THE SYSTEM C-O IN EQUILIBRIUM WITH GRAPHITE AT HIGH-PRESSURE AND TEMPERATURE - AN EXPERIMENTAL-STUDY

The fluid system C-O has been studied experimentally in equilibrium with graphite at 7.5 to 20 kbars and 1100 to 1500-degrees-C. The results are compared to calculated results from the Redlich-Kwong equation of state and the Saxena and Fei corresponding states equation and are also fitted to a virial equation of state to obtain interaction parameters and a new equation to calculate the oxygen fugacity of the graphite-oxygen (CCO) buffer. Experimental results were found to be lower in CO than calculated values, especially at high pressures and temperatures. Several experiments performed at different quench rates showed decreasing CO with increased quench time suggesting that CO reacts during the quench to form CO2. The data obtained from the quench experiments allow determination of the rate constant, k, for the quench reaction at different P and T and calculation of zero-time concentrations.