Synthesis and Characterisation of Biodiesel Using Waste Cooking Oil and Calcium Oxide From Welders Slurry
Chapter One
Research Objectives
This research aims to evaluate the pollution level from automobile and generator exhaust gases in Nsukka town by monitoring gaseous emissions from petrol, diesel, and biodiesel blend engines.
The specific objectives of the research include;
- To determine and compare the concentrations of gaseous emissions (CO, CO2and NOx) from different automobile types.
- To determine and compare the concentrations of gaseous emissions(CO, CO2and NOx) from small and large capacity generators.
- To produce biodiesel from waste cooking oil.
- To analyse the impact of biodiesel blends on exhaust emissions.
CHAPTER TWO
LITERATURE REVIEW
Air pollution
Air pollution is the presence of pollutants in the atmosphere from man-made or natural substances in quantities likely to harm human, plant, or animal life; to damage man-made materials and structures; to bring about changes in weather or climate; or to interfere with the enjoyment of life or property (Elsom, 1987). The amount of pollutants released to the atmosphere by fixed or mobile man-made sources is generally associated with the level of economic activity. Meteorological and topographical conditions affect dispersion and transport of these pollutants, which can result in ambient concentrations that may harm people, structures, and the environment. In general, the effects on people are most intense in large urban centers with significant emission sources, unfavorable dispersion characteristics, and high population densities. Although urban air quality in industrial countries has been controlled to some extent during the past two decades, in many developing countries it is worsening and becoming a major threat to the health and welfare of people and the environment(WHO/UNEP, 1992).
Air pollutants are classified in two main categories as either primary or secondary. Primary pollutants are emitted directly into the atmosphere by a stationary or mobile source. Secondary pollutants are formed in the atmosphere as a result of physical and chemical processes such as oxidation. The primary pollutants include CO and NOx. Secondary pollutants include nitrogen dioxide, photochemical oxidants e.g. Ozone, etc. The main sources of air pollutants are either natural or anthropogenic. Natural sources include forest fires, volcanoes, vegetative matter, etc. The anthropogenic sources include industrial processes, power generation, commercial and domestic fuel use, solid waste disposal, transport, etc. Automobiles are by far the predominant contributor to air pollution among the mobile sources.
Vehicle Emissions
Motor vehicles produce more air pollution than any other single human activity (WRI, 1997). Nearly 50 % of global CO and NO2 emissions from fossil fuel combustion come from petrol and diesel engines. In city centres and congested streets, traffic can be responsible for 80-90 % of these pollutants and this situation is particularly severe in cities in developing countries (Whiteleggand Haq, 2003). Vehicle emissions mainly result from fuel combustion or evaporation. The most common types of transport fuels are petrol (in leaded or unleaded form) for light-duty vehicles (such as cars) and diesel fuel for heavy-duty vehicles (such as buses and trucks). Other commercial fuels used in light-duty vehicles include alcohols (such as ethanol and methanol), petrol-alcohol mixtures, compressed natural gas (CNG), and liquefied petroleum gas (LPG). For heavy-duty vehicles other commercially available fuels include petrol, CNG, and LPG. Emissions from motor vehicles with spark ignition engines (for example, petrol fueled vehicles) are from the exhaust, engine crankcase, and fuel system (carburetor, fuel line, and fuel tank). CO2 and water vapour (H2O), the main products of combustion, are emitted in vehicle exhaust(Onursaland Gautam, 1997). The major pollutants emitted from petrol fueled vehicles include CO, and NOX. The air conditioning system, tires, brakes, and other vehicle components also produce emissions.
Factors affecting the emission levels
Internal combustion engines and conventional fuels are the leading contributors to transport related pollution. Road-traffic emissions come from a number of sources. They include exhaust pipe emissions and contributions from friction processes and resuspended road dust. Emission levels depend on three major factors that are categorized as engine design characteristics, non-engine components characteristics, traffic characteristics, road characteristics, and fuel quality.
