Impact of liquid split ratio on separation performance of a multiple dividing wall column pilot plant

Abstract

Multiple dividing wall columns are a promising intensified process to reduce energy consumption of conventional distillation sequences by up to 55 %. Their operation is of course more complex, in particular with regard to the internal split ratios of the liquid and vapor flows at the dividing walls. Theoretical studies have shown that the split ratios may not need to be at a specific value but in a certain range, which would simplify operation. However, until recently no experimental setup existed to prove this observation in reality. This work presents the first comprehensive experimental study in this regard obtained from an approximately 10 m high multiple dividing wall column pilot plant. The plant has two dividing walls, so the column consists of a prefractionator, a middle and a main column. The results validate the theoretical observations. With the chosen mixture in particular the middle column is found to be operable in a certain range. Temperature profiles prove that internally different separations are performed, while the resulting product compositions are unaffected.