PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

University of the South Pacific

Faculty of Science and Technology

MASTER OF SCIENCE: STATEMENT OF INTENT

PREPARATION, CHARACTERIZATION AND ENGINE

PERFORMANCE OF COCONUT OIL BASED HYBRID

FUELS. Author’s Name: Pranil. J. Singh (s11014513) Project Supervisors: Dr Anirudh Singh Senior Lecturer in Physics School of Engineering and Physics University of the South Pacific Fiji Islands Dr. Jagjit Khurma Associate Professor in Chemistry Division of Chemistry University of the South Pacific Fiji Islands Research Duration: 18 months (Commencing in semester I 2008)

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Date of Submission: April 2009

PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

1.1 GENERAL AREA OF STUDY The emphasis of this thesis will be Renewable Energy particularly Hybrid Fuels. The

specific topic will be ‘Preparation, Characterization and Testing of Coconut Oil based

Hybrid Fuels’.

1.2 IMPORTANCE The importance of this study is reflected in the recent move by the government of the Fiji

Islands to introduce biofuels in Fiji. This is being implemented through the Technical

Working Group (TWG) in biofuel energy development programme (Department of

Energy – Fiji), and the National Biofuels Energy Dialogue.

The recent increase in world oil prices, and Pacific Nations increasing concern over their

energy security coupled with the growing awareness of the environmental problems

associated with the use of petroleum fuels, has led to the renewed interest on biomass-

based fuels. The motivations for using these fuels are twofold, its environmental benefits

and its impact on the economy. These fuels are non-toxic, renewable sources of energy,

which do not contribute to the net global carbon dioxide build-up. For a country that

heavily relies on imported petroleum oils for its energy needs, but that has an abundant

supply of alternative energy source (in particular coconut), the use of coconut oil will

certainly have a positive impact on the country’s economy in terms of foreign reserves

savings. Their use could also revitalize the rural economies, since a growing demand for

coconut oil will result in increased production in such area. With such incentives, the

need for further research based on locally available resources is both real and significant.

1.3 LITERATURE AND BACKGROUND Vegetable oils have their own limitations to use in place of diesel due to their high

viscosity. The high viscosity results in poor atomization of the fuel when the oil is

injected into the combustion chamber of a compression ignition (CI) engine. This can

lead to extended ignition delay periods for initial combustion to commence and

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

consequently a reduction in engine performance due to incomplete combustion of the

injected fuel particles [7, 8]. The methods available for reducing the viscosity of vegetable

oils are [5, 6]:

• Pyrolysis

• Microemulsification

• Transesterification process

• Dilution or blending and

• Increasing the fuel temperature

This research will be focused on the technique of microemulsification and blending. The

viscosity of vegetable oils can be reduced through the formation of self organized

systems called fuel formulations or microemulsion [23, 24, 25, 26]. The vegetable oil is

blended with diesel or ethanol. The stability of this mixture is increased in the presence of

some additives called surface active agents or surfactants. It is generally called hybrid

fuel if the viscosity of vegetable oil is reduced by blending it with diesel or ethanol in the

presence of surfactants

1.3.1 What are Microemulsions?

Two mutually insoluble liquids (usually water and hydrocarbon) can be converted into an

optically transparent and thermodynamically stable emulsion by adding an appropriate

surfactant or a mixture of surfactants. This unique class of optically clear,

thermodynamically stable and usually low viscous solutions, is called microemulsion.

Therefore, microemulsions are defined as transparent, thermodynamically stable colloidal

dispersions in which the diameter of the dispersed-phase particles is less than one-fourth

the wavelength of the visible light. The stability of microemulsions is further increased,

by adding medium chain alcohols which are termed as co-surfactants.

1.3.2 Fuel Properties

In general, a good fuel has a characteristic of low viscosity, high energy content, high

saponification value and low iodine value [14]. There are a number of physical and

chemical characteristics of a good fuel. Firstly, it has to be efficiently combustible. The

energy produced by its complete combustion is measured by its energy value. For a fuel

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

to burn it has to vaporise to some extent and this is dependant on the viscosity. The

viscosity of an oil is related to the number of carbon atoms in a molecule. As the number

of carbon atoms increases, it gets progressively oilier, waxier and finally solid [14]. For a

good fuel, the viscosity should be low, which would translate into a more volatile fuel.

The saponification value (SV) is the measure of the average length of carbon chains. The

higher the SV, the lower the average carbon chains. Oils with shorter carbon lengths

readily auto-ignite on injection into the combustion chamber reducing the extent of

ignition lag. The iodine value (IV) is the measure of the unsaturated bonds in the

hydrocarbon chain [19]. The higher the IV, the higher the potential for the oil to form

gums, coke and varnishes. This is a damaging characteristic of vegetable oils if it were to

be used in a CI engine [20]. It can lead to build up on the injectors, gumming up piston

rings, glazing cylinder walls and formation of coke. Previous investigators [21] who

carried out experiments on crude palm oil having an IV of 54 have reported valve

sticking as the main cause of engine performance degradation. The cetane number (CN)

is a measure of the combustion quality of diesel fuel during compression ignition. Cetane

number is actually a measure of a fuel's ignition delay; the time period between the start

of injection and start of combustion (ignition) of the fuel [22]. The higher the CN, the

lower the self-ignition temperature. Fuels having higher CN are suited for CI engines.

