Measurement and correlation of biodiesel densities at pressures up to 130 MPa

Correlation and prediction of biodiesel density for extended ranges of temperature and pressure

“…Literature usually reports biodiesel density measurements made close to the ambient temperature (285-295) K and atmospheric pressure [8][9][10][11][12][13][14] and few measurements of this property have been reported in wider temperature ranges [15][16][17][18][19][20]. The inclusion of pressure has been made in the works by Pratas et al [1], Tat and Van Gerpen [2,21,22], Nikolic et al [23], Aparício et al [24], Dzida and Prusakiewicz [25], and recently by Chhetri and Watts [26] and Schedemann et al [27]. Since density depends on the used raw material from which biodiesel was produced, FAMEs profile is crucial for applying the correlation and prediction models to that property, which also has not been provided by authors [23][24][25].…”

“…To correlate pure FAME and biodiesel densities the Tait equation of state (EoS) [28] has been used [1,24,27]. Pratas et al [1] used this EoS to correlate density of pure FAME (methyl laurate, myristate, and oleate), methyl biodiesels from palm (P), soybean (S), and rapeseed (R) oils, binary (RP, SP, SR) mixtures, and ternary mixture (SRP) for temperatures from 283 K to 333 K and pressures up to 45 MPa.…”

“…Pratas et al [1] used this EoS to correlate density of pure FAME (methyl laurate, myristate, and oleate), methyl biodiesels from palm (P), soybean (S), and rapeseed (R) oils, binary (RP, SP, SR) mixtures, and ternary mixture (SRP) for temperatures from 283 K to 333 K and pressures up to 45 MPa. Schedemann et al [27] used Tait equation to correlate data for methyl linoleate at temperatures between 278 K to 367 K and pressures between 0.4 MPa and 130 MPa. The relative deviations in density obtained from those correlations have been usually lower than 0.01%.…”

“…Pratas et al [1] applied the CPA EoS to correlate pure FAME density, and the calculated pure component parameters were applied to predict the density of methyl biodiesels with deviations ranging from 0.79% to 2.5%. Schedemann et al [27] used the VTPR method to predict density data of methyl linoleate and biodiesel. For the biodiesel deviations %1% were found at 396.8 K and pressures up to 55 MPa whereas at temperatures lower than 386.9 K and pressures up to 130 MPa deviations ranged from À1% to À7%.…”

“…Aiming to gather a sufficiently large amount of data, and for the sake of statistical significance for biodiesel density correlation and prediction, the measured densities for cottonseed made in this study were combined with biodiesel data provided by Pratas et al [1], Tat and Van Gerpen [1,22], and Schedemann et al [27].…”