ABSTRACT
The development of a sustainable alternative source of renewable energy has been the greatest global challenge of the century. With the growing population and subsequent increasing demand for energy especially in Nigeria, coupled with the under-developed electrical energy platforms and the vast problems of the convectional energy sources vis-à-vis the continuous gas flaring, its enormous energy crisis needs to be contained and alternative energy resource considered hence, biodiesel development is seen as an important alternative bio-fuel since is economically viable, cheap, clean and green in contrast to conventional fossil fuels. This is due to its environmental benefits and simple industrial production from renewable energy resources. Consequently the attempt to determine the long storage oxidation stability of biodiesels produced from three feed stocks were examined and the quality of the biodiesels and their blends (B100, B10, B20, B30 and D100) as developed comparatively studied and analyzed. The biodiesels were produced from neem seed oil (NSO), palm kernel seed oil (PKSO) and Castor bean seed oil (CBSO) through transesterification reaction. The bio-oil were transestrified using sodium hydroxide as catalyst at methanol/sample molar ratio of 6:1, 60mins time, 60ºC temperature and agitation speed of 250rpm The physio-chemical properties of the three blends were measured to ascertain their adherence with the ASTM standard for biodiesel. The results showed a moderate percentage yield from most of the feedstock. Viscosity obtained at temperature of 40ºC, indicated that the highest value of 4.09mm2/sec was from B100 of neem biodiesel and the lowest value of 3.72mm2/sec was from B100 of castor biodiesel. The B100 castor biodiesel had the highest value (9.7hrs) of oxidation stability at 110 ºC while neem had the lowest value at 6.5hrs. Overall, other values for oxidation stability, density, acid value, flash point, API gravity, anisidine point and cetane index all conformed to the ASTM standard range.
TABLE OF CONTENTS
Title page i
Declaration ii
Dedication iii
Certification iv
Acknowledgement v
Table of contents vi
List of Tables ix
List of Figures x
List of Plates xii
Abstract xiii
Nomenclature list xiv
CHAPTER 1: INTRODUCTION 1
1.1 Statement of Problem 4
1.2 Aim and Objectives of Study 5
1.3 Scope of Study 5
1.4 Justification of Study 6
CHAPTER 2: LITERATURE REVIEW 7
2.1 Biodiesel Production 13
2.2 Methods for Assessing the Oxidation of Biodiesel 16
2.3 Comparism Between Methods 16
2.4 Antioxidant Effects on Oxidation Stability 18
2.5 Storage Stability of Biodiesel 19
2.6 Effect of Metal Impurities and the Storage Vessels on the Biodiesel Stability 22
2.7 Effect of Antioxidants on the Biodiesel Stability 23
CHAPTER 3: MATERIAL AND METHODS 27
3.1 Materials 27
3.2 Methods 28
3.2.1 Sample collection and oil extraction 28
3.2.2 Oil characterization 28
3.2.3 Biodiesel production (Transesterification) 34
3.2.4 Biodiesel purification by wet washing method (base neutralization) 36
3.2.5 Thermal oxidation stability 36
3.2.6 Preparation of biodiesel blends and storage stability studies 37
CHAPTER 4: RESULTS AND DISCUSSION
4.1 Characterization Results of the Bio-oil Samples 38
4.1.1 Free fatty acid 39
4.1.2 Peroxide 39
4.1.3 Saponification value (SV) 39
4.1.4 Iodine (IV) 40
4.1.5 Moisture 41
