Solubilities of Nitrogen in Heavy Normal Paraffins from 323 to 423 K at Pressures to 18.0 MPa

Abstract

The solubilities of nitrogen in selected n-paraffin hydrocarbons (decane, eicosane, octacosane, hexatriacontane) were measured using a static equilibrium cell over the temperature range from 323.2 to 423.2 K at pressures to 18.0 MPa. The uncertainty in the measured solubilities is estimated to be less than 0.001 in mole fraction. The data were analyzed using the Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) equations of state. In general, the two equations represent the experimental data well when a single interaction parameter C ij is used for each binary system. The data display a trend of increasing solubility of nitrogen with increased temperature, pressure, and n-paraffin chain length.

A Parametric Study of the Choice of Binary Interaction Parameter and Equation of State for High Pressure Vapor-Liquid Equilibrium of Nitrogen – n-Dodecane Binary System

“…Gao et al (1999) have reported temperature dependent k ij values, k ij (T) and an average value of k ij =0.2082 and k ij =0.2226 for PR-EOS and SRK-EOS respectively. Figure 1 shows the influence of different k ij values with PR-EOS on the liquid-phase nitrogen mole fraction in a binary nitrogen-n-dodecane system as a function of ambient pressure, for three ambient temperatures.…”

“…The binary interaction parameter, k ij is taken from literature (Curtis & Farrell (1992), Gao, Robinson Jr., & Gasem (1999)). The fugacity coefficient of the i th component in the liquid-or the gas-phase is evaluated using Eqs.…”

“…There are also a few data reported for systems containing hydrocarbons heavier than n-decane (Azarnoosh & McKetta, 1963;D'Avila, Kaul & Prausnitz, 1976;Lin, Kim & Chao, 1981;Llave & Chung, 1988;de Leeuw, de Loos, Kooijman, & de Swaan Arons, 1992;Tong, Gao, Robinson Jr. & Gasem, 1999;Gao, Robinson Jr., & Gasem, 1999). The vapor-liquid phase behavior of a binary mixture is predicted using a real-gas equation of state (EOS), along with proper mixing rules.…”

“…For instance, more than one binary interaction parameter value has been reported for nitrogen-n-dodecane binary system. Gao, Robinson Jr., & Gasem (1999) reported different values of k ij to be employed in Peng Robinson EOS (PR-EOS) (Peng & Robinson, 1976) and Soave Redlich Kwong EOS (SRK-EOS) (Soave, 1972), which were temperature dependent. They had also reported an average k ij value for each EOS.…”

“…A limited number of experimental data is available for nitrogen−n-dodecane for a moderate range of pressures and temperatures (Llave & Chung, 1988;Gao, Robinson Jr., & Gasem, 1999). However, a theoretical model to predict the same, after due validation with experimental values, especially for a wide range of ambient pressures and temperatures, is scarce.…”