Development of a highly accurate vapor-phase equation of state with application to methane, ethane, carbon dioxide, nitrogen, and hydrogen

A highly accurate 29 constant vapor phase equation of state has been developed for pure methane applicable over a wide range of temperature and pressure. It has been used to successfully correlate methane PVT data from near the triple point temperature of 91 K up to a temperature of 623 K and a pressure of 259 MPa. Within the custody transfer region, 265-335 K (17-143 {dollar}spcirc{dollar}F) and 0-12 MPa (0-1750 psia), the average absolute deviation of the computed compressibility factors is with the {dollar}pm{dollar}0.01% uncertainty of the most accurate experimental data. Except for near the critical point the deviations in compressibility factor are on average well within 0.1%. Above 210 K the deviations for methane velocity of sound data at temperatures are generally within 0.1% except at the lowest temperatures and highest pressures.; The equation has been extended to ethane by the use of 10 additional terms which are a function of adjusted acentric factor. Ethane PVT data used in this work ranged in temperature from 248-623 K and extended up to a pressure of 40 MPa. The average absolute deviation in ethane compressibility factor is within 0.1%.; The equation has been extended to carbon dioxide by using an additional 10 terms which are a function of reduced quadrupole moment, bringing the total number of terms to 49. The carbon dioxide data which were used range in temperature from 217-448 K and up to a pressure of 70 MPa. The average absolute deviation in carbon dioxide compressibility factor is within 0.1%.; The equation has been successfully applied to nitrogen and hydrogen by fitting only three pure component parameters for each fluid. Nitrogen data which were used extend in temperature from 156-423 K up to a pressure of 100 MPa. The hydrogen data which has been employed range in temperature from 273-353 K up to a pressure of 28 MPa. The average absolute deviation in compressibility factor for nitrogen and hydrogen is well within 0.1%.