Improving the cold flow properties of biodiesel from waste cooking oil by ternary blending with bio‐based alcohols and diesel from direct coal liquefaction

Abstract

The utilization and popularization of biodiesel are always limited by its poor cold flow properties. Both bio-based alcohol and diesel from direct coal liquefaction (DDCL) has potential to enhance the cold flow properties of biodiesel. In this study, ternary blends of waste cooking oil biodiesel (BWCO) with DDCL and bio-based ethanol (ET) or 1-butanol (BT) were conducted to improve the cold flow properties of biodiesel. The pour point (PP), cold filter plugging point (CFPP), and cloud point (CP) of BWCO-ET, BWCO-BT, and BWCO-DDCL binary blends, and BWCO-ET-DDCL and BWCO-BT-DDCL ternary blends were comparatively assessed. Ternary phase diagrams were also applied to analyze the blending effect of the three components on the cold flow properties of biodiesel. Results showed that both DDCL, ET, and BT can remarkably enhance the cold flow properties of BWCO. When the ternary blends contain 20 vol.% BWCO and less than 40 vol.% ET or BT, DDCL together with ET or BT exerted positive effects on enhancing the low-temperature flow properties of BWCO, especially on the CP and CFPP. For ternary blends in 20:10:70 blending ratio, BWCO-BT-DDCL exhibited the lowest PP, CFPP, and CP of À23, À19, and À17 C, respectively. The crystallization behavior and crystal morphology of blended fuels are also observed via a polarizing optical microscope, and find that DDCL together with BT in biodiesel can effectively retard the aggregation of large crystals and inhibit crystals growth. K E Y W O R D S bio-based alcohol, cold flow properties, diesel from direct coal liquefaction, ternary blends, waste cooking oil biodiesel

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

“…Our findings align with the practice of blending biodiesel with smaller FAMEs to improve flowability (Ghanei, 2015). Similarly, cloud point of binary blends of biodiesel made from waste cooking oil and bio‐based ethanol increased from −5 to 5°C by increasing the biodiesel concentration from 10 to 90 vol.% due to addition of more saturated FAMEs (Xue et al, 2021).…”