间歇精馏常规设计和优化设计的模型及算法

Model and algorithm of conventional design and optimum design of batch distillation

建立了板式间歇精馏塔在恒馏出液组成操作状况下常规设计及优化设计的数学模型。常规设计模型用数值方法编程求解,对二元理想及非理想溶液均适用。优化设计模型以间歇精馏系统年效益最大为优化目标,用菲波那契法求解单变量优化问题,用复合形法求解多变量优化问题。模型同时考虑对整个间歇精馏系统(包括塔主体、塔顶冷凝器及塔底再沸器)进行优化,更符合工程实际情况。求解模型可得到间歇精馏过程最优的一系列设计和操作参数(如理论板数,塔径,操作回流比,塔釜蒸发量,釜残液组成,冷凝器传热面积及冷却水出口温度,再沸器传热面积及加热蒸汽温度等)。算例表明,对恒馏出液组成间歇精馏单变量及多变量优化设计比常规设计分别提高年效益2.6%和18.9%。

A conventional and optimum design mathematical model of plate batch distillation was established,which was operated un-der constant distillate composition.The conventional design model was solved by numerical methods,which could be applied to binaryideal or non-ideal solution.The objective of the optimum design model was the maximum annual total benefit.The optimum design ofsingle-variable was solved by Fibonacci method and the optimum design of multivariable was solved by complex method.The whole sys-tem(including main body of the tower,the condenser on the top of the tower,the reboiler in the bottom)was considered in optimum de-sign model.This model was more suitable to the engineering practice.A series of the optimum parameters of design and operation(such as the theoretical plates,the tower diameter,the operation reflux,the amount of tank evaporation,the composition of tank re-mainder liquid,the heat transfer area of the condenser and the reboiler,the temperature of outlet cooling water and beating vapor)wereobtained by figuring out the model.The practical example indicated that,for the batch distillation under the constant distillate composi-tion,the annual total benefit by the single-variable optimum design was increased by above 2.6% than that by conventional design,themultivariable optimum design by above18.9%.