Measurement of bubble point pressures and critical points of carbon dioxide and chlorodifluoromethane mixtures using the variable-volume view cell apparatus

The bubble point pressures and the critical points of carbon dioxide (CO2) and chlorodifluoromethane (HCFC-22) mixtures were measured by using a high-pressure experimental apparatus equipped with a variable-volume view cell, at various CO2 compositions in the range of temperatures above the critical temperature of CO2 and below the critical temperature of HCFC-22. The experimental bubble point pressure data were correlated with the Peng-Robinson equation of state (PR-EOS) to estimate the corresponding dew point compositions at equilibrium with the bubble point compositions. The experimentally measured bubble point pressures and the mixture critical points gave good agreement with those calculated by the PR-EOS. The variable-volume view cell equipment was verified to be an easy and quick way to measure the bubble point pressures and the mixture critical points of high-pressure compressible fluid mixtures.