4.1.6 Refractive index 41
4.1.7 Kinematic viscosity 41
4.1.8 Yield. 41
4.2 Characterization Results for the Biodiesel Samples 42
4.3 Results for the Long Storage Oxidation Stabilities of the Biodiesels Produced 43
4.3.1 Oxidation stability 44
4.3.2 Acid number 46
4.3.3 Density 49
4.3.4 Kinematic viscosity 51
4.3.5 Flash point 54
4.3.6 API gravity 56
4.3.7 Anisidine value 59
4.3.8 Cetane number / index 61
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 64
5.1.1 Contributions to knowledge 64
5.2 Recommendations 65
References 66
Appendices 72
LIST OF TABLES
4.1 Result for the Characterization of the Raw Bio-oil Samples 38
4.2 Results for the Characterization of the Biodiesel (B100) Samples and their Standard Parameter Values. 43
LIST OF FIGURES
3.1 Principle of oil aging in the Rancimat 37
4.1 Effect of storage on oxidation stability @110°C for palm kernel biodiesel. 43
4.2 Effect of storage on oxidation stability @110°C for Neem biodiesel 44
4.3 Effect of storage on oxidative stability @110°C (hr) of castor 44
4.4 Effect of storage on Acid value (mgKOH/g) of Palm Kernel biodiesel 45
4.5 Effect of storage on Acid value (mgKOH/g) of Neem biodiesel 46
4.6 Effect of storage on Acid value (mgKOH/g) of Castor biodiesel 46
4.7 Effect of storage on Density (kgm-3) of Palm Kernel biodiesel 49
4.8 Effect of storage on Density (kgm-3) of Neem biodiesel 49
4.9 Effect of storage on Density (kgm-3) of Castor biodiesel 50
4.10 Effect of storage on kinematic viscosity (mm2/sec) of Palm kernel biodiesel 51
4.11 Effect of storage on kinematic viscosity (mm2/sec) of Neem biodiesel 52
4.12 Effect of storage on kinematic viscosity (mm2/sec) of Castor biodiesel 52
4.13 Effect of storage on Flash point (°C)of palm kernel biodiesel 54
4.14 Effect of storage on Flash point (°C)of Neem biodiesel 54
4.15 Effect of storage on Flash point (°C) of Castor biodiesel 55
4.16 Effect of storage on API gravity of Palm kernel biodiesel 56
4,17 Effect of storage on API gravity of Neem biodiesel 57
4.18 Effect of storage on API gravity of Castor biodiesel 57
4.19 Effect of storage on Anisidine point of palm kernel biodiesel 58
4.20 Effect of storage on Anisidine point of Neem biodiesel 59
4.21 Effect of storage on Anisidine point of Castor biodiesel 59
4.22 Effect of storage on Cetane of palm kernel biodiesel 61
4.23 Effect of storage on Cetane of Neem biodiesel 61
4.24 Effect of storage on Cetane of Castor biodiesel. 62
LIST OF PLATES
D-1 Refractometer manufactured by Hanna instrument Romania. (H19800) 84
D-2 Hot Air oven manufactured by Samsung. 84
D-3 Oil extraction by soxhlet method. 85
D-4 Biodiesel production process 85
D-5 Purified biodiesel sample 86
D-6 Magnetic hot plate manufactured by Metler Toledo (Meter LR12) 86
NOMENCLATURE
Kg Kilogram
oC Degree centigrade
% Percentage
g Grams
hrs Hours
MPa Mega pascal
β Beta
γ Gamma
α Alpha
δ Delta
μm micro meter
ml Milliliters
N Newton
S Seconds
Min Minutes
N/A Not applicable
mm2 square millimeter
rpm revolution per minute
ppm part per minute
w/w Weight by Weight
m/m Mass by Mass
v/v Volume by Volume
≤ Less than or equal to
˃ Greater than
˂ Less than
KOH Potassium Hydroxide
Fe Iron
Ni Nickel
Mn Manganese
Co Cobalt
Cu Copper
PKO Palm kernel oil
NSO Neem Seed oil
CBO Castor bean oil
PME Palm kernel methyl ester
NME Neem methyl ester
CME Castor methyl ester
API American Petroleum Institute.
