LAUSR

Abstract The focus of this work is to study the control of a Kaibel divided-wall column (KDWC) for separating benzene, toluene, o-xylene and 1, 3, 5-trimethylbenzene mixtures. Two control structures based on a simple single-loop (decentralized) PI controller are proposed: five-temperature control loops (CS1), improved control structure (CS2) with combining pressure-compensated scheme into CS1. The control performance of CS1 and CS2 are investigated in terms of the control of component purities under various disturbances in feed conditions, which indicates that CS1 weakly controls product purity of the lower-side stream. Due to pressure compensation, CS2 is superior to CS1 in terms of purity control at the lower-side stream product under larger disturbances in feed conditions. CS2 that is based on temperature measurements can be easily implemented during practical operation of a KDWC in industry. From an industrial operation perspective, the pressure-compensated temperature control structure (CS2) provides potential solutions for a four-product KDWC.