ABSTRACT
This research was conducted to investigate the suitability of using a renewable, sustainable and environmentally friendly biodiesel as part or full substitute of the petroleum diesel. Biodiesel from Cotton, Jatropha and Neem seeds, were produced and their compositions were analysed using Gas Chromatography-Mass Spectroscopy. The biodiesels were then blended with petro-diesel, thereby forming binary blends and multi-blends in different percentages and the physico-chemical properties for all the blends were determined and analysed. The physico-chemical properties of different biodiesel feedstocks from past literature were reviewed and their mean values computed. The performance of the biodiesel and the blends in a stationary multi cylinder Compression Ignition engine at full load with variable speeds of 1000 rpm, 1500 rpm, 2000 rpm and 2500 rpm were investigated and the composition of their exhaust gas emissions were recorded and analysed. A model was developed for the compression ignition engine with the test rig’s specifications using the GT-Power modelling software. The primary data obtained were used to validate the modelled engine during simulation, while the performance of biodiesels from the secondary data sources were further simulated under similar conditions. The results revealed that, the Cotton, Jatropha and Neem seed oils are reliable sources of biodiesel which are renewable and have the potential to replenish the partial energy demands in an eco-friendly way. The physico-chemical properties of most the fuels and blends conform to the ASTM standards, which suggests that they are suitable for use in CI engines operations. The quality of atomisation, combustion, fuel droplets and air-fuel mixing can be improved in CI engines by using these blends. The best performances in terms of brake power were recorded by using B10J, B20C B20J, and B30C blends. In terms of brake specific fuel consumption, the least value was generated by B10C, the Jatropha blend B25J is the overall best blend at most speeds. B30J has very low brake mean effective pressure at all speeds, while at maximum speed the highest value of brake mean effective pressure was generated by B30C. The highest values of brake thermal efficiency were recorded with B20J and B15N blends. Pure biodiesel samples and the B15C, B15J, B20C and B20J gave the lowest NOx and CO2 emissions. The values of SO2 emissions were null for most of the fuels except B20C at all speeds and B15C at 2500rpm in both cases which have a negligible SO2 value of not more than 0.12 % in all cases. The engine performance simulation in GT-power confirms that the software is valid to be used in compression ignition engine simulation with biodiesel from any feedstock and at all speeds because both experimented and simulated results are very close with identical curves. The simulation of the secondary fuel data revealed that, highest brake specific fuel consumption was depicted by castor followed by coconut and then tallow, the highest brake mean effective pressure was observed during the simulation of the compression ignition engine performance with sun flower, tallow, waste cooking oil and soy biodiesels correspondingly. The highest brake thermal efficiency values were depicted by soy, sunflower, palm and safflower in descending order during the Cussons stationary 4 cylinder CI engine simulations with GT Power software.
TABLE OF CONTENTS
Declaration iv
Certification v
Acknowledgement vi
Dedication viii
Abstract ix
List of Figures xiii
List of Tables xv
List of Plates xvii
List of Appendices xviii
Abbreviations and Symbols xix
CHAPTER ONE 1
INTRODUCTION 1
1.1 Background of the Study 1
1.2 Statement of Research Problem 3
1.3 The Present Research 5
1.4 Aim and Objectives of the Research 5
1.5 Justification 6
1.6 Scope 8
CHAPTER TWO 9
LITERATURE REVIEW 9
2.1 Relevant Literatures 9
2.1.1 Diesel fuel 9
2.1.2 Nigerian diesel 9
2.1.3 Biodiesel 10
2.1.4 Advantages of biodiesel 10
2.1.5 Disadvantages of biodiesel 11
2.1.6 Feedstocks used for biodiesel production 11
2.1.7 Biodiesel production and purification 12
2.1.8 Biodiesel blending 14
2.1.9 Physico-chemical properties of biodiesel 14
2.1.10 Use of biodiesel in compression ignition engines 15
2.2.1 Engine performance parameters 15
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2.2.2 Modelling 18
2.2.3 Simulation 20
2.2.4 GT Power 20
2.3.1. Biodiesel properties, engine performance and emissions 22
2.3.2. Direct injection CI engines modelling and simulations using GT-Suite 25
CHAPTER THREE 29
MATERIALS AND METHODS 29
3.1 Materials and Equipment 29
3.1.1 Raw materials 29
