Viscosity of methane and ethane at temperatures from (100 to 225) K and at pressures up to 10 MPa

• Viscosity of methane and ethane was measured at temperatures from 100 to 225 K. • Good agreements were obtained between measurements and the reference correlations. • The results were correlated with the Tait-Andrade equation. • The correlations developed for both methane and ethane are in good agreement with the experimental results. Liquefied Natural Gas is considered to be a pivotal component in the global energy transition. Viscosity is a crucial factor in the analysis of phase behavior, fluid metering, the simulation and optimization of the liquefaction process, and the design of fluid machinery for Liquefied Natural Gas. However, research on the viscosity of cryogenic fluids at temperatures below 223 K is scarce. Notably, there were significant differences between data sets. In this work, viscosity measurements of methane and ethane were performed at temperatures ranging from 100 to 225 K and pressures up to 10 MPa. The combined expanded uncertainty ( k = 2 ) of the viscosity measurements was estimated to be 2.0 % across all temperature and pressure ranges. The experimental results obtained in this study, along with data from the literature, were compared with reference correlations to determine a reliable data set of measurement. These data sets were then correlated using the modified Tait-Andrade equation. The correlations developed for both methane and ethane in this work are in good agreement with the experimental results.