In this paper, a complex industrial distillation system, designed in a traditional manner without considering the interactions of design and control, is introduced and shown to be severely ill-conditioned, Through rigorous modelling and sensitivity analysis, a new control scheme is first proposed for overcoming the history of operational difficulties experienced by the system. A simultaneous dynamic optimisation-based approach is then implemented to highlight the economic and operability benefits that could have been obtained if design and control interactions had been systematically considered in the first place.