DIRECTION DES ETUDES ET DES SERVICES ACADEMIQUES
MEMOIRE DE FIN D’ETUDE D’INGENIEUR DE L’ EQUIPEMENT RURAL
Présenté par : Landry TCHEGNONSI
Thème :
Etude des huiles végétales comme bio carburant Use of vegetable oils as biofuel
MEMBRES DU JURY 1. Pr. Yézouma COULIBALY Président UTER Génie Energétique 2. Dr. Francis FORSON Encadreur et Industriel 3. Joel BLIN Membre 4. Susan STRAND Membre Use of vegetable o ils as biofuels – GEE / KNUST
LIST OF CONTENT
LIST OF TABLES ...... 3 LIST OF FIGURES ...... 4 LIST OF PHO TOS ...... 5 ABBREVIATIONS AND ACRONYMS ...... 6 ABSTRACT ...... 7 RESUMÉ ...... 8 ACKNOWLEDGEMENTS ...... 9 DEDICATION ...... 10
CHAPTER 1 – GENERAL INTRODUCTION ...... 11 1. Background ...... 11 2. Scope and objectives ...... 12 3. Justification of st udy ...... 12 4. Methodology ...... 12 5. Presentation of KNUST ...... 12 6. Organiza tion of the report ...... 13
CHAPTER 2 – LITERATURE REVIEW ...... 14 1. Fuel properties for diesel engines ...... 14 2. Previous works about the use of biofuel in diesel engines ...... 15 a. Straight vegetable oil as fuel source ...... 16 b. Vegetable Oil, Diesel Blends as Potential Fuel Sources ...... 20 c. Conclusion ...... 22 3. Facts about some vegetable oils ...... 23 a. Cotton oil ...... 23 b. Sunflower oil ...... 23 c. Coconut oil ...... 24 d. Peanut oil ...... 25
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CHAPTER 3 - EXPERIMENTAL PROCESS AND THEORY ...... 27 1. Intr oduction ...... 27 2. Physical and chemical properties ...... 27 a. Viscosity ...... 27 b. Calorific value ...... 29 c. Density ...... 31 3. Engine performance tests ...... 32 a. Torque (T ) ...... 33 b. Brake power (bp) ...... 34 c. Mass flow rate (Mf) ...... 34 d. Specific fuel consumption (Sfc) ...... 35
e. Brake thermal efficiency ( ηb)...... 35
CHAPTER 4 – RESULTS AND DISCUSSIONS ...... 36 1. Introduction ...... 36 2. Physical and chemical properties ...... 36 a. Kinemati c viscosity results ...... 36 b. Calorific value results ...... 39 c. Density results ...... 40 d. Conclusion ...... 41 3. Engine performance test ...... 42 4. Economic performance ...... 47
CHAPTER 5 - CONCLUSION AND RECOMMANDATIONS ...... 48
APPENDIX A – REFERENCE ...... 50 APPENDIX B – RESULTS OF THE CALOR IFIC VALUE TEST ...... 52 APPENDIX C – RESULTS OF THE ENGINE PERFORMANCE TESTS ...... 55 APPENDIX D – BIODIESEL VERSUS SVO ...... 58
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LIST OF TABLES
Table 1: Vegetable oils yields ...... 26
Table 2: Kinematic viscosity results in centistokes ...... 38
Table 3: Calorific value results ...... 40
Table 4: Density results ...... 41
Table 5: Sum mary of physical and chemical properties tests ...... 41
Table 6: Cost in Ghana as April 25th, 2006 ...... 47
Table 7: Cost in Burkina Faso as June 13th, 2006 ...... 47
Table 8: Calorific value results - 100% Diesel fuel ...... 52
Table 9: Calorific value results - Blend of cotton oi l (10%) and diesel (90%) ...... 52
Table 10: Calorific value results - Blend of sunflower oil (10%) and diesel (90%) ... 53
Table 11: Calor ific value results - Blend of coconut oil (10%) and diesel (90%) ...... 53
Table 12: Calorific value results - Blend of peanut oil (10%) and diesel (90%) ...... 54
Table 13: Engine performance parameters - 100% Diesel oil ...... 55
Table 14: Engine performance parameters - blend of cotton oil (10%) and diesel
(90%) ...... 55
Table 15: Engine performance parameters - blend of sunflower oil (10%) and diesel
(90%) ...... 56
Table 16: Engine performance parameters - blend of coconut oil (10%) and diesel
(90%) ...... 56
Table 17: Engine performance parameters - blend of peanut oil (10%) and diesel
(90%) ...... 57
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LIST OF FIGURES
Figure 1: Diagram of a bomb calorimeter ...... 29
Figure 2: Variation of kinematic viscosity with temperature for the SVO ...... 37
Figure 3: Variation of the kinematic viscosity with temperature for the blends ...... 38
Figure 4: Calorific value - Variation of temperature with time ...... 39
Figure 5: Graph of thermal efficiency against torque ...... 42
Figure 6: Graph of thermal efficiency against brake power ...... 43
Figure 7: Graph of brake power against torque ...... 44
Figure 8: Graph of mass flow rate against torque ...... 45
Figure 9: Graph of specific fuel consumption against torque ...... 46
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LIST OF PHOTOS
Photo 1: Redwood N°1 Viscometer at the Mechanical Engineering Laboratory of
KN UST ...... 28
Photo 2: Front view of the single cylinder diesel engine ...... 32
Photo 3: Back side of the single cylinder diesel engine ...... 32
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ABBREVIATIONS AND ACRONYMS
GEE: Group EIER -ETSHER
KNUST: Kwame Nkrumah University of Science and Technology
UTER: Unité Thématique d’Enseignement et de Recherche
OPEC: Organization of Petroleum Exporting Countries
CV: calo rific value
SVO: straight vegetable oil bp: Brake power
FC: Fuel consumption
Mf: Mass flow rate
Sfc: Specific fuel consumption
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ABSTRACT
The high cost of energy supplies as well as the concern over availability of petroleum which is the main energy sour ce for our modern civilization have made desirable for many countries, especially those of the developing world, to search for alternative energy resources. More and more researches are now performed about vegetable oils and their blends.
The GEE which is an inter -national institution of higher education and research based in Burkina Faso sent a student in Ghana in order to investigate the use of vegetable oils as biofuels in the Mechanical Engineering Laboratory of the KNUST .
This report presents the expe rimental investigation of key properties of f our vegetable oils: cotton oil, sunflower oil, coconut oil and peanut oil. The density, viscosity and calorific values of these oils were determined and results are presented on tests in an unmodified single cyl inder, direct injection, and four -stroke engine .
Blends of vegetable oils and diesel in proportion of 10% / 90% by volume were used on this engine, as well as straight vegetable oils.
All the tests showed that when unheated, these oils could not be used w ith the unmodified engine due to their very high viscosity which is 4 to 6 times greater than that of diesel fuel. However the 10%/90% blends have similar properties than diesel fuel in term of density and viscosity but a slightly lower calorific value . Th ey gave the highest thermal efficiencies and performed better than pure diesel fuel in our short term engine performance tests .
Keywords : Biofuel, diesel, biodiesel, biomass, vegetable oil
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RESUM ÉÉÉ
Le prix élevé de l’énergie et les problèmes de di sponib ilité du pétrole qui est la source principale d’énergie de notre civilisation moderne, emmènent plusieurs pays et spécialement ceux en développement à rechercher des sources alternatives d’énergie. De plus en p lus de recherches sont menées à ce sujet sur l es huiles végétales et de leurs mélanges avec le gasoil.
