Combustion and Product Characteristics of Environmentally Friendly Flame Retardant 1,1,3,3,3‐Pentafluoropropene With Three Flammable Working Fluids

The environmental friendliness and safety of refrigerants are often difficult to balance. To avoid or reduce the risk of leakage and explosion of flammable refrigerants throughout their entire lifecycle, flame retardants can be added. 1,1,3,3,3‐pentafluoropropene is not only non flammable, but also environmentally friendly. Therefore, this article tested the flammability limits of different proportions of 1,1,3,3‐pentafluoropropene mixed with difluoromethane, 3,3‐trifluoropropene, and 2,3,3,3‐tetrafluoropropene. After adding 1,1,3,3,3‐pentafluoropropene, the flame intensity of the flammable working fluids significantly decreased near their upper flammability limits. The flame retardant effect of 1,1,3,3,3‐pentafluoropropene on three combustible working fluids, from strong to weak, is as follows: 2,3,3,3‐tetrafluoropropene, difluoromethane, and 3,3,3‐trifluoropropene. In addition, the initial decomposition of three working fluids and the oxidative decomposition characteristics of mixed working fluids at different ratios and temperatures were simulated, and it was found that toxic substances CO and HF were the main decomposition products. The research results can provide theoretical basis and data support for the safe design, explosion‐proof transformation, and engineering application of new environmentally friendly refrigerants, and have important engineering value in promoting the substitution of green refrigerants.