DESIGN, CONSTRUCTION AND SIMULATION OF MAIZE COBS FLUIDIZED BED COMBUSTOR

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Author

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Department of Engineering

ABSTRACT
This study adopts the theory of fluidisation to design a combustor suitable for use in the rural communities of Nigeria. The Combustor, which will use sand particles as bed material, will burn maize cobs supplied at 5kg/h to generate heat energy for thermal applications including steam generation. Like most African countries, lack of adequate electricity supply in Nigeria has hampered economic activities, with less than 40% of the rural community connected to the national grid due to high cost of rural electrification exercise. Furthermore, the rural population continuously rely on direct burning of solid biomass (like fuel wood) as means of obtaining much needed heat energy for basic applications like cooking and heating, constituting an environmental nuisance. The study contends that using a bubbling fluidised bed combustor, it is possible to reduce energy poverty in the rural areas of Nigeria, while complying with the sustainable development goals. Chapter one discusses the background of the study, identifying the objectives, research problems, justification and scope of the work. Chapter two reviews the previous documentation on fluidised bed combustion including its history, principle of fluidization and advantage of fluidized beds over conventional methods of burning biomass. This chapter explains the theoretical background of the combustor and also introduces the Ergun 6.2 modeling software used in this work. The third chapter identifies the materials selected and the equations governing the design of the fluidised bed system. The simulation of the fluidised bed, construction procedure and equipment used are also defined in this chapter. Chapter four presents the result of the flue gas analysis, fluid bed and flue gas temperature measurements, with subsequent discussions. The fifth chapter summarizes and concludes the entire study. vii The temperatures of the fluid bed and flue gas during combustion were measured at 837 ºC and 220 ºC respectively using the MASTECH multipurpose clamp meter. The flue gas constituents were also analysed using the gas analyser which gave the concentrations of CO, NOx and SOx at 2ppm, 5ppm and 1ppm respectively.