Engine Design Parameters
Motor vehicle fuel is used to overcome engine and driveline losses, standby and idling, accessories such as air conditioning, overcoming aerodynamic drag, inertia and tyre rolling resistance. The vehicle characteristics that affect the level of emission include type, size, age of a vehicle and condition of its engine. The age of a vehicle and poor maintenance contributes to the higher emission in all classes of vehicle. Further the quality of fuel has a direct effect on the exhaust emissions(Faiz et al., 1996).There are two major types of internal combustion engines that include the diesel engine and the spark ignition petrol engine often called the Otto engine. The petrol engine uses a spark plug to ignite the fuel, while combustion in a diesel engine is started by auto-ignition, due to the heat created during compression. Certain engine design parameters are capable of inducing significant changes in emissions. Most notable among these are air/fuel ratio and mixture preparation, ignition timing, and combustion chamber design and compression ratio.
Air/Fuel Ratio and Mixture Preparation
The air/fuel ratio has a significant effect on all major pollutants (CO and NOx) from petrol engines. In fact, CO emissions are almost totally dependent on air/fuel ratio whereasNOx emissions rates can be strongly influenced depending on other engine design parameters (Robin et al., 2000). For diesel vehicles, HC emissions have a dependence on the equivalence ratio that is defined as actual fuel versus air ratio normalized with respect to the stoichiometric fuel versus air ratio.
CHAPTER THREE
EXPERIMENTAL
Sample Collection
The waste cooking oil was obtained from Chitis restaurant at the University of Nigeria, Nsukka. The waste cooking oil was then transferred into a clean plastic bottle. Afterwards, it was sieved to remove bits of food residues. The sieved waste cooking oil was then collected in a clean conical flask and used for the study.
Characterization of Waste Cooking Oil
Specific Gravity
Specific gravity bottle was used to determine the specific gravity of the oil. A clean and dry specific gravity bottle of 25ml capacity was weighed (W0) and then filled with the water, stopper inserted and reweighed to give (W1). The water was substituted with oil after washing and drying the bottle and weighed to give (W2) (Ibrahim and Onwualu, 2005).The expression for specific gravity (Sp.gr) is: Sp.gr
CHAPTER FOUR
RESULTS AND DISCUSSION
RESULTS
Tables 4.1 to 4.2 are the results of the oil and biodiesel characterization while Tables 4.3 to 4.14 ere the results of exhaust gases measurements.
CHAPTER FIVE
CONCLUSION
This study shows that pollution in Nigeria is high and will continue to increase if left unabated. Tail pipe emission findings from vehicles and generators estimated the highest mean level of NOx emission at 27.1ppm, CO at 3511.7ppm and 6.6% of CO2 for petrol engines and for diesel engines estimated the highest mean level of NOx as 114.7ppm, CO at 744.8ppmand CO2 at 1.6%. Diesel vehicles emit more NOx than the petrol vehicles while petrol engines emit more CO2 and CO than the diesel engines. The emissions from both small and large capacity generators are within the range of vehicular emissions.These amounts exceeded the second European standard (EU 2 standard) for vehicular emissions which Nigeria adopted as its current standard. This implies that persons exposed to these emissions on a daily basis are likely to develop health complications over time as the concentration increases in their bodies.
Large capacity generators emit lesser quantity of the harmful CO and NOx than the small capacity generators.Waste cooking oil which is readily availableis a good feedstock for biodiesel production. Blending petrol or diesel with biodiesel produced from this feedstock reduced exhaust emissions. Biodiesel-diesel blend reduced CO2 and CO emissions in diesel generators but increased the emission of NOx. On the other hand, biodiesel-petrol blend reduced the emission of CO, CO2 and NOx in petrol generators but increased the emission of NOx in petrol motorcycles. This implies that using of biodiesel blended petrol is perfect for both small and large capacity petrol generators but could actually enhance greater NOx emission in biodiesel blended diesel generators and petrol motorcycles.
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