CNO has an order of 60-70 CN, which is higher than petroleum diesel and other common

vegetable oils.

CNO has low IV, high SV and high CN. This makes CNO the most suitable alternative

vegetable oil fuel for diesel engines [5, 7, 8]. The only drawback in terms of fuel properties

is the high viscosity, which this research aims to overcome using the blending and the

microemulsification techniques.

1.4 REASONS FOR INTEREST IN HYBRID FUELS A lot of research has been carried out using the transesterification process where

biodiesel is produced and used as the alternative to petroleum diesel. The technique of

microemulsification, producing hybrid fuels has the following advantages over biodiesel

and is therefore more economically viable [9]:

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

• Preparation of hybrid fuel is very simple whereas preparation of bio-diesel is

complicated.

• Cost involved in the preparation of hybrid fuel is very small. Therefore, hybrid

fuel is cheaper compared to bio-diesel.

• A big set up is required for the preparation of bio-diesel where as for the

preparation of hybrid fuel a small set up is required.

• Hybrid fuels are spontaneously formed by mixing the vegetable oil with other

constituents.

• Hybrid fuel is prepared in situ whereas bio-diesel is brought from the industry

where it is prepared.

Therefore, transportation cost is also involved in case of bio-diesel where as

transport cost is nil in case of hybrid fuel.

• Hybrid fuel preparation is a time saving process compared to bio-diesel

preparation.

The vegetable oils may be blended to reduce the viscosity with diesel and/or ethanol in

presence of some additives to improve the properties of diesel as well as vegetable oil

with ethanol. The blends of conventional diesel fuel with vegetable oils have also been

called hybrid fuels and microemulsion-based fuels are sometimes also termed “hybrid

fuel”.

1.5 OBJECTIVES This study is to investigate the technical feasibility and potential for hybrid fuels,

prepared using the microemulsification technique, as an alternative to petroleum diesel in

compression ignition engines by:

a) blending coconut oil (CNO) with ethanol and determining the limit of stability of

the blend at room temperature.

b) using the microemulsification technique to prepare CNO based hybrid fuel

c) determining the relevant fuel properties such as the viscosity, energy content,

density, saponification value, iodine value, cetane number and the melting point.

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

d) Testing the engine performance using the blend and hybrid fuel to find the

efficiency using the various test fuels.

1.6 DISCIPLINES INVOLVED This research will be a multidisciplinary project involving the expertise and resources of

Physics and Chemistry division. The project will be supervised by Dr Anirudh Singh,

Senior Lecturer in Physics and Dr Jagjit Khurma, Senior Lecturer in Chemistry. This will

ensure expertise from the physical and chemical point of view.

1.7 SKILLS NEEDED TO UNDERTAKE THE RESEARCH I have completed a postgraduate diploma unit, PH400, Research Project in Physics in

Semester II of 2007, where I undertook a project titled ‘Biofuels for Diesel Generators’.

Pure CNO and Coconut Methyl Ester (Biodiesel) was tested in the project. The viscosity

of CNO was lowered by blending with 10% of ethanol and the efficiency found along

with other important physical and chemical properties. The skills attained from

undertaking that project would be of great help in this current research.

1.8 LOCATION OF RESEARCH This research will be based in the Laucala Campus of USP with the Physics and

Chemistry divisions.

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

1.9 REFERENCE [1] Peterson, C.L., 1983. Winter rape oil fuel for diesel engines, Journal of American

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[3] Ryan, T.W., 1984. Effects of vegetable oil properties on injection and combustion

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[4] Etherington, Dan, M., and David, H., 1995. Coconut oil as Fuel: Final Report,

Phase IIA. Australian and Pacific Science Foundation.

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

[9] Reddy, M.C.S., 2006, Hybrid Fuel-Fuel of the Future, Advances in Energy

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[10] Solly, R., 1982. Coconut oil and coconut-ethanol derivatives as a fuel for diesel

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

performance and exhaust emissions, Society of Automotive Engineers of Japan,

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[22] http://en.wikipedia.org/wiki/Cetane_number

{Accessed on 10th December 2007]

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[24] Goering C.E. and B.Fry, 1984, Engine durability screening test of a diesel oil/soy

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PREPARATION, CHARACTERIZATION AND TESTING OF COCONUT OIL BASED HYBRID FUELS

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[25] Neuma de Castro Dantas T., A.C.da Silva and A.A.D.Neto, 2001, New

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