用填料塔将异丙醇连续共沸精馏脱水  

The Use of Packing Columns in Dehydration of 2-Propanol by Successively Azeotropic Distillation

作　　者：胡湖生[1] HU Hu-sheng(Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 102201,China)

机构地区：[1]清华大学核能与新能源技术研究院,北京102201

出　　处：《浙江化工》2018年第3期18-24,31,共8页Zhejiang Chemical Industry

摘　　要：用填料塔(柱)进行了用环己烷作夹带剂的连续共沸精馏法异丙醇(IPA)脱水生产无水异丙醇的实验,系统地研究了连续共沸精馏脱水的各影响因素。结果表明,连续共沸精馏最佳条件是进料位置在提馏段填料高度占全塔填料高的4/5处,进料流速为2mL·min^-1,回流比为17和塔釜温度为83℃。在最佳条件下可得到高纯无水异丙醇。实验比较了工业化的两个流程方案:(1)由预浓缩精馏塔、共沸精馏塔、异丙醇精制塔和夹带剂回收塔各1个构成的4塔流程;(2)3塔流程(比方案(1)少1个异丙醇精制塔)。结果表明,方案(1)的共沸精馏塔易产出无水异丙醇-环己烷混合物,再在精制塔中得到含水和环己烷分别小于0.2 wt%和0.1 wt%的高纯度无水异丙醇产品,此方案共沸塔操作弹性大(釜温75℃~82℃)、易于连续生产。方案(2)同样可产出高纯度无水IPA,且比方案(1)节能139kWh/t IPA,但对共沸精馏塔的操作自控严格(釜温82℃~83℃),一旦塔釜进入较多水分(如1wt%)则要中断进料、蒸馏约2h排水。The experimental-scale packing columns sequence were used for azeotropic distillation of 2-propanol(IPA)-water mixtures for production of anhydrous 2-propanol,and the effects of feeding flow velocity,reflux ratio,still temperature,etc,on the contents of water and cyclohexane in product were investigated in detail.The optimized conditions were:the position of feeding was at where the packing height of stripping section was equal to 4/5 of total height of packing;the feeding flow velocity was 2 mL/minute,the temperature in still was 83℃,and the reflux ratio was 17.The following two flowsheets consisted of different packing column sequence were proposed and compared.The flowsheet(1)was the sequence with 4-column,including a preconcentrator column,an azeotropic column,a refining distillation column being attached to the azeotropic distillation column,and an entrainer recovery column.The flowsheet(2)was 3-column sequence,except a refining distillation column in flowsheet(1).The experimental results indicated that,the flowsheet(1)can obtain the qualified anhydrous IPA product with impurities of cyclohexane was less than 0.1 wt%and water less than 0.2 wt%respectively,and it can successively produce,and it had greater flexibilities in operation of the azeotropic column(still temperature 75℃~82℃)and more stability to obtain the high quality product from refining distillation column.The flowsheet(2)can also obtain qualified IPA product,and saving energy 139 kWh/t IPA,but it was strict to control the azeotropic column(still temperature 82℃~83℃),because once the bigger amount of water(e.g.,[H2O]1 wt%)enters into the azeotropic column still(due to fluctuating of conditions),then the water was discharged very slowly by distillation and needed at least 2 hours for discharging the water completely under stop feeding.

关 键 词：填料塔 共沸精馏 异丙醇 环己烷 脱水 

分 类 号：TQ223.123[化学工程—有机化工]