A comparative study of different arrangements for methanol distillation process

The current study presents an effective method of determining and optimizing distillated methanol alternative arrangements. To complement the information required to run the rigorous simulation, Vminmethod is used as a base for the selection of the optimum arrangement among different alternatives. Results obtained from Vmindiagram and shortcut simulation are utilized, by means of the simulator, for the precise simulation of alternative arrangements of methanol distillation under optimum conditions. Taking into account target function profit and the process parameters and conditions, the most optimum parameter value for reaching maximum profit was obtained, based on which all the arrangements with or without their heat integration were compared to each other. Technical and economic analysis results indicate, that increased profit by Prefractionator with heat integration arrangement is 4.79% compared to the base arrangement, while the three-column, four-column and five-column arrangements have benefits increase by 3.61%, 3.55% and 3.46%, respectively.

Design and control of methyl acetate-methanol separation via heat-integrated pressure-swing distillation

Design and control of pressure-swing distillation(PSD) with different heat integration modes for the separation of methyl acetate/methanol azeotrope are explored using Aspen Plus and Aspen Dynamics. First, an optimum steady-state separation configuration conditions are obtained via taking the total annual cost(TAC) or total reboiler heat duty as the objective functions. The results show that about 27.68% and 25.40% saving in TAC can be achieved by the PSD with full and partial heat integration compared to PSD without heat integration. Second,temperature control tray locations are obtained according to the sensitivity criterion and singular value decomposition(SVD) analysis and the single-end control structure is effective based on the feed composition sensitivity analysis. Finally, the comparison of dynamic controllability is made among various control structures for PSD with partial and full heat integration. It is shown that both control structures of composition/temperature cascade and pressure-compensated temperature have a good dynamic response performance for PSD with heat integration facing feed flowrate and composition disturbances. However, PSD with full heat integration performs the poor controllability despite of a little bit of economy.