Experimental Measurement of Soret Coefficient of Binary Hydorcarbon Mixtures

Measurement of diffusion coefficients is essential for simulation and prediction of oil reservoirs. Recently, a new experimental set-up has been built at Ryerson University to measure the transport coefficient of transparent liquid mixtures. Laser-based optical digital interferometry techniques using a Mach-Zehnder Interferometer have been used for measuring the diffusion coefficients. This method is non-intrusive, highly accurate, and can provide a detailed 2-D visualization of temperature and concentration fields. Five binary liquid mixtures of Decane (C10H22) - Isobutylbenzene (IBB), Decane (C10H22) - 1,2,3,4 Tetrahydronaphthalene (THN), Dodecane (C12H26) - Isobutylbenzene (IBB), Dodecane (C12H26) - 1,2,3,4 Tetrahydronaphthalene (THN) and Isobutylbenzene (IBB) - 1,2,3,4 Tetrahydronaphtha-lene (THN) have been selected. The mixtures have been prepared from pure C10H22, C12H26, IBB and THN for 50% mass fractions. These five binary mixtures are representatives of binary interactions between alkane, one-ring aromatic and two-ring aromatic hydrocarbons. The thermal designs of the diffusion cell, as well as the data analyze method, have been improved. A comparison of experimental data with theoretical analysis based on the Firoozabadi model for measuring thermodiffusion coefficient and Peng-Robinson equation of state (PR-EOS) for measuring the physical properties have been conducted. Experimental results showed a maximum deviation of less than 2% for IBB- C12H26 and THN-IBB and 9% for THN-C12H26 from the available benchmark results. Accurate knowledge of refractive index is highly relevant to correlations with concentration, temperature, wavelength and pressure in non-intrusive experiments carried out with transparent fluids. It can be used for the identification and characterization of pure materials and for the measurement of concentration of multi-component mixtures. In this current scope, refractive indices of five binary mixtures C10H22-IBB, C10H22-THN, C12H26-IBB, C12H26-THN and IBB-THN have been measured using both the Mach-Zehnder Interferometer and a multi-wavelength Abbemat refractometer. Temperature and concentration coefficients of refractive indices, or so-called contrast factors, as well as their individual correlation to calculate refractive indices have been presented for a wide range of visible spectrums such as 436 nm to 657 nm. Comparison with available literature and mixing rules shows that new correlations can predict the experimental data with deviations of less than 0.001.