Recovery of lactic acid by reactive dividing wall column

Abstract

Lactic acid is widely used in the food, chemical and pharmaceutical industries, and there is an increasing demand for Lactic acid as the raw material of poly lactic acid (PLA), which is a biodegradable polymer. Lactic acid production has been changing over from production by synthesis to production by fermentation, since the fermentation process is more nature friendly and economic. However, the fermentation method generates excess water and impurities with high boilers. The presence of high boilers and non volatility of lactic acid makes the separation of lactic acid very difficult job. Also, the purification-separation process requires the many investment costs and energy costs. The separation method that uses the reaction was proposed in order to overcome these problems. Esterification of lactic acid with methanol followed by hydrolysis of the separated methyl acetate was proposed as a technique to overcome these difficulties. Reactive distillation concept was also introduced for the process, giving higher selectivity and yield compared to the convention method [1]. Recently, the process consisting of evaporator, two-phase CSTR, a reactive distillation column, and distillation column was proposed for the purification of lactic acid by Kumar et al. [2–3]. We introduce a new highly integrated process, reactive diving wall column, to reduce the capital and energy cost for producing a pure lactic acid. The reactive dividing wall column combines reactive distillation and dividing wall column. The dividing wall column provides higher thermodynamic efficiency than conventional distillation sequences. We compared capital and energy cost required for the purification of lactic acid the between the proposed process and the process of Kumar et al. [2#x2013;3] and examined the effect of major process variables on the process performance.