ABSTRACT
Analysis of exhaust emissions from engines fueled with petrol, diesel and their blends with biodiesel was carried out.The biodiesel was produced from waste cooking oil via transesterification. Physicochemical analysis of the waste cooking oil and biodiesel were carried out using ASTM methods. Analysis of exhaust emissions (CO, CO2, O2 and NOx) from petrol and diesel vehicles as well as big and small generators were also carried out using a Bacharach Portable Combustion Analyzer 2. Ten of each of the petrol vehicles (motorcycles, tricycles, mini-buses and small cars) were analysed and their average CO, CO2 and NOx emissions were calculated. Ten small and ten large capacity generators were also analysed. Petrol and diesel were blended with biodiesel and used to fuel 3 generators and 1 motorcycle at different blend ratios ranging from B5 to B40. The results of the analysis for biodiesel are as follows: moisture content (0.05%), specific gravity (0.90), acid value (0.22 mgKOH/g), sulphur content (0.01%), flash point (155 oC), kinematic viscosity (1.90 m2/s), pour point (-3.00 oC), ash content (0.09%), iodine number (13.45 gI2/100g) and calorific value (34,400 kJ/g). Mini-buses emitted the highest concentration of CO (3511.7 ppm) and CO2 (6.0%) while small cars emitted the highest concentration of NOx (27.1 ppm) and the lowest concentration of CO (2131.9 ppm) and CO2 (3.5%). However, tricycles emitted the lowest concentration of NOx (3.5 ppm). For diesel vehicles (6 tankers and 6 trailers), the Trailers emitted the highest CO (744.8 ppm) while tankers emitted higher CO2 (1.6%) and NOx (114.7 ppm). Although the diesel vehicles are heavy duty vehicles, they emitted significantly (P<0.05) lower concentrations of CO and CO2 but with a significantly (P<0.05) higher NOx than the petrol vehicles. The concentrations of CO from all the petrol and diesel vehicles exceeded the 2nd European emission standard (1996) adopted by Nigeria. Small generators emitted more CO (2876.8 ppm) while the large generators emitted more NOx (30.6 ppm) and CO2 (6.58%). However, there was no significant difference (P>0.05) between the emissions from large and small capacity generators. At every blend ratio, there was a significant percentage reduction in CO, CO2 and NOx emitted in the small and large petrol-biodiesel generators but an increase in NOx in motorcycle with every increase in blend ratio. There was also an increase in the emission of NOx in diesel-biodiesel generator and a decrease in CO and CO2 with every increase in the blend ratio. With the inability of the vehicular emissions to adhere to an already obsolete adopted Nigerian emission standard, it is expected that the Nigerian environment with about 10 million vehicles and numerous generators will not meet the WHO (2016) air quality standard of 9 ppm (CO) and 0.0128 ppm (NOx) which the sixth (2014) European vehicular emission standard was designed to achieve. Therefore these emissions would enhance health and environmental hazards associated with exposures to these pollutants.
TABLE OF CONTENTS
TITLE PAGE………………………………………………………………………………..……..i
CERTIFICATION ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
ABSTRACT v
Table of Contents vi
List of Figures ix
List of Tables x
CHAPTER ONE: INTRODUCTION 1
1.1 Introduction 1
1.2 Transport and Climate change 3
1.3 Impact of different emission types 6
1.3.1 Carbon monoxide 7
1.3.2 Nitrogen Oxides (NOX) 7
1.4 The Kyoto Protocol 8
1.5 Justification for the Study 9
1.6 Research Objectives 10
CHAPTER TWO: LITERATURE REVIEW 11
2.1 Air pollution 11
2.2 Vehicle Emissions 11
2.3 Factors affecting the emission levels 12
2.3.1 Engine Design Parameters 12
2.3.1.1 Air/Fuel Ratio and Mixture Preparation 13
2.3.1.2 Ignition Timing 14
2.3.1.3 Compression Ratio and Combustion Chambers 14
2.3.2 Vehicle Non – Engine Components 14
2.3.2.1 Tyres 14
2.3.2.2Cooling technology 15
2.3.2.3 Lighting 15
2.3.2.3Traffic characteristics 15
2.3.2.4 Road Characteristics 16
2.3.2.5 Fuel Quality 16
2.4 Health Effects of Exhaust Emissions— Case Studies 17
2.5 Biodiesel 19
CHAPTER THREE: EXPERIMENTAL 21
3.1 Sample Collection 21
3.2 Characterization of Waste Cooking Oil 21
3.2.1 Specific Gravity 21
3.2.2 Moisture Content 21
3.2.3 Determination of Viscosity 21
3.2.4 Acid Value/Free Fatty Acid (FFA) 22
3.2.5 Peroxide Value 22
3.2.6 Iodine Value 23
3.2.7 Saponification Value 23
3.2.8 Refractive Index 24
3.3 Biodiesel Production 24
3.4 Separation of biodiesel from by-products 24
3.5 Purification of biodiesel by washing 24
3.6 Characterization of Biodiesel 24
3.6.1 Specific Gravity 24
3.6.2 Kinematic Viscosity 25
3.6.3 Moisture Content 25
3.6.4 Flash Point: 25
3.6.5 Pour Point 26
3.6.6 Acid Number 26
3.6.7 Sulphur Content 26
