Data Bank (DDB) . Even though there are no specific unit operation models for mDWCs available in conventional process simulators, the thermally coupled column configuration can almost directly be transferred into the simulation software. The modelling approach for the pilot plant was derived from the 4-column setup used to model DWC . The 4-column setup is extended to a thermodynamically consistent 7-column setup to accommodate the second dividing wall. It should be noted that Aspen HYSYS cannot include the heat capacity of the mechanical structures inside the column into the dynamic simulation. In addition, the condenser setup of the pilot mDWC without any liquid holdup cannot be exactly replicated, as there always needs to be a liquid holdup in the condenser of the simulation model. This is considered by selecting a condenser with a minimized size. The Dynamics tool in Aspen HYSYS is used to perform the start-up operation.