Evaluation of Mixing Rules on the Vapor-Liquid Phase Equilibrium of Systems Containing Ammonia

Mixing ammonia with hydrocarbon(HC) and hydrofluorocarbon(HFC) may reduce the toxicity and flammability of ammonia, and improve its miscibility with mineral oil, which could extend its application in refrigeration field. In this paper, 10 mixing rules were investigated on the description of ammonia+HCs/HFCs systems. The mixing rules used include EoS mixing rules and EoS/GE mixing rules. The simple VDW mixing rule cannot reproduce the vapor-liquid phase equilibrium of the systems concerned. The other EoS mixing rules behave well in the R717 + R125 system, while badly in the R717 + R1270 and R717 + R600 systems. In the EoS/G~E mixing rules,the Gibbs energy and zero pressure based mixing rules-MHV1 and MHV2 give good regression in all systems. Among the mixing rules studied, MHV1 is the best mixing rule.