Thermodynamic models for vapor–liquid equilibria of nitrogen+oxygen+carbon dioxide at low temperatures

Abstract

For the design and optimization of CO 2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N 2 +O 2 +CO 2 .Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N 2 and O 2 in CO 2 are predicted by molecular simulation. An easy-touse thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO 2 -rich region.

Static and Dynamic Properties of Curved Vapour-Liquid Interfaces by Massively Parallel Molecular Dynamics Simulation

“…Canonical ensemble MD simulations were also conducted for multi-component systems containing nitrogen, oxygen, and argon -at the ratio prevalent in the earth's atmosphere -as well as carbon dioxide with a greater partial density than at saturation. The molecular models employed for this purpose, introduced by Vrabec et al [29], are well-established with respect to fluid phase equilibria [29,30,31]. For these systems, the analysis of the carrier gas effect according to Wedekind et al [23] is confirmed qualitatively by the determined droplet formation rates J ℓ , given in Tab.…”

Detection of bubble and dew point using optical thin-film interference

“…Typical sources include power plants, refineries, upgraders, cement plants and steel plants. The presence of impurities in the CO 2 stream significantly impacts the phase behavior, as indicated by current models [4][5][6][7]. For instance, phase diagrams of CO 2 and N 2 binary mixtures studied equation of state models show significant deviation from pure CO 2 phase behavior (e.g.…”

“…a 40% increase in saturation pressure at 0 • C of CO 2 with 5 mol% N 2 ) [4]. In another approach, a ternary mixture of N 2 , O 2 and CO 2 at low temperature was modeled by combining experimental data from the three binary subsystems [5]. In general models indicate that even relatively low concentrations of air-derived impurities (N 2 , O 2 and Ar) can considerably increase the saturation pressure and decrease the critical temperature of CO 2 streams [4,6].…”

PVTxy properties of CO2 mixtures relevant for CO2 capture, transport and storage: Review of available experimental data and theoretical models

“…Vrabec et al [78] proposed to use the PR EOS combined with a model based on Henry's law constants for the ternary mixture CO 2 /N 2 /O 2 at low temperatures (218-251K). Their results show that the PR EOS describes both binary and ternary experimental data well, except at high pressures close to the critical region.…”