回收产品的要求，对乙酸乙酯轻、中组分废水进行了系统的萃取精馏实验研究。研究结果表明，以水作溶剂来脱除乙酸乙酯、水、乙醇多元混合物中的乙醇十分有效，塔顶馏出物中乙酸乙酯含量高达90%，乙醇含量低于1%，水含量约为10%。通过改变回流比、溶剂比等参数得出乙酸乙酯轻组分废水比较适宜的工艺条件是:操作回流比为0.5～1.0,溶剂比为1.0～1.5：1.0；乙酸乙酯中组分废水比较适宜的工艺条件是:操作回流比为0.5～1.0,溶剂比为0.6～0.8：1.0。对乙酸乙酯重组分废水进行了精馏实验结果表明，乙酸乙酯重组分废水用简单精馏即可有效回收其中的有用组分。
三种组分废水经精馏后，塔顶产物中水的质量含量都约为10%。以硫酸钠为干燥剂，对塔顶产品进行干燥脱水，实验结果表明，1摩尔硫酸钠对乙酸乙酯干燥能结合大约4摩尔结晶水，脱水后的轻，中，重组分符合产品回收方案要求，水含量小于0.4﹪。干燥剂再生实验结果表明，吸水后的硫酸钠在102℃气流干燥下很容易再生，再生时间大约60分钟。
针对工业级应用要求，用ASPEN PLUS流程模拟系统对乙酸乙酯轻、中组分废水回收的关键环节萃取精馏进行了工业级模拟计算和操作参数灵敏度分析，得到了相应的工艺操作参数。模拟计算结果表明，轻、中组分废水萃取精馏塔顶模拟结果与实验结果一致。
通过对乙酸乙酯废水回收分离工艺分析与评价表明，三种废水的回收处理可以采用同一装置完成，回收工艺乙酸乙酯具有良好经济效益和环境效益。
Ethyl acetate is an excellent solvent and extractant and is an important chemical material too. During the process of ethyl acetate, three kinds of waste water were let out because of separating, refining the product and products changing of the device. These waste water contain a great of ethyl acetate which can be reclaimed. Usually, the waste water were sold as low value products or were burn off as waste, even were let out to pollute environment. In order to reclaiming ethyl acetate form these waste water, separate projects of these waste water were studied in this paper.
According to the different components of the waste water and reclaiming requests, extractive distillation experiment was studied with the light and middling components of waste water. The experimental results indicated that the effect of extracting ethanol is obvious using water as an extractant, and the content of ethyl acetate in top distillation could receive 90%, in which the content of ethanol was no more than 1% and water was about 10%. Changing the reflux ratio and solvent quantity indicated that when the reflux ratio was 0.5~1.0 and solvent quantity ratio was 1.0~1.5:1.0, the separate effect of the light components waste water was the most obvious and of the middling components waste water, the reflux ratio was 0.5~1.0, solvent quantity ratio was 0.6~0.8:1.0. A simple distillation was able to recover the valuable components from weightily components waste water.
The content of water in the three top distillates was about 10%. Drying the top distillates with sodium sulfate showed that 1 mol sodium sulfate could be combined with 4 mol water and the water content in the products was no more than 0.4% after dehydration. The experimental result indicated that the desiccant could be regenerated by dry air under 102℃ with about 60 minutes.
In order to applying the method to industry, the extractive distillation of light and middling components waste water, the key link of the method, was simulated with ASPEN PLUS and its manipulate parameters were analyzed. It showed that simulating results were consistent with experimental results.
The separating methods and processes were analyzed and evaluated. The results
showed that three kinds of waste water can be treated with a same equipment, recovered products from ethyl acetate waste water could bring an obvious benefit in economy and environment.