Le GEE qui est une institution internationale d’enseignement supérieur et de recherche basée au Burkina Faso a envoyé l’un de ses étudiants au Ghana afin d’ étudier l’utilisation des huiles végétales comme biocarburant au Laboratoire de
Génie Mécanique de KNUST. Les études expérimentales des propriétés de quatre huiles sont ici présentées . Il s’agit de l’huile de coton, l’huile de tournesol, l’huile de coco et l’huile d’arachide. La densité, la viscosi té et le pouvoir calorifique de ses huiles sont déterminés et les résultats des tests sur un moteur non modifié à un cylindre, quatre temps et injection directe sont présentés. Des mélanges d e ces huiles végétales et de gasoil en proportion à 10% / 90% par volume ont été utilisés dans ce moteur ainsi que les huiles végétales pures.
Tous les tests ont montré que les huiles, quand elles ne sont pas chauffées , ne pouvaient pas être utilisées avec le moteur non modifié et ceci à cause de leur viscosité élevée d e l’ordre de 4 à 6 fois supérieure à celle du gasoil. Cependant les mélanges à 10% / 90% ont des propriétés similaires à celles du gasoil en terme de densité et de viscosité mais des valeurs calorifiques légèrement plus faibles. Ils donnent de plus grandes valeurs de rendement thermique et des performances meilleures à celles du gasoil dans nos tests à court terme sur le moteur diesel.
Mots clé: biocarburant, diesel, biodiesel, biomasse, huile végétale
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ACKNOWLEDGEMENTS
I wish to express my profound grati tude to my supervisors, Dr F.K. Forson head of the Mechanical Engineering Department at KNUST, Ghana and Pr. Yezouma
Coulibaly head of the Energy and Industrial Engineering UTER at GEE, Burkina Faso for their guidance during the entire duration of this project.
Next, I wish to thank all the KNUST Mechanical Engineering L aboratory technicians, especially Messrs Sampson Anokye Boateng, Samuel Manu Kumah,
Kwadwo Budu Diabene and Edward Samuel Bansah. With their assistance , all the tests have been performed an d they gave me good tutorials about internal combustion engines.
I finally thank Mr. Emmanuel Ramde for his help during my stay in Kumasi and the advice s he provided to me.
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DEDICATION
TO MY FATHER TCHEGNONSI HENRI AND MY MOTHER BONOU JUSTINE I lo ve you so much
TO MY LATE COUSIN TODONOU PATRICK May your soul rest in peace
TO SILLA YAHAYA, YATTARA MOHAMMED CHABI GILBERT AND MY CLASSMATES You proved me your friendship
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CHAPTER 1 ––– GENERAL INTRODUCTION
1. Background The concept of using veg etab le oil as an engine fuel dates back to 1895 when Rudolf
Diesel (1858 -1913) developed the first engine to run on peanut oil, as he demonstrated at the World Exhibition in Paris in 1900. Unfortunately, he died in 1913 before his vision of a vegetable oil powered engine was fully realized.
"The use of vegetable oils for engine fuels may seem insignificant today. But
such oils may become in the course of time as important as the petroleum and
coal tar products of the present time"
Rudolph Diesel, 1912
Thi s idea is nowadays widely shared. The world’s petroleum resources are diminishing at an alarming rate and there is more anxiety about the supply of this precious resource. By the 1970's, most African countries were dependent on foreign oil. Their supply of crude oil, as are all supplies of fossi l fuels, was limited. In 1973 the world experienced the first of two crises. OPEC, the Middle Eastern organization controlling the majority of the oil in the world, reduced supplies and increased prices.
The second o ne came five years later in 1978. From this time the potential of biofuels re -entered the public consciousness. There is also the environment al issue and climate change due to the greenhouse effect which made research to find good substitute to diesel fuel to be intensified.
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2. Scope and objectives The object of this project is to run blends of vegetable oil and diesel fuel in a diesel engine. Main objectives are, therefore
• To determine and compare fuel properties of diesel fuel and the selected
vegetable o ils
• To compare engine performance of vegetable oils and their blends
3. Justification of study Diesel engines are used extensively in rural areas for transportation, electricity generation and for powering machinery. They have a relatively long life and will doubtlessly be a widely utilized power unit for some years to come. This project has an ultimate aim of finding a local substitute to diesel fuel used in these engines.
4. Methodology Data were largely obtained from laboratory experiments. The Mechanical Engi neering
Laboratory of KNUST (Kumasi , Ghana) has the necessary equipments at its disposal.
Therefore the physical and chemical fuel properties were determined there, as well as the engine performance test.
5. Presentation of KNUST Kwame Nkrumah University of Science and Technology is established at Kumasi, the cultural capital of Ghana. The vision of KNUST is to be globally recognised as the premier Centre of excellence in Africa for teaching in Science and Technology for development; producing high calibre gr aduates with knowledge and expertise to support the industrial and socio -economic development of Ghana and Africa.
The mission of KNUST is to provide an environment for teaching, research and entrepreneurship training in Science and Technology for develop ment of Ghana and
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Africa. KNUST will also provide service to the community, be open to all the people of Ghana and positioned to attract scholars, industrialists and entrepreneurs from
Africa and other international communities.
More information about this University can be found at http://www.knust.edu.gh
6. Organization of the report This report has five chapters. Chapter 1 is the general introduction which consists of background statements, scope and objectives, justification of the study, methodology and organization of the report. The literature review is presented in chapter 2. The third chapter deals with the methodology and experimental set -up, details are given about the experiments conducted and the way the results were obtained. A discussion of the experimental result is presented in chapter 4. The last chapter presents conclusions and recommendations.
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CHAPTER 2 ––– LITERATURE REVIEW
1. Fuel properties for diesel engines When using fuels in diesel engine, some important properties concerning these fuels have to be known and measured. They relate to their physical and chemical structure and give an overview on what can be expected from the engine.
Cetane number rates the ignition properties of diesel fuels. It's a measure of a fuel's willingness to igni te when it's compressed. The higher the cetane number, the more efficient the fuel. This parameter should not be too high or too low for perfect combustion in the engine: in case of too high cetane number , combustion can occur before the fuel and air are p roperly mixed, resulting in incomplete combustion and smoke; in case of too low cetane number , engine roughness, misfiring, higher air temperatures, slower engine warm-up and also incomplete combustion occur .
Kinematic v iscosity refers to how easily the fuel flows under gravity . This parameter depends on temperature and is important: if the viscosity is too low, the fuel loses some of its ability to lubricate the fuel injectors. If it is too high, the spray pattern at the injector nozzle tips will be affe cted. This condition can be particularly pronounced at lower temperatures and results in poor burning.
Volatility measures how quickly the fuel forms a vapour at ordinary temperatures . The fuel should be sufficient ly volatile to form a combustible mixtur e ready to self ignite at low temperature. A measure of the volatil ity is given by the
Project report by Landry Tchegnonsi – June 2006 14 Use of vegetable o ils as biofuels – GEE / KNUST flash point which is the lowest temperature at which an ignitable mixture with air can be formed.
The iodine value is an expression of the degree of unsaturation. The higher the iodine value , the more unsaturated the fuel and the higher is its potential to polymerize into a plastic -like solid. In the high temperatures commonly found in internal combustion engines, the process is accelerated and the engine can quickly be come gummed -up and fail.
The calorific value measures the quantity of heat liberated when unit mass of fuel is combusted. That is this heat which is converted in mechanical work by the engine.
