Shengkun Jia

Control structure selection for four-product Kaibel column

Dividing wall column configurations have a large savings potential in terms of capital and energy. This paper uses dynamic simulation to investigate three alternative control structures for one of these configurations, namely the Kaibel column. Four components, here selected as methanol, ethanol, n-propanol and n-butanol, are separated into pure products within a single column shell. Control structure 1 (CS1) uses only temperature controllers and is therefore particularly interesting from an industrial point of view. Since the control objective is to control the four product compositions, the two other control structures use also composition controllers. Surprisingly, for composition control, the simple temperature control scheme (CS1) is almost as good at steady-state and much better from a dynamic point of view than the two other more complex control structures.

Design and control of azeotropic dividing wall column for separating furfural-water mixture

Abstract A conventional azeotropic distillation (AD) process is usually employed for separating the binary minimum-boiling azeotrope of furfural and water. This paper considers the design and control of the separation of furfural and water mixture via an azeotropic dividing wall column (ADWC). The rigorous simulation of the conventional AD process and the ADWC process are achieved using Aspen Plus software. The obstruction of industrialization of the dividing wall column (DWC) is because of the lack of experience, or fear of controllability and operability issues. In order to test the dynamic controllability of the ADWC process, a conventional PID control structure is proposed. Results show that the conventional PID control structure is able to handle the expected disturbances for the ADWC process. This extends the use of azeotropic distillation and dividing wall column. Besides, being a promising and practical process intensification technology, ADWC will increase energy savings in chemical industry.