Experimental study on the influence of trifluoroiodomethane on the flammability of difluoromethane and propane

Abstract

In this paper, an apparatus with a 12 L flask according to ASHRAE standards was used to study the influence of trifluoroiodomethane (R13I1) on the flammability of difluoromethane (R32) and propane (R290). The accuracy of this experimental system was verified by the tests of pure R290 and R32. The flammability limits of R32 + R290, R13I1 + R32 and R13I1 + R290 binary mixtures were measured at 60 °C and atmospheric pressure. The experimental data of R32 + R290 can be well predicted by Le Chatelier's formula with maximum absolute deviation of 1.0%. The flammability limit range of R13I1 + R32 reduces with the increase of the molar ratio of R13I1 to R32 and the critical suppression ratio is 0.2. As for R13I1 + R290, the upper flammability limit (UFL) has two inflection points while the lower flammability limit (LFL) always increases. The same phenomenon could be found in the experimental result of R13I1 + R32 + R290 mixture. An extended Le Chatelier model was used to correlate the experimental data of mixtures containing inert gas and the maximum absolute deviation is less than 0.8%. It is expected that the measured values will be useful for the safe application of R13I1/R32/R290 binary and ternary mixtures.