The sulphur content indicates how cleanly the fuel is burnt . Oxides of sulphur are released to the atmosphere when it is burnt. These oxides, especially in higher concentrations, represent a hazard to the well -being of vegetation and animal life, including humans. Therefore low sulphur fuel is preferred in diesel engines.
2. Previous works about the use of biofuel in diesel engines Diesel engines have compression ignition: the air is compressed and combustion starts on contact as the fuel is injected into this hot air which is at a high temperature. Because of this, a wide variety of fuels can be used. Environment al issues as well as the increasing cost of petroleum products and their availability made the research about biofuel to be intensified.
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Biofuel is any fuel that derives from biomass (recently living organis ms or their metabolic by -products ). It is a renewable energy source, unlike other natural resources such as petroleum, coal and nuclear fuels. The carbon in biofuels is extracted from atmospheric c arbon dioxide by growing plants. Therefore, burning it does not result in a net increase of carbon dioxide in the Earth's atmosphere. As a result, biofuels are seen by many as a way to reduce the amount of carbon dioxide released into the atmosphere by using them to replace non renewable sources of energy.
There is three ways to run an engine on biofuel using vegetable oils.
• The oil can be used just as it is. It is therefore called straight vegetable oil
(SVO)
• It can be mixed with diesel fuel
• It can be c onverted to biodiesel by a chemical process called trans -
esterification (Appendix D gives more information about the difference
between biodiesel and SVO)
The two first methods are of much interest and m any previous works had been done in the past about them .
a. Straight vegetable oil as fuel source
During World War II, Seddon (1942) [ 7] 1 experimented with using several different vegetable oils in a Perkins P 6 diesel engine with great success. The results of this experiment showed that vegetable oils could be used to power a vehicle under normal operating conditio ns. However, it was noted that much more work
1 Numbers in brackets refer to references in Appendix A
Project report by Landry Tchegnonsi – June 2006 16 Use of vegetable o ils as biofuels – GEE / KNUST was needed before vegetable oils could be used as a reliable substitute for diesel fuel.
Bacon et al. (1981) [7] evaluated the use of several vegetable oils as potential fuel sources. Initial engine performance tests using vegetable oils were found to be acceptable, while noting that the use of these oils caused carbon build up in the combustion chamber. Continuous running of a diesel engine at part-load and mid - speeds was found to cause rapid carbon deposit ion rates on the injector tips. Short
2-hour tests were used to visually compare the effects of using different vegetable oils in place of diesel fuel. Although short-term engine test results were promising,
Bacon recommended long -term engine testing to determine the overall effects of using vegetables oils as a fuel in diesel engines.
Tahir et al. (1982) [ 7] tested sunflower oil as a replacement for diesel fuel in agricultural tractors. Sunflower oil viscosity was 14% higher than diesel fuel at 37 °C.
Engine performance using the sunflower oil was similar to that of diesel fuel, but with a slight decrease in fuel economy. Oxidation of the sunflower oil left heavy gum and wax deposits on test equipment, which could lead to engine failure.
Engler et al. (1983) [ 7] found that engine performance tests using raw sunflower and cottonseed vegetable oils as alternative fuels gave poor results.
Engine performance tests for processed vegetable oils produced results slightly better than similar tests for diesel fuel. However, carbon deposits and lubricating oil
Project report by Landry Tchegnonsi – June 2006 17 Use of vegetable o ils as biofuels – GEE / KNUST contamination problems were noted, indicating that these oils are acceptable only for short-term use as a fuel source.
Over 30 different vegetable oils have been used to operate compression engines since the 1900’s (Quick, 1980) [7]. Initial engine performance suggests that these oil -based fuels have great potential as fuel substitutes. Extended operation indicated that carbonization of critical engine components resulted from the use of raw vegetable o il fuels, which can lead to premature engine failure. Blending vegetable oil with diesel fuel was found to be a method to reduce coking and extend engine life.
Pryde (1982) [7] reviewed the reported successes and shortcomings for alternative fuel research. This article stated that short-term engine tests using vegetable oils as a fuel source was very promising. However, long -term engine test results showed that durability problems were encountered with vegetable oils because of carbon build -up and lubricating oil contamination. Thus, it was concluded that vegetable oils must either be chemically altered or blended with diesel fuel to prevent premature engine failure.
Studies involving the use of raw vegetable oils as a replacement fuel for diesel fuel indicate that a diesel engine can be successfully fuel led with 100% vegetable oil on a short-term basis. However, long -term engine durability studies show that fuelling diesel engines with 100% vegetable oil causes engine failure due to engine oil contamination, stuck piston rings, and excessive carbon build -up on internal
Project report by Landry Tchegnonsi – June 2006 18 Use of vegetable o ils as biofuels – GEE / KNUST engine components. Therefore 100% unmodified vegetable oils are not reasonable diesel fuel replacements.
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b. Vegetable Oil, Diesel Blends as Potential Fuel Sources Deere and Company ( Barsic and Humke , 1981) [7] studied the effects of mixing peanut oil and sunflower oil with diesel fuel in a single cylinder engine. The vegetable oil blends were observed to increase the amount of carbon deposits on the combustion side of the injector tip when compared with 100% diesel fuel. The vegetable oil fuel blends were found to have a lower mass -based heating value than that of diesel fuel. Fuel filter plugging was noted to be a problem when using crude vegetable oils as diesel fuel extenders.
Interna tional Harvester Company ( Fort et al. 1982) [7] reported that cottonseed oil, diesel fuel blends behaved like petroleum -based fuels in short-term performance and emissions tests. The experimental fuels performed reasonably well when standards of judgment were power, fuel consumption, emissions, etc.
However engine durability was an issue during extended use of these fuel blends because of carbon deposits and fuelling system problems.
A project to investigate the feasibility of using palm oil directly as an engine fuel was initiated in 1984 in Malaysia. When compared to diesel, crude palm oil resulted in lower pollution. Sapuan, Masjuki and Azian (1996) [4] continued this work and demonstrated in 1996 that the performance and exhaust gas emissions using pa lm oil and its blends with conventional diesel fuel in stationary diesel engines were comparable with those of conventional diesel. They reported that typical calorific value of palm kernel oil is 38,750 kJ/ kg; density of this fuel is 912 kg/m 3 while the density of gas oil is 830 kg/m 3. There was also a difference for values of specific
Project report by Landry Tchegnonsi – June 2006 20 Use of vegetable o ils as biofuels – GEE / KNUST gravities: 0.875 for palm oil and 0.832 for conventional diesel. This indicated that this oil was heavier than diesel fuel. The kinematic viscosity of palm oil was reported to be 45.2 c entistokes at 40°C and it reduces with increasing temperature. According to
Sapuan et al (1996) , field tr ials in Malaysia on commercial vehicles running on methyl ester of palm oil was successful. They concluded that the physical properties of palm oil were not very different from conventional diesel fuel except that it has a higher specific gravity and viscosity. Economic prospects of palm oil are not yet promising unless efforts are made to reduce the production cost.
Recent works were conduc ted in 2002 by Oduro and Hammond -Donkoh on
Jatropha curcas oil [2] . They noticed that performances of the diesel engine tested were comparable after warm-up with the baseline test for diesel engine. They also noticed that the blend of jatropha curcas oil w ith diesel gave a significant improvement in thermal efficiency and hydrocarbon emission, compared with diesel fuel.
