Energy Saving through Control in an Industrial Multicomponent Distillation Column

The problem of reducing the energy consumption in an industrial multicomponent distillation column is addressed. The column is subjected to step feed and distillate flow rates, the distillate impurity is regulated by adjusting the heat duty with a PI temperature controller, and the objective is to save energy through control upgrade. First, the nonlinear feedforward output-feedback robust advanced control problem is addressed, drawing the control construction and the solvability conditions. Then, the behavior of the advanced controller is recovered using a PI temperature controller with a dynamic feedforward setpoint compensator driven by the three measured flow rate disturbances. The approach is illustrated and tested through numerical simulations with a model calibrated with industrial data, finding that: the distillate impurity mean is maintained, its variability is reduced by 80 %, and the energy consumption is reduced by 15 %.