ABSTRACT
Some time ago we were teaching an advanced thermodynamics course to process technologists of AKZO NOBEL. Subjects included phase equilibria, the thermodynamics of mixtures, and models from molecular thermodynamics applied to industrial situations. The question was raised whether some time could be spent on the subject of ‘‘exergy analysis of processes,’’ then a subject with which we were less familiar because energy-related issues fell less within the scope of our activities. We fell back on a small monograph by Seader [1] and the excellent textbook by Smith and Van Ness [2], who dedicated the last chapter not so much to exergy but to the thermodynamic analysis of processes. Concepts such as ideal work, entropy production, and lost work were clearly related to the efficient use of energy in industrial processes. The two industrial examples given-one on the liquefaction of natural gas, the other on the generation of electricity in a natural gas-fired power stationlent themselves very well for illustrative purposes but also for applying the exergy concept and exergy flow diagrams [3, 4]. The latter concepts quite appealed to us because of their instrumental and visual power in illustrating the fate of energy in processes (Fig. 1).
