正丙醇脱水共沸精馏节能设计与动态控制

Design and Dynamic Control of Energy Efficient Azeotropic Distillation for Dehydration of n-Propanol

针对正丙醇脱水过程设计了减压共沸精馏(ADRP)与共沸精馏隔壁塔(ADWC)2种节能流程,分别从稳态优化与动态控制2个方面对ADRP和ADWC 2种流程进行研究.基于年度总费用(TAC)最低的稳态优化后可以得出,ADWC具有更优的节能效果,其TAC值低于ADRP约25.65%.动态控制研究中,ADRP可以对±20%进料组分波动进行有效控制,而ADWC只能有效控制±10%进料组分波动,且由于使用组成控制器串级方案,其回稳时间较长.结果表明,ADWC在节能方面具有较大优势,但动态控制结构较复杂且抗干扰能力有限是影响其广泛工业应用的重要问题.

Two energy-saving processes, the azeotropic distillation under reduced pressure (ADRP) and the azeotropic dividing-wall column (ADWC), were designed for the dehydration process of n -propanol in steady state optimization and dynamic control, respectively. After steady state optimization based with the lowest total annual cost (TAC), ADWC process demonstrates better energy saving effect, and its TAC value is less than that of ADRP by about 25.65%. The dynamic control structures were also evaluated and compared. The control structure for ADRP could effectively handle ±20% feed input fluctuation. However, the control structure for ADWC could only handle ±10% feed input fluctuation, and it needs more time to stabilize ADWC process due to its composition/temperature cascade control structure. Although ADWC process is more energy efficient, the successful industrial application of ADWC process might be an issue because of its complex dynamic control structure and limited anti-interference capability.