High-temperature oxidation and a comprehensive kinetic mechanism of HFO-1234yf

Abstract

To cope with the environmental problems caused by the greenhouse effect, the world has focused on the issue of refrigerant replacement. The potential alternative 2,3,3,3-tetrafluoropropene (CH2CFCF3, HFO-1234yf) has excellent thermal properties, system performances and environmental characteristics, while has the risk of combustion. In this study, the oxidation process of HFO-1234yf was first studied by synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). The important oxidation products of HFO-1234yf were detected, which included fluorine-containing compounds CH2F2, CHF3, CH2FCF3 and CF3CF3 except for CO, CO2, H2O. The molar fraction distributions of these specific fluorine-containing species were derived by the photoionization cross section measurements, which provided new test data to construct the combustion mechanism of HFO-1234yf. Furthermore, eleven newly oxidation paths of HFO-1234yf were proposed by the quantum chemistry calculation method. A modify kinetic model for HFO-1234yf combustion was established, which included 1,557 reactions and 193 species. In addition, rates of production (ROP) analysis of intermediates C2H2, CH2F2, CHF3, CF3CF3 were performed to probe the microscopic paths of HFO-1234yf oxidation. The results showed that most of HFO-1234yf were consumed by reacting with free radicals of O, H, OH, F and CF3. The sensitivity analysis indicated that HFO-1234yf was most sensitive to chemical reactions H + O2 = O + OH and CF3 + O2 = CF3O + O, and these reactions provided plenty of free radicals to promote the decomposition of HFO-1234yf.