Thermal stability and pyrolysis products of HFO-1234yf as an environment-friendly working fluid for Organic Rankine Cycle

Abstract HFO-1234yf is considered as one of the most promising working fluids for Organic Rankine Cycle (ORC) owing to its good environmental performance and thermal performance. In this study, an experimental system was designed to determine the thermal stability of HFO-1234yf. The results showed that pyrolysis temperature ranges of HFO-1234yf were 170–190 °C. The pyrolysis products of HFO-1234yf were gas and liquid products. Six gases detected in vapor phase products were HF, CHF3, CH2F2, CF4, C2F6 and C3F8. The concentration of HF in vapor phase had an absolute advantage in the gas products. The thick yellow oily liquid product was observed and their chemical composition and the corresponding forming mechanism were studied. There mainly were 3 monomer units (A, B and C) in the liquid polymers. The optimal generation pathways of the liquid polymers were studied by density functional theory (DFT) method, and the theoretical calculation results were consistent with the experimental results. Finally, the effects of pressure on the thermal stability of HFO-1234yf were discussed.