Untitled

Measurements of Vapor Pressures from 280 to 369 K and (p, ρ, T) Properties from 340 to 400 K at Pressures to 200 MPa for Propane

“…The data by Dittmer et al [4] and Thomas and Harrison [6] agreed reasonably with the present results to within ±0.14 and ±0.15% in density, respectively. Figure 2 shows relative density deviations of the present measurements from the Helmholtz-type equation of state proposed by Miyamoto and Watanabe [15]. The behaviors of density values calculated from the pressure-explicit mBWR-type equation of state developed by Younglove and Ely [16] and the multi-parameter Helmholtz-type equation of state developed by Span and Wagner [17] are also included for comparisons.…”

An Approach to Calculate Thermodynamic Properties of Mixtures Including Propane, n-Butane, and Isobutane

“…For the purpose of comparison of the present statistical model with available analytical models, we have selected the thermodynamic models for hydrocarbons recently published by Miyamoto and Watanabe [6][7][8][9] which cover a wide range of temperatures and pressures. For propane the equation covers from the triple point temperature (85.48 K) to 623 K, at pressures up to 103 MPa, and at densities up to 741 kg · m −3 ; for n-butane from 134.87 to 589 K, at pressures up to 69 MPa, and at densities up to 745 kg · m −3 ; and for isobutane from 113.56 K (the triple point temperature) to 573 K, at pressures up to 35 MPa, and at densities up to 749 kg · m −3 .…”

“…However, these equations have exhibited some noticeable defects, such as poor agreement with experimental data at moderate densities. On the other hand, we can use complex equations of state with many constants (Benedict-Webb-Rubin [1] (BWR) EOS, Lee-Kessler [1] EOS, Benedict-Webb-Rubin-Starling-Nishiumi [1] EOS, modified BWR [1,2] (MBWR) EOS, Jacobsen-Stewart (JS) [2,3] EOS, Tillner-Roth-Watanabe-Wagner (TRWW) [4][5][6][7][8][9] EOS, etc.). These equations are more complicated and highly accurate for states where data are available, but they have no insight into the microstructure of matter and often exhibit poor agreement with experimental data outside interpolation limits.…”

“…Somewhat larger deviations can be found in the region near the critical point due to the large influence of fluctuation theory and the singular behavior of some thermodynamic properties in the near-critical region. The perturbation models based upon SAFT theory (LLL) yield Relative deviations of thermodynamic properties of the saturated vapor for equimolar mixture of propane + n-butane calculated using the model of this work from values calculated using a classical model (TRWW[6][7][8][9]). …”

“…Relative deviation of thermodynamic properties at the (a) saturated vapor and (b) saturated liquid for equimolar mixture of isobutane + n-butane calculated using the model of this work from values calculated using a classical model (TRWW[6][7][8][9]). …”