双塔精馏回收环己醇工艺模拟与优化

Simulation and optimization of cyclohexanol recovery by twin towers distillation

针对双塔精馏回收环己醇工艺,采用Fenske-Underwood-Gilliland-Kirkbride方程和Rad Frac模块对双塔进行简捷设计和严格模拟,保证预分离塔条件不变,利用响应面优化法(RSM)对萃取精馏塔的设计参数进行实验设计,得到最终优化的操作条件:预分离塔板数N1=28,环己醇进料流量F=440 kg/h,操作压力P1=-0.007 5 MPa,回流比R1=6.5;萃取精馏塔塔板数N2=22,操作压力P2=96.401 k Pa,回流比R2=2.49,萃取剂水质量分数为0.36。在最佳操作条件下,塔顶环己醇质量分数为95.9%,环己醇回收率为84.2%,投资成本5.34×10~6元,运行成本为2.19×10~6元,为环己醇回收工艺提供模型和数据基础。

The Fenske-Underwood-Gilliland-Kirkbride equation and the Rad Frac module are used to design and rigorously simulate the twin towers as for the cyclohexanol recovery process.Basing on the pre-separation tower conditions remaining unchanged,the design parameters of the extractive distillation tower are experimentally designed by using the response surface method（ RSM）. The final optimized operating conditions are obtained as follows： the number of preseparation tower plates N1= 28,the feed flow rate of cyclohexanol F = 440 kg·h-1,the operating pressure P1=-0. 007 5MPa,the reflux ratio R1= 6. 5; the number of extraction distillation tower plates N2= 22,the operating pressure P2=96. 401 k Pa,reflux ratio R2= 2. 49,water content in extractant is 0. 36.Under the optimum operating conditions,the mass fraction of cyclohexanol at top of tower is 95. 9%,the recovery rate of cyclohexanol is 84. 2%,the investment cost is RMB5. 34 million,and the running cost is RMB 2. 19 million. This paper provides models and data for cyclohexanol recovery process.