加盐萃取精馏回收制药废液中四氢呋喃的模拟研究

Simulation of salt extractive distillation for recycling tetrahydrofuran from pharmaceutical wastewater

建立了加盐萃取精馏过程的数学模型,利用ChemCAD流程模拟软件,在101.3 kPa下,对以乙二醇-氯化锂为复合萃取剂的甲醇-四氢呋喃-水溶液加盐萃取精馏回收四氢呋喃的过程进行模拟计算,并进行了实验验证。考察了复合萃取剂对原料液气液平衡的影响及精馏理论塔板数、萃取剂进料位置、原料进料位置、回流比等对塔顶四氢呋喃含量的影响。模拟结果表明,最佳理论塔板数为30、萃取剂最佳进料板数为6、原料最佳进料板数为18、最佳回流比为5.0。最佳工艺条件下,塔顶四氢呋喃的质量分数可达99.2%。模拟了最佳工艺条件下精馏塔的特性参数分布,模拟值与实验值吻合良好。

The mathematical model of the salt extraction distillation process is established in this study. The salt extractive distillation of methanol-THF-H20 solution with ethylene glycol-lithium chloride as extractant for recycling tetrahydrofuran （THF） is simulated by ChemCAD simulation software at 101.3 kPa. The effects of composite extraction agent on liquid solution-steam balance of raw material, and the effect of the theoretical plate number, input positions of feed and extractant and reflux ratio on the THF mass fraction at the tower top are investigated. The optimal operation conditions are shown as follows： 30 of theoretical plate number, 6 and 8 of input positions of extractant and feed, respectively,and 5.0 of reflux ratio. Under the optimal operation condition, the mass fraction of THF at tower top can achieve 99. 2%. The distribution characteristic parameters of the column were simulated under optimum conditions. Simulation results and experimental data agree satisfactorily.