Comparative study on utilization of charcoal, sawdust and rice husk in heating oven
Segun R. Bello1, T. A. Adegbulugbe2, P. S. N. Onyekwere1
(1. Department of Agricultural Engineering, Federal College of Agriculture P.M.B 7008 Ishiagu, Ebonyi State Nigeria;
2. Department of Agricultural Engineering, Federal College of Agriculture, Moor Plantation, Ibadan Nigeria)
Abstract: Three biofuels, charcoal, sawdust and rice husk were used in furnace and their thermal capacities and efficiency were measured. 0.01 m3 of each fuel used in the tests were measured to and fired in the heating chamber until all the material completely burn out. Air is supplied into the furnace by natural convection through air ducts. The drying chamber was lagged (insulated) by a 25.4 mm air space between inner wall and the outer casing to prevent heat loss. Three tests were replicated on each fuel and the mean values were used to evaluate heat flow by conduction, radiation and the thermal efficiency of the oven. The performance characteristics of the machine, including overall efficiency, drying chamber efficiency and thermal capacities of each fuel were evaluated. The results indicated that charcoal exhibit the highest combustion properties producing 2.54 kJ of energy per hour, sawdust produced 2.68 kJ while rice husk produced the least energy of 1.96 kJ per kg of burnt the products per hour. The overall furnace efficiency of the oven was 75%, and drying chamber efficiency was 62%. Characteristic temperature curves observed in the drying chamber indicated that charcoal attained very high thermal value within a short period than other fuels, while saw dust and rice husk had much lower heat buildup and longer temperature rise response time. By these results, charcoal is suitable for short time heat processes such as baking and roasting, rice husk could be suitable for milk and fruit juice pasteurization, which require heat processing conditions between 63–85℃ for about 15 to 30 minutes. Sawdust can be used in sterilization of meat, fish; soup etc. Charcoal is more environmentally friendly than the other products because of the smokeless burning process thus suitable for indoor cooking.
Keywords: Thermal capacity, heat process, thermal efficiency, differential, temperature
Citation: Segun R. Bello, T. A. Adegbulugbe, P. S. N. Onyekwere. Comparative study on utilization of charcoal, sawdust and rice husk in heating oven. Agric Eng Int: CIGR Journal, 2010, 12(2): 29-33.