Dynamic controllability of temperature difference control for the operation of double liquid-only side-stream distillation

The investigation of dynamic controllability of double liquid-only side-stream distillation (DLSD) is necessary due to its good potential for separating multicomponent mixtures in industrial practice. However, control strategy for DLSD is unique and complex owing to the existence of liquid side transfer streams. This study proposed three temperature control schemes without composition measurement for DLSD, i.e., single temperature control without feedforward structure (CS1), single temperature control and temperature difference control with feedforward structure (CS2 and CS3). Results demonstrate that DLSD process can be operated smoothly under +20% feed flow rate and composition disturbances. The use of feedforward structure in CS2 and CS3 eliminates the transient deviations in the responses of product purities in CS1. Overall, CS3 provides better control for DLSD than CS1 and CS2 in terms of lower total sum of integral absolute error (by a factor of nearly 50 and 10, respectively). (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The investigation of dynamic controllability of double liquid-only side-stream distillation (DLSD) is necessary due to its good potential for separating multicomponent mixtures in industrial practice. This study proposed three temperature control schemes without composition measurement for DLSD, and the results demonstrate that CS3 provides better control for DLSD than CS1 and CS2.