The start-up of a multiple dividing wall column – A theoretical and experimental study

Multiple dividing wall columns are a promising extension of the concept of dividing wall columns offering energy savings of up to 55 % compared to conventional distillation sequences for four products. This paper presents the first systematic study on the start-up of a multiple dividing wall column. The study aims to develop a start-up strategy for the first pilot multiple dividing wall column worldwide commissioned at Ulm University. The start-up process is investigated using a dynamic simulation model that facilitates the investigation of different start-up strategies and the influence of different factors on the start-up process. Based on these dynamic simulations a viable start-up procedure for the column is found. Through improvements to the procedure a significantly shortened start-up process is achieved. The dynamic response of the column shows that the cold and dry plant is able to reach the desired operating point within few hours. Simulation results are confirmed with experimental data from the pilot column.