Measurement of Thermal Diffusivities and Fick Diffusion Coefficients of n –Heptane + n –Decane Binary Mixtures from (298.15–523.15) K and Up To 10 MPa

Transport properties, including thermal diffusivity and the Fick diffusion coefficient, are key parameters for optimizing chemical processes and ensuring production safety. In this work, the thermal diffusivity and Fick diffusion coefficient of the n–heptane + n–decane binary mixture were measured by dynamic light scattering at n–heptane amount fractions from 0.25 to 0.75. Measurements were performed along five isobars at 0.1, 2.5, 5.0, 7.5, and 10 MPa. Thermal diffusivity was determined over 298.15–523.15 K, except at 0.1 MPa, where the temperature range was limited to 298.15–373.15 K, while Fick diffusion coefficients were obtained from 298.15 to 373.15 K. The relative expanded uncertainties in thermal diffusivity and Fick diffusion coefficient were estimated to be 0.094 and 0.146, respectively, at a confidence level of 0.95 (k = 2). The effects of temperature, pressure, and composition on thermal diffusivity and Fick diffusion coefficient were analyzed, aiming to offer guidance for optimizing the design of industrial processes and ensuring operational safety and reliability.