CHEMICAL AND PYROLYTIC THERMOGRAVIMETRIC CHARACTERIZATION OF NIGERIAN BITUMINOUS COALS

Abstract

The discovery of new coal deposits in developing countries like Nigeria, presents solutions to energy crises and the prospects of socioeconomic growth and development. Furthermore, the quest for sustainable energy to limit global warming, climate change and environmental degradation has necessitated the exploration for alternatives using clean technologies such as coal pyrolysis. However, lack of comprehensive data on their chemical and thermochemical properties has greatly limited their utilization. The chemical properties, rank (classification) and thermal decomposition profiles under pyrolysis conditions of two Nigerian bituminous coals, Afuze (AFZ) and Shankodi-Jangwa (SKJ) were studied. The results indicate that the coals contain high proportions of CHNSO and sufficiently high heating value for future utilization. Coal classification revealed that Afuze (AFZ) coal possesses high rank, maturity and coal properties compared to Shankodi-Jangwa (SKJ) coal. Thermal analysis demonstrated pyrolysis of the coals occurred in three stages; drying (30-200 °C), devolatilization (200-600 °C) and char decomposition (600-1000 °C). Thermal analysis also indicated that pyrolysis at 1000 °C is not sufficient for complete pyrolysis. In general, the thermochemical and pyrolytic fuel properties indicate the coals can be potentially utilized for future clean coal applications.