These results were confirmed in 2006 by Asante Lawrence Kyei and Osei
Owusu Martin [3] . They fuelled a single cylinder four -stroke engine with sample of esterified jatropha and blends of esterified jatropha/kerosine . The kinematic viscosity of the esterified jatropha oil was higher than that of diesel fuel but the engine performances were good when it was preheated .
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c. Conclusion From the rese arch done so far, it can be established that vegetable oils are a potential substitute for diesel fuel but there are problems associated with their use .
Short-term engine testing indicates that vegetable oils can readily be used as a fuel source when the v egetable oils are used alone or are blended with diesel fuel. Long term engine research shows that engine durability is questionable when fuel blends contain more than 20% vegetable oil by volume. Especially deposits are observed on the pistons, valves, c ombustion chambers and injectors when these oils are used with an unmodified engine for long period [6] . They are not properly atomized when the fuel injectors spray them into the combustion chamber and they do not combust properly, the injectors get coked up, leading to poor performance, higher exhaust emissions and reduced engine life when they are used for long period. More work is needed to determine if fuel blends containing less than 20% vegetable oil can be used successfully as diesel fuel extenders.
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3. Facts about some vegetable oils a. Cotton oil Cotton is grown primarily for the fibres or lint, but the oil containing seeds are highly important. World production of cotton seed oil averaged 2,673,000 tons in
1964 -66. The cotton plant is a stiff growing he rbaceous annual outside the tropics, with fairly large, lobed leaves. The fruits are capsules which dehisce as they ripen.
The lint and see ds are harvested from the dehisc ed bolls, partly by hand but now largely by machin e. The longer lint is removed from the seeds mechanically at cotton gins, and then baled. The seeds of most varieties are still covered with short fibres or linters after the ginning. The seeds consist about half of hull and half of kernel. The kernels contain 28 to 40% oil. In extracting t he oil the seeds are cleaned, delinted, and pressed or put through expellers either whole or after dehulling. A ton of seeds yields around 136. 08 kilograms of oil. The meal or press cake is a valuable high - protein livestock feed and the cotton fields, afte r the harvest, may be used for livestock pasturage. The oil is used mainly for shortenings. Smaller quantities are used for cooking and salad oils, margarines, and soap manufacture.
b. Sunflower oil Sunflower is native to the western U.S., but principal commercial production of the seed for oil is in other countries, especially Russia. World production of oil averaged near 2,670,000 tons from 1964 to 1966. The plant is a large, rough annual, with a stiff stem up to 304 .80 or 365 .76 centimetres tall. Leaves ar e rough, up to
30 .48 centimetres long. The angular seeds are up to 0.64 centimetres long, and are densely packed in the flat, terminal heads, which may be more than a foot across.
Seeds are exposed in the head during growth. Seeds normally contain about 25 % of
Project report by Landry Tchegnonsi – June 2006 23 Use of vegetable o ils as biofuels – GEE / KNUST the semi-drying oil, but this has been increased by breeding to above 40 % in selections in Russia. Oil is usually expressed by an initial cold press, followed by hot pressing. The cold -press oil is used as a salad and cooking oil and for margarine, the hot -press mainly in industry. The press cake is a very valuable animal feed. Seeds are also consumed as nuts.
c. Coconut oil The coconut palm may reach to 100 feet or more. The leaves are very large, up to 548.64 centimetres long, with leaflets up to 91. 44 centimetres long. The fruits are produced in clusters near the growing tip. They vary in shape, but are generally near globose to oblong, up to a foot or more in length. The nut is encased in a thick, fibrous husk which is persistent and must be cut awa y to expose the nut. The shell is very hard and woody, near 0.25 inch thick. The edible, oily flesh or kernel adheres to the shell, and is about 0.25 inch thick, with a hollow centre which contains a liquid during growth. The dried flesh or meat is the cop ra of commerce, produced in great quantities mainly for its oil.
In preparing copra, the dried meat of the coconut, the nuts are cut in half, the milk drained off, and the nuts are exposed to sun. The partially dried meat contracts and can be readily remov ed from the shell. Further drying reduces the moisture to under 8 percent, necessary to prevent mold growth. Artificial heat is often used for this. The fresh meats contain 30 to 40 % of oil, the dried copra 60 to 70 %. The oil is extracted from the copra by heating and pressing in various types of expellers. The oil is used for margarines and vegetable shortenings. The press cake is used for
Project report by Landry Tchegnonsi – June 2006 24 Use of vegetable o ils as biofuels – GEE / KNUST livestock feed. Crude oil is made into soap. World production of coconut oil is near
2,400,000 tons.
d. Peanut oil The peanut is grown mainly for food and as a source of edible oil, but is also used as forage. When the plants with adhering seeds or nuts are harvested they are stacked to dry before threshing. In dry areas this may be on the ground; but in humid areas, they are stacked around poles with cross pieces to hold the plants off the ground. After threshing to remove the seed pods the straw or hay is valuable livestock feed. The runner varieties of peanuts are sometimes planted to be used as hog feed, in which case h ogs are turned into the fields and root out the seeds, consuming both seeds and tops.
Among edible vegetables oils, peanut oil is exceeded in world production only by soybean. World production of peanut oil, 1964 -66, averaged 3,166,000 tons. In extracting the oil, the cleaned nuts are passed through hullers or shellers to separate the kernels. The kernels, which contain 48 to 56 % of oil, are then crushed, heated and pressed hot in hydraulic presses. The oil is used in the manufacture of margarines and shor tenings, and as a salad and cooking oil. The press cake is used for cattle food.
The following table gives conservative estimates about the vegetable oils yields in the world.
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Typical oil Kg of oil per Litre of oil per Crop extraction f rom 100 hectare hectare kg. of oil seeds (kg) Cotton 273 325 13 Sunflower 800 952 32 Coconut 2260 2689 62 Peanut 890 1059 42 Table 1: Vegetable oils yields
Data above are estimated, crops yields can vary widely.
Project report by Landry Tchegnonsi – June 2006 26 Use of vegetable o ils as biofuels – GEE / KNUST CHAPTER 3 --- EXPERIMENTAL PRO CESS AND THEORY
1. Introduction The experiments described in this thesis have been carried out at the Mechanical
Engineering Laboratory of the KNUST, Kumasi, Ghana. This chapter presents the steps used to determine the parameters related to the selected oils . The tests performed on a diesel engine running with these oils are also explained and described.
2. Physical and chemical properties Four different oils have been selected for their availability: coconut oil, peanut oil, sunflower oil and cotton oil. They were all bought, ready for human consumption, directly at the local market except for the cotton oil which came from Bobo -Dioulasso, Burkina
Faso.
Three parameters were determined, based on the available equipment in the laboratory.
They are density, visc osity and calorific value.
a. Viscosity The kinematic viscosity has been determined using a special apparatus call ed Redwood viscometer. There are two sizes of this equipment: the smaller is said to be N°1 and is designed for light oils; the larger is called N°2 and is used for thicker oils. For our experiment, we used a Redwood N°1 Viscometer . An illustration of this equipment is shown on the next page .
Project report by Landry Tchegnonsi – June 2006 27 Use of vegetable o ils as biofuels – GEE / KNUST
Photo 1: Redwood N°1 Viscometer at the Mechanical Engineering Laboratory of KNUST
Redwood viscometer is based on the principle of laminar flow through capillary tube of standard dimension (1.6 mm bore and 10 mm long) under falling head. The viscometer consists of a vertical cylinder with an orifice at the centr e of the base of inner c ylinder.
