Coal Deposits in Nigeria: Recent Organic Geochemical Data Interpreted in the Line of their Energy Conversion Efficiencies

Abstract

Coal deposits in Nigeria occur within the Maastrichtian Mamu Formation in the Anambr Basin at Enugu (Enugu State), Owukpa (Benue State), Okaba, Ogboyaga and Omelehn (Kogi State) in the Turonian Awgu Formation in the Middle Benue Trough at Shankodi ner Lafia-Obi (Nasarawa State); in the Maastrichtian Gombe Formation at Maiganga (Gombe State) and within the Turonian Lamja Formation at Lamza (Adamawa State). The Maastrichtian coals are sub bituminous in rank while the Turonian deposits are of high volatile bituminous rank. The deposita Owukpa, Okaba, Oghoyaga, Omelehu, and Lafia-Obi were selected for study of their energy conversion efficiencies. Local combustion, organic geochemical Leco Carbon Sulfur and Rock Eval data were generated on the coals. Combustion studies recording the time it takes same quantimes of water to attain boiling point using some quantities of coal show that the Okaba coal is the moit efficient with 10.0mins; followed by Omelehu (11.4 mins), Owukpa (13.2 mins and 25.0 mins) while the Lafla-Obi coal never brought the water to boiling point. Leco CS shows that higher Corg (TOC) values equivalent to burnable carbon are recorded in the Okaba and Ogboyaga coals. Rock-Evaldat show that highost Hydrogen Index (HI) values equivalent to fuel contentsare recorded in the Okahs coals followed successively by Ogboyaga, Omelchu, Owukpa and the least in Lafia Obi coals High Oxygen Index (OD) values equivalent to smoke or retardants are recorded in the Ogboyaga coul followed successively by the Lafia-Obi, Omelehu, Owukpa and the least in Okaba coals. Integrating and combining the results, the coals from Okaha have the best energy conversion efficiency and therefore most efficient for use in smokeless fuel production and electricity generation with line negative impacts on man and the environment. The Ogboyaga, Lafia-Ohi and Omelchu couls have too much of retardants and will produce too much smoke The Owukpa coals, although low on retardants, have insufficient fuel The Lafia-Obicoals are deficient in fuel and have high retardants in addition to being poorly combustible