Study on the inhibition of lubricating oil in conjunction with a flame retardant on the flammability of propane

Abstract

As the key part of the refrigeration systems, heat pump systems, and Organic Rankine Cycle (ORC) systems, most working fluids with low global warming potential (GWP) are flammable. This paper proposed a novel method called indirect inhibition to mitigate their flammability to enhance the applicability of low-GWP working fluids. Firstly, the effect of lubricants oil, indirect flame retardants (IFR), and mixtures of the two on the flammability of propane were investigated. The experimental results showed that lubricating oil promoted the combustion of propane to a certain extent. The introduction of indirect flame retardant (CP-52) weakened the combustion intensity of propane. The lubricating oil, in conjunction with a flame retardant, could inhibit the combustion of propane. Secondly, the effects of the indirect flame retardant and mineral oil on the flammability of propane were theoretically analyzed using density functional theory (DFT). The theoretical calculation results showed that the ability of IFR to capture reactive free radicals was comparable to that of traditional flame retardants. The research results are of great significance for improving the safety of the cycle system and reducing the risk of accidents.