Discussions
Corn cob particles are not strongly bound together their 100 % briquettes had higher moisture content than other compositions produced. The moisture content is a measure of the amount of water in the fuel. In solid fuels, moisture can exist in two forms: as free water within the pores and interstices of the fuel, and as bound water which is part of the chemical structure of the material (Borman et al. 1998). Moisture content is a very important property and can greatly affect the burning characteristics of the briquettes (Yang et al. 2005). The briquettes of 100% corn cob had the highest values of moisture content when compared to other compositions of briquettes. The briquetting of coal and corn cob reduces the moisture content. The density decreased with addition of corn cob to the coal and 100% coal briquettes had the highest value. The 100% coal briquettes contained more sulphur but with the briquetting of coal and corn cob, introduction of the sulphur fixing agent Ca(OH)2 the sulphur content reduced. When cooking fuel contained free particles of combustible material it produces more volatile matter, 100% corn cob briquettes generated more volatile matter upon heating than 100% coal briquettes. To reduce the volatile matter and make the briquettes more suitable for combustion the composition of coal and corn cob were varied to yield briquettes with reduced volatile matter. Fixed carbon indicates the proportion of char that remained after the devolitization phase, production of briquettes from coal and corn cob by varying their compositions results in briquettes with reduced carbon content. Since coal is denser than corn cob, the briquettes produced with higher composition of coal had a higher density value than those briquettes of corn cob. The lower the porosity index of the briquettes the higher the density of the briquettes produced, the values showed that 100% coal briquette has a higher density than 100% corn cob. The calorific value (or heating value) is the standard measure of the energy content of a fuel. It is defined as the amount of heat evolved when a unit weight of fuel is completely burnt and the combustion products are cooled to 298k. The ignition time of the briquettes improved with blending coal and corn cob. The briquettes produced are portable, safe to handle and with improved cooking efficiency due to the addition of the corn cob to the coal