Comparison of the performance and emissions of different biodiesel blends against petroleum diesel
Comparison of the performance and emissions of different biodiesel blends against petroleum diesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biodiesel, an alternative fuel of petroleum diesel, is mainly used to reduce the environmental impact of emissions without modifying engines. This study compares the performance and emissions characteristics of different biodiesel blends with petroleum diesel using an internal combustion engine (Kubota V3300) and following ISO 8178 standards. Two types of biodiesel, type A (80% tallow and 20% canola oil methyl ester) and type B (70% chicken tallow and 30% waste cooking oil methyl ester), were tested in this study. It was found that the performance (mainly torque and brake power) of both biodiesel fuels reduces with increasing blend ratio which can be attributed to lower energy content of biodiesel. Specific fuel consumption increases for both biodiesels compared with diesel fuel, as expected. Some of the greenhouse gas emissions were found to be higher than petroleum diesel, whereas some were lower. Overall, Biodiesel A was found to produce lower emissions across the board compared with diesel and Biodiesel B.
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P. McCarthy, M.G. Rasul* and S. Moazzem
Central Queensland University, Rockhampton, Queensland 4702, Australia
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Abstract
1 INTRODUCTION
It is well known that petroleum diesels are the major source
of air pollutions that create an adverse impact on human
health and overall greenhouse gases. Biodiesel has some
great benefits over petroleum diesel, such as it produces 4.5
units of energy against every unit of fossil energy [1, 2] and
also it has some environment-friendly properties such as it
is non-toxic, biodegradable and safer to breathe [3].
Biodiesel is also a clean-burning and stable fuel [3].
Properties of biodiesel such as oxygen content, cetane
number, viscosity, density and heat value are greatly
dependent on the sources (soybean, rapeseed or animal fats) of
biodiesel [4, 5]. Engine performance and emissions depend
on the properties of biodiesels. Biodiesel is a highly
oxygenated fuel that can improve combustion efficiency and can
reduce unburnt hydrocarbons (HCs), carbon dioxide (CO2),
carbon monoxide (CO), sulphur dioxides (SO2), nitric oxide
(NOx) and polycyclic aromatic HC emissions. However,
brake-specific fuel consumption slightly increases [6].
Popularity of biodiesel as renewable sources of alternative
fuel of petroleum diesel is growing quickly due to increased
environmental awareness and the rising price of diesel. It is an
earth-friendly choice of consumers that already occupies a
great volume of the worlds fuel sector due to its clean
emission characteristics.
Developments of biodiesel fuels in many countries are
driven by the necessity to reduce the greenhouse gas emissions
which is the major issue for todays world, and the scarcity of
the source of petroleum diesel also enhances the development
and production of biodiesel fuel around the world. Biodiesel is
generally produced from vegetable oils or animal fats through a
chemical process known as transesterification process.
Vegetable oil was first used to run an engine by Rudolf
Diesel (1858 1913) who developed the first engine. But
sometimes, vegetable oils create adverse effects on engine
components which may be due to their different volatility and
molecular structure from diesel fuel as well as high viscosity
compared with diesel fuel [4, 5, 7]. Currently, this problem is
being eliminated by applying different chemical processes such
as transesterification, supercritical, catalyst-free process etc., on
vegetable oils to convert into biodiesel.
This paper aims to investigate the engine performances
( power, torque, fuel consumption) and emissions (unburnt
HCs, carbon dioxide, carbon monoxide and nitric oxide) of a
diesel engine using two different biodiesels. Two different
sources of biodiesel, type A [80% tallow (beef, pork and
sheep) and 20% canola oil methyl ester] and type B (70%
chicken tallow and 30% waste cooking oil methyl ester), were
used for the experimentation in this study. Fuel types such as
B5, B10, B20, B50 and B100 are analysed and discussed.
2 THEORETICAL CONSIDERATION
Performances of a compression ignition (CI) engine are tested
by running them at different loads and speeds and taking
sufficient data for performance criteria. Engine performance
depends on the testing conditions and the form in which the
engine i (...truncated)