【作者】 万辉；

【导师】 管国锋；

【作者基本信息】 南京工业大学 ， 化学工程， 2003， 硕士

【摘要】 本文在综述醋酸-水体系分离方法的基础上，以醋酸丁酯、醋酸异丁酯、醋酸异丙酯为挟带剂，对醋酸水溶液进行共沸精馏过程研究，详细研究了填料高度、水与挟带剂的配比、醋酸初始浓度等对共沸精馏分离效果的影响；对醋酸-水体系进行普通精馏和共沸精馏过程模拟计算，讨论了回流比、理论板、进料位置、进料温度和浓度对精馏过程的影响，获得了对醋酸-水体系精馏过程实际生产具有指导意义的较佳的工艺操作参数、共沸精馏塔的工艺设计放大的基础数据，并对两种精馏方法的投资、操作能耗进行了比较；同时在共沸精馏模拟计算的基础上进行了共沸精馏塔的初步工艺设计计算，并对填料塔的主要辅助设备及塔内件进行了初步选型。研究结果表明：(1) 共沸精馏时，醋酸丁酯、醋酸异丁酯和醋酸异丙酯作为挟带剂，分离效果相近；塔顶醋酸浓度始终很低；随着水与挟带剂的比值的减小或进料醋酸含量的增加，塔釜醋酸浓度增加，但随着水与挟带剂比值的进一步减小，醋酸丁酯和醋酸异丁酯作为挟带剂时，塔釜中会出现挟带剂，而醋酸异丙酯作为挟带剂时，塔釜中未出现醋酸异丙酯；三种挟带剂在水中溶解较少，基本可以回收利用。(2)普通精馏模拟计算时，用“化学理论” 修正汽相非理想性和用NRTL方程计算液相活度系数，得到了精馏操作的较佳条件：回流比为4.0~4.5，理论板37~43块；共沸精馏模拟计算时，采用NRTL方程计算液相活度系数，Hayden-O’Connell关联式修正有缔合组分的汽相非理想性，得出的较佳的条件为：回流比3.0~3.5，理论板数30~35。(3)与普通精馏比较，分离要求相同时，共沸精馏时所需要的理论板数要低于普通精馏所需要的理论板数，回流比减小，可降低设备投资70万元，塔釜加热量减少36%。(4)确定了不同回流比下，四股进料的最佳进料位置，如：普通精馏时，R=4.0下的最佳进料位置，F1：18、F2：41、F3：42和F4：39；共沸精馏时，R =3.0下的最佳进料位置，F1：9、F2：33、F3：34和F4：30。进料处于最佳进料位置时，分离效果最好。随着进料位置从最佳进料位置上移或下降，分离效果降低。(5)随着进料温度的升高，塔顶醋酸浓度升高，塔釜醋酸浓度降低，分离效率变差；进料中醋酸含量增加时，塔顶、塔釜醋酸浓度均随之增加。(6)确定了回流比3.0下的共沸精馏塔的工艺参数：填料：钛质250Y板波纹填料，塔径：4.0m；填料高：25.92m；填料层压降：2959.05Pa；填料塔四段的平均泛点气速分别为：5.22m/s，4.97 m/s，3.63 m/s和3.05 m/s；平均持液量分别为：0.025 m3/m3，0.032 m3/m3，0.044 m3/m3，0.050 m3/m3。更多还原

【Abstract】 On the basis of summarizing separation method of acetic acid-water system, we studied the azeotropic distillation process of acetic acid-water system, selecting butyl acetate, isobutyl acetate and isopropyl acetate as entrainers. The influence of packing height, ratio of water to entrainer and acetic acid initial concentration to separation effect of azeotropic distillation was studied in detail. Simulation calculations of general distillation and azeotropic distillation were carried out. The influence of reflux ratio, theoretical plate, feed position, feed temperature and feed concentration to distillation process were discussed. Preferred process operation parameter, which had guiding meaning to practical production of distillation process were obtained. Basic data for the process amplifying design of azeotropic distillation tower were provided. Invest and operation energy consumption of two distillation methods were compared. The elementary technical design of azeotropic distillation tower was carried out on the basis of result of simulation calculation. The type of major auxiliary equipments and inner parts of packed tower were selected.The research results are as follows: (1) Butyl acetate, isobutyl acetate and isopropyl acetate could be selected as entrainer, and separation effect was near. Acetic acid concentration of tower top was always very low. With the decrease of the ratio of water to entrainer or increase of acetic acid concentration of feed, acetic acid concentration of tower bottom increased. When butyl acetate and isobutyl acetate were selected as entrainer, tower bottom production contained entrainer, with the further decrease of the ratio of water to entrainer. When isopropyl acetate was selected as entrainer, isopropyl acetate didn’t appear in the tower bottom production. Three entrainers rarely dissolve in the water and can be reclaimed. (2) When general distillation was simulated, the "chemical theory" was used to correct the nonideality of vapor phase and NRTL equation was used to calculate active coefficient in the liquid phase. The preferred condition of general distillation was obtained as follows: reflux ratio was 4.0~4.5 and the number of theoretical plate was 37~43; When azeotropic distillation was simulated, NRTL equation was used to calculate active coefficient in the liquid phase and Hayden-O’Connell equation was used to correct the nonideality of vapor phase with associated molecules. The preferred condition of azeotropic distillation was obtained as follows: reflux ratio was 3.0~3.5 and the number of theoretical plate was 30~35. (3) Compared with general distillation, the number of theoretical plate which azeotropic distillation needed was less under the same separation demand. The reflux ratio of azeotropic distillation could decrease. Equipment invest could be decreased 700000 yuan. Water vapor could be saved 36%. (4) Optimum feed positions of four feeds were confirmed. Optimum positions of general distillation were F1: 18, F2: 41, F3: 42 and F4: 39, when reflux ratio was 4.0;<WP=5>Optimum feed positions of azeotropic distillation were F1: 9, F2: 33, F3: 34 and F4: 30, when reflux ratio was 3.0. When feeds were situated in optimum positions, separation effect was best. Separation effect became worse when feed position rose or fell from optimum position. (5) With increasing of feeds temperature, acetic acid concentration of tower top increased and acetic acid concentration of tower bottom decreased. With increasing of initial concentration of acetic acid, acetic acid concentration of tower top and bottom increased. (6) Technical parameters of azeotropic distillation tower were obtained when reflux ratio was 3.0. Packing was 250Y titanium corrugated-plate packing. Diameter of tower was 4.0m, and height of packing was 25.92m. The pressure drop of packing was 2959.05Pa. Average flood point gas velocity of four parts of packed tower were 5.22m/s, 4.97 m/s, 3.63 m/s, 3.05 m/s. Average liquid holdup of four parts of packed tower were 0.025 m3/m3, 0.032 m3/m3, 0.044 m3/m3, 0.050更多还原