Improving the cold flow properties of biodiesel from waste cooking oil by ternary blending with bio-based alcohols and diesel from direct coal liquefaction
Yuan Xue1,2,*, Lihong Wang3, Hualin Lin2, Sheng Han1,2,* , Shiyou Zheng2,*
1 School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China
2 School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, China
3 Department of Science and Technology, Shanghai Urban Construction Vocational College, Shanghai 201415, China
* Corresponding author: Fax: +86-021-60873565, Tel: +86-02160873685; Email address: sit_xueyuan@163.com (Yuan Xue),syzheng@usst.edu.cn (Shiyou Zheng), hansheng654321@sina.com (Sheng Han)
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. Ternary blends of waste cooking oil biodiesel (BWCO) with DDCL and bio-based ethanol (ET) or 1-butanol (BT) for improving 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 into 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. BT and DDCL presented a better synergistic depression effect. For ternary blends in 20:10:70 blending ratio, BWCO-BT-DDCL exhibited the lowest PP, CFPP, and CP of −23 °C, −19 °C, and −17 °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.
Keywords: waste cooking oil biodiesel; ternary blends; cold flow properties; bio-based alcohol; diesel from direct coal liquefaction