3.1.2 Equipment 29
3.2.1 Sample preparation 32
3.2.2 GC-MS Analyses 33
3.2.3 Engine test procedure 40
3.2.4 Exhaust gas analyses 41
3.2.5. Secondary Biodiesel Data Sourcing and Analyses 42
3.2.6 Modelling and simulation of engine performance 42
CHAPTER FOUR 48
RESULTS AND DISCUSSIONS 48
4.1 GC-MS Results 48
4.1.1 Cotton oil methyl ester 50
4.1.2 Jatropha oil methyl ester 50
4.1.3 Neem oil methyl ester 51
4.2 Physico-Chemical Properties of Biodiesel from Cotton, Neem and Jatropha Seeds 53
4.3 Results of Physico-Chemical Properties from Secondary Data Analyses 65
4.3.1 Kinematic viscosity 65
4.3.2 Density 66
4.3.3 Flash point 67
4.3.4 Heating value 68
4.3.5 Specific gravity 68
4.3.6 Pour point 69
4.3.7 Cloud points 70
4.3.8 Cold filter floggingpoints 71
4.3.9 Cetane number 72
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4.4 Engine Performance Results Using Cotton, Jatropha and Neem Biodiesel 73
4.4.1 Exhaust gas temperature 73
4.4.2 Brake power 76
4.4.3 Brake specific fuel consumption (bsfc) 79
4.4.4 Brake mean effective pressure (bmep) 83
4.4.5 Brake thermal efficiency (bte) 85
4.5 Exhaust Emissions Results Using Cotton, Jatropha and Neem Biodiesel 88
4.5.1 Combustion efficiency 88
4.5.2 Carbon monoxide (CO) emissions 90
4.5.3 Nitrogen oxide (NOx) emissions 95
4.5.4 Oxygen emissions 99
4.5.5 Carbondioxide (CO2) emissions 100
4.5.6 Sulphurdioxide (SO2) emissions 102
4.5.7 Excess Air 105
4.6 Modeling and Simulation Using GT Power Software 107
4.6.1 Model validation 107
4.6.2 Simulation of biodiesel in CI engine 112
CHAPTER FIVE 117
SUMMARY, CONCLUSION AND RECOMMENDATIONS 117
5.1 Summary 117
5.2 Conclusion 120
5.3 Recommendations 121
REFERENCES 122
APPENDICES 142
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Energy supply to a nation must be made in a responsible and sustainable deportment, which is an approach that not only convenes the needs of the present generation but also guarantees the future generations to meet their demands (Sambo, 2011). Unfortunately, one of the challenges facing the actualisation of meeting the future generations’ developmental needs is the unsympathetic effects of climate change because of the disconcert of natural balance of greenhouse gases (GHG) in the atmosphere, predominantly, carbon dioxide. Several researches were carried out and many others are still ongoing in search for solutions to the environmental menace and socioeconomic sustainability. One of the cleanest ways of burning fossil fuels is by blending them with biofuels (Akindale, 2011). The use of vegetable oil and animal fats to obtain biodiesel is theoretically attractive due to their compatibility with the current automobiles and diesel supply chains. However, the profitability of biodiesels depends heavily on the economics of the byproducts like glycerol. For sometimes, glycerol has been a valuable byproduct of the biodiesel industry. Nigeria has joined the league of countries seeking for alternatives to fossil fuels. Biofuels have emerged as a credible alternative to blend stock for the environmentally polluting petroleum resources (Izah and Ohimain, 2012).
Over the decades, fossil fuels and other carbonising energy sources have been used to generate power for sustainable industrial growth; for transportation, lighting, powering of heating and cooling devices and for prime moving in machining and production processes.
The effects of fossil fuels to our environment particularly, in climate change which is principally due to the discharge of greenhouse gases during the combustion of fossil fuels
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cannot be overemphasised. However, research has justified the use of biodiesel and bio ethanol in diesel and petrol fuels respectively to produce efficiently combustible fuels which burn in internal combustion engines with reduced carbon dioxide emissions and similar power outputs as conventional diesel (Kaisan, 2014).
According to the National Energy Policy, NEP (2014), Nigeria shall:
i- Vigorously pursue the development of an optimal energy mix for the transport sector,
ii- Ensure regular and adequate availability of all fuel types for the transport sector,
iii- Ensure the use of efficient and environmentally friendly technologies in the transport sector.
As part of the strategies enlisted in the NEP (2014), there is need for “Encouraging the use of the diesel for commercial and mass transit transportation”. Therefore, it has become absolutely necessary for the Nigeria to optimise its energy mix through the use of more environmentally friendly diesels (biodiesels) in the transportation sector.
Furthermore, biodiesel resources are abundant in Nigeria; so many crops and other resources which have high potentials of producing biodiesel in large quantities are either cultivated on Nigerian soil or are abundantly found in natural habitats. These include Jatropha curcas, palm oil, flax, field pennycress, mustard, sunflower (Ma et al., 1998), wild grape seeds or Lannea microcarpa (Nafiu et al., 2011; Kaisan et al., 2013), virgin oil and fat feed stocks (Adams et al., 1983) and used cooking oil (Stevenson, 2003).
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Microalgae has also received much attention recently because it has high lipid contents, fast growth rates and potentials to mitigate the competition for land-use and food-for-fuel conflicts (Hu et al., 2008). They are also able to reduce the GHG effects via CO2 sequestration (BP, 2012).
Therefore, since Nigeria has a very good reserve of some of the feedstock, it is appropriate to work on the integration of these feed stocks into the Compression ignition engines’ fuel supply so as to optimise the nation’s energy mix principally in the transport sector, and broadly in industrial, residential and commercial sectors.
1.2 Statement of Research Problem
Many problems are associated with the Nigerian oil and gas sector, and there is an urgent need to arrest the situation. First of all, Nigeria still depends on foreign nations for the supply of refined fuel products, most of the existing refineries in the country are not working to their full installed capacities, and there has not been expansion in the sector for some decades now while the countries energy demand increases rapidly due to the fast growing population of over 160 million people (Izah and Ohimain, 2012; Kannahi and Arulmozhi, 2013).
Secondly, there is price hike in petroleum products in Nigeria. This affects the costs of raw materials, processed goods and services as a result of cost incurred by the farmers, traders and manufacturers while powering plants and machineries, during transportation, lighting and conditioning residential and commercial buildings (Izah and Ohimain, 2012; Kannahi and Arulmozhi, 2013)
Thirdly, greenhouse gas (GHG) emissions; climate change is given serious global attention because of its adverse effects on the environment. The effects include but not limited to flooding, acid rain, rise in sea pH which claim aquatic lives, oil spillage and dessert encroachment among others.
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It has been established in the literature that, burning pure petro-diesel contributes to the GHG emissions (Izah and Ohimain, 2012; Kannahi and Arulmozhi, 2013; EIA, 2013). Gas flaring is also one of the problems of petroleum exploration in Nigeria. The rate of flaring is high and as such, Nigeria was tagged the most enormous gas flaring country in Africa in particular, and the world at large (Kaisan et al., 2010; EIA, 2013).
Fuel subsidies saga is also a great issue globally (EIA, 2013). In Nigeria for instance, on the 1st of January, 2012, the divergence over the removal of fuel subsidy has led to nationwide strikes (Onyishi et al., 2012). It is an apparent bit of evidence that, the consequential strike has caused a brutal financial loss to Nigeria. Fuel subsidy in Nigeria is a policy of the federal government meant to assist the people of Nigeria to cushion the effects of their economic hardship. Subsidies were introduced in the Nigerian energy sector in the mid 1980’s (Onyishi et al., 2012). Something of a creeping phenomenon, the value of the subsidies has gone from 1 billion USD in the 1980s to an expected 6 billion Dollars in 2011 (Onyishi et al., 2012). In this period, the specific products targeted for subsidy have changed. Diesel oil has had its associated subsidy removed while petrol and kerosene continue to enjoy a 54.4 % subsidy over the international spot market price at the Nigerian pump until the year 2016.
Ultimately, security risks are also associated with petroleum exploration in Nigeria (EIA, 2013). Sometimes the experts are being kidnapped, oil rigs and pipelines vandalised by militants, and tankers been attacked by armed robbers leading to serious energy crises.
Fourthly, there are problems associated with non simulation of biodiesel feedstock into diesel engines. There are only a few researches that consider the simulation of binary biodiesel blends only, but no attention was given to biodiesel from pure feedstock and multi-blends.
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1.3 The Present Research
The present research focused on finding renewable and sustainable alternative fuels for use in the compression ignition engines from a range of biodiesel feedstocks. Thus, this thesis investigated the chemical composition of biodiesel samples, forms various binary and fractional blends between the biodiesels and diesel, and tested the physico-chemical properties, performance and exhaust emission characteristics of these blends in a stationary four-cylinder compression ignition engine.
Same engine was modelled and simulated using the GT-Power software and the primary data was used to validate the model. Secondary data was obtained for properties of so many other biodiesel feedstock; the mean of the data was computed, GT Power software was used to model some compression ignition engines, the primary and secondary data were used to feed the model. The engines performance and exhaust emissions were optimised using the GT simulations. The results were presented, analysed and discussed to make constructive inferences.
1.4 Aim and Objectives of the Research
The aim of this research is to model and simulate biodiesel blends performance in a compression ignition engine using GT Power software for environmental sanity and energy sustainability.
