Exergy Analysis of MRU Processes in Offshore Platforms

Abstract

The theory of exergy analysis (ExA) of the previous chapter is now specifically applied to the three main types of MRU commercially available to offshore oil and gas platforms. The first point to address is the definition of the reference environment reservoir (RER). The RER definition has a great influence on the ExA results, therefore two kinds of RER approaches are considered in this work giving very different exergy efficiencies: RER Approach #1 and RER Approach #2. In this chapter, it is shown that only one of them makes sense to carry out useful ExA of MRUs. RER Approach #2 allows much better discrimination of exergy efficiencies and better identification of exergy sinks in all studied MRUs. RER Approach #1, although consistent and correct, failed to provide discrimination of exergy performances and realistic results, whereas the proposed novel RER Approach #2 is able to provide much more realistic and meaningful exergy efficiency values. Under RER Approach #2 the existing irreversibilities are more easily revealed and, thus, affect with more impact the calculation of exergy efficiencies, better discriminating them.