Experiment And Simulation Study On Extractive Distillation By Dividing Wall Column

Dividing Wall Column was a special column which was installed a vertical plate in the conventional column to separate the ternary mixture or more mixture compotents, and implemented the separation task in a column which was normally completed by a sequence of conventional distillation columns. This kind of column can save the energy consumption and reduce the costs of equipment.A dividing wall column was applied in extractive distillation in order to gain anhydrous n-propyl alcohol. The column was simulated with Aspen Plus and the parameters were determined, such as the number of theoretical total plate in main column, the reflux ratio, the mass ratio of extractive solvent to feed, the feed stage and the solvent feed stage. Composition and flow rate profiles in dividing wall column and conventional extractive distillation processes were compared. The result showed that the energy consumption in reboiler of dividing wall extractive distillation column can be reduced by12.5%compared with conventional extractive distillation process. The costs of equipment and the energy consumption were reduced.A dividing wall column was applied in extractive distillation in order to separate tetrahydrofuran and ethanol. Composition and flow rate profiles in dividing wall column and conventional extractive distillation processes were compared. The result showed that the energy consumption in reboiler of dividing wall extractive distillation column can be reduced by10.1%compared with conventional extractive distillation process. The costs of equipment and the energy consumption were reduced, it did a further conviction of its principle of energy saving.In addition, the separation of n-propyl and water was researched in the self-designed lab experiment equipment. When the the mass fraction of n-propanol was0.7of feed potency, the influence of solvent ratio, reflux ratio, feeding speed on seperation results in the dividing wall column rectification was analysised. Through designed orthogonal experiments and single factor experiments, the best conditions were determined:the solvent ratio was3, the reflux ratio R1was2.5, R2was3.0, the feed speed was2.0mL/min. Under the optimal experimental conditions, the mass fraction of n-propanol was0.960in the top of main column, the mass fraction of water was0.902in the top of attached column, the mass fraction of glycol was0.994in the bottom of column. The results indicated that the data of experiment was identical with the data of simulation by the process simulation with software Aspen plus and the average relative deviation within the permissible values.According to the experiment and simulation study on extractive distillation by dividing wall column. It provided a basis for industrial applications of dividing wall column and for energy saving renovation of the existed distillation system.