3.6.8 Iodine Value 26
3.6.9 Ash Content 27
3.6.10 Determination of Calorific Value 27
3.7 Sample Size of Vehicles and Generators 27
3.8 Equipment Setup and Exhaust Gas Measurement 28
CHAPTER FOUR: RESULTS AND DISCUSSION 29
4.1 RESULTS 29
4.2 DISCUSSION 35
CONCLUSION 59
REFERENCES 60
LIST OF FIGURES
1.1: Global Share of CO2emission by Sector 5
1.2: Projected growth in CO2 emission levels in the world. 6
4.1: Percentage petrol vehicular emission 38
4.2: Percentage emission from tankers and trailers……….…………………………..41
4.3: Percentage petrol generator emissions 46
4.4: Percentage emissions from generators. 48
4.5 and 4.6: Percentage reduction of CO and NOx with biodiesel Blend 50
4.7 and 4.8 Percentage reduction of CO and CO2 with biodiesel Blend 51
4.9 Percentage reduction of NOx with biodiesel Blend 51
4.10 and 4.11 Percentage reduction of CO and CO2 with biodiesel Blend 53
4.12 Percentage reduction of NOx with biodiesel Blend 53
4.13 to 4.15: Percentage reduction of CO, CO2 and NOx biodiesel Blend 55
LIST OF TABLES
2.1: Effect of improved petrol on the emissions of non-catalyst vehicles. 16
4.1: Result of waste cooking oil Characterisation 29
4.2: Result of Biodiesel Characterisation 29
4.3: Concentrations of gaseous emissions from motorcycle 30
4.4: Concentrations of gaseous emissions from Tricycles 30
4.6: Concentration of gaseous emissions from Private Vehicle 31
4.7: Concentrations of gaseous emissions from Tankers 32
4.8: Concentrations of gaseous emissions from Trailers 32
4.9: Concentrations of gaseous emissions from Small Capacity Generators 33
4.10: Concentrations of gaseous emissions from Large Capacity PetrolGenerators 33
4.11: Concentrations of gaseous emissions from small capacity generators fueled by Biodiesel-Petrol Blend 34
4.12: Concentrations of gaseous emissions from large capacity generator fueled by Biodiesel-Petrol Blend 34
4.13: Concentrations of gaseous emissions from Motorcycle fueled by Biodiesel-Petrol Blend 34
4.14: Concentrations of gaseous emission from generator fueled by Biodiesel-Diesel Blend 34
4.15: Mean concentrations of petrol vehicular emissions 38
4.16a:Correlation Table of CO from petrol vehicular emissions 40
4.16b:Correlation Table of CO2 petrol vehicular emissions 41
4.16c:Correlation Table of NOx petrol vehicular emissions 41
4.17: Mean concentrations of diesel vehicular emissions 42
4.18: Correlation table of CO, CO2, and NOx from diesel vehicular emissions. 43
4.19: Mean petrol generator emissions 45
4.20:Correlation table of CO, CO2, and NOx emissions from petrol generators….47
4.21: Emission from petrol-biodiesel fueled SCGG and Effect of biodiesel blend on CO, CO2 and NOx emissions……………………….…………………51
4.22:Effect of biodiesel blend on CO, CO2 and NOx emissions from LCGG. 51
4.23: Emission from petrol-biodiesel fueled motorcycle and effect of biodiesel blend on CO, CO2 and NOx emissions from motorcycle 52
4.24: Emission from diesel-biodiesel fueled generator and effect of biodiesel blend on CO, CO2 and NOx emissions from LCDG 54
CHAPTER ONE
INTRODUCTION
1.1 Introduction
In the last century, the level of carbon dioxide in the atmosphere has increased by more than 30% as a result of human activities. The effects of climate change are becoming more pronounced and they include droughts, floods, heat waves and changes in the weather patterns. Global temperatures have increased by almost 0.8°C over the past 150 years. Without any global action, it is expected that temperatures will increase further by 1.8 – 4 °C by 2100 (IPCC, 1996). It is anticipated that this rise will result in sea level increment of 15 to 95 centimeters. While the transportation sector is crucial to a nation’s economy and personal mobility, it is also a significant source of GHGs. Nearly 50% of global CO, HCs, and NOx emissions from fossil fuel combustion come from internal combustion engines (ICE). The contribution of the transport sector to total CO2 emissions in developed nations is forecast to increase from 20% in 1997 to 30% in 2020 (Ken et al., 2004). The transport sector accounts for almost all the oil demand growth around the world (Ming et al., 2009). The world transportation oil demand has continuously risen with increasing GDP. World forecasts show that transport oil demand in developing nations will increase three times more than in developed nations. Increasing income will cause a tremendous increase in car ownership in developing countries, where the vehicle stock is expected to triple (IEA, 2006). Developing countries account for about 10% of the global automobile population and a little over 20% of the global transport energy consumption. In comparison, the United States alone consumes about 35% of the World’s transport energy (Shiva, 2006).
