Concluding Remarks

Abstract

The need to avoid hydrate formation is undeniable in offshore natural gas fields, especially in deep-water environments, where favorable conditions for hydrate formation are easily found. In this context, MEG injection is an approved technology to successfully displace the hydrates equilibrium loci to lower temperatures in ultra-deep subsea gas production pipelines. Further, Rich MEG has to be processed in MEG Recovery Units (MRU) in order to be recovered as Lean MEG to be pumped back as refreshed THI, saving costs. Also, as distillation-based processes, MRUs are very intensive in terms of heat consumption. Energy is related to properties that depend only on the present state of the material in the system at hand. On the other hand, Exergy is a property that depends both on the state of the material in the system and on the definition of the Reference Environment Reservoir (RER). Thus, two choices of MEG state in the RER were investigated so as to perform Exergy Analysis for three MRU technologies designed to operate on offshore NG production rigs: Traditional Process (TP), Full-Stream Process (FS), and Slip-Stream Process (SS). This chapter brings the main conclusions of this book, which covered several qualitative and quantitative aspects related to hydrate inhibition and offshore MRUs, studied from their fundamental aspects to engineering aspects and from Energy Performance to Exergy Performance assessments by handling advanced topics like Exergy Analysis through many approaches, including classical Thermodynamic Analysis of separation processes.