根据废水组成的不同及回收产品的要求，对乙酸乙酯轻、中组分废水进行了系统的萃取精馏实验研究。研究结果表明，以水作溶剂来脱除乙酸乙酯、水、乙醇多元混合物中的乙醇十分有效，塔顶馏出物中乙酸乙酯含量高达90%，乙醇含量低于1%，水含量约为10%。通过改变回流比、溶剂比等参数得出乙酸乙酯轻组分废水比较适宜的工艺条件是:操作回流比为0.5～1.0,溶剂比为1.0～1.5：1.0；乙酸乙酯中组分废水比较适宜的工艺条件是:操作回流比为0.5～1.0,溶剂比为0.6～0.8：1.0。对乙酸乙酯重组分废水进行了精馏实验结果表明，乙酸乙酯重组分废水用简单精馏即可有效回收其中的有用组分。
三种组分废水经精馏后，塔顶产物中水的质量含量都约为10%。以硫酸钠为干燥剂，对塔顶产品进行干燥脱水，实验结果表明，1摩尔硫酸钠对乙酸乙酯干燥能结合大约4摩尔结晶水，脱水后的轻，中，重组分符合产品回收方案要求，水含量小于0.4﹪。干燥剂再生实验结果表明，吸水后的硫酸钠在102℃气流干燥下很容易再生，再生时间大约60分钟。
针对工业级应用要求，用ASPEN PLUS流程模拟系统对乙酸乙酯轻、中组分废水回收的关键环节萃取精馏进行了工业级模拟计算和操作参数灵敏度分析，得到了相应的工艺操作参数。模拟计算结果表明，轻、中组分废水萃取精馏塔顶模拟结果与实验结果一致。
通过对乙酸乙酯废水回收分离工艺分析与评价表明，三种废水的回收处理可以采用同一装置完成，回收工艺乙酸乙酯具有良好经济效益和环境效益。
Ethyl acetate is an excellent solvent and extractant and is an important chemical material too. During the process of ethyl acetate, three kinds of waste water were let out because of separating, refining the product and products changing of the device. These waste water contain a great of ethyl acetate which can be reclaimed. Usually, the waste water were sold as low value products or were burn off as waste, even were let out to pollute environment. In order to reclaiming ethyl acetate form these waste water, separate projects of these waste water were studied in this paper.
According to the different components of the waste water and reclaiming requests, extractive distillation experiment was studied with the light and middling components of waste water. The experimental results indicated that the effect of extracting ethanol is obvious using water as an extractant, and the content of ethyl acetate in top distillation could receive 90%, in which the content of ethanol was no more than 1% and water was about 10%. Changing the reflux ratio and solvent quantity indicated that when the reflux ratio was 0.5~1.0 and solvent quantity ratio was 1.0~1.5:1.0, the separate effect of the light components waste water was the most obvious and of the middling components waste water, the reflux ratio was 0.5~1.0, solvent quantity ratio was 0.6~0.8:1.0. A simple distillation was able to recover the valuable components from weightily components waste water.
The content of water in the three top distillates was about 10%. Drying the top distillates with sodium sulfate showed that 1 mol sodium sulfate could be combined with 4 mol water and the water content in the products was no more than 0.4% after dehydration. The experimental result indicated that the desiccant could be regenerated by dry air under 102℃ with about 60 minutes.
In order to applying the method to industry, the extractive distillation of light and middling components waste water, the key link of the method, was simulated with ASPEN PLUS and its manipulate parameters were analyzed. It showed that simulating results were consistent with experimental results.
The separating methods and processes were analyzed and evaluated. The results
showed that three kinds of waste water can be treated with a same equipment, recovered products from ethyl acetate waste water could bring an obvious benefit in economy and environment.
引文
[1] 程能林,胡声闻.溶剂手册.化学工业出版社,1986.
[2] 张俊华,陈永生.乙醛法合成乙酸乙酯.精细化工.1998,15(4):55-57.
[3] King,C.J., “Separation Processes" . 2nd,McGraw-Hill New York,1980.
[4] 蒋维钧主编.新型传质分离技术.化学工业出版社,1992.
[5]费维扬,王德华,尹晔东.化工分离技术的若干新进展. 化学工程.2002,30(1):63-67.
[6] 陈洪钫,刘家祺.化工分离过程.北京:化学工业出版社,1995.