ASTM American Society for Testing and Materials
EN European Standard (European Norms)
B100 Pure biodiesel
D100 Petrol diesel
CHAPTER 1
INTRODUCTION
The greatest global challenge of the century has been how to develop a sustainable alternative source of renewable energy. In this regard, biodiesel is considered as an important alternative bio-fuel due to its environmental benefits and simple industrial production from renewable resources (Jain and Sharma, 2011). Several reasons for the growing interest in bio-fuels include: environmental concerns, climate change mitigation, guaranteeing secure vitality supplies, and the improvement of cleaner, economical, and more naturally inviting fuels. besides, oil costs proceed to rise relentlessly as a result of expanded fossil fuel utilization together with developing energy requests and needs. This in turn adds to the declining of already existing socioeconomic and environmental problems that need to be faced (Jain and Sharma, 2011).
Industries are hereby encouraged to continue to invest in Research Development and Implementation aimed at developing sustainable fuels from renewable sources with the greatest standards quality. In specific, the improvement of feasible, cost-competitive and environmentally-friendly transportation fuels have driven to a discernible worldwide increment within the generation and commercial utilization of biodiesel within the last decade. Biodiesel has numerous benefits over petroleum-derived fuel according to Muñoz et al., (2011) such as being a non-toxic and biodegradable fuel, decreased deplete emanations, its lubricity, being free of sulfur and aromatics and the possibility of lessening our dependence on fossil energy sources etc. Furthermore, biodiesel is totally miscible with petroleum diesel fuel (i.e., conventional diesel). Subsequently, it can be utilized to deliver biodiesel or conventional diesel blends. (Kivevele et al., 2011).
According to Kivevele et al. (2011) chemical definition of biodiesel; it is composed of a blend of alkyl esters obtained by the transesterification of triglycerides from vegetable oils and animals fats, which is the routine course for biodiesel production at an industrial scale. The triglycerides are reacted with a low molecular of alcohol, as a rule methanol or ethanol, resulting in the forming of alkyl esters of fatty acids (biodiesel) and removing glycerol as a by-product. The response is ordinarily catalyzed with homogeneous catalysts, either acids or bases. Due to their wide accessibility at a sensibly financial cost, NaOH or KOH are ordinarily utilized within the industry (Kivevele et al., 2011).
Biodiesel according to Jha and Das, (2017) is mainly esters, which are produced by the transesterification of vegetable oils or animal fat triglycerides with simple alcohols, such as methanol, ethanol, etc. Biodiesel can be created from different feed stocks, such as vegetable oils (edible or non-edible), animal fats, used cooking oil, etc. The triglycerides, such as oils or fats, cannot be utilized straightforwardly as fuel within the existing motors due to the high viscosity of these substances. According to Jha and Das, (2017), the transesterification process diminishes the viscosity of the oil for utilize as a fuel in spite of the fact that biodiesel is conspicuous for petroleum-based diesel in numerous viewpoints. Be that as it may, it has a few disadvantages and the main disadvantage of biodiesel is the increased cost of the feedstock due to its limited availability, though the cost issue could be managed by the use of abundant sources in selected regions. For examples, palm oil in Indonesia and Malaysia, coconut oil within the Philippines, soybean oil within the United States, rapeseed (canola) oil in Europe, used cooking oils in exceedingly populated zones, non-edible oils like jatropha and castor in nations with overflowing fruitless lands, etc. as reported by Mohammed and Bandari, (2017) are areas where they were utilized as biofuels.
The use of government subsidies is another attractive feature related to the management of cost. Subsequently, other distinguished hitch for biodiesel utilization is its low stability than that of petroleum-based diesel which ruins its long-term capacity since it is more vulnerable to oxidation and/or auto-oxidation amid long-term capacity Dantas et al., (2011). On the other hand, this also suggests that biodiesel is unsteady and loses quality and properties over time. Intense studies, however are on-going to advance the yield, quality and stability of biodiesel as well as to decrease its production cost (Jain and Sharma, 2011).
Neem (Azadirochtaindica A. Juss) as a good fuel feedstock is a native Indian tree well known for its medicinal features. Some of its parts like the bark, leaves, flower, fruit, seed and root can be utilized in the field of medicine Ragit et al. (2011). In their research, Muthu et al. (2010) explained that It is an evergreen tree correlated to mahogany, developing in nearly each state of India, South East Asian nations and West Africa. It grows in drier regions and in all sorts of soil. It contains a few thousands of chemicals which are terpenoids in nature. A develop neem tree has a beneficial life span of 150 to 200 years and produces 30 to 50 kg fruit each year. Ragit et al. (2011) research added that it has the ability to survive on drought and poor soils at a very hot temperature of 44°Cand a low temperature of up to 4°C, and its high oil content of 39.7 to 60%.
