Physicochemical characterization and thermal decompostion of Garin Maiganga coal

Abstract

The paper examined physicochemical and thermal characteristics of the newly discovered Garin Maiganga (GMG) coal from Nigeria. The physicochemical characterization comprised of elemental, proximate, calorific value, and classification (rank) analyses. Thermal analysis was examined using combined Thermogravimetric (TG) and Derivative Thermogravimetric analyses (DTG). Hence, the coal was heated from 30°C to 1000°C at 20°C/min under inert conditions to examine its thermal degradation behaviour and temperature profile characteristics (TPC). The results indicated that the GMG coal fuel properties consist of low Ash, Nitrogen, and Sulphur content. Moisture content was > 5%, Volatile Matter > 50%, Fixed Carbon > 22%, and Heating Value (HHV) 23.74 MJ/kg. Based on its fuel properties, the GMG coal can be classified as a Sub-Bituminous B, non-agglomerating low rank coal (LRC). The GMG coal TPCs – onset, peak, and offset temperatures – were 382.70°C, 454.60°C, and 527.80°C, respectively. The DTG profile revealed four (4) endothermic peaks corresponding to loss of moisture (drying), volatile matter (devolatization), and coke formation. The residual mass Rm was 50.16%, which indicates that higher temperatures above 1000°C are required for the complete pyrolytic decomposition of the GMG coal. In conclusion, the results indicate that the GMG coal is potentially suitable for future utilization in electric power generation and the manufacture of cement and steel.