[7] 潘鹤林,田恒水,于水.萃取精馏分离甲醇-碳酸二甲酯二元恒沸物. 华东理工大学学报.1998,24(4):389-392.
[8] 李光兴,熊国玺.糠醛萃取精馏分离甲醇-碳酸二甲酯二元共沸物研究. 化学工程.2000,28(4):12-14.
[9] 白润生,杨慧文,胡熙恩.甲醇-乙醇-水三元系精馏分离流程研究. 化学工程.2001,29(3):8-11.
[10] 雷志刚,周荣琪,叶坚强.加盐反应萃取精馏分离醇水溶液. 化学工业与工程.2001,18(5):290-294.
[11] 何志成,林善良.从四氢呋喃-乙酸乙酯-水三元共沸物中分离四氢呋喃的研究.沈阳药科大学.1996,10(2):143-149.
[12] 邱学青,杨东杰,杨卓如.丙酮—乙酸乙酯分离工艺方法的研究. 化学工业与工程.1998,25(3):25-30.
[13] 江莉,雷良恒.一步法合成乙酸乙酯的分离工艺研究-萃取精馏塔、水洗塔. 现代化工.1996,16:34-36.
[14] 李永红,刘家祺,马沛生.萃取反应精馏合成高纯度乙酸乙酯.精细化工.1996,25(4):719-723.
[15] 廖安平,蓝平,李媚.盐液萃取提纯乙酸乙酯研究. 广西民族学院学报.1998,4(1):23-25.
[16] Rosen, E.M., Steady State Chemical Porcess Simulation:A State-of-the-Art Review, "Computer Applications to Chemical Engineering",ACS Symposium Series,No.124,American Chemical Society,p.3,1980.
[17] 彭秉璞.化工系统分析与模拟.北京:化学工业出版社,1990.
[18] 陈晓春,马桂荣.动态模拟技术与化学工程. 现代化工.2002,22(3):14-17.
[19] Aspen Engineering Suit V10.2 and Installation Manuals.AspenTech.
[20] Aspen License Manager V10.2 and Installation Manual.AspenTech.
[21] R.H.Ewell et al., Azeotropic Distillation,IEC, 36(10),871,1944.
[22] 梁爱民,马奉瑞.1-己烯产品分离工艺优化.当代石油石化.2002,10(2):30-32.
[23] 成弘,余国琮.蒸馏技术现状与发展方向. 化学工程.2001,29(1):52-56.
[24] 宋海华,孙伟,王秀丽,王明涛.萃取精馏溶剂选择的研究进展. 化学工业与工程.2002,19(1):83-87.
[25] Horsley L.H.,Azeotropic Data .Advances in Chemistry Series,American Chemical Society, 458—459, 1973.
[26]Laroche L.,Bekiaris N.,Anderson h.w.,et al.Homogggeneous Azeotropic Distillation:Separability and Flowsheet synthesis.Ind. Eng. Chem. Res.31(9):2190,1992.
[27] E.J.Henley and J.D.Seader,Equlibrium-Stage Separation Operation in Chemical Engineering. chapter 1,John Wiley & Sons,1981.
[28] L.M.Naphtali, D.P.Sandholm, Multi-component Separation Problem Formulation and Convergence,AICHE J., 10(5),698, 1964.
[29] 郑学明,李坤英.盐效应对乙酸乙酯-甲醇-水体系液-液平衡的影响. 高校化学工程学报.1997,11(3):304-307.
[30] 韩晓锋,张清等.ASPEN PLUS在甲醇合成中的应用. 煤化工.1999,87(2):32-37.
[31] 杨绪壮,屈一新.反应精馏过程模拟—— ASPEN PLUS应用范例. 内蒙古石油化工.2002,27(1):53-57.
[32] 陈新志，蔡振云，胡望明.化工热力学.化工出版社,2001.
[33] 赵瑞红,赵焕祺,张向京.UNIFAC法在甲醇精馏过程模拟计算中的应用. 化学工程.2000,28(1):48-52.
