CRITICAL-POINT CALCULATION WITH NONZERO INTERACTION PARAMETERS

The authors evaluated critical pressure and temperature for a number of mixtures including the 32 given by Peng and Robinson. For the Peng-Robinson mixtures the average of the authors absolute values of errors in critical pressures was 2. 81% and in critical temperatures was 1. 19%. The corresponding values of Peng and Robinson were 2. 33% and 1. 31%. The authors attribute the differences between their results and those of Peng and Robinson to differences in binary interaction parameters. The solution procedure given by M. L. Michelson and R. A. Heidemann is suitable for solving certain equations. The authors solved these equations simultaneously using Newton-Raphson iterations.