Simulation and optimization of pressure-swing batch distillation for separating the methanol-acetonitrile system
GUO Haoqian1,2,3
LI Xuefei1,2,3
LI Xiaoliang1,2,3
Abstract：In order to effectively reduce the COD and raw material cost of discharged wastewater, a pressure swing batch distillation process to separate the lowest azeotrope formed from methanol and acetonitrile was adopted. For methanol and acetonitrile azeotrope, the feasibility for separation of azeotrope was analyzed based on the Txy phase diagram and the simulation flow Sheet was established by using the Aspen Plus and Aspen Dynamics simulation software. To minimize total cost，the feed composition，liquid division ratio，and operating pressure were optimized. Results show that when the methanol feed composition is 85 mol%，the liquid division ratio is 0. 5, the operating pressure of the two columns is 1 atm and 3 atm respectively，the total annual cost($268 514) is the lowest. Based on the above parameters，the purity of each component in the separated methanol-acetonitrile azeotrope is higher than 99. 9 mol%;in the methanol product tank，the purity of methanol finally reaches 99.96 mol% and the liquid holding capacity is 80.15 kmol; in the acetonitrile product tank，the purity of acetonitrile reaches 99. 999 mol% and the liquid holding capacity reaches 15.6 kmol.
Keywords：pressure swing batch distillationazeotropesystem separationsimulation optimizationannual total costraw material compositionliquid fractionoperating pressure
Publication Date：2020-03-10
Pages：7( 21-26,33 )