Minimizing Entropy Production Rate in Binary Tray Distillation

In this work we increase the second law efficiency in an ideal binary tray distillation column by allowing heat exchangers on all trays. We find by numerical optimization, the duties of the heat exchangers that give the highest second law efficiency of the column. The entropy production rate was reduced by 30-50% compared to adiabatic operation for two different columns. The numerical optimum was in agreement with the result of an Euler-Lagrange minimization in which the total entropy production rate was described by irreversible thermodynamics. The minimum was not characterized by equipartition of forces. This paper was presented at ECOS'00, Enschede, July 5-7, 2000