DESIGN AND FABRICATION OF A MEDIUM SIZED HOUSEHOLD BIOGAS PLANT. A RESEARCH PROJECT MATERIAL ON MECHANICAL ENGINEERING
1.1 BACKGROUND OF THE STUDY
Energy is one basic tool for development. Its application ranges from domestic uses to industrial applications for heating furnaces, lighting and running electric motors and other transport applications. It can thus be referred to as a cornerstone of economic and social development (El-Saeidy, 2010). Due to over dependence on biomass and fossil fuel, developing countries like Nigeria face added dilemmas regarding environmental protection. Adaramola and Oyewola (2011) opined that Nigeria is endowed with huge volume of conventional energy resources (crude oil, tar sands, natural gas and coal) as well as reasonable amount of renewable energy resources (e.g. hydro, solar, wind and biomass). However, there is energy shortage in Nigeria because of less potential energy to harness, making hydropower a less desirable energy source (Okoye, 2007). Projected refining capacity only supports 445,000 barrels a day and actual output of these refineries is far below capacity (Okoye 2007).
Scarcity of petroleum and coal threatens supply of fuel throughout the country.This and problems associated with poorpetroleum products combustion has led to research on renewable energy resources. Solar energy, wind energy, different thermal and hydro sources of energy, biogas are all renewable energy resources. Biogas is distinct from other renewable energiesbecause of its unique characteristics of using, controlling and collecting organic wastes and at the same time producing fertilizer and water for use in agricultural irrigation. Biogas does not have any geographical limitations it does not require advanced technology for producing energy.It is very simple to use and apply(Okafor., 2010).
Fossil fuel is one of the principal sources of energy. 86% of all the energy consumed comes from fossil fuels(Kaliyan and Morey , 2009). There are many problems associated with fossil fuels such as high costs and fluctuation of prices, increase in demand, disruption in supply, and environmental pollution. These problems arise because fossil fuels give off carbon dioxide when burnt thereby causing a greenhouse effect. It is therefore a major contributory factor to global warming experienced today.
Agricultural residues and animal wastes are increasingly being diverted for use as domestic fuel to displace fossils fuel and reduce environmental pollution and reduce emission of greenhouse gases. Cassava solid wastes, amongst other plant wastes have been widely used(Oladeji, 2012). Agricultural residues in their natural forms cannot yield desired result as they are mostly loose and are of low density. More so, their combustion cannot be effectively controlled (Oladeji, 2012). Agricultural residues are thus combined with animal wastes and used in production of biogas.