Presented at Distillation'2002 Symposium,
MINIMUM ENERGY AND ENTROPY REQUIREMENTS IN
MULTICOMPONENT DISTILLATION
Ivar
J. Halvorsen1 and Sigurd Skogestad
Department of Chemical Engineering,
1) Currently at SINTEF Electronics and Cybernetics,
N-7465
Email: Ivar.J.Halvorsen@sintef.no, Sigurd.Skogestad@chembio.ntnu.no
ABSTRACT
In the evaluation of minimum energy consumption (1st law) we here also discuss minimum entropy production, or lost work (2nd law). This leads us to the reversible Petlyuk arrangement. However the total required heat supply is higher in this case than for the typical (adiabatic) Petlyuk arrangements, but there is a potential for further reduction by use of internal heat integration. This principle can also be applied to general arrangements (not only reversible) and we compare set of alternative distillation arrangements for a given feed example. We also conjecture that the generalised extended adiabatic (not reversible) Petlyuk arrangement require less energy than any other adiabatic arrangement at constant pressure when we consider configurations without internal heat integration. The simple Vmin-diagram is shown to be very useful in evaluating alternative arrangements, including the use of double-effect (dual pressure) heat-integrated schemes.