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An experimental evaluation of the kinetics and equilibrium capacities of pure fluids as a fast and effective means to screen an adsorbent's gas separation potential is described. Equilibrium adsorption capacities for pure N2, CH4, and CO2 have been determined using a Micromeritics ASAP2020 sorption analyzer, for three commercially available zeolites: natural chabazite, H+ mordenite, and Linde 4A molecular sieve over the temperature range from (248 to 302) K and pressure range from (0.001 to 120) kPa. Toth models were regressed to the equilibrium data for each gas and used to generate inferred equilibrium selectivity maps over a wider range of temperature and pressure for the purpose of targeting any future mixture measurements. For each gas, the rate of adsorption at 100 kPa was measured as a function of temperature and used with a linear driving force model to calculate mass transfer coefficients. In most cases the ratio of the mass transfer coefficients for each pair of gases was close to unity and did not give rise to a significant kinetic selectivity. However the Linde 4A molecular sieve at 273 K and 100 kPa had a kinetic selectivity for CO2 over CH4 of 6.2. This approach to screening adsorbents with pure fluids can assist in optimizing the design of subsequent mixture measurements by identifying the most promising temperature and pressure ranges to target.

The viscosity of the ethanol + toluene binary system has been measured with a falling-body viscometer for seven compositions as well as for the pure ethanol in the temperature range from 293.15 to 353.15 K and up to 100 MPa with an experimental uncertainty of 2%. At 0.1 MPa the viscosity has been measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of 1%. A total of 209 experimental measurements have been obtained for this binary system, which reveals a non-monotonic behavior of the viscosity as a function of the composition, with a minimum. The viscosity behavior of this binary system is interpreted as the result of changes in the free volume, and the breaking or weakening of hydrogen bonds. The excess activation energy for viscous flow of the mixtures is negative with a maximum absolute value of 335 J · mol −1 , indicating that this binary system is a very weakly interacting system showing a negative deviation from ideality. The viscosity of this binary system is represented by the Grunberg-Nissan and the Katti-Chaudhri mixing laws with an overall uncertainty of 12% and 8%, respectively. The viscosity of methanol (23 point) has also been measured in order to verify the calibration of the falling-body viscometer within the considered T, P range.

The separation of methane and nitrogen from binary mixtures using a commercial activated carbon, Norit RB3, was investigated. The adsorption of pure fluids and CH4 + N2 mixtures were measured at temperatures of 242, 273, and 303 K, at pressures ranging from 53 to 5000 kPa using a high pressure volumetric apparatus and at pressures from 104 to 902 kPa using a dynamic column breakthrough apparatus (DCB). The pure gas equilibrium adsorption capacities were regressed to Toth, Langmuir, Langmuir–Freundlich, and Sips isotherm models; the Toth model gave the best prediction of measured capacities at pressures from 800 to 5000 kPa. The uptake of components from gas mixtures calculated using the Ideal Adsorbed Solution Theory (IAST), Extended Langmuir and Multi-Sips models were all within the uncertainties of the measured adsorption capacities, suggesting that for this adsorbent there is no significant advantage in using the more computationally intensive IAST method. A linear driving force (LDF)-based model of adsorption in a fixed bed was developed to extract the lumped mass transfer coefficients for CH4 and N2 from the pure gas DCB experimental data. This model was used with results from the pure gas experiments to predict the component breakthroughs from equimolar CH4 + N2 mixtures in the DCB apparatus. The Norit RB3 exhibited equilibrium selectivities for CH4 over N2 in the range 3 to 7 (measured selectivites have an average uncertainty of 37%), while the lumped mass transfer coefficients of CH4 and N2 were similar for this activated carbon, ranging from 0.004 to 0.052 s–1. The results presented can serve as a reference data set upon which industrial PSA processes for separating CH4 + N2 mixtures using generic activated carbons can be developed and optimized over a wide range of pressures and temperatures.

The density of the asymmetrical binary system composed of ethanol and heptane has been measured (630 points) for nine different compositions including the pure compounds at five temperatures in the range (293.15 to 333.15) K and 14 isobars up to 65 MPa with a vibrating-tube densimeter, The experimental uncertainty is estimated to be 0.5 kg‚m -3 . The isothermal compressibility, the isobaric thermal expansion, and the excess molar volume have been derived from the experimental density data, revealing that a volume expansion occurs for this binary system. The results have been interpreted as due to changes in the molecular free-volume, disruption of the order molecular structure, and the breaking of hydrogen bonds within the self-associating alcohol.