(605c) Experimental Study in a Reacive Dividing Wall Column Based on Ethyl Acetate Synthesis

The reactive dividing wall column(RDWC) is a special form of distillation column. It is the combination of reactive distillation and the dividing wall column, which achieves the chemical reactions and the distillative separation into multiple product fractions in one column.Since the middle of 1980s, the RDWC was proposed, Scholars have been studying it, but the industrialization of the RDWC still has great challenges.In a manner similar to that of a conventional distillation column, a suitable prediction model and good operability, the RDWC can be used to achieve its potential commercial value. Therefore, it is very necessary to carry on the thorough basic research.

The esterification reaction of Acetic acid and ethanol is one of the most common reactive distillation system. It has been involved in many scholars' researches.

Due to the high degree of coupling inside the RDWC, the interaction between the factors is very complex.How to operate correctly to keep it at its best is very important. In our recent researches, We give a series of explorations on the operational performance of RDWC, Including the dosage of azeotrope agent n-butyl acetate, liquid split ratio, the reflux ratio, the concentration of acetic acid and other factors.

In the experiment, n-butyl acetate was chosen as the entrainer, and the water produced by the reaction of acetic acid and ethanol was separated from the main column in the form of the lowest azeotrope. Duo to the loading method of catalyst directly affects the conversion of the reaction and the pressure drop in the RDWC, a novel loading method is proposed, the experimental results show that this method has many obvious advantages. It not only ensures the high conversion, but also has enough gas channel.

Results: there is an optimal value of the amount of n-butyl acetate, in addition, because of the timely removal of water generated from the reaction, the reaction can be promoted to improve the conversion of ethanol. Liquid split ratio is an important parameter to adjust the flow rate on both sides of the baffle, and is a sensitive factor to the change of energy consumption. When the reflux ratio is too small, the separation of light and intermediate components is non-split, and alcohol content will be higher in the main column; and when the reflux ratio is too large, a large number of ethyl acetate reflux into the reaction zone, then the conversion of ethanol decreased. The more water content of acetic acid in feed, the more the amount of azeotropic agent needed, The higher the reboiler energy consumption, the lower the conversion of the ethanol.

Summing up, the operability of the RDWC can reflect its huge economic and ecological potentials.