Design of Lactic Acid Production Process and Purification of Lactic Acid by Reactive Distillation Using Column with Side Stream

The process of purifying lactic acid from fermentation broth is complex due to the low volatility of lactic acid and the presence of organic compounds with a high molecular weight in the fermentation broth. Reactive distillation is an attractive method for increasing lactic acid purity. The process begins with the esterification of lactic acid and methanol in one column, followed by the hydrolysis of methyl lactate back into lactic acid in a second column. Numerous design parameters make the design of a reactive distillation column challenging. Using Aspen Plus to simulate the process, this study investigates the effects of side draw and the location of the reactive zone on the reactive distillation columns in the lactic acid purification process. The location of reactive zone is varied from the overall, top, middle, and bottom of the column. The location of the side draw of interest is in the reactive zone. The most interesting case for the esterification column, based on simulation results, is the lower half reactive zone column with the side draw in the reactive zone, whereas the side draw is inappropriate for the hydrolysis column. The interesting configuration for hydrolysis column is a reactive zone at either the middle or bottom of column.