Road vehicles are among the main consumers of world energy and they dominate global oil utilization, consuming up to 80% of transport energy. The transport sector’s share of oil consumption has been increasing steadily at around 0.6% per year. Current policies are not sufficient to control road vehicle energy use. Even if governments implement all the measures that are currently being considered, projections by the International Energy Agency (IEA) show that road vehicle energy use would still rise between now and 2030 at 1.4% per annum respectively(IEA, 2006). In developing nations, it is envisaged that with rising income and the rapidly rising mobility that accompanies it, the increase in automobile emissions will be even greater than the developed nations. Steady growth in vehicular populations has put environmental stress on urban centers in various forms particularly causing poor air quality. There is growing evidence that links vehicle pollutants to human ill health. Motor vehicles are major emission sources for several air pollutants, including nitrogen oxides (NOx) and carbon monoxide (CO) (Suresh et al., 2009). These pollutants have significant adverse effects on human beings and the environment. Vehicle emissions cause both short and long term problems associated with health effects. For example, HCs and NOx are the precursors of ozone gas, which has effects ranging from short term consequences such as chest pain, decreased lung function, and increased susceptibility to respiratory infection, to possible long-term consequences, such as premature lung aging and chronic respiratory illnesses (WHO, 2005).
The most affected group is the urban inhabitants especially the traffic policemen who are exposed to the fumes for a long period of time. Children attending a school located near a busy way in Utrecht, Netherlands were compared with children attending a school located in the middle of a green area in a suburban area. It was discovered that respiratory diseases were more pronounced in the urban than suburban children (Suresh et al., 2009). The severity of the problem increases when traffic flow is interrupted and the delays and start-stops occur frequently. These phenomena are regularly observed at traffic intersections, junctions and at signalized roadways. Emission rates depend on the characteristics of traffic, vehicles and type of road intersections. The age of a vehicle and maintenance levels also contribute to the emissions of all classes of vehicles. Further, the fuel quality has a direct effect on the vehicular exhaust emissions (Perry and Gee, 1995).
In most developing countries of the world vehicular growth has not been checked properly by environmental regulating authorities leading to increased levels of pollution (Han et al, 2006). Traffic emissions contribute about 50-80% of NO2 and CO concentration in developing countries (Fu, 2001; Goyal, 2006). This situation is alarming and is predicated on the poor economic disposition of developing countries. Poor vehicle maintenance culture and importation of old vehicles, which culminates in an automobile fleet dominated by a class of vehicles known as ‘’super emitters’’ with high emission of harmful pollutants, has raised this figure of emission concentration(Ibrahim, 2009). The increase in this traffic-related pollution is not based on the aforementioned factor only, but also on low quality fuel, poor traffic regulation and lack of air quality implementation force. These are clear indices to high levels of traffic-related pollution in developing countries.
In Nigeria as well as in other developing countries, which are not yet fully industrialized, majority of the air pollution problems result from automobile exhaust. In the major towns of some developing countries, because of tropical nature of the climatic conditions, many activities are performed outdoors. People stay along the busy roads every day either to do their work or to sell their wares. Therefore, the ill effects on health due to air pollution resulting from automobile exhaust emission must be very serious indeed (Ayodeleand Bayero, 2009).