TABLE OF CONTENTS
Title Page……………………………………………………………………………i.
Certification Page…………………………….……………………………………..ii.
Dedication……………………………………………………………………….….iii.
Acknowledgement…………………………………………………………………..iv.
Abstract………………………………………………………………………………v.
Table of contents………………………………………………………………..……vi.
List of Tables……………………………………………………………………..…ix.
List of graphs………………………………………………………………..……….x
List of Figures……………………………………………………………………….x
List of Abbreviations………………………………………………………………..xi
CHAPTER ONE: INTRODUCTION………………………………………………1.
1.1. Avocado fruit…………………………………..………………………..………27.
1.1.1 Cultivars and Varieties………………………..……………………………….36.
1.1.2. Taxonomy of Avocado……………………………………………………….30.
1.1.3. Description of the avocado fruit pulp oil…………………………………….31
1.2. Biodiesel and other fuels………………………………………………………31.
1.2. Biodiesel production…………………………………………………………………..32.
1.2.1. Transesterification process……………………………………………………33.
1.2.2. Catalysts for biodiesel production………………………………..……………36.
1.2.3. Types of Biofuels……………………………………………………………37.
1.2.4. Alcohols used in biodiesel production………………………………………..39.
1.2.5 Biodiesel standard fuel properties………….….………….………………….40
1.2.6 Uses of biodiesel co-product: glycerol………………..………………………42
1.6. Aim and Specific Objectives of the Study………………………………………42
1.6.1. Aim of the Study………………………………………………………………42
1.6.2. Specific Research Objectives……..……………..……………………………42
CHAPTER TWO: MATERIALS AND METHODS
2.1. Materials………………….………………………………..…………………….44
2.1.1. Instruments/Equipment………….………………………….………………….44
2.1.2. Chemicals…………………………………….…………………………….…45
2.1.3. Samples……………………………………….………..……………………..46
2.2. Methods…………………………………….…………………………………..46
2.2.1. Preparation of reagents……………….……………………………..……….46
2.2.2. Preparation of avocado fruit for oil extraction…….……..…………………..47
2.2.3. Extraction of the avocado pulp oil………..…….…..…………………..……47
2.2.4. Characterization of the samples…………………..………………….….……..48
2.2.4.1. Determination of the Physical properties of the samples…………….…….48
2.2.4.2.Determination of Chemical properties ………………………………………54.
2.2.5.5 Production of biodiesel from the avocado pulp oil…………………………58
CHAPTER THREE: RESULTS
3.1. Estimation of percentage yield of avocado pulp oil (APO)…………………..60
3.2. Characterization of avocado pulp oil (APO)………………………………60
3.2.1. Physical properties …………………………………………………………..60
3.2.2. Chemical properties……………………………………………………………61
3.3. Gas chromatography analysis of APO………………….……………………….63
3.4. The APO biodiesel production……………………….……………………….64
3.5. Characterization of the APO biodiesels…………………………………………64.
3.5.1. Physical properties…………………………………………………………65
3.5.2. Chemical properties…………………………………………………………….65
3.6. Gas chromatography analysis of methyl ester…………….…………………….66
3.7. Gas chromatography analysis of ethyl ester……………………………………..67
3.8. Comparative analysis of the fuel properties……………………………………70
CHAPTER FOUR: DISCUSSION
4.1. Discussion………………………………………………………………………72
4.2 Conclusion……………………………………………………………………
REFERENCES……………………………………………….………………….….80
LIST OF TABLES
Table 1: Average weight percentage (%) yield of avocado pulp oil….…………58.
Table 2: Physical properties of the avocado pulp oil (APO) in average values….59.
Table 3: Chemical properties of the APO in average values………….………….60.
Table 4: Components of the avocado pulp oil analysed…………………………61.
Table 5: Average percentage (%) yield of the methyl and ethyl esters………….63.
Table 6: Physical properties of the methyl and ethyl esters……………………..64.
