Energy integration of industrial processes based on the pinch analysis method extended to include exergy factors

摘要

The energy integration of industrial processes is becoming increasingly more effective thanks to new methodological developments such as pinch technology. This paper aims at extending the number of factors considered in pinch analysis towards a life-cycle optimisation and proposes new synthesis representation schemes. The original pinch method centres primarily on maximizing the internal heat transfer with the choice of appropriate ΔTmins. The proposed extension takes into account the complete heat transfer exergy losses, the pressure drop exergy losses and the exergy associated with the fabrication of the heat exchangers. The extended composite curves graphically represent the above-mentioned losses on a Carnot factor versus heat rate diagram. In a similar way, other high exergy inputs and outputs linked, for example, to the introduction of heat pumps and cogeneration units, are represented on a topping electricity versus Carnot factor diagram. Such an extended exergy synthesis results in an improved and more coherent exergy balance for comparing energy recovery schemes. It offers a new insight and permits the identification of solutions which are more stable in time and fairly independent of changing economic conditions. The proposed approach is suitable for future extension to include pollution and resource scarcity factors.