Abstract

Two quantum versions of the statistical associating fluid theory (SAFT) where monomeric segments interact with potentials of variable range (VR) but incorporate quantum effects (Q), namely the SAFT-VRQ PI for Square-Well fluids, and the SAFT-VRQ Mie have been applied to model selected thermodynamical properties of pure quantum fluids (i.e., normal-hydrogen, deuterium, helium, and neon), such as phase equilibria, enthalpy of vaporization, second virial coefficient, Joule-Thompson inversion, and the properties of pure quantum fluids confined in solids (i.e., NOTT-202, CuBOTf metal-organic framework (MOF), activated carbon with KOH, and single-walled carbon nanohorns) including adsorption isotherms and isosteric heat. In order to obtain a correct characterization of the bulk phase and solid-fluid properties, the SAFT-VRQ EoSs parameters have been optimized by using the available experimental data of both fluids (i.e., vapor pressure and liquid density) and solids (i.e., pore volume and radius). According to the results, SAFT-VRQ PI EoS and SAFT-VRQ Mie EoS reproduce the properties of the subcritical phase equilibria (i.e., temperature-density and pressure-temperature) with good agreements, but near to the critical state, the SAFT-VRQ Mie EoS is superior to the SAFT-VRQ PI EoS. The enthalpy of vaporization is similarly predicted from both models, but at low temperatures, the SAFT-VRQ PI EoS reproduces the experimental data with high accuracy, especially for hydrogen. The second virial coefficient predictions display good agreement with both SAFT-VRQ EoS, whereas the Joule-Thompson curve is notoriously best predicted using the SAFT-VRQ Mie EoS. For the cases of quantum fluid-solid systems, the SAFT-VRQ PI EoS is able to predict the adsorption isotherms and the isosteric heat more rigorously than the SAFT-VRQ Mie EoS.