燃料乙醇三塔差压蒸馏工艺模拟研究

Simulation of three column differential pressure distillation process for fuel ethanol

对燃料乙醇蒸馏工段的工艺流程方案进行设计,在现有的生产工艺基础上提高了效率,大幅度降低能耗。采用三塔差压精馏,根据原料组分物性选定专用的ALCOHOL热力学模型,采用NRTL活度系数模型来描述体系的气液相平衡,采用SRKM改进型的状态方程来预测体系的密度、焓、熵。利用PROⅡ流程模拟软件分别对粗馏塔Ⅰ、精馏塔Ⅱ、精馏塔Ⅰ的工艺参数进行模拟分析和优化,分别确定了理论板数、进料位置、侧采位置以及侧采量,最后对其做全流程的稳态模拟,其蒸馏工段得到乙醇产品纯度为92. 5%(质量分数),回收率达99. 39%。

The process scheme of fuel ethanol distillation section was designed in this paper,based on the existing production process to improve the efficiency and significantly reduce energy consumption.Using three tower differential pressure distillation.A special ALCOHOL thermodynamic model was selected according to the physical properties of the raw materials.The NRTL activity coefficient model was used to describe the vapor liquid phase equilibrium of the system.Using the SRKM improved equation of state to predict the density,enthalpy and entropy of the system.Using PROⅡflow simulation software,the process parameters of crude distillation columnⅠ,distillation columnⅡand distillation columnⅠwere simulated and optimized respectively.The number of theoretical tray,the position of feed,the position of side mining and the side recovery were determined respectively.Finally,the steady state simulation of the whole process was done.The purity of the ethanol product is 92.5%(mass fraction),and the recovery rate is 99.39%.