3.2.2 Influence of ternary blends on the low-temperature flow properties of BWCO
BWCO-ET-DDCL and BWCO-BT-DDCL ternary blends were mixed in specific volume ratios. The comparative results of the PP, CFPP and CP of BWCO-ET-DDCL and BWCO-BT-DDCL ternary blends are presented in Table 5. The bending ratios of these ternary blends are as follows: 5:5:90, 10:10:80, 20:80:0, 20:70:10, 20:60:20, 20:50:30, 20:40:40, 20:30:50, 20:20:60 and 20:10:70.
Table 5 shows that DDCL and ET or BT exerted synergistic effects on enhancing the low-temperature flow properties of biodiesel to a certain degree. Thus, the ternary blending of BWCO and DDCL together with ET or BT resulted in further improvement of the PP, CFPP and CP of BWCO. More importantly, both ET and BT are bio-based alcohol fuels derived from inexpensive, green, and renewable biomass materials via fermentation method [21-23], thus making these ternary blends environmentally and financially feasible.
However, ternary blends of BWCO-BT-DDCL presented lower CP, CFPP and PP than those of BWCO-ET-DDCL. Such result can be attributed to the good intermiscibility of BWCO-BT- DDCL in contrast to that of BWCO-ET-DDCL with identical proportions. When the ternary blends contain 20 vol.% BWCO, the value of CFPP decreased with the increase in the amount of DDCL. As BWCO mixed with BT and DDCL in 20:10:70, 20:20:60, 20:30:50, 20:40:40, and 20:50:30 blending ratios, the CP and CFPP were relatively better than those of BWCO-ET, BWCO-BT and BWCO-DDCL binary blends that contained 20 vol.% BWCO. PP also stabilized in the range of −19 °C to −23 °C. Notably, BWCO-BT-DDCL ternary blends with the blending ratio of 20:10:70 presented the lowest CP (−17 °C) and CFPP (−19 °C) among the blends with 20 vol.% biodiesel, PP also decreased to −23 °C. Moreover, the amount of BWCO is still the major factor depressing the low-temperature performance of biodiesel blends. Ternary blends of BWCO-BT-DDCL with blending ratios of 10:10:80 and 5:5:90 presented better cold flow properties, and the CFPP values (−30 °C and −35 °C) decreased by 11 °C and 16 °C in contrast to those of BWCO-BT-DDCL blends with the blending ratio of 20:10:70 (−19 °C), and were also superior to the corresponding binary blends. In other word, the neat BWCO may be unsuitable for using in a low-temperature climate because of the deficiencies of its cold flow properties. Nevertheless, blending DDCL and BT together with BWCO can obviously improve the low-temperature flow properties of biodiesel and widen its temperature ranges for application.
Table 5 Influence of BWCO-ET-DDCL and BWCO-BT-DDCL ternary blends on CP, CFPP, and PP of BWCO.