Rheology and MT-DSC studies of the flow properties of ethyl and methyl babassu biodiesel and blends

Abstract

Biodiesel is an increasingly attractive alternative to diesel fuel. The main component of Babassu biodiesel is lauric acid (C12:0), which is a saturated fatty acid with a high melting point. Controlling flow properties, such as viscosity and the cold filter plugging point, is critical because viscosity affects atomization, and crystal formation resulting from decreases in temperature can negatively affect engine starting and performance. To evaluate its flow characteristics more fully, the rheological properties of babassu biodiesel were analyzed, taking into account variations in temperature. The crystallization temperature was determined by modulated temperature differential scanning calorimetry (MT-DSC). The curve of biodiesel viscosity as a function of the biodiesel refrigeration temperature contained an inflection point (corresponding to a steep increase in viscosity) that was coincident with both the transition from a Newtonian-type flow to a pseudoplastic-type flow and the crystallization temperature obtained by MT-DSC, indicating that the appearance of crystals in the biodiesel increased its viscosity. The rheological properties of fatty acid methyl and ethyl mixtures (FAME and FAEE) with metropolitan diesel were also evaluated; a higher FAME percentage reduced viscosity in blends up to B100.

Densities and Viscosities of Fatty Acid Ethyl Esters and Biodiesels Produced by Ethanolysis from Palm, Canola, and Soybean Oils: Experimental Data and Calculation Methodologies

“…Some of the existing methodologies which can be applied to calculation of viscosity or density of ethyl esters, or could be extended to these calculations by further adjustment, depend on a great number of parameters and/or equations as well as the knowledge of specific group division methodology, the existence of reference experimental data, or the previous determination of other physical properties. Similarly, little experimental data are available on the determination of these physical properties in BPEs from different vegetable oils, − highlighting the fact that BPE is an interesting alternative as a completely renewable biofuel.…”

Polymer Cold-Flow Improvers for Biodiesel

“…At the same time, some more knowledge-intensive methods are essential for the study of BD blends and formulations and the investigation of the effect of cold-flow improvers. These methods are differential scanning calorimetry (DSC) or modulated temperature DSC (MT-DSC) [ 84 , 85 ], light scattering [ 86 ] and precision rheometry [ 84 , 87 , 88 ]. The use of these methods allows determining the temperatures of the phase transitions in BD samples with high accuracy.…”

Flow and crystallization of saturated fatty acid methyl esters and their binary mixtures

“…Specifically, FAME chain length and degree of saturation in biodiesels can alter the rheology. For example, the viscosity and crystallization temperature of biodiesel made from babassu oil showed a significant increase in viscosity and transition from Newtonian to non‐Newtonian behavior during cooling (Santos et al, 2011). Flow in the context of this paper is shear flow generated in a rheometer, which is quantified by shear rate (Macosko, 1994).…”