甲缩醛甲醇分离之萃取精馏与变压精馏的设计与控制.pdfVIP

ABSTRACT In this paper, two methods for methylal/methanol separation is presented using extractive distillation (ED) and fully heat integrated pressure swing distillation (PSD). Rigorous steady state and dynamic simulations for this neat operation are implemented on commercial simulators (Aspen Plus and Aspen Dynamics). For ED, N,N-dimethylformamide was selected as an suitable entrainer by comparing infinite dilution relative volatilities. On the basis of global economic optimization, a design with optimized operation conditions for this process is developed. For dynamic simulations, feed flow rate and feed composition disturbances are used to evaluate the dynamic performance of several control structures. The results reveal that the control structure with fixed reflux ratio can handle all disturbances well, except one kind of composition disturbance. An improved control structure with R/F ratio scheme is used to maintain the two products purity requirements. Dynamic simulation results reveal that this control structure can handle feed flow rate and composition disturbances quite effective. For PSD, based on the proposed partially optimization and global economical optimization, an optimized configuration for this fully heat integrated pressure swing distillation is developed. Several control structures for this fully heat integrated pressure swing distillation system are presented. The dynamic simulation results reveal that the proposed basic control structure is unable to maintain the two bottom product at their quality specification. This problem can be resolved by using a pressure-compensated temperature control scheme. The dynamic responses show that this control structure works pretty well for this fully heat integrated pressure swing distillation, even for la