Gen-Ichi Kaminishi

Vapor pressures of binary mixtures of carbon dioxide with benzene, n-hexane and cyclohexane up to 7 MPa

The total vapor pressures of three CO2ue5f8C6 hydrocarbon systems; CO2ue5f8benzene, CO2ue5f8n-hexane, and CO2ue5f8cyclohexane systems, have been measured at 273.15, 283.15, 298.15 and 303.15 K over the whole composition range by a bubble point method. For the CO2ue5f8n-hexane system, the densities of the liquid mixtures have also been measured. From the data and the calculated results by the Peng—Robinson equation of state, the activity coefficients of CO2 and the Henrys constants of CO2 in CO2ue5f8C6 hydrocarbon systems have been obtained. The vapor pressure data have been compared with the results calculated by the Barkers method and by the Peng—Robinson equation of state with the use of four mixing models.

Concentration of triethylene glycol, diethylene glycol and ethylene glycol in supercritical carbon dioxide up to 16 MPa at 313. 15 and 333. 15K

Abstract The concentrations of triethylene glycol (TEG), diethylene glycol (DEG) and ethylene glycol (EG) in supercritical carbon dioxide (CO 2 ) up to 16 MPa at 313. 15, and 333. 15K were measured by a vapor recirculation method. The concentrations of these glycols increase with increasing pressure and markedly increase from about 8 MPa at 313. 15 K and from about 11 MPa at 333. 15 K. A plot of the concentration of TEG, DEG and EG vs the density of pure CO 2 shows a gradually increasing curve. Also the concentrations were in the order of the vapor pressures of the glycols. The data were correlated using the following three methods: 1) Modified Redlich—Kwong (MRK) equation, 2) Peng—Robinson (PR) equation, 3) virial equation. From the results, it was found that the MRK equation gave a better fits than 2) or 3). However the correlation by the modified Peng—Robinson (MPR) equation proposed by Mohamed et al. gave almost the same results as the MRK equation.