The cylinder is surrounded by a water bath, which can maintain temperature of the liquid to be tested at required temperature. The water bath is heated by electric heater. The cylinder, which is filled up to fixed height with liquid whose viscosit y is to be determined is heated by water bath to the desired temperature. The orifice is opened and the time required to pass 50 ml of oil at the desired temperature is noted. The viscosity is then quoted as n seconds Redwood N°1 at this temperature. The u sual reference temperature is 100°F which is equivalent to 37.8°C. In the International System of Units (the SI - system), the theoretical unit is m 2/s or commonly used Stoke (St) where 1 St = 10 -4 m2/s. The conversion factor is given roughly by the followin g formula
Project report by Landry Tchegnonsi – June 2006 28 Use of vegetable o ils as biofuels – GEE / KNUST
1.88 υ = 0.0026t − t
Where,
υ is the kinematic viscosity in Stokes
t is the time in seconds to discharge 50 ml of oil through the capillarity tube
To appreciate the influence of temperature variation, the oil is tested at various temperatures, starting with the room temperature and at increment of 10°C. A graph of
Redwoods seconds against temperature is then plotted for better appreciation.
b. Calorific value This experiment involves the determination of the quantity of heat liberated w hen unit mass of fuel is combusted in a bomb calorimeter.
Figure 1: Diagram of a bomb calorimeter
Project report by Landry Tchegnonsi – June 2006 29 Use of vegetable o ils as biofuels – GEE / KNUST Th e apparatus is composed of a sturdy stainless bomb ( A) which is immersed in water ( B) in a metal bucket called the calorimeter vessel ( C). The apparatus contains a thermometer
(D) to measure the temperature of the water and a stirrer ( E) to insure uniform temperature throughout the system, and is insulated from the surroundings by two air spaces ( F) and a non -conducting shell ( G).
Additional devices are usually connected to this apparatus: a firing box connected to the top cover of the bomb by the mean of two electrical leads, a stirring gear used to move the stirrer at a continuous rate, and a n electronic timer .
The general metho d for this experiment follows these steps:
• The calorimeter vessel is weighed and about 2400 ml of water is added. The
calorim eter vessel is then reweighed to determine the correct weight of water
• An empty crucible is weighed and approximately 0.7 gram of o il is added in it. The
crucible is then reweighed to determine the correct weigh of oil
• the crucible is positioned with oil therein, in the seating of the bomb cover and a
suitable piece of ignition wire (a platinum wire) is attached across the terminals,
but touching the oil surface
• 15 ml of distilled water is poured into the base of the bomb and it is charged with
oxygen to 25 atmospheres to assist the combustion
• The bomb is set in place in the calorimeter vessel; the electrical leads, stirrer and
thermom eter are connected, and the stirring gear is set in motion
• The thermometer readings are observed and noted at one minute intervals for a
preliminary period of five minutes, and then the firing circuit is completed. The
thermometer readings are still noted at one minute intervals until the maximum
temperature is attained. After that, the temperature is observed for a further five
minutes at one minute intervals.
Project report by Landry Tchegnonsi – June 2006 30 Use of vegetable o ils as biofuels – GEE / KNUST After these steps some calculations are necessary to complete the experiment. The calorific valu e is obtained by the following formula
Wf ⋅ Q = (Ww + Wa )× T × 4.2
Where,
∆T is called the rise in temperature and is obtained by plotting the
temperature reading against time
Wf is the weigh of fuel expressed in kg
Q is the calorific value expressed in k J/kg
Ww is the weight of water in the calorimeter vessel
Wa is the water equivalent of the ap paratus (is given equal to 0.482 kg)
c. Density The oils density measurement was done with a 50 ml graduated flask. This flask was weighed on an electronic scale. E ach vegetable oil was transferred from container to a different 300 ml bottle and these bottles were used to fill the flas k such that the bottom of the meniscus is at the graduation mark. The flask's weight was then measured again .
After each use, the flas k was emptied and dried. All measurement s were made at room temperature and the density at this temperature is obtained by
m ρ = V
Where, ρ is the density in kg/m 3
m is the oil mass in kg V is the volume of oil in m 3
Project report by Landry Tchegnonsi – June 2006 31 Use of vegetable o ils as biofuels – GEE / KNUST 3. Engine performance tests The engine performance test work based at the KNUST had involved an experimental installation which consists of a single cylinder diesel engine.
Photo 2: Front view of the single cylinder Photo 3: Back side of the single cylinder diesel engine diesel engine
It is an air -cooled, direct injection, four -stroke engine. The fuel supply system was a manual one and was composed of a fuel tank connected to a graduated test tube by a transparent rubber tube and another rubber tube going from the test tube to the injection pump. A hand operated, two -positional directional control valve allows rapid switching between the tank and the test tube in one hand to fill it, and in th e other hand between the test tube and the injection pump to feed it under gravity.
Project report by Landry Tchegnonsi – June 2006 32 Use of vegetable o ils as biofuels – GEE / KNUST
Others tests involved usage of a dynamometer coupled to a spring balance to load the engine at increments of 1 kg to a maximum load of 5 kg. Before starting to load the en gine, the torque radius arm was determined directly on the engine, using a graduated ruler. At each loading, the following parameters were measured:
• The speed of the shaft , using a hand held tachometer
• The time taken for 5 cm 3 of fuel to flow through the t est tube, using a
stopwatch
Some calculations were therefore necessary to get a number of physical terms used to discuss the engine performance and they are summarized below.
a. Torque (((T ))) The torque is a rotating force being produced at a distance. It is given by
d T = ()W S ×− 2
Where,
W is the weight in N (Newton) = load (kg) x 9.81 m2/s
S is the spring balance reading = 8.025 N
d is the diameter of the dynamometer
Project report by Landry Tchegnonsi – June 2006 33 Use of vegetable o ils as biofuels – GEE / KNUST b. Brake power (((bp ))) The brake power is the measured output of the engine. It is g iven in kW by the following formula
2 ⋅ π ⋅ N ⋅ T bp = 60000
Where,
T is the torque (in Nm) measured at the output shaft
N is the speed of the engine (in rpm)
c. Mass flow rate (((Mf ))) The mass flow rate indicates t he fuel consumption in kg/h and is given by
3600 × FC × ρ Mf = 1000
Where,
FC is the fuel consumption in cm 3/s
ρ is the density of fuel in g/cm 3
Project report by Landry Tchegnonsi – June 2006 34 Use of vegetable o ils as biofuels – GEE / KNUST d. Specific fuel consumption (Sfc) The specific fuel consumption is the mass flow rate consumed per unit power output expressed in kg/kW .h and given by
Mf Sfc = bp
Where,
Mf is the mass flow rate in kg/h
bp is the brake power in kW
e. Brake thermal efficiency ( ηηηbbb))) The brake thermal efficiency is the overall efficiency of the engine and it relates the maximum availabl e heat energy in the fuel to the heat equivalent of the brake power that the engine produces. It is given by the following formula
3600 ⋅ bp η = b Mf ⋅ Q
Where,
bp is the brake power in kW,
Mf is the mass flow rate in kg/h
Q is the fuel calorific valu e in kJ/kg Project report by Landry Tchegnonsi – June 2006 35 Use of vegetable o ils as biofuels – GEE / KNUST CHAPTER 4 ––– RRRESULTS AND DISCUSSIONS
1. Introduction The chemical and physical properties of the straight vegetable oils were determined by and they were tested in the diesel engine described in chapter 3. The engine started to run with the unhea ted oils but quickly stopped. Test runs were, therefore, carried on blends of diesel fuel and the vegetable oils, in the proportion of 90% of diesel fuel and
10% of vegetable oil ( We knew from the literature that engine durability is questionable when fuel blends contain more than 20% vegetable oil by volume). This chapter presents the properties of the oils, the performances of the engine and discusses some problems faced during the experimentation.