Table 7: Chemical properties of the methyl and ethyl esters……………………65.
Table 8: Components of the APO methyl esters………………………………..66.
Table 9: Components of the APO ethyl esters………………………………….67.
Table 10: Comparison of fuel properties of the APO methyl and ethyl esters with petrodiesel and biodiesel standards………………………………………………70.
LIST OF FIGURES
Figure 1: Pictorial view of avocado fruit………………………………….29.
Figure 2: Biodiesel processing flow diagram…………………………….33.
Figure 3: Transesterification of TAG to yield FAAE…………………….35.
Figure 4: Saponification taking place as a side reaction when a basic
catalyst is used for feedstocks high in FFA………………………………37.
Figure5: Hydrolysis of biodiesel to yield FFA and methanol…….……….37.
Figure 6: Chromatogram of avocado pulp’s oil (APO)……………..……..62.
Figure 7: Chromatogram of the methyl ester………………………….….68.
Figure 8: Chromatogram of the ethyl ester… .………………………..…..69.
LIST OF ABBREVIATIONS
APO Avocado pulp’s oil.
| A.V. Acid Value. | |
| ASTM American Standard Testing and Materials.
CN Cetane number. |
|
| DAG Diacylglycerol.
DME Dimethyl ether DMF 2,5 Dimethylfuran D.P.F. Diesel particulate filter E.G.R. Exhaust gas recirculation system. E.P.A. Environmental protection agency. |
|
| EN European biodiesel standard. | |
| FAAE Fatty acid alkyl esters. | |
| FAEE Fatty Acid Ethyl Esters. | |
| FAME Fatty Acid Methyl Esters. | |
| FAO Food and agricultural Organization. | |
| FFA Free fatty acid. | |
| F.K.M. Fat kid mentality.
HMN 2,4,4,6,8,8-heptamethylnonane. |
|
| I.V. Iodine Value. | |
| IUPAC International Union of Pure and Applied Chemists. | |
| MAG Monoacylglycerol | |
| N.A.S.A. National auronautic and space administration.
N.B.B. National biodiesel board. N.O.R.A. National oilheat research alliance. O.R.N.L. Oak Ridge National Laboratory. P.V. Peroxide Value. |
|
| S.V. Saponification Value. | |
| TAG Triacylglycerol. |
U.L.S.D. Ultra low sulfur diesel.
CHAPTER ONE
INTRODUCTION
There is a need for alternative energy sources to petroleum-based fuels due to the depletion of the worlds’ petroleum reserves,global warming and environmental concerns. American standard testing and materials defined biodiesel as a fuel composed of monoalkyl esters of long-chain fatty acids derived from renewable vegetable oils or animal fats and meets the requirements of ASTM 6751(ASTM, 2008). Ozone depletion,global warming,greenhouse gases concerns have promoted biodiesel as an alternative renewable and eco-friendly fuel.The concept of biofuel is notnew. Rudolph Diesel was the first to use a vegetable oil(peanut oil) in a diesel engine in 1911(Akoh et al ., 2007 ; Antczak et al., 2009). The use of biofuels in place of conventional fuels would slow the progression of global warming by reducing sulphur,carbon oxides and hydrocarbon emissions (Fjerbaek et al., 2009). Because of its high viscosity and low volatility, the direct use of vegetable oil in diesel engines can cause problems including;high carbon deposits,scuffing of engine liner,injection nozzle failure,gum formation,lubricating oil thickening,high cloud and pour point (Fukuda et al., 2001; Murugesan et al.,2009). In order to avoid these problems, the feedstock is chemically modified to its derivatives which have properties more similar to conventional diesel (Fukuda et al., 2001).Transesterification is the process by which biodiesel is produced,in this process vegetable oil reacts with an alcohol(methanol) to form methyl ester (biodiesel) and another alcohol (glycerol) with NaOH as catalyst (Pinto et al., 2005). Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe.