A novel continuous flow apparatus with a video camera system for high pressure phase equilibrium measurements

A novel continuous flow apparatus with a camera system was developed and constructed for high pressure phase equilibrium measurements. Vapor pressures of ethanol, diphenylmethane, n-heptane, toluene and water and bubble point pressures of three binary systems, ethanol + water, diphenylmethane + n-heptane and diphenylmethane + toluene, were measured at high temperatures and pressures (T = 473–597 K, P = 0.2–12 MPa). The results of vapor pressure and the ethanol + water system measurements were compared with literature values. Absolute average vapor pressure deviation was found to be lower than 0.03 MPa for all measured vapor pressures. The ethanol + water system were modeled with the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state. Absolute average pressure deviation was 0.09 MPa for data points measured in this work whereas the deviation was 0.11 MPa for literature data points. To conclude, the measured values in this work agreed well with the data found from literature and the constructed apparatus with the developed measurement method can produce data with good quality. The behavior of diphenylmethane + n-heptane and diphenylmethane + toluene systems was at first predicted with the PC-SAFT and the Peng–Robinson equations of state without binary interaction parameters. Additionally, parameters were regressed to optimize the performance of the used models. Both equations of state modeled the behavior of systems well.