화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.52, No.33, 11463-11478, 2013
Design and Control of Dimethyl Carbonate-Methanol Separation via Pressure-Swing Distillation
Separation of dimethyl carbonate/methanol azeotropic mixture by using distillation process has been a hot-point in the study of the synthesis process of dimethyl carbonate by urea methanolysis method. Most studies focus on the steady-state design, and only few papers have dealt with the dynamic performance and control of this binary azeotropic system. This paper explores the design and control of pressure-swing distillation systems for separation of dimethyl carbonate/methanol. The steady-state and dynamic simulations are carried out with Aspen Plus and Aspen Dynamics. Then, on the basis of the global economical analysis, an optimized separation configuration is proposed. The vital operating parameters and geometric parameters are determined according to the simulation and optimization results. Furthermore, two control strategies, CS1 and CS2, are proposed. With disturbance, the proposed basic control structure (CS 1) can only maintains the quality specification of products from the bottom of the first column. However, the second control structure (CS2) succeeds in holding the bottom product purity for two distillation columns, even for large feed flow rate and large composition disturbances. Detailed analysis for CS1 and CS2 is made based on dynamic simulation which illustrates that the control structure CS2 outperforms CS1 to handle the disturbances.