Adsorption of gases on coals and heattreated coals at elevated temperature and pressure. 2. Adsorption from hydrogen-methane mixtures

Experimental data were obtained using a static system for adsorption of H₂CH₄ mixtures at temperatures from 22 to 207 °C and pressures up to ≈ 4.1 MPa on PCB activated carbon, Pittsburgh bituminous coal, Pittsburgh coke, Montana lignite and Montana char. The ideal adsorbed solution theory of Myers and Prausnitz gave excellent predictions except for the two raw coal samples. Deviations of experimental data from the theory were in opposite directions for the two coals: CH₄ was preferentially adsorbed on Pittsburgh coal and H₂on Montana coal. Except for the two raw coals, the temperature and pressure dependences of the selectivity ratio agreed with the theoretical predictions. A modified correlation procedure for the Dubinin-Polanyi theory is presented for adsorption under supercritical conditions. The modified method has been applied to activated carbon and Montana char with satisfactory results. A comparison is given between this method and the Myers-Prausnitz theory.