Determination of Compressive Strength and Combustibility Potential of Agricultural Waste Briquette

Abstract

This study evaluates the development of a substitute and alternative solid fuel in the form of briquette from agricultural wastes (rice husk, sawdust and cotton stalk charcoal). Four sets of briquette with different grades were produced using a discontinuous briquette production technology, where a single briquette is produced at a time in a closed mould. Some physical properties such as; Length of briquettes (170 mm), diameter of briquettes (50 mm), mass of briquettes (140-160 g), volume of briquettes (133.5 cm3), density of briquettes (1.05-1.20 gm3), texture of briquettes (rough), and colour of briquettes (brown, light brown and mud black), were investigated using physical methods of evaluation. The result of the proximate analysis (moisture 10.5-10.8%, ash 30.3-33.8%, volatile matter 20.5-25.9% and fixed carbon contents 45.2-52.6%. The burning potential tests carried out on the formed briquettes compared to that of firewood showed that firewood boils 5 litres of water in 60 minutes, while Rice husk, Sawdust, Cotton stalk charcoal blended with rice husk, and Sawdust briquettes boils the same volume of water in 35, 30, 20 and 25, minutes respectively. Compressive strength of the briquettes was determined as 155.9, 155.9, 158.1 and 158.1 KN/m2 for rice husk, sawdust, cotton stalk charcoal blended with rice husk and sawdust briquettes respectively. Energy dispersed x-ray fluorescence spectrometer (ED-XRF) analyses revealed the existence of minor and major elemental percentage compositions (Cl, Br, P, K, Ca, Ba, Cu, Zn, Fe, Mn and Si, Ti, V, Cr, Ni, Sr, Rb). Liebig’s and Kjeldahl’s methods of laboratory analyses confirmed the presence of organic elements (C, H, O, N and S) that contributes to the heating value, increase in ignitability, smooth combustion. It can, therefore, be concluded that briquettes produced in this research work provide a better alternative to firewood and charcoal energies, they are eco-friendly, having high heat intensity with smooth burning and are easy to handle, store and transport, they are very cheap, affordable to both rural and semi-urban dwellers.