An improved viscosity model based on Peng–Robinson equation of state for light hydrocarbon liquids and gases

Recently, a PRμ viscosity model was developed by Fan et al. It is applicable to both the liquid and gas hydrocarbons, but some large deviations might be obtained when applied to some multi-component mixtures. This short communication proposes an improvement method to enhance the accuracy of this model. The method replaces the universal critical compressibility factor in the original model with each component's real critical compressibility factor. The experimental viscosity data of pure methane, pure propane and thirteen light liquid hydrocarbon mixtures were adopted to validate the improved model. The results show the improved model is suitable to both the light hydrocarbon liquids and gases with satisfactory accuracy. The average ARD of the PRμ model was enhanced 4.78% when applied to thirteen hydrocarbon mixtures. Additionally, when applied to five complicated Qatari synthetic natural gas mixtures, the improved PRμ model is essentially comparable in predictability to five other viscosity prediction models.