苯酚-环己酮-水混合物共沸-萃取精馏耦合分离的设计与模拟

Design and simulation of separating phenol-cyclohexanone-water mixture by azeotrope-extractive coupling distillation

针对环己基苯氧化分解制苯酚和环己酮工艺中苯酚-环己酮-水的分离和回收,以热力学数据为依据,筛选出合适的萃取剂三乙二醇,并设计了共沸-萃取精馏耦合分离流程。采用Aspen plus流程模拟软件,热力学方法选择UNIQUAC模型并校核体系二元交互作用参数,考察了萃取剂与原料的质量比(溶剂比)、理论塔板数、进料位置等工艺参数对分离过程的影响。模拟计算结果表明,设计的共沸-萃取精馏工艺流程合理,可实现苯酚、环己酮和水的高效分离。在满足苯酚纯度99.95%(w)和环己酮纯度99.9%(w)条件下,优化后的工艺参数为:非均相共沸精馏塔理论塔板数10块,进料位置为第2块塔板;萃取精馏塔理论塔板数35块,溶剂比1.2,原料进料位置为第13块塔板,萃取剂进料位置为第5块塔板,萃取剂进料温度50℃,回流比0.21;萃取剂回收塔理论塔板数6块,进料位置为第5块塔板,回流比0.2。在此工况下,单位产品(苯酚+环己酮)热负荷为1.027 GJ/t。

Azeotropic-extractive distillation coupled separation process was designed for the separation and recovery of phenol-cyclohexanone-water in the process of oxidative decomposition of cyclohexylbenzene to phenol and cyclohexanone.The suitable extractant,triethylene glycol,was screened out based on the thermodynamic data.Based on the Aspen plus process simulation software,the thermodynamic model of UNIQUAC with the verified binary interaction parameters were used to investigate the effects of major design parameters,such as mass ratio of extractant and feed(solvent ratio),theoretical tray number,feed position and other process parameters on the separation process.The results show that the designed azeotropic-extractive distillation process is reasonable,which can realize the efficient separation of phenol,cyclohexanone and water.To meet phenol mass fraction of 99.95%(w)and cyclohexanone mass fraction of 99.9%(w),the optimized operating conditions are obtained:theoretical tray number for the heterogeneous azeotropic distillation column of 10,the feeding position of 2^(nd);theoretical tray number of the extractive distillation column of 35,the solvent ratio of 1.2,the phenol-cyclohexanone feeding position of 13^(th),the extractant feeding position of 5^(th),the extractant feeding temperature of 50℃and reflux ratio of 0.21;theoretical tray number of the extractant recovery column of 6,the feeding position of 5^(th),and reflux ratio of 0.2.Under the conditions,the heat duty per ton of phenol+cyclohexanone is 1.027 GJ/t.