Geochemistry and Industrial Applications of Brown Coals of the Ogwashi-Asaba Formation in Parts of Anambra State, Nigeria

Abstract

Geochemical studies have been carried out on brown coal of the Ogwashi-Asaba Formation in parts of Anambra State, Nigeria, using proximate and ultimate analytical results to evaluate its potentials for industrial utilization. An understanding of the physico-chemical characteristics such as moisture content , volatile matter content, fixed carbon content, and ash content are essential for establishing the quality of the coal. The chemical analysis of the brown coal samples results suggest that fixed carbon varies from 1.51 to 37.50 wt%, moisture content varies from 2.40 to 39.80 wt%, volatile matter varies from 2.44 to 39.92 wt%, and ash content ranges from 6.60 to 70.75 wt%, carbon content ranges from 11.59 wt% to 59.33 wt%, oxygen content ranges from 0.06 to 13.87 wt%, hydrogen content ranges from 0.13 to 4.59 wt%, sulfur content varies from 0.04 to 2.48 wt% and the nitrogen content varies from 1.30% to 1.85 wt%. The high-moisture content poses several challenges for the utilization of lignite, because it lowers the energy density of the fuel and makes its transportation uneconomic over long distances. The analytical results show that the coal cannot be employed in the steel industry for the generation of substantial heat for the working of the furnace but can be used as a steam coal. Proximate analysis and calorific data suggest that the coal belongs to the lowest rank i.e. lignite. The brown coal is less hazardous to the ecosystem because of its significantly low sulfur and nitrogen contents. Based on the results of the study, the brown coal can be used for power generation, gasification, production of industrial chemicals and cement production.