In order to reduce carbon dioxide emissions for chemical processes one would like to make them as reversible as possible. Patel ET. Al have shown that in some cases one can analyse processes in terms of their work and heat requirements. In particular for processes there exist a temperature that is called ‘the Carnot Temperature' at which one can satisfy the work requirement for the process using the heat that needs to be added or removed via a heat engine.

The analogy of heat engine and Carnot temperature is applied to chemical processes using a graphical approach. The approach looks at chemical processes holistically, where only the inlet and outlet streams are considered, and represents them in the space. Chemical processes are classified in different thermodynamics regions as defined in the space and their feasibility in terms of heat and work requirement is discussed. This approach allows determining whether heat at an appropriate temperature is sufficient to meet the work requirement of a chemical process or other means should be considered. The approach is used to investigate and discuss the possibility of combining chemical processes classified in different thermodynamic regions in the space, with the purpose to make infeasible processes possible or, minimize or even nullify the work requirement of the combined process.