Experimental Studies on a DI Diesel Engine Fueled with Jatropha Methyl Ester-Wood Pyrolysis Oil Emulsions

Abstract

The major technical problems associated with the use of biodiesel in large proportions are
(i) more prone to oxidation which can cause the fuel to become acidic and to form insoluble
gums and sediments that can plug fuel filters, (ii) cold flow properties and (iii) higher NOx
emissions compared to diesel fueled engines. It is reported that addition of antioxidants,
emulsifying water with biodiesel, addition of fuel with high latent heat of vaporization, and
low cetane fuel can reduce the NOx emissions in biodiesel fueled engines. Addition of
antioxidants to biodiesel can improve both the cold flow properties and oxidation stability,
and reduce the NOx emission, the reason being that, the antioxidants contain phenolic
compounds. Also, in economic point of view, the cost of biodiesel is higher at this moment
because, the availability of seeds is limited. This motivates less use of biodiesel in many
countries. The use of alternative hydrocarbon sources other than petroleum fuels, as extenders
for biodiesel can solve this problem. Many literatures report that pyrolysis oil obtained from
biomass sources contain hindered phenols in them. Therefore, bio oil can be used as an
extender to biodiesel. The bio oil not only contains phenolic compounds, it also contains
small percentage of water which is inseparable.