2. Physical and chemical properties a. Kinematic v iscosity re sults The kinematic viscosity varies with temperature: the higher temperature, the lower viscosity. The following graph shows this variation for the vegetable oils tested.
Project report by Landry Tchegnonsi – June 2006 36 Use of vegetable o ils as biofuels – GEE / KNUST
Figure 2: Variation of kinematic viscosity with temperat ure for the SVO
Blending these oils with diesel fuel in proportion of 90% diesel and 10% oil was a way to reduce this high viscosity: all the values were then slightly lower than that of diesel fuel as it is shown in the following graph .
Project report by Landry Tchegnonsi – June 2006 37 Use of vegetable o ils as biofuels – GEE / KNUST
Figure 3: Variation of the kinematic viscosity with temperature for the blends
The Redwood seconds obtained by experimentation were converted to centistokes and the kinematic viscosity is given at the usual reference temperature (100°F which i s equal to
37.8°C) in table 2
Kinematic viscosity at 37.8°C (cSt) Diesel fuel 5.91 Cotton oil 39.63 Sunflower oil 37.02 Coconut oil 29.41 Peanut oil 45.84 Blend of cotton oil (10%) and diesel (90%) 4.63 Blend of sunflower oil (10%) and diesel (90% ) 4.99 Blend of coconut oil (10%) and diesel (90%) 4.63 Blend of peanut oil (10%) and diesel (90%) 5.01 Table 2: Kinematic viscosity results in c entistokes
Project report by Landry Tchegnonsi – June 2006 38 Use of vegetable o ils as biofuels – GEE / KNUST The kinematic viscosity of the vegetable oils were also far above that o f diesel fuel. They were 4 to 7 times greater, so these oils would not easily flow through the engine and thus they would not be well atomized by the injection system. That would result in poor or incomplete burning in the engine combustion chamber and it would explain why the engine could not run with these unheated oils during the engine performance test. After being mixed with diesel fuel all the values moved down and the kinematic viscosity of the blends were around the value of that of diesel fuel.
b. CCCaCaaalorific value results The graph below show s the variation of temperature with time. The analytical values are presented in appendix C . From this, the rise in temperature was obtained and therefore the calorific values have been computed.
Figure 4: Calorific value - Variation of temperature with time
Project report by Landry Tchegnonsi – June 2006 39 Use of vegetable o ils as biofuels – GEE / KNUST All straight vegetable oils were not able to burn in the bomb calorimeter. We suspected water to be present in them but even after been boiled, there was no result. This suggests th at these oils are more resistant to ignition than diesel fuel. However the tests were successful with the blends and calorific values obtained from them where lower than that of diesel fuel as it is noticed in the following table which summarizes the resul ts.
Calorific value (kJ/kg)
Diesel fuel 44962
Cotton oil 39468(*)
Sunflower oil 41883 (*)
Coconut oil 39814 (*)
Peanut oil 41861 (*)
Blend of cotton oil (10%) and diesel (90%) 33592
Blend of sunflower oil (10%) and diesel (90%) 40622
Blend of coconut oil (10%) and diesel (90%) 35715
Blend of peanut oil (10%) and diesel (90%) 38279
Table 3: Calorific value results
c. Density results Table 4 presents values of density for the oils and their blends with diesel. It is noticed th at all the vegetable oils tested had a high density, higher than the diesel fuel one. That means that equal volumes of these oils are heavier that diesel fuel. However, when they are blended with diesel fuel, the density falls within reasonable range and they have almost the same value than that of diesel fuel.
Project report by Landry Tchegnonsi – June 2006 40 Use of vegetable o ils as biofuels – GEE / KNUST
Density at 27.5°C (kg/m 3) Diesel fuel 846 Cotton oil 913 Sunflower oil 916 Coconut oil 918 Peanut oil 910 Blend of cotton oil (10%) and diesel (90%) 842 Blend of sunflower oil (10%) and di esel (90%) 844 Blend of coconut oil (10%) and diesel (90%) 840 Blend of peanut oil (10%) and diesel (90%) 852
Table 4: Density results d. Conclusion The experiments have shown that the straight vegetable oils have higher density an d kinematic viscosity that diesel fuel. But when they are blended in the proportion of 10% of oil and 90% of diesel fuel, the above properties mentioned are comparable with that of diesel fuel. Table 5 summarizes all the results.
Density at Kinematic Calorific 27.5°C viscosity at value (kg/m 3) 37.8°C (cSt) (kJ/kg)
Diesel fuel 846 5.91 44962
Cotton oil 913 39.63 -
Sunflower oil 916 37.02 -
Coconut oil 918 29.41 -
Peanut oil 910 45.84 -
Blend of cotton oil (10%) and diesel (90%) 842 4.63 33592
Blend of sunflower oil (10%) and diesel (90%) 844 4.99 40622
Blend of coconut oil (10%) and diesel (90%) 840 4.63 35715
Blend of peanut oil (10%) and diesel (90%) 852 5.01 38279
Table 5: Summary of physical and chemical properties te sts
Project report by Landry Tchegnonsi – June 2006 41 Use of vegetable o ils as biofuels – GEE / KNUST 3. Engine performance test The engine performance tests were performed in a single cylinder, four -stroke diesel engine and the different results are shown in tables 13 to 17 in appendix C. From these analytical values, some graphs had been p lotted for be tter interpretatio n.
Figure 5: Graph of thermal efficiency against torque
The figure above shows the variation of thermal efficiency with torque, when the engine is loaded. In each case, thermal efficiency increases with inc reasing torque and all the blends gave higher value of thermal efficiency than that of pure diesel fuel. The highest ones are observed for the blends of cotton oil and diesel and coconut oil and diesel. It can be noticed that these two blends have the lowe st calorific value s.
Project report by Landry Tchegnonsi – June 2006 42 Use of vegetable o ils as biofuels – GEE / KNUST
Figure 6: Graph of thermal efficiency against brake power
The variation of thermal efficiency of the diesel engine with the brake power is shown in the graph above. For all the fuels used during this te st, the thermal efficiency increases with increasing brake power. Once again, the blends of cotton oil and diesel and coconut oil and diesel had the higher thermal efficiency .
Project report by Landry Tchegnonsi – June 2006 43 Use of vegetable o ils as biofuels – GEE / KNUST
Figure 7: Graph of brake power against torque
All the fuels used gave almost the same variation in the graph shown above. The nature of these curves suggests that for these fuels there is a linear variation between brake power and the torque applied to the engine. The highest brake power is obtained for the blends of cotton oil and diesel and sunflower oil and diesel, but their values are only slightly above the other ones .
Project report by Landry Tchegnonsi – June 2006 44 Use of vegetable o ils as biofuels – GEE / KNUST
Figure 8: Graph of mass flow rate against torque
The variation of mass flow rate with the torque of the engine is presented in the graph above. It is noticed that the mass flow rate increases with the increasing torque and the curve for the pure diesel fuel is clearly above the other ones. That implies that the highest mass flow rate was always reached f or the diesel fuel .
Project report by Landry Tchegnonsi – June 2006 45 Use of vegetable o ils as biofuels – GEE / KNUST
Figure 9: Graph of specific fuel consumption against torque
The results for the variation in the brake specific fuel consumption with increasing torque on the engine for the fuels are shown in the figure above. All the curves move in the same manner: the specific fuel consumption decrease with increasing torque on the engine . This decrease is higher for small loads and is almost constant for heavier loads. It may be due to the high thermal efficiency of t he engine at high loads .
