New methodology for the measurement of diffusion coefficients of pure gases into gas mixtures

The new technique of reversed-flow gas chromatography has been used for the measurement of diffusion coefficients of pure gases into gas mixtures. As pure gases, carbon monoxide (CO) and carbon dioxide (CO2), were used, while the gas mixtures consisted of hydrogen (H-2) and helium (He) with various percentage compositions. The experimental diffusion coefficients of CO and CO2 into various percentage mixtures of H-2 and He (25% v/v H-2 + 75% v/v He, 50% v/v H-2 + 50% v/v He, 75% v/v H-2 + 25% v/v He) were compared with those calculated theoretically, using an empirical equation in which the percentage v/v composition of the gas mixtures and the theoretical values of the diffusion coefficients of the CO and CO2 into the pure gases of the mixture were taken care of as they were found from the Fuller-Schettler-Giddings equation. All the comparisons show small deviations, indicating that both the experimental technique of reversed-flow gas chromatography, and the proposed empirical equation, can be successfully used for the determination of diffusion coefficients of pure gases into gas mixtures.