Environmental Engineering Reference
In-Depth Information
Table 4
Mass consumption (g/h) and energy consumption (MJ/h) vs. engine charge (kW) of
blends of diesel and diesel + 5% vol ethanol with waste olive oil
biodiesel
Sample
0 kW
0.08 kW
0.95 kW
1.90 kW
2.85 kW
3.80 kW
Diesel
g/h
485.9
472.4
556.1
638.4
710.1
783.4
MJ/h
21.7
21.1
24.9
28.5
31.8
35.0
Diesel + 5% vol
waste olive
oil biodiesel
g/h
405.2
408.1
512.8
571.0
617.4
713.1
MJ/h
18.1
18.2
22.9
25.4
27.6
31.8
%
−16.6
−13.7
−8.0
−10.9
−13.2
−9.1
Diesel + 5%
vol ethanol
g/h
482.6
473.9
558.0
663.8
704.3
826.1
MJ/h
21.7
21.4
25.2
29.9
31.8
37.3
%
0
+1.4
+1.2
+4.9
0
+6.6
Diesel + 5% vol
ethanol + 5%
vol waste olive
oil biodiesel
g/h
426.1
418.8
504.3
588.4
624.6
688.4
MJ/h
19.1
18.8
22.7
26.4
28.0
31.0
%
−12.0
−10.9
−8.8
−7.4
−11.9
−11.4
results with BE-diesel fuel showed an increase in NO
x
emissions, albeit for a different
ethanol-biodiesel-diesel fuel ratio
[15]
. Oxygenate diesel fuel blends are known to
reduce total PM emissions, although the mechanisms are not clear. Soot formation
mainly takes place in the fuel-rich zone at high temperatures and pressures, specifically
within the core region of the fuel spray.
It is commonly assumed that oxygenates blended with diesel fuel effectively
deliver oxygen to the pyrolysis zone of the burning diesel spray, resulting in reduced
PM generation. The blends of fossil diesel + biodiesel and fossil diesel + ethanol
shows good results in the reduction of PM (−6.1% and −13.1%, respectively), but
the ternary blends of BE-diesel shows an increase of PM (+2.0%), in contrast to
previous reported results
[15]
. This difference could be explained by the lower
amount of biodiesel used in our experiments that described in the literature
[15]
.
From a practical point of view, the advantage of reducing NO
x
emissions by one third
should be balanced against a slight increase in the PM emission when using this
ternary BE-diesel fuel blend.
The binary blends of fossil diesel and biodiesel show a decrease in the consumption
from −16.6% at the lowest engine power to −9.1% at the highest power. On the con-
trary, the binary blends of fossil diesel and ethanol always show an increase in fuel
consumption. However, the ternary blends of BE-diesel fuel show a reduction
in the fuel consumption at all engine powers tested. This, coupled with the reduction in
the NO
x
emissions, makes this fuel a good promise for diesel cars in a near future.
Conclusions
The transesterification reaction of waste olive oil with methanol, catalysed with
sodium methoxide, to produce biodiesel follows a first order kinetics in methanol
and in triglycerides, with a rate constant of
k
= 0.2245 L mol
−1
min
−1
. The reaction
