Operation of divided wall column with vapor sidedraw using profile position control

Divided wall column is a promising energy-alternative for separation process which is capable of achieving typically 30% energy and capital cost savings compared with a conventional distillation system. Despite such advantages, divided wall column (DWC) is not widely used from the fear to run into controllability problems due to the DWC complexity. A profile position control scheme was proposed to overcome the control problems. Relative gain array analysis and singular value decomposition were used to determine optimal control configuration. Dynamic simulation showed that the profile position–product composition cascade control can keep the product purities at the desired values in the face of feed and internal disturbances.