Solubility limitations of residual steryl glucosides, saturated monoglycerides and glycerol in commercial biodiesel fuels as determinants of filter blockages

Abstract

Newer, improved high pressure common rail diesel engines require increased protection from damaging particles in fuel, resulting in tighter, low-micron filtration requirements. The unobstructed flow of fuel through filters underlies the well-known efficiencies and reduced exhaust emissions of diesel engines, and when flows are hindered, these efficiencies become severely compromised. Biodiesel fuels frequently contain saturated monoglycerides, glycerol (GLY) and/or steryl glucosides, systemic impurities that become problematic when low concentrations exceed ill-defined solubility limits, usually unexpectedly at low temperatures. Here, filters and blended fuels from seven flow obstruction incidents were subjected to detailed compositional analyses. With one exception the fuels contain estimated levels within international specifications, yet exhibit heterophase (HP) formation in the laboratory at 2 C, well above measured cloud points. Feedstock composition, pretreatment and/or purification processes are found to modulate insolubility risks. Interferences in standard gas chromatography methods used without modification can hide or complicate estimates of residual levels of GLY. The data show that classical variables controlling solubility, such as concentrations and temperatures, play important roles in setting the risks associated with in situ formation of HPs from these common impurities. Further, such risks are likely attenuated considerably by reductions in critical impurities beyond currently specified limits.

Development of Simplified and Efficient Sample Preparation Methods for the Analysis of Problem Material within the Diesel Fuel Delivery System

“…Free glycerol levels in biodiesel are limited to 0.02% mass in both EN 14214 and ASTM D6751, and this is monitored using test methods EN 14105 in Europe and D6584 in the USA . Despite these tests, fuels containing glycerol within these limits have been linked with incidences of fuel filter plugging …”

“…The TD 1.0 approach is time efficient and eliminates solvent use; therefore, it is important that TD 2.0 is similarly time efficient and uses minimal solvent. The method used in this work is straightforward, takes a maximum of 20 min, and uses a small volume of solvent (∼6 mL per sample), and this is a significantly shorter and more sustainable sample preparation method than those used by Heiden et al and Csontos et al , DCM and methanol were the solvents used, and the method is described in the Experimental Section of this paper. The results of filter 2 are shown to demonstrate the results of the TD 2.0 approach.…”

“…Water present in the fuel as a result of improper handling or condensation can enable microbial growth. Microorganisms can then feed on components in the fuel expediting degradation processes. , It is well-documented that fluctuations in temperature have an effect on the solubility of FAME species as well as trace components such as SMGs. ,,, Long-term storage of biodiesel can result in an accumulation of problematic species, potentially amplifying the issues listed above. It is essential to identify these problematic components in fuel and filter material to give an indication of the source of blockages; this information can subsequently be used to develop mitigation strategies to prevent these blockages from occurring.…”

“…It is essential to identify these problematic components in fuel and filter material to give an indication of the source of blockages; this information can subsequently be used to develop mitigation strategies to prevent these blockages from occurring. Although diesel fuel is subjected to rigorous testing procedures that ensure quality, several studies have highlighted filterability issues with fuels that meet international standards. ,, Specifically, Heiden et al and Cardeo et al. saw the formation of insoluble material within the fuel at temperatures above the measured cloud point.…”

Evaluation of biocatalysts synthesized with lipase from Pseudomonas cepacia supported on glycol-modified MOF-199 in the synthesis of green biodiesel

“…Despite these characteristics, MOFs as catalytic support for lipase anchoring have the drawback that coordination interactions are weak (Wang et al, 2019); for this reason, their modification is necessary before using them as an immobilizer for Pseudomonas cepacia enzymes. In addition to the previously mentioned catalysts, the synthesis of catalysts that allow the incorporation of glycerin as a component of biodiesel in the form of monoglycerides aids in the reduction of impurities (Heiden et al, 2021), thus improving the biofuel's quality (Krishnasamy and Bukkarapu, 2021). The addition of glycerol to the mixture of fatty acid methyl esters (FAMEs) in biodiesel is formulated as Ecodiesel and has the advantage of increasing the lubricity (Milano et al, 2022) of the energy solution.…”