Page 433 - Advances in Eco-Fuels for a Sustainable Environment

386 Advances in Eco-Fuels for a Sustainable Environment

Fig. 13.14 Heat release rate with respect to crank angle for biodiesel-diesel-alcohol blends at
NOP of 500bar and FIT of 27° bTDC.

13.4 Conclusions

The performance, emissions and combustion characteristics of CRDI assisted diesel
engine fuelled with biodiesel-diesel-pentanol and biodiesel-diesel-hexanol blends
were experimentally investigated. Further, biodiesel process parameters were opti-
mized using response surface methodology based central composite design. The main
conclusions are summarized below.

l The 98.5% biodiesel yield was achieved from WFO under the following reaction conditions:
temperature of 55°C, 150min of time, molar ratio of 6:1 (methanol to oil), 1.5wt% of cat-
alyst concentration, and 975rpm of stirrer speed. Further increases of molar ratio above 6:1
reduced the biodiesel yield due to the effect of reversed reaction. If the catalyst concentration
is >1.5wt%, it causes soap formation during the transesterification process and this in turn
resulted in reduced biodiesel yield. WFO is the promising feedstock for biodiesel synthesis
due to its easy availability and cost.
l The maximum BTE of 35.39% was obtained in B90-D5-H5 blend at NOP of 500bar and FIT
of 27°CA bTDC, which was 1% less than diesel and 2% higher than B100, and 7% higher
than B85-D5-P10 at NOP of 500bar and FIT of 19°CA bTDC. The B90-D5-H5 blend
obtained the maximum BTE as related to other tested fuels irrespective of NOP and FIT.
This is due to more calorific value and lower viscosity than the other tested blends.
B90-D5-H5 has maximum BTE at advanced FIT and higher NOP due to the fact that higher
NOP enhances the atomization process and reduces the droplet size, resulting in complete
combustion and higher BTE.
l The minimum CO emission of 0.04% vol. was obtained in B85-D5-P10 blend at 500bar and
27°CA bTDC, which was 0.13% vol. less than the diesel at 200bar 19°CA bTDC.
B85-D5-P10 has the minimum UBHC emission of 10ppm at NOP of 500bar and FIT of
27°CA bTDC, which was 62.5% lower than diesel and 60% lower than the B100 fuel at
NOP of 600bar and FIT of 27°CA bTDC. B85-D5-P10 blend has the minimum CO and
UBHC emission as related to other biodiesel alcohol blends due to more oxygen presence