Project report by Landry Tchegnonsi – June 2006 46 Use of vegetable o ils as biofuels – GEE / KNUST 4. Economic performance Four different oils have been selected for their availability: coconut oil, peanut oil, sunflower oil and cotton oil. They are all edible, so they had been bought directly at the local market except for the c otton oil which came from Burkina Faso. The following tables indicate the cost of fuel per litre at Kumasi (Ghana) and Ouagadougou (Burkina Faso) .
Fuel Cost per litre in cedi (¢) Diesel 6400 Cotton oil - Sunflower oil 22000 Coconut oil 21000 Peanut oil 36000
Table 6: Cost in Ghana as April 25th, 2006
Fuel Cost per litre in francs CFA Diesel 603 Cotton oil 700 Sunflower oil 1190 Coconut oil - Peanut oil 1175
Table 7: Cost in Burkina Faso as June 13th, 2006
It is noticed from the table s that vegetable oils are more expensive than diesel fuel. This was predictable since these oils are edible and their costs included the package and other cost such as those related to transportation .
We can h ypothesize that costs would have be en lower if the extraction methods are improved and if the oils are locally produced .
Project report by Landry Tchegnonsi – June 2006 47 Use of vegetable o ils as biofuels – GEE / KNUST CHAPTER 5 --- CCCONCLUSION AND RECOMMANDATIONS
At the start of the project under discussion, two engines were available: a single cylind er engine and a four cylinders engine. The last one required a continuous flow of water to work but there was a serious lack in the laboratory. Therefore, only the single cylinder engine had been used.
The performance of the engine upon using blends of veg etable oils and diesel as compared to pure diesel fuel is very acceptable. There is improvement in thermal efficiency and the brake power is comparable with diesel fuel. All the blends of vegetable oils and diesel require no preheating to start the engine. This suggests that they are sufficiently volatile to be directly used with the engine. But, the physical and chemical properties of the straight vegetable oils, especially their kinematic viscosity which were too high, prevent them to make the engine run properly when they are not heated before being injected into the engine combustion chamber.
The high costs of vegetable oils compared to diesel fuel make them economically not viable for use as diesel substitute, especially in rural areas in Africa. Howeve r, blending them could reduce the cost and be a more interesting alternative.
As student from a French -speaking country and in the field of rural engineering, this study was of great interest. Even if we spent a lot of time at the earlier stage of this s tudy in tutorials and basic principles of diesel engines , it was necessary for a good understanding of the experiments. As a counterpart, we were not able to carry out tests about blends of vegetable oils and diesel in other proportions. We only focus in t he proportion of 10% of vegetable oils and 90% of diesel, since we knew from the literature
Project report by Landry Tchegnonsi – June 2006 48 Use of vegetable o ils as biofuels – GEE / KNUST that long term engine research show ed that engine durability is questionable when fuel blends contain more than 20% vegetable oil by volume.
From the study, it can be recommended that
• Further test on blends of vegetable oils and diesel in various proportions by
volume should be carried out for each oil to get the optimal blend in term of
efficiency
• Further test on preheating the vegetable oils before using them shou ld be
carried out
• The long term effect of running these vegetable oils and their blends on engine
performance should be studied ; especially in term of corrosion and wear
Project report by Landry Tchegnonsi – June 2006 49 Use of vegetable o ils as biofuels – GEE / KNUST APPENDIX A --- REFERENCE
1- Performance of jatropha oil blends in a diesel engine , by F.K. Forson, E.K. Oduro and E. Hammond -Donkoh , ELSEVIER - Renewable Energy 29
2- Experimental studies on a stationary single cylinder diesel engine run on blends of Jatropha oil and diesel, by Evans Hammond -Donkoh , Internal Report KNUST
3- Experimenta l investigation of the use of esterified jatropha oil and blends of esterified jatropha/kerosene in a single cylinder engine, by Asante Lawrence Kyei and Osei Owusu Martin , Internal Report KNUST
4- The use of palm oil as a diesel substitute, by S.M. Sapu an, H.H. Masjuki and A. Azian , Journal of Power and Energy, IMechE 1996
5- Biomass -based fuels for diesel engines, by J.M Cruz, A.S. Ogunlowo , W.J. Chancellor and J.R. Goss , Presented at the Pacific Region Annual Meeting AMERICAN SOCIETY OF AGRICULTURAL ENGINEERS, March 18 -20, 1980
6- Coconut oil as a biofuel in Pacific Islands – Challenges and opportunities, by Jan Cloin
7- Using Unmodified Vegetable Oils as a Diesel Fuel Extender, by Sam Jones and Charles L. Peterson
8- The redwood Viscometer, by W.H.Herschel , Technology Papers of the Bureau of Standards, Washington, August 5, 1921
Project report by Landry Tchegnonsi – June 2006 50 Use of vegetable o ils as biofuels – GEE / KNUST
9- http://journeytoforever.org/biodiesel_svo.html
10 - http://journeytoforever.org/biodiesel_yield.html
10 - http://renewable -energy -source.info/bio fuel .htm
10 - ht tp://www. wikipedia.org
11 - http://www.hort.purdue.edu/newcrop/default.html
Project report by Landry Tchegnonsi – June 2006 51 Use of vegetable o ils as biofuels – GEE / KNUST APPENDIX B ––– RESULTS OF THE CALORIFIC VALUE TEST
Temperature (°C) Time (m inute ) First test Second test 0 29 .6 31 .5 1 29 .6 31 .5 2 29 .6 31 .5 3 29 .6 31 .5 4 29 .6 31 .5 5 29 .6 31 .5 6 32 .0 33 .6 7 33 .2 34 .8 8 33 .7 35 .1 9 33 .8 35 .2 10 33 .9 35 .2 11 33 .9 35 .2 12 33 .9 35 .2 13 33 .9 35 .2 14 33 .9 35 .2 15 33 .9 35 .2
Table 8: Calorific value results - 100% Diesel fuel
Temperature (° C) Time (minute) First test Second test 0 30 .4 27 .8 1 30 .4 27 .8 2 30 .4 27 .8 3 30 .4 27 .8 4 30 .4 27 .8 5 30 .4 27 .8 6 32 .3 29 .5 7 32 .8 30 .2 8 32 .9 30 .3 9 32 .9 30 .4 10 32 .9 30 .4 11 32 .9 30 .4 12 32 .9 30 .4 13 32 .9 30 .4 14 32 .9 30 .4 15 32 .9 30 .4
Table 9: Calorific value results - Blend of cotton oil (10%) and diesel (90%)
Project report by Landry Tchegnonsi – June 2006 52 Use of vegetable o ils as biofuels – GEE / KNUST
