Comparative chemical upgrading of Thar and Lakhra coals for enhanced fuel quality

Pakistan features the most extensive coal reserves in the Thar and Lakhra regions; nevertheless, a significant portion remains untapped due to its moisture content, ash impurities, and low energy yield. This study examines the value of hydrogen peroxide and nitric acid in purifying the rock and enhancing its endurance. Laboratory analyses encompassed immersing samples, doing X-ray diffraction, and quantifying routine fuel metrics such as gross calorific value and BTU per pound. Coal samples from the Thar and Lakhra coalfields were analyzed through a regulated chemical process involving nitric acid and hydrogen peroxide. The impact of the treatments was methodically assessed by proximate analysis, Gross Calorific Value measurement, saturation behaviour evaluation, and X-ray diffraction (XRD) characterization to investigate alterations in fuel quality and mineralogical composition. The results obtained validate that immersion in nitric acid removes persistent minerals such as calcite, allowing carbon to emerge and enhancing the fuel's quality in both domains. Hydrogen peroxide also creates more pores without compromising the integrity of the coal. Lakhra coal exhibits the most significant increase, reaching 33,600.15 kJ/kg and 14,446.5 BTU/lb, thereby categorising itself within the bituminous range. Thar coal, still saturated with moisture and mud, reaches 31,603.15 kJ/kg, nearly surpassing the bituminous threshold. Soaking examinations demonstrate inconsistent porosity and water retention, whilst XRD corroborates the mineral alterations sequentially. The study indicates that cost-effective, user-friendly additives can enhance low-quality coal, resulting in cleaner combustion and increased energy density, hence improving its suitability for modern clean-coal technology, industrial heating, and power generation. The team indicates that the subsequent step involves drying moist coal, refining the chemical composition, and examining the environmental consequences to facilitate a statewide implementation.