Thermal stability and pyrolysis mechanism of working fluids for organic Rankine cycle: A review

Abstract

Summary Organic Rankine cycle (ORC) is an effective method used to convert renewable energy and waste heat into electricity. The screening of working fluids is crucial to the design of the ORCs, and their thermal stability is a key factor for the selection of ORC working fluids. This review emphasized the thermal stability studies of ORC working fluids. We reviewed the research methods and thermal stability results of hydrocarbon, fluorine‐containing, and siloxane working fluids and analyzed the effects of working fluid pyrolysis on the performance and safety of ORCs. Compared with the previous articles, which only introduced the thermal stability studies of working fluids, this review also focused on the research methods and the status quo of the working fluid pyrolysis mechanism. The feasibility of the density functional theory method and the ReaxFF force field for the study of working fluid pyrolysis mechanism was demonstrated. Finally, the disadvantages of working fluid thermal stability and pyrolysis mechanism studies were analyzed, and the prospects in this field were also discussed.

Thermal decomposition of n-hexane in organic Rankine cycle: a study combined ReaxFF reactive molecular dynamic and density functional theory

“…However, the supercritical ORC has a high heat source temperature, and the working fluid may decompose in the process of circulation (Huo et al, 2017;Huo et al, 2022a;Huo et al, 2022b). The decomposition products of the working fluid may consist of gaseous, liquid, and solid states, which will affect the performance and even the safety of ORC (Huo et al, 2017;Huo et al, 2019a).…”