Energy savings in the operation of distillation columns

A systematic methodology to reduce the energy consumption during the operation of distillation columns is presented. A non-linear programming problem is solved where the objective function is the minimisation of the energy consumption during the operation. A rigorous simulation of the distillation columns is carried out throughout the optimisation procedure. Two continuous variables, the reflux and product flow rate, and the feed location, also considered as a continuous optimisation variable, are used to improve the separation and reduce the energy consumption by way of its optimum location. The feed location is an important option that should be systematically selected to decrease the energy consumption under feed perturbations, also increasing the flexibility of the design. The sensitivity of the energy consumption to the feed location will be analysed. The energy savings achieved in the columns of the separation sector of a real petrochemical plant will be reported.