Glycerol Monooleate (GMO): A Valuable Biobased Lubricity and Pour Point Enhancer Blend Component for the ULSD Fuel

Novel value-added usage of glycerol (biodiesel coproduct) derivatives has been indispensable due to the extensive production of biodiesel. The physical properties of ultralow-sulfur diesel (ULSD) improved with the addition of technical-grade glycerol monooleate (TGGMO) with increasing concentration from 0.01 to 5 wt %. The influence of increasing concentration of TGGMO was studied on the acid value, cloud point, pour point, cold filter plugging point, kinematic viscosity, and lubricity of its blend with ULSD. The results showed improved lubricity for the blended ULSD with TGGMO as shown by the reduced wear scar diameter from 493 to 90 μm. The low-temperature flow properties were also improved as shown by lower pour points of -36 °C for the 1% TGGMO/ULSD blend compared to -25 °C for ULSDTGGMO blends in ULSD of up to 1 wt %, which met the ASTM standard D975 specifications. We also investigated the blending effect of the pure-grade monooleate (PGMO, purity level >99.98%) on the physical properties of ULSD at a blend concentration of 0.5 and 1.0%. Compared to PGMO, TGGMO significantly improved the physical properties of ULSD with increasing concentration from 0.01 to 1 wt %. Nevertheless, PGMO/TGGMO did not significantly affect the acid value, cloud point, or cold filter plugging point of ULSD. A comparison between TGGMO and PGMO showed that TGGMO improves the ULSD fuel lubricity and pour point more effectively than PGMO. PDSC data indicated that although addition of TGGMO will lower the oxidation stability slightly, it is still better than the addition of PGMO. Thermogravimetric analysis (TGA) data showed higher thermal stability and lesser volatility for TGGMO blends compared to those for PGMO blends. The cost effectiveness of TGGMO makes it a better ULSD fuel lubricity enhancer than PGMO.