Temperature (°C) Time (minute) First test Second test 0 34.0 32 .1 1 34.0 32 .1 2 34.0 32 .1 3 34.0 32 .1 4 34.0 32 .1 5 34.0 32 .1 6 35.0 34 .0 7 35.1 34 .5 8 35.2 34 .6 9 35.2 34 .7 10 35.2 34 .7 11 35.2 34 .7 12 35.2 34 .7 13 35.2 34 .7 14 35.2 34 .7 15 35.2 34 .7
Table 10 : Calorific value results - Blend of sunflower oil (10%) and diesel (90%)
Temperature (°C) Time (m inute ) First test Second test 0 32.7 34 .3 1 32.7 34 .3 2 32.7 34 .3 3 32.7 34 .3 4 32.7 34 .3 5 32.7 34 .3 6 34.2 36 .2 7 34.5 36 .7 8 34.7 36 .9 9 34.7 36 .9 10 34.7 36 .9 11 34.7 36 .9 12 34.7 36 .9 13 34.7 36 .9 14 34.7 36 .9 15 34.7 36 .9
Table 11 : Calorific value results - Blend of coconut oil (10%) and diesel (90%)
Project report by Landry Tchegnonsi – June 2006 53 Use of vegetable o ils as biofuels – GEE / KNUST
Temperature (°C) Time (m inute ) First test Second test 0 37.5 36 .1 1 37.5 36 .1 2 37.5 36 .1 3 37.5 36 .1 4 37.5 36 .1 5 37.5 36 .1 6 39.3 37 .7 7 39.9 38 .3 8 40 .0 38 .4 9 40.0 38 .5 10 40.0 38 .5 11 40.0 38 .5 12 40.0 38 .5 13 40.0 38 .5 14 40.0 38 .5 15 40.0 38 .5
Table 12 : Calorific value results - Blend of peanut oil (10%) and diesel (90%)
Project report by Landry Tchegnonsi – June 2006 54 Use of vegetable o ils as biofuels – GEE / KNUST APPENDIX C ––– RESULTS OF THE ENGINE PERFORMA NCE TESTS
Load Torque Speed Brake Time Fuel Mass Specific fuel Brake (N) (Nm) (rpm) power (s) consumption flow consumption thermal (kW) (cm 3/s) rate (kg/kW. h) efficiency (kg/h) (%) 9,81 0,2053 1480 0,0318 35,47 0,14096 0,42932 13,49445 0,5995 19,62 1,3334 1460 0,2039 30,91 0,16176 0,49266 2,41654 3,3477 29,43 2,4616 1400 0,3609 29,94 0,16700 0,50862 1,40936 5,7401 39,24 3,5897 1380 0,5188 26,16 0,19113 0,58211 1,12211 7,2095 49,05 4,7179 1340 0,6620 26,06 0,19186 0,58434 0,88265 9,1655
Table 13 : Engine performance parameters - 100% Diesel oil
Load Torque Speed Brake Time Fuel Mass Specific fuel Brake (N) (Nm) (rpm) power (s) consumption flow consumption thermal (kW) (cm 3/s) rate (kg/kW .h) efficiency (kg/h) (%) 9,81 0,2067 1480 0,0320 39,1 0,12788 0,38771 12,10191 0,8856 19,62 1,3349 1420 0,1985 34,72 0,14401 0,43662 2,19965 4,8721 29,43 2,4630 1400 0,3611 32,75 0,15267 0,46289 1,28190 8,3602 39,24 3,5912 1390 0,5227 30,94 0,16160 0,48997 0,93732 11,4336 49,05 4, 7193 1390 0,6869 29,97 0,16683 0,50583 0,73634 14,5544
Table 14 : Engine performance parameters - blend of cotton oil (10%) and diesel (90%)
Project report by Landry Tchegnonsi – June 2006 55 Use of vegetable o ils as biofuels – GEE / KNUST
Load Torque Speed Brake Time Fuel Mass Specific fuel Brake (N) (Nm) (rpm) power (s) consumption flow consumption thermal (kW) (cm 3/s) rate (kg/kW. h) efficiency (kg/h) (%) 9,81 0,2067 1430 0,0310 37,56 0,13312 0,40428 13,06027 0,6786 19,62 1,3349 1410 0,1971 37,06 0,13492 0,40974 2,07883 4,2630 29,43 2,4630 1400 0,3611 35,28 0,14172 0,4 3041 1,19195 7,4350 39,24 3,5912 1380 0,5190 32,32 0,15470 0,46983 0,90531 9,7891 49,05 4,7193 1380 0,6820 30,88 0,16192 0,49174 0,72102 12,2911
Table 15 : Engine performance parameters - blend of sunflower oil (10%) and diesel (90%)
Load Torque Speed Brake Time Fuel Mass Specific fuel Brake (N) (Nm) (rpm) power (s) consumption flow consumption thermal (kW) (cm 3/s) rate (kg/kW .h) efficiency (kg/h) (%) 9,81 0,2067 1400 0,0303 41,1 0,12165 0,36788 12,13910 0,8304 19,62 1, 3349 1390 0,1943 37,81 0,13224 0,39989 2,05809 4,8976 29,43 2,4630 1380 0,3559 36,16 0,13827 0,41814 1,17476 8,5803 39,24 3,5912 1360 0,5114 33,22 0,15051 0,45515 0,88992 11,3266 49,05 4,7193 1345 0,6647 33,11 0,15101 0,45666 0,68701 14,6719
Table 16 : Engine performance parameters - blend of coconut oil (10%) and diesel (90%)
Project report by Landry Tchegnonsi – June 2006 56 Use of vegetable o ils as biofuels – GEE / KNUST
Load Torque Speed Brake Time Fuel Mass Specific fuel Brake (N) (Nm) (rpm) power (s) consumption flow consumption thermal (kW) (cm 3/s) rate (kg/kW .h) efficiency (kg/h) (%) 9,81 0,2067 1400 0,0303 39,56 0,12639 0,38785 12,79783 0,7349 19,62 1,3349 1390 0,1943 36,13 0,13839 0,42467 2,18559 4,3030 29,43 2,4630 1380 0,3559 32,25 0,15504 0,47576 1,33663 7,0361 39,24 3,5912 1360 0,5114 31,75 0,15748 0,483 25 0,94486 9,9535 49,05 4,7193 1340 0,6622 30,84 0,16213 0,49751 0,75126 12,5186
Table 17 : Engine performance parameters - blend of peanut oil (10%) and diesel (90%)
Project report by Landry Tchegnonsi – June 2006 57 Use of vegetable o ils as biofuels – GEE / KNUST APPENDIX D ––– BIODIESEL V ER SSSUS SVO
What is biodiesel?
Biodie sel is the name for a variety of ester -based fuels (fatty esters) generally defined as the monoalkyl esters made from vegetable oils, such as soybean oil, canola or hemp oil, or sometimes from animal fats through a simple transesterification process. This renewable source is as efficient as petroleum diesel in powering unmodified diesel engine.
Biodiesel v ersus SVO
Biodiesel has some clear advantages over SVO : it works in any diesel engine, without any conversion or modifications to the engine or the fuel system. Biodiesel is non - toxic , biodegradable and it is a clean, safe, ready -to -use, alternative fuel, whereas it's fair to say that many SVO systems are still experimental and need further development . It reduces the emission of harmful pollutants (mainl y particulates) from diesel engines (80% less CO 2 emissions, 100% less sulphur dioxide) but emissions of nitrogen oxides
(precursor of ozone) are increased. Biodiesel has a high cetane number (above 100, compared to only 40 for diesel fuel). The high cetan e numbers of biodiesel contribute to easy starting and low idle noise. Biodiesel replaces the exhaust odour of petroleum diesel with a more pleasant smell of popcorn or French fries. The use of biodiesel can extend the life of diesel engines because it is more lubricating and, furthermore, power output are relatively unaffected by biodiesel. Unlike SVO, it's backed by many long -term tests in many countries, including millions of miles on the road.
On the other hand, biodiesel can be more expensive, dependin g how much you make, what you make it from and whether you're comparing it with new or used oil (and on where you live). And, unlike SVO, it has to be processed first.
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