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. 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.