Prediction of ethane and CO₂solubilities in heavy norma paraffins using generalized-parameter soave and peng-robinson equations of state

Abstract

A study was made of the abilities of the Soave and Peng‐Robinson equations to represent the phase behavior of ethane + n‐paraffin and CO2 + n‐paraffin systems. These equations are capable of describing the phase behavior of such systems; however, the level of precision obtained varies with the degree of complexity used in representing the interaction parameters in the mixing rules employed. For ethane/C02 with n‐paraffins extending from C3 to n‐C44, an uncertainty of about 1 % is obtained for bubble point pressures (or about 0.005 mole fraction for solubilities) when two system‐specific interaction parameters per isotherm are used. Simple generalized correlations are presented for the equation‐of‐state interaction parameters which allow prediction of the bubble point pressures with an expected uncertainty of about 5.7% (0.014 in mole fraction).

Correlation and Prediction of Carbon Dioxide Solubility inn-Paraffin Systems

“…Some authors have used traditional cubic equations [31,32]; others have used group contribution equations of state [33,34]. In order to compare theirs results with the numbers presented in Tabs.…”

“…5. I used the PRSV equation of state [35] because it gives a good agreement to experimental vapor pressure and has the two binary parameters that are needed [32] to adjust data in asymmetric systems. The systems included in Tab.…”

“…For each solvent three ways to do the calculation were done: two binary parameters for each temperature, two binary parameters for all temperatures, and one binary parameter for all temperatures. This last case is not an adjustment; the binary parameter was picked from the literature [32]. The two first cases are correlation modes; the last case is a prediction mode.…”

Improved structure–property relationship models for prediction of critical properties

“…Physical properties [66,70,75] as well as saturation properties [86] have been correlated successfully using variations of this function. Similarly, Tsonopolous and Tan [73] proposed the following for correlating the critical properties of n-alkanes:…”

“…Several authors (Kreglewski and Zwolinski [65], Gasem [66], Gasem et al [70]) have developed correlations for critical properties based on the number of carbon atoms. Further, they have proposed that many n-paraffin physical properties are asymptotic in nature; that is, a limiting value for the physical property is reached asymptotically at very large carbon number.…”