[34] 唐勇.丙烯酸装置提纯系统的模拟与优化. 精细化工.2002,19(5):307-309.
[35]王崇智.乙腈萃取精馏分离丁二烯的工艺流程模拟. 弹性体.1998,8(1):30-35.
[36] 陈志奎,武宝琛.合成氨(油头)甲醇洗流程模拟- ASPEN PLUS应用范例. 化学工程.1999,27(3):52-54.
[37] 杨德明,钱三鸿.ASPEN PLUS用于重催装置中吸收塔的改造计算. 抚顺石油学院学报.1999,19(1):32-34.
[38] Henley, E.J.and E.M.Rosen, "Material and Energy Balance Computation",Wiley,1969.
[39] Shacham,M.and R.S.H. Mah,A Newton Tpye Linearization Method for Solution of Nonlinear
Equations. "Computers and Chemical Engineering",Vol.2,P.64,1978.
[40] 谭天恩，麦本熙，丁惠华编著。化工原理.化学工业出版社,1992.
[41] D.H艾伦著,陈演汉译.工程项目经济评价入门.化学工业出版社,1980.
[42] 沈永金,周格非.实用经济预测.中国物资出版社,1986.
[43] Grant, E.L., W.G.Ireson and R.S.Leavenworth. "Principles of Engineering Economy".7th edition,Wiley, New York,1982.
[44] 王静康主编.化工设计.化学工业出版社,1995.
[45]Pikilik,A.,and H.E.Diaz, "Cost Estimation for Major Process Equipment" ,Chem.Eng.,Oct.10,107-122,1977.
[46] Ulrich,Gael D., "A Guide to Chemical Engineering Process Design and Economics",Tohn Wiley,Inc.1984.
[2] 张俊华,陈永生.乙醛法合成乙酸乙酯.精细化工.1998,15(4):55-57.
[3] King,C.J., “Separation Processes" . 2nd,McGraw-Hill New York,1980.
[4] 蒋维钧主编.新型传质分离技术.化学工业出版社,1992.
[5]费维扬,王德华,尹晔东.化工分离技术的若干新进展. 化学工程.2002,30(1):63-67.
[6] 陈洪钫,刘家祺.化工分离过程.北京:化学工业出版社,1995.
[7] 潘鹤林,田恒水,于水.萃取精馏分离甲醇-碳酸二甲酯二元恒沸物. 华东理工大学学报.1998,24(4):389-392.
[8] 李光兴,熊国玺.糠醛萃取精馏分离甲醇-碳酸二甲酯二元共沸物研究. 化学工程.2000,28(4):12-14.
[9] 白润生,杨慧文,胡熙恩.甲醇-乙醇-水三元系精馏分离流程研究. 化学工程.2001,29(3):8-11.
[10] 雷志刚,周荣琪,叶坚强.加盐反应萃取精馏分离醇水溶液. 化学工业与工程.2001,18(5):290-294.
[11] 何志成,林善良.从四氢呋喃-乙酸乙酯-水三元共沸物中分离四氢呋喃的研究.沈阳药科大学.1996,10(2):143-149.
[12] 邱学青,杨东杰,杨卓如.丙酮—乙酸乙酯分离工艺方法的研究. 化学工业与工程.1998,25(3):25-30.
[13] 江莉,雷良恒.一步法合成乙酸乙酯的分离工艺研究-萃取精馏塔、水洗塔. 现代化工.1996,16:34-36.
[14] 李永红,刘家祺,马沛生.萃取反应精馏合成高纯度乙酸乙酯.精细化工.1996,25(4):719-723.
[15] 廖安平,蓝平,李媚.盐液萃取提纯乙酸乙酯研究. 广西民族学院学报.1998,4(1):23-25.
[16] Rosen, E.M., Steady State Chemical Porcess Simulation:A State-of-the-Art Review, "Computer Applications to Chemical Engineering",ACS Symposium Series,No.124,American Chemical Society,p.3,1980.
