Thermodynamics analysis of processes. 1. Implications of work integration

This paper describes a new technique to analyze processes with a positive change in the Gibbs free energy, AG, based on the second law of thermodynamics. In particular, the application of a two-stage process, consisting of an endothermic high-temperature first stage and an exothermic low-temperature second stage, has been investigated. This paper considers chemical reaction processes as heat engines and that by the appropriate flow of heat at a specific temperature (and, hence, with a specified exergy level) work can be added or removed from a process. The technique also investigates the integration of such processes in terms of work flows. The technique is useful in the early stages of the design process as well as for retrofitting. It helps identify opportunities and set targets for the process. The method does not require detailed information regarding the process and is based only on thermodynamic properties of the system.