Experimental P−T−ρ Measurements of Supercritical Mixtures of Carbon Dioxide, Carbon Monoxide, and Hydrogen and Semiquantitative Estimation of Their Solvent Power Using the Solubility Parameter Concept

Abstract

The P-T-F behavior of the CO 2 -CO-H 2 system was studied in the supercritical region under operative conditions close to those adopted to perform hydrogenation and hydroformylation reactions in dense CO 2 , thus providing new interesting information on this fluid mixture. Experiments were performed in a fixed volume reactor in the temperature range from 298 K to 343 K changing the density and the composition of the fluid phase. The onecomponent (Hildebrand) solubility parameter of the mixture was estimated from experimentally measured P vs T profiles, and its dependence on the density and composition of the system was analyzed to study the antisolvent effect of the permanent gases. We have found that, under adopted operative conditions, the Peng-Robinson equation of state (PR-EOS) can be used to predict with good accuracy the values of the Hildebrand solubility parameter of the binary and ternary mixtures without using adjustable binary interaction parameters. The PR-EOS was eventually used to calculate the dependence of the solubility parameter of CO 2 -containing mixtures on the composition, pressure, and density. By this approach, it seems that the antisolvent effect of CO and H 2 is mainly due to the reduction of the density of the fluid phase, at fixed T and P, when the mole fraction of syn-gas components is increased.

All-dimensional H2–CO potential: Validation with fully quantum second virial coefficients

“…The density data of Cipollina et al . 15 are at pressures too high to be able to extract virial coefficients.…”

“…The few available vapor-liquid 4–6 and vapor-solid 7,8 equilibrium data are at cryogenic temperatures far from the conditions of most industrial interest. The available gas-phase data 9–15 will be discussed in Section IV C.…”

The phase equilibrium and density studies of the ternary mixtures of CO 2 + Ar + N 2 and CO 2 + Ar + H 2 , systems relevance to CCS technology

“…Recently, much attention has been given to studies of the thermodynamic properties, such as vapour-liquid equilibrium (VLE) and density of CO2 mixtures with impurities. A number of research groups have studied some of these key binaries, such as CO2/N2 (Fandino et al, 2015;Mantovani et al, 2012;Tenorio et al, 2015;Westman et al, 2016b), CO2/Ar (Coquelet et al, 2008;Köpke and Eggers, 2007;Mantovani et al, 2012;Yang et al, 2015a), CO2/H2 (Cipollina et al, 2007;Fandino et al, 2015;Sanchez-Vicente et al, 2013;Tenorio et al, 2015), CO2/O2 (Mantovani et al, 2012;Westman et al, 2016a), CO2/SO2 (Coquelet et al, 2014;Köpke and Eggers, 2007), CO2/CO (Cipollina et al, 2007), CO2/H2S (Chapoy et al, 2013a) and CO2/H2O (Hou et al, 2013;Valtz et al, 2004), which either focused on the binaries with an insufficient amount of data under the conditions relevant to CCS or aimed at reducing experimental uncertainties. A comprehensive data survey of the available thermodynamic properties of binary systems with CO2 can be found in the monograph by Kunz et al (2007) and in the recent reviews by Munkejord et al (2016) and Li.…”

Solubility Parameter of Carbon Dioxide—An Enigma

“…A single value of the solubility parameter of scCO 2 was reported by Wai and Wang 33 without disclosing its source: δ H /MPa 1/2 = 13.5 at T = 333.15 K and P = 22.7 MPa. Cipollina et al 34 also specified this temperature, T = 333 K, but reported only the range of pressures 7 ≤ P/ MPa ≤ 40 at which 2.7 ≤ δ H /MPa 1/2 ≤ 12.6, values that are rather lower than those given by other authors. The most recent and definite equation of state of Span and Wagner 35 for carbon dioxide yielded numerical data of the specific internal energies and densities for supercritical conditions.…”