[17] 彭秉璞.化工系统分析与模拟.北京:化学工业出版社,1990.
[18] 陈晓春,马桂荣.动态模拟技术与化学工程. 现代化工.2002,22(3):14-17.
[19] Aspen Engineering Suit V10.2 and Installation Manuals.AspenTech.
[20] Aspen License Manager V10.2 and Installation Manual.AspenTech.
[21] R.H.Ewell et al., Azeotropic Distillation,IEC, 36(10),871,1944.
[22] 梁爱民,马奉瑞.1-己烯产品分离工艺优化.当代石油石化.2002,10(2):30-32.
[23] 成弘,余国琮.蒸馏技术现状与发展方向. 化学工程.2001,29(1):52-56.
[24] 宋海华,孙伟,王秀丽,王明涛.萃取精馏溶剂选择的研究进展. 化学工业与工程.2002,19(1):83-87.
[25] Horsley L.H.,Azeotropic Data .Advances in Chemistry Series,American Chemical Society, 458—459, 1973.
[26]Laroche L.,Bekiaris N.,Anderson h.w.,et al.Homogggeneous Azeotropic Distillation:Separability and Flowsheet synthesis.Ind. Eng. Chem. Res.31(9):2190,1992.
[27] E.J.Henley and J.D.Seader,Equlibrium-Stage Separation Operation in Chemical Engineering. chapter 1,John Wiley & Sons,1981.
[28] L.M.Naphtali, D.P.Sandholm, Multi-component Separation Problem Formulation and Convergence,AICHE J., 10(5),698, 1964.
[29] 郑学明,李坤英.盐效应对乙酸乙酯-甲醇-水体系液-液平衡的影响. 高校化学工程学报.1997,11(3):304-307.
[30] 韩晓锋,张清等.ASPEN PLUS在甲醇合成中的应用. 煤化工.1999,87(2):32-37.
[31] 杨绪壮,屈一新.反应精馏过程模拟—— ASPEN PLUS应用范例. 内蒙古石油化工.2002,27(1):53-57.
[32] 陈新志，蔡振云，胡望明.化工热力学.化工出版社,2001.
[33] 赵瑞红,赵焕祺,张向京.UNIFAC法在甲醇精馏过程模拟计算中的应用. 化学工程.2000,28(1):48-52.
[34] 唐勇.丙烯酸装置提纯系统的模拟与优化. 精细化工.2002,19(5):307-309.
[35]王崇智.乙腈萃取精馏分离丁二烯的工艺流程模拟. 弹性体.1998,8(1):30-35.
[36] 陈志奎,武宝琛.合成氨(油头)甲醇洗流程模拟- ASPEN PLUS应用范例. 化学工程.1999,27(3):52-54.
[37] 杨德明,钱三鸿.ASPEN PLUS用于重催装置中吸收塔的改造计算. 抚顺石油学院学报.1999,19(1):32-34.
[38] Henley, E.J.and E.M.Rosen, "Material and Energy Balance Computation",Wiley,1969.
[39] Shacham,M.and R.S.H. Mah,A Newton Tpye Linearization Method for Solution of Nonlinear
Equations. "Computers and Chemical Engineering",Vol.2,P.64,1978.
[40] 谭天恩，麦本熙，丁惠华编著。化工原理.化学工业出版社,1992.
[41] D.H艾伦著,陈演汉译.工程项目经济评价入门.化学工业出版社,1980.
[42] 沈永金,周格非.实用经济预测.中国物资出版社,1986.
[43] Grant, E.L., W.G.Ireson and R.S.Leavenworth. "Principles of Engineering Economy".7th edition,Wiley, New York,1982.
[44] 王静康主编.化工设计.化学工业出版社,1995.
[45]Pikilik,A.,and H.E.Diaz, "Cost Estimation for Major Process Equipment" ,Chem.Eng.,Oct.10,107-122,1977.
[46] Ulrich,Gael D., "A Guide to Chemical Engineering Process Design and Economics",Tohn Wiley,Inc.1984.
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