Design and Control of Dividing-Wall Column for tert-Butanol Dehydration System via Heterogeneous Azeotropic Distillation

In this Article, a three-column model of azeotropic dividing-wall column (A-DWC) for heterogeneous azeotropic distillation (HAD) is investigated by demonstrating the design and control of tert-butanol (t-butanol) dehydration using cyclohexane as entrainer. Significant energy consumption savings of 23.80% and a minimal total annual cost (TAC) reduction of 19.93% between the optimum A-DWC design and the original two-column design can be obtained, respectively. Sensitivity analysis of whether the liquid split ratio (βL) can be a manipulated variable to maintain the product purities is conducted before the control structure for the A-DWC is established. Meanwhile, with two reboiler duties (QRs) still preserved in the A-DWC, the proposed control structure can solve disturbance issues and maintain the product purities very close to the set points with small deviation and short settling time.