【作者】 姚俊峰；

【导师】 白鹏；

【作者基本信息】 天津大学 ， 化学工程， 2004， 硕士

【摘要】 由于在分离共沸物或近沸点混合物方面优点突出，间歇萃取精馏正受到日益广泛的重视。本文首先进行了间歇萃取精馏全过程的实验研究，重点实验考察了过渡馏分的操作控制，同时研究了主要操作参数如回流比、溶剂比等对分离的影响；然后进行了工业间歇萃取精馏塔分离叔丁醇的实验研究；最后提出了一种改进的间歇萃取精馏操作方式，即带塔底储罐的间歇萃取精馏,并进行了实验研究。本文将间歇萃取精馏全过程分为三个阶段进行了实验研究。这三个阶段为精馏开始到产品全部采出、过渡馏份的采出及溶剂回收。重点实验考察了过渡馏分段和溶剂回收阶段的规律。实验表明，在加入溶剂后全回流操作一段时间后，塔顶浓度上升基本稳定，而且在产品采出过程中塔顶浓度也维持稳定。在过渡馏分的采出过程中，以恒回流比操作时，塔顶浓度开始时下降很快，然后逐渐变缓。在溶剂回收段，当塔顶溶剂浓度开始上升时，塔顶馏出量将突然减小到几乎为零，然后又迅速增大，同时塔顶温度迅速上升。在对间歇萃取精馏全过程的实验研究中，还考察了操作参数，如回流比和溶剂比对产品纯度和收率等的影响。本文在工业塔上以乙二醇为溶剂成功的完成了叔丁醇－水共沸物的间歇萃取精馏分离，生产获得了无水叔丁醇（99.5%以上），同时进一步考察及验证了间歇萃取精馏过渡馏分段和溶剂回收阶段的规律。针对间歇萃取精馏塔釜容积很大和塔釜加热控制复杂的缺点，本文提出并研究了带塔底储罐的间歇萃取精馏。实验表明带塔底储罐间歇萃取精馏釜温稳定，加热易于控制，而且由于具有塔底储罐，可减小塔釜体积，从而允许有较大的溶剂流率。更多还原

【Abstract】 Owning to the predominant advantages in separating azeotropic and close- boiling point mixtures, batch extractive distillation is being paid more and more attention. In this paper the study on the whole process of batch extractive distillation was carried out in a laboratory column to investigate operations of the slop cut withdrawal and solvent recovery, and evaluate the effect of operating parameters such as reflux ratio and solvent ratio on the column performance. Then the separation of tert-butyl alcohol from aqueous solution was tested with an industrial column in the way of batch extractive distillation. Finally an improved operation mode of batch extractive distillation with a storage tank connecting to the still was proposed. In this paper, it is considered that the batch extractive distillation process has three stages, which are withdrawal of the product, withdrawal of slop cut and solvent recovery. Slop cut withdrawal and solvent recovery was studied intensively. The experiment showed that the overhead concentration rises to a primarily stable value after the solvent is introduced and keeps constant during the product withdrawing. When the slop cut is withdrawn under constant reflux ratio, the overhead concentration descends sharply at the beginning, then smoothly afterwards. In solvent recovery stage, as the concentration of solvent begins to increase, the vapor flow rate in the column decreases soon, almost to zero, and then increases rapidly accompanied with the higher top temperature. The effect of operation parameters such as solvent ratio and reflux ratio on product purity and recovery ratio was studied also. The separation of the azeotropic mixture of tert-butyl alcohol and water in an industrial scale column was tested, which produced tert-butyl alcohol of purity >99.5% by using glycol as the solvent. The phenomena of slop cut withdrawal and solvent recovery of batch extractive distillation were verified profoundly. For disadvantages of large still in volume and difficult heating control of batch extractive distillation, a storage tank connecting to the still was introduced. The experiment results indicated that the temperature of the still in the new operation mode was relatively stable, and the heating control was more easy.更多还原