New volume translated PR equation of state for pure compounds and gas condensate systems

The purpose of this paper is to improve the Peng–Robinson equation of state (PR EOS 1978) prediction of saturated liquid density of pure compounds and gas condensate systems by volume translation method. Thus, a temperature-dependent volume translation factor has been proposed. Also, a new mixing rule for volume translation factor of mixtures has been proposed. The new model requires only adjusted critical compressibility factor for each compound which has been determined and reported for 29 compounds. No binary interaction coefficients kij are used.The average absolute percent deviation (AAPD) of predicted liquid densities has been calculated in the reduced temperature range (0.3–0.99) for the pure compounds of the alkanes (methane to eicosane), ethylene, propylene, carbon dioxide, carbon monoxide, hydrogen sulfide, nitrogen, and ammonia. The AAPD of PR EOS for aforementioned pure compounds is 8.40%. By using the proposed volume translation model, the AAPD reduced to 1.11 and 1.29 for the optimized parameters and the generalized correlations, respectively. Moreover, the AAPD for 62 different systems of binary, ternary, and up to eight-component systems has been calculated. The AAPD of PR EOS for these mixtures is 7.26%; however, using the proposed model reduced this value to 1.17 and 1.19 for the optimized parameters and the generalized correlations, respectively.

► Improved liquid density of pure compounds and gas condensate by temperature-dependent volume translation PR EOS.
► Extended the proposed model to multicomponent mixtures.
► A new mixing rule is proposed for the application to multicomponent mixtures.
► This model accuracy was compared with other prediction methods.
► The proposed model has the least average absolute error% for pure compounds and mixtures.