The specific objectives of this research are to:
i. produce biodiesel from Cotton, Jatropha, Neem oils and to analyse the composition using Gas Chromatography/Mass Spectroscopy (GC-MS) analyses;
ii. blend the biodiesels produced from Cotton, Jatropha and Neem seed oil with petro-diesel, thereby forming binary blends and multi-blends of each biodiesel with petroleum diesel in different percentages and to examine the physico-chemical properties like specific gravity, viscosity, flash point, calorific value, sulphur content,
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cetane number, acid value, copper strip corrosion, iodine value, and colour for each of these blends;
iii. review the physico-chemical properties of different biodiesel feedstocks from literature and compute the mean of the physico-chemical properties of the biodiesels data sourced from the literature;
iv. investigate the performance of the biodiesel and the blends in a stationary four-cylinder Compression Ignition engine at full load with variable speedsand to investigate exhaust gas emissions during the combustion of these blends in the CI engine, and
v. develop compression ignition engine model with the test rig’s specifications using GT Power software, use the primary data obtained to validate the modelled engine, and simulate the engines performances of the biodiesel multi-blends and biodiesels from the literature sources under full loading condition at variable speeds.
1.5 Justification
It is important for Nigeria to explore other potential economic means in order to improve her already pulverised economy (Izah and Ohimain, 2012) through renewable and alternative fuel sources; hence, the issue of biodiesel is of paramount significance in tackling this problem. Moreover, there is availability of biodiesel feedstock in Nigeria most of which are non-edible crops (Idusayi et al., 2014). Since there are so many non-edible feedstock that decay naturally into the earth crust without been properly harnessed, it has only become necessary for those feedstock to be utilised in biodiesel production so that they could add value instead of them to be left as a constituent of environmental pollutions. Hence, there are economic benefits of converting from waste to wealth.
Global warming (Idusayi et al., 2014) has claimed so many lives in Nigeria due to flooding, desertification, increased in ocean pH which claims aquatic lives, and acid rain
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which was proved to be carcinogenic. One of the major causes of global warming is the burning of petro-diesel in power generation and hence we have to reduce these to its barest minimum. It was confirmed by prior researches that biodiesel blending has serious impact in reducing global warming; as such this research is vital and timely. Also, this is in line with the Kyoto protocol of 1997 which Nigeria is a signatory and which has the main mandate of reducing global emissions of flue gases from CI engines, gas flaring as well as coal fired power plants (Idusayi et al., 2014.
Additionally, there is a potential market of biodiesel in Nigeria (Idusayi et al., 2014). Production, procurement and blending of biodiesel for use in conventional CI engines in Nigeria will lead to increased job creation, reduction in rural-urban migration and increase in agricultural participation.
One of the most popular softwares used in internal combustion engines and engine components design, modelling, optimisation, simulation and analyses is GT-power which is an integral component of the GT-Suite developed by Gamma technology Inc. The software is deficient of biodiesel data in its library (Rahim et al., 2012a), as such, there is need to simulate a CI engine with biodiesel data obtained from the literature in the GT-Power interface. Therefore, this research work is justifiable by all the aforementioned assertions.
This thesis has established how binary and multi-blends of biodiesel can be used effectively in CI engines to curtail the environmental menace caused by burning petroleum diesel in the engines. The thesis has suggested the tendency of controlling climate change by blending biodiesel with diesel, this leads to further reduction in the propensities of having acid rain, desert encroachment, and flood as well as the continuous lost in aquatic lives. It would also help in reducing the problems of over dependency on foreign nations, price hike of petroleum products, job creation, reduced rural-urban
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migration and wipe out the pain of fuel subsidy saga. Hence, the findings will help in achieving environmental sanity, energy sustainability and renewable energy integration into the nations’ economy.
1.6 Scope
The scope of this research includes the production of biodiesel samples from Cotton, Jatropha, Neem seed oil, carrying out gas chromatography-mass spectroscopy (GC-MS) analyses and moisture content test to determine the percentage of methyl esters present in the samples. In addition, to mix the biodiesel with diesel, forming various binary blends with the diesel as well as multi-blends.
In addition, there was experimental testing of the physico-chemical properties of the blends, and to determine the engine performance parameters as well as the exhaust emissions in a stationary four-cylinder diesel engine. In addition, secondary data was obtained for the Physico chemical properties of other biodiesels from the literature and the data was computed. The scope further includes the development of the test rig model in the GT Power software and using the primary data to validate the model. Besides, the secondary data was used to feed the model. GT Power was also used to simulate the modelled engine performances as carried out by Kofar bai and Zeng (2014).
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