The integration of mass and energy flows within the entire chemical process operation(s) is necessary for an efficient design. Thermodynamics tell us about process energy requirements for each operation, reversibility and equilibrium. Putting these ideas together, it is possible to design or evaluate existing processes in order to make them more efficient.

The value of Gibbs energy (positive or negative) has special implications in the design of a process. The use of the second law of thermodynamics in integration studies in particular has proved to be a valuable tool in such studies. Various authors have discussed methods of energy integration using thermodynamics focussing on specific reaction type in reference to the whole process 1-4. In a recent paper (Patel et al, 2005)4 looked at applying fundamental concepts of thermodynamics, and specifically the concept of exergy, to the design and synthesis of chemical processes. Nakaiwa et al (2005)5 has presented a paper of heat integration for a reactive distillation column while a plethora of papers have reported different graphical based methods for the design of reactive distillation processes.

In this paper by making parallels to the approach reported by Bilal (2005), we investigate how one could use similar exergy analysis and graphical topological analysis to asses the feasibility of integrating reaction and separation processes (i.e. reactive distillation) for a desired chemical process/operation. We use the esterification of acetic acid with alcohols (C2-C6) as case studies.

Key words: exergy, reactive distillation, equilibrium Reference 1 Denbigh, K. G. Chem. Eng. Sci., 1956, 6, 1-9 2 Hinderdrink, A. P.; et al. Chem. Eng. Sci. 1996, 51 920), 4701-4715 3 Leites, I. L., Sama, D.A., Lior N. Energy 2003, 28, 55-97 4 Bilal Patel, Diane Hildebrandt, David Glasser and Brendon Hausberger; Ind. Eng. Chem. Res. 2005, 44, 3529-3537 5 M. Nakaiwa, K. Huang, K. Iwakabe, A. Tsutsumi; Chem. Eng. Sci. 60 (2005) 4901-4914