The method for correlating the parameters of Peng-Robinson equation of state has been improved. As compared with the original Peng-Robinson equation and Soave-Redlich-Kwong equation of state

the modified Peng-Robinson model significantly improves the predictions of saturated vapor pressure and liquid density of heavy hydrocarbons(C7+)

however

only minor improvement in saturated vapor density prediction if observed. For light components(C7-)

theprediction of saturated vapor pressure and vapor density by the modified Peng-Robinson model is as good as Soave-Redlich-Kwong and Peng-Robinson equations of state. However

the description of the saturated liquid density is far superior. The modified Peng-Robenson model is used to predict the phase behavior fo gas condensates (dew point pressure

constant mass expansion and constant volume depletion processes)

and better results are obtained.