Production of Smokeless Briquette Fuel from Sub-bituminous Coal for Domestic and Industrial Uses

摘要

This study highlighted on coal production and reserves in Nigeria, chemical characteristics of air dried coal and utilization potential of the Nigerian coal in the domestic and industrial sectors. It discussed coal briquetting technology and processes involved in producing smokeless briquette fuel - coal drying, screening, crushing and carbonization to remove obnoxious volatile matters. The coal briquetting press developed at Energy Research Center University of Nigeria, Nsukka was used to produce three different briquette samples (B), (C) and (D) using a sub-bituminous coal obtained from Onyeama Mine in Enugu. The coal sample was pulverized, sieved and carbonized at the temperature of about 550℃, and mixed with 5%, 10% and 15% starch-binder concentrations respectively and compacted under pressure of 9 N/mm~2 and allowed to stay for five minutes before ejection. The briquette D possessed better handling quality than briquette B and C, but has lower calorific value, higher ignition time and lower burning rate. The moisture contents and volatiles of the briquettes tend to increase with increase in starch-binder concentrations, while the ash content decreased with an increase in starch-binder concentration. The calorific values and fixed carbon content of the produced briquettes decreased with an increase in the starch-binder concentrations and this could be due to decrease in the coal content of the briquettes, which has a higher calorific value and fixed carbon.