Jatropha - Bioenergy Crop Plants - page 343

Banapurmath et al. (2008) reported the hydrocarbon (HC) emissions with SOME, HOME, and
JOME in a 5.2-kW, single-cylinder, four-stroke diesel engine to be slightly more than that of the
diesel. This is attributed to the incomplete combustion because of their lower volatility and higher
viscosity. Pradeep and Sharma (2007) reported that smoke and HC emissions from JB were lower
than diesel at peak loads with and without EGR.
Kumar et al. (2003a) found that the smoke emissions for JO increased particularly at higher loads
because of poor atomization of the fuel. The smoke level at the maximal power output of 3.7 kW was
found to be 4.4 BSU (Bosch's smoke unit) with pure JO as compared with 4 and 3.8 BSU with JB and
diesel, respectively. Also, it was observed that an increase in the methanol admission beyond 30%
along with JO leads to a further reduction in smoke emissions up to the value of 2.6 BSU at 67% of
methanol substitution, which was at the best efficiency point. The HC emissions were found to be 100
ppm with diesel and 130 ppm with neat JO at maximal power output and they increased to 150 ppm in
the dual-fuel operation. Pradeep and Sharma (2007) reported that the smoke emissions from JB were
found to be lower than diesel at peak loads with and without EGR. Kumar et al. (2003b) reported that
induction of 7% hydrogen in JO was found to be the optimum for reducing HCs from 130 to 100 ppm
in a diesel engine. The corresponding reduction in HCs with diesel as the pilot fuel was found to be
from 100 to 70 ppm. The smoke level also dropped from 4.4 to 3.7 BSU with JO and from 3.9 to 2.7
BSU with diesel. However, a significant rise in NO level from 735 to 875 ppm with JO and from 785
to 894 ppm with diesel was reported because of the higher combustion temperature.
Reddy and Ramesh (2006) reported that the emissions from a 4.5-kW, single-cylinder, four-
stroke diesel engine when operated with JO under optimal conditions were 2 BSU whereas with
diesel they were 2.7 BSU. However, while evaluating the emissions of a 7.4-kW diesel engine when
fueled with unheated and heated JO, Agarwal and Agarwal (2007) found that HCs and smoke opac-
ity were higher for JO compared with diesel and they increased with an increasing proportion of JO
in the blends. These emissions were found to be closer to diesel for preheated JO.

14.6 other uses oF JatroPha ByProducts

14.6.1 u SE of J atropha S hEll /h ull
Crude enzymes can be prepared by decomposing jatropha hull (Sharma et al. 2009). It was reported
that inoculation of lignocellulolytic fungi resulted in better compost of jatropha hulls within 1
month. However, phytotoxic compounds present in the compost resulted in the low germination of
cress seed ( Lepidium sativum ). When this compost was matured after 4 months, the phytotoxicity
was reduced in terms of the germination index (≈ 80%). Therefore, it would be advisable to continue
the composting of jatropha hulls for 4 months to reduce the phytotoxicity of compost by the action
of enzymes secreted by lignocellulolytic fungi. Because compost has alkaline pH, it can be applied
to acidic soil as manure to neutralize soil pH. The potential of lignocellulolytic fungi used in this
study to produce higher quantities of cellulolytic enzymes can be tapped in an effective manner by
using them for the solid state fermentation or submerged fermentation of jatropha hulls. It was also
reported that the resultant crude enzyme preparations can be exploited for fermentation of hulls to
produce ethanol that can be used as an additional source of biofuel.
Jatropha seed husk can be used to obtain producer gas in a down-draft gasifier. The laboratory
study conducted by Singh et al. (2008) in an open-core down-draft gasifier with jatropha seed husk as
feedstock found that the maximal gasification efficiency was 68.31% at a gas flow rate of 5.5 m 3 /h and a
specific gasification rate of 270 kg/h m 2 . The calorific value of producer gas, the concentration of CO in
the producer gas, and the gasification efficiency in general increased with the increase in gas flow rate.

14.6.2 u SE of S hEll B riquEttES
The very high ash content (14.88%) of the jatropha shell fuses the ash at temperature above 750°C.
As the temperature in the oxidation zone of the gasifier reaches 900-1000°C, the jatropha shell