This study addresses the design and modification of a gasoline generator to use biogas as an alternative fuel. The biogas was produced from fresh cow dung using a 10m3 fixed dome bio digester and the produced biogas scrubbed to improve its energy content per unit volume. A 1.0 kW Tigmax air-cooled gasoline generator was used for the investigation. The modification involved the fabrication and mounting of a simple external mixing chamber on the air-duct of the carburetor. A comparative analysis of the performance and combustion characteristics of the engine was evaluated separately with petrol and biogas using ten number 100 watts bulb as variable loads. Power output was optimal at 0 to 500 watts, while rapid power output deterioration was noticed above load condition of 500 watts. Overall rated power output reduction of 47% was observed in the study due mainly to high percentage of carbon dioxide. Exhaust gas temperature of the modified engine was comparable to the unmodified engine at load condition of 100-200 W, above 200 W the exhaust temperature lost the linearity. The exhaust emission revealed an improvement in emission at load range of 100-200 W, while 200 W the achieved superiority was lost due to an increased emission of CO and CO2. Improving the scrubbing capacity of the purification and the external mixing chamber is here-by recommended.


Title Page
Table of Contents
List of Tables
List of Figures
List of Appendixes

1. Introduction
1.2. Problem statement
1.3. Objectives
1.3.1. General objective
1.3.2. Specific objectives

2. Literature review
2.1. Overview of Electricity Generation in Nigeria
2.2. Biogas
2.3. Common biomass feedstock for biogas production in Nigeria
2.4. Biomass energy resources in Nigeria
2.5. Biogas plant
2.6. Anaerobic digestion
2.6.1.   Hydrolysis
2.6.2. Acidogenesis
2.6.3. Acetification
2.6.4. Methanization
2.7. Factors affecting the rate of biogas production in anaerobic digestion
2.7.1 Nature of feedstock
2.7.2 pH value
2.7.3 Temperature
2.7.4 Carbon-Nitrogen (C/N) ratio
2.7.5 Retention time
2.7.6 Seeding and start-up procedure
2.7.7 Mixing/stirring
2.8 Biogas utilization
2.8.1 Production of heat and steam
2.8.2 Electricity production or combined heat and power
2.8.3 Vehicle fuel
2.9 Limitation of biogas utilization
2.10 Purification of Biogas
2.10.1Absorption using chemical
2.10.2 Absorption using water
2.10.3 Pressure swing absorption
2.10.4 Membrane separation
2.11 biogas and internal combustion engine utilization
2.12 Modification of engines for biogas utilization
2.12.1 Modification of compression ignition engine
2.12.2. Modification of spark ignition engine
2.13 Component of an internal combustion engine

3. Materials and Methods
3.1 Gasoline generator modification
3.1.1 Test gasoline generator and technical details
3.1.2. Design and fabrication of modification components External mixing chamber Purification chamber
3.1.3 Assembling and installation procedure Installing the mixing chamber Assembling of the component system
3.2 Biogas production
3.2.1 Source of raw material and preliminary handling
3.2.2 Digestion of cow dung
3.3 Evaluation of cow dung and fermenting slurry
3.3.1 Physicochemical analyses. (Analyses of wastes) Moisture content Ash content Crude fibre content Crude protein Crude fat content Total solids Volatile solid
3.3.2 Biochemical analyses (pH and temperature)
3.3.3 Total viable counts (TVC)
3.4 Gas analyses
3.4.1 Flammability test
3.4.2 Composition of flammable biogas
3.5 Performance evaluation of modified gasoline generator
3.5.1 Measurement schemes Electric power output Exhaust gas temperature and emission
3.6 Data collection

4. Results and discussion
4.1 Anaerobic digestion
4.1.1 Digestion evaluation Biogas production Physicochemical analyses (proximate analyses) Biochemical analyses (pH and temperature)
4.1.2 Total viable counts (TVC)
4.2 Modified engine performance evaluation
4.2.1 Electricity voltage output and load bearing capacity
4.2.2 Exhaust gas temperature characteristics
4.2.3 Exhaust emission characteristics

