Page 197 - Biofuels for a More Sustainable Future

Inedible vegetable-oil based biodiesel in Northern Viet Nam 179

Agency (US EPA, 2002), with base case emissions of petrodiesel in road
transport vehicles (buses and heavy-duty truck) and maritime navigation
from a report about emissions of transport in the Netherlands (Klein
et al., 2016). Although these findings may not reflect a quantitatively accu-
rate prediction of the actual differences, they could provide a proper trend
for comparison.

4.1.1 Variations in the characteristics of combustion emissions from
diesel engines with diesel and biodiesel blends
US EPA (2002) developed regression models for estimating the percent
change in exhaust emissions as a function of the concentration of biodiesel
in conventional diesel fuel. This study has been widely recognized and
applied in various biodiesel assessment reports (Air Quality Expert Group,
2011; Charman et al., 2012; Lapuerta et al., 2008). The original equation
was adapted following the scope of this study.
Regression equations were applied to estimate the difference between
the use of biodiesel and diesel in Viet Nam. The estimation was made using
the following equation:
SF x ¼ e ð a x vol%bdfÞ (6.3)

where SF x is emission scaling factor of emission x and a x is coefficient related
to emission x which were considered as statistically significant with 95%
confident (Table 6.3), and vol%bdf is the volumetric percentage of biodiesel
in the blend ranging from 0 to 100.

Table 6.3 Coefficients of basic emission correlations (US EPA, 2002)
Emissions Coefficients
0.0010375
NO x
PM 0.047395
HC 0.0118443
CO 0.0058238
0.0000177
CO 2
Acetaldehyde 0.001606
Ethylbenzene 0.006970
Formaldehyde 0.001696
Naphthalene 0.002847
Xylene 0.004078