Chemical Engineering & Technology, Vol.38, No.5, 907-916, 2015
Distillation Control Structure Selection for Energy-Efficient Operations
Few studies have been reported concerning the energy efficiency of various distillation column control structures. The choice of an energy-efficient control configuration by incorporating thermodynamics second law in the selection criteria is described. In addition to a relative gain array for assessing control loop interactions, a relative exergy array is used in evaluating the energy efficiency of various control structures. The preferred control structure should have both good operability and good energy efficiency as distillation columns are the major energy consumer in the chemical industry. The performance of the control structures in the dynamic mode is analyzed in detail. The proposed method is demonstrated on two binary distillation columns: methanol-water separation and benzene-toluene separation. Dynamic simulation results prove the efficiency of the proposed distillation control structure selection method.