5. Conclusion and Recommendations
5.1 Recommendations
5.2 Conclusion



Energy is an integral component of any socio-economic development and a central factor for eliminating poverty in any society (Aderemi et al., 2009). In Nigeria located on the west coast of Africa, lack of access to wide range of modern energy services has remained a major barrier to improving key indicators of human development (Onafeso, 2006). Presently over 60% of the country population depends almost entirely on fire wood for cooking, heating and agro-processing activities. Petroleum products such as kigasoline and kerosene are marked by acute shortages and mounting price, with the product sold over 300% above the official pump price (Anonymous, 2008). Additionally, electricity which is the foundation of modern economies is non-available and if available is of poor quality or better still unreliable as less than 4,000 MW of the 7,876 MW installed electricity capacity is been generated (Sambo et al., 2010).

The introduction of mechanization and automation of food processing operations to drive conveyors, pumps, compressors and equipments like steam boilers, dryers, refrigeration equipments, ventilation and ovens has made the use of electricity critical in food industries. The non-availability of electricity supply or poor quality and unreliable nature of electricity supply by Power Holding Company of Nigeria (PHCN) has resulted in the increasing use of stand-by generators of various shapes and sizes (Adegoke and Akintude, 2000), which depends entirely on petroleum products as fuel. In spite of the obvious advantage offered by these stand-by generators as a dependable solution to erratic power supply; the re-current perennial petroleum products scarcity and it rising cost contribute to high cost of production and loss of competitive advantage of processed foods when placed side-by-side with the imported ones (Aderemi et al., 2009). Additionally petroleum products are finite in nature and their combustion bye products are major contributors to environmental degradation, climate change and global warmng (Das et al., 2000). Awareness of the limitations of the convectional fuel has enhanced the growing interest in the search for alternate cleaner and sustainable source of energy (Goodger, 1980). Biogas which has a relatively significant comparative advantage due to the country huge biomass

potential estimated to be about 8 x 102 MJ offers a promising sustainable solution (Nwoke and Okonkwo, 2006), however the wastes are usually dumped indiscriminately in landfills and unauthorized areas contributing further to environmental degradation and global warming (Adeola, 1996; Igbinomwanhia and Olanikpekun, 2009). In-order to reduce the current over dependence on fossil fuel, enhance energy availability and safeguard the natural eco-system in the face of Nigeria huge biomass potential (Garba and Sambo, 1992), biogas technology represents a viable alternative due to its simple technology and rural possible adaptability. (Diaho et al., 2005). Biogas is a fuel gas consisting of a mixture of methane (CH4), carbon
dioxide (CO2) and traces of other gases, produced through microbial processes under anaerobic

conditions from bio-degradable materials (Dennis and Burke, 2001). It’s a renewable high quality fuel that burns without leaving soot’s or particulate matter (Merchaim, 1992). Although biogas technology is yet to be adequately exploited in Nigeria and other Africa countries, the technology is a common place in countries like India, China, Pakistan, U.S.A and most European nations (Nwoke and Okonkwo, 2006). Utilization of biogas as fuel in internal combustion engines have witnessed a substantial breakthrough and improvement over the years (Mitzlaff and Mkumbwa, 1980; Mitzlaff, 1988; Huang and Crookes, 1998; Midkiff et al, 2001; Eshan and Naznin, 2005) Although biogas engines are presently not available in Nigeria markets; the crippling fuel prices and high cost of food processing coupled with the growing problem of food wastes management has remain an intractable national problem. Modifying these existing engines via rural adaptable technology to use biogas produced from these food wastes is an essential springboard for a shift to an eco-system friendly technology and sustainable rural development.

1.2 Problem Statement
Energy is a key instrument in accelerating economic growth, alleviating poverty and creating employment opportunities. Epileptic power failure has resulted in an over-dependence on generators driven by fossil fuel. Apart from this, fossil fuel is non-renewable and fast depleting and contributes to ecological degradation. Due to the endemic power shortage in the country and the current fragile enforcement laws governing waste management and use of generators in Nigeria, it is highly appropriate to researched on the use of biogas produced from food and other biodegradable wastes as alternative fuel source for internal combustion engines.....

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Item Type: Project Material  |  Size: 81 pages  |  Chapters: 1-5
Format: MS Word   Delivery: Within 30Mins.


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