For this reason, the start-up of DWC with a single dividing wall is dealt with in different works in literature. A simple, universal start-up concept without complex process control was developed by Niggemann et al. , based on the study of Ruiz et al . This type of strategy is widely used in industry . The feed flow rate is constant throughout the whole process. product pump is deactivated. Then the side product is withdrawn in intervals so the fluctuations in the composition of the side product can be controlled. When the side product fraction in the bottom is zero, the operating mode of the reboiler is switched to control the reboiler temperature, instead of the column pressure drop. The feed stream, with its steady state flowrate, is introduced into the column and the reboiler level is controlled by the bottom product flow rate. All products are withdrawn at set flow rates. When the temperature profile inside the column has stabilized, the start-up is completed.