Similarly, Castor oil plant (Ricinuscommunis L.) is specie of blooming plant within the spurge family, Euphorbiaceous. It is classified as a monotypic genus. Its seed is the castor bean and it is inborn to the Southeastern Mediterranean basin, Eastern Africa, and India, but far reaching all through tropical regions (Muthu et al., 2010). Castor seed is the source of castor oil, which encompasses a wide variety of employments. The seed contains between 40 - 60% oil that's rich in triglycerides, basically ricinolein. The seed contain ricin, a toxin, which is additionally display in lower concentrations all through the plant.
Different perspectives of biodiesel stability have been investigated already. In this research, distinctive fuel parameters influencing the degree of oxidation stability, and the effects of antioxidants on biodiesel stability were investigated. The role of anti-oxidation on the biodiesel and comparative analysis of the three samples developed from non-edible palm kernel oil (PKO), Neem seed oil (NSO) and Castor seed oil (CSO) respectively will be examined.
1.1 STATEMENT OF PROBLEM
The oxidation stability of biodiesel is lower than that of petroleum-based diesel and this ruins its long-term capacity since it is more vulnerable to oxidation and/or auto-oxidation amid long-term storage. On the other hand, according to Lapuerta et al. (2012) this suggests that biodiesel is unsteady and loses quality and properties over time. The oil source composition determines the oxidation stability, the polyunsaturated methyl esters and unsaturated being the more responsive species. How susceptible it will be to oxidation, and its deterioration is determined by the level of unsaturation in an alkyl ester. However, other than depending on the degree and arrangements of olefinicun saturations, the presence of antioxidants and storage conditions will also determine biodiesel resistance against oxidation (Berman et al., 2011). Hence there is need to progress the quality, stability and yield of biodiesel as well as reducing its production cost. Consequently, to achieve this aim and determine the oxidation stability effect of biodiesel during long storage, three biodiesel fuels feed stock samples developed from non-edible (PKO), (NSO) and (CSO) respectively, were utilized for the study.
1.2 AIM AND OBJECTIVES OF STUDY
The aim of this study is to determine the long storage stabilities oxidation of biodiesels produced from three fuel feedstock and their blends, with the following specific objectives:
i) To produce biodiesel from need seed oil (NSO), palm kernel seed oil (PKO), and castor seed oil (CSO) respectively.
ii) To obtain the fuel (physical and chemical) properties such as acid value, viscosity value at 40°C, peroxide value, density, iodine value, API gravity, Anisidine value, cetane index and fire point of the developed bio-oils and their respective biodiesels.
iii) To determine the acetone index value for the establishment of the ignition quality of the engine during combustion.
1.3 SCOPE OF STUDY
The scopes of this study include:
i) Extraction of oil from the samples.
ii) Characterization of the oil samples extracted.
iii) Biodiesel production
iv) Characterization of the biodiesel samples produced, and
v) Determination of long storage stability oxidation of the biodiesels produced.
1.4 JUSTIFICATION FOR THE STUDY
Many researchers have been working to discover the substances that can restrain this oxidation process and retain the quality of biodiesel without deterioration. Castor bean biodiesel composed of approximately 90% ricin oleic acid, had been proven to increase the stability of the biodiesel oxidative (Berman et al., 2011). Because of the stability issues, some non-edible seed used for biodiesel production and the favorable characteristics of castor seed oil, neem seed oil, and crude PKO biodiesels when blended with other fuel especially conventional petro-diesel very suitable in the improvement of fuel suitable stability. In this way, experimental design methods would provide a convenient approach to identifying an ideal mixture composition that yields a product with increased oxidative stability.
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