Densities and Viscosities of Fatty Acid Methyl and Ethyl Esters

Abstract

To develop reliable models for the densities and viscosities of biodiesel fuel, reliable data for the pure fatty acid esters are required. Densities and viscosities were measured for seven ethyl esters and eight methyl esters, at atmospheric pressure and temperatures from (273.15 to 363.15) K. A critical assessment of the measured data against the data previously available in the literature was carried out. It is shown that the data here reported presents deviations of less than 0.15 % for densities and less than 5 % for viscosities. Correlations for the densities and viscosities with temperature are proposed. The densities and viscosities of the pure ethyl and methyl esters here reported were used to evaluate three predictive models. The GCVOL group contribution method is shown to be able to predict densities for these compounds within 1 %. The methods of Ceriani and Meirelles (CM) and of Marreiro and Gani (MG) were applied to the viscosity data. It is shown that only the first of these methods is able to provide a fair description of the viscosities of fatty acid esters.

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

“…Pratas et al obtained A = À5.7 Â 10 À4 MPa À1 [36] by fitting Eq. (10) to high pressure densities for laurate, myristate, and oleate methyl esters, reported by Pratas et al [55,56]. The Eq.…”

“…With this extension (extended GCVOL) densities of tertiary alcohols, alkynes, carboxylic acids, allenes, cycloalkanes, fluorides, bromides, iodides, thiols, sulfides, sulfates, amines, nitriles, and nitro compounds were calculated with an average mean deviation of 1.5% for a database of 1040 compounds. Pratas et al [55,56] applied the original CGVOL to density prediction of pure FAMEs present in biodiesel in greater content, and those existing in minority. They concluded that for the majority FAMEs the density can be predicted within an ARD of 0.5%, except for the methyl linoleate since the model describes poorly the effect of unsaturation on density.…”

“…Pratas et al [36] also applied the original and the extended GCVOL models to 18 biodiesel samples of soy, rapeseed, palm, cottonseed, jatropha, and mixtures thereof at temperatures between 273.15 and 373.15 K and densities from 815 to 898 kg m À3 , and obtained overall ARDs of 0.6% and 2.7% for the original and the extended GCVOL, respectively. To solve the precision lack for the polyunsaturation ester effect, Pratas et al [36] found new parameter values A i , B i , and C i relative to the double bond (ACH@) contribution, based on density data measured for FAMEs [55,56]. This revised variant of GCVOL was applied to the 18 biodiesels leading to a decrease in the overall ARDs to 0.25% in density, corresponding to %2 kg m À3 [36].…”

Microalgal Species Selection for Biodiesel Production Based on Fuel Properties Derived from Fatty Acid Profiles

“…(Table 2). On the other hand, υ, CFPP and ρ are largely influenced by the degree of unsaturation [39,40]. Therefore, both saturation and unsaturation of FAMEs should have an optimal balance for high biodiesel quality.…”

Physiochemical and Phase Behaviour Study of Jatropha curcus Oil - Ethanol Microemulsion Fuels Using Sorbitane Fatty Esters

“…For instance, the cetane number and gross heating values are directly related to density and affect fuel efficiency [26][27][28]. Similarly, viscosity is an important parameter for development of fuels that governs the engine operation [29][30]. Surface tension is one of the vital PCP that directly affects fuel atomization due to cohesive forces and hence the biodiesel with higher surface tension values hamper the correct fuel atomization on an engine combustion chamber due to difficulty in small fuel droplet formation [31].…”