Entropy production and economic analysis in diabatic distillation columns with heat exchangers in series

Abstract

Distillation columns with adiabatic stages inherently entail high entropy production because heat is only supplied to the reboiler and removed from the condenser. DDC (Diabatic distillation columns) can reduce the entropy production and they can be realized through the installation of heat exchangers in series at the stages in the column by circulating a cooling fluid in the rectifying section from the condenser and by circulating a heating fluid in the stripping section from the reboiler. Although the diabatization of stages can effectively reduce the entropy production, it can cause an increase in the equipment cost because more heat exchanges are installed and in the operation cost because the total heat load supplied or removed in the diabatic column is higher than that in the adiabatic column. In this work, the entropy production and economic (i.e., total annual cost) criteria are assessed for diabatic distillation columns. A solution procedure that combines numerical analysis and rigorous simulations is proposed. For the presented examples, the existence of a trade-off between entropy production and total annual cost was demonstrated.