Coal quality enhancement by using bio extracts of carissa carandas fruits in combination with Hydro Fluoric acid

• Published in: International journal of coal preparation and utilization 2024-12, Vol.44 (12), p.2119-2138
• Main Authors: Reddy Ulavapalli, Gangadhara, Koyilapu, Rambabu, Charan, T. Gouri, Krishna, V. Murali, Reddy, G. V. Subba
• Format: Article
• Language: English
• Subjects: Alkaline earth metals; Aluminum oxide; Ash; Ashes; Beneficiation; bio extract; Biomaterials; Biomedical materials; Bituminous coal; Calorific value; Clinker; Coal; Coal beneficiation; Combustion; Fruits; Hydrofluoric acid; Iron oxides; Leaching; Metal oxides; Mineral composition; Power plants; Silica; Sulfur; Sulfur content; Thermal power; Thermal power plants
• ISSN: 1939-2699; 1939-2702
• DOI: 10.1080/19392699.2024.2310653

This paper addresses the imperative need for environmentally sustainable beneficiation technologies tailored for low-rank coals, constituting about 50% of global coal deposits. The focus is on recent advancements in bio-beneficiation methods for sub-bituminous coals in thermal power stations, employing "bio extract of Carissa carandas fruits" with lower concentrations of Hydrofluoric acid. The objective is to enhance coal quality by reducing ash content and adjusting mineral composition to mitigate clinker formation during combustion. The research investigates simultaneous coal treatment with bio extract and low-concentration Hydrofluoric acid. While traditional beneficiation techniques, such as physical, chemical, and physicochemical methods, have been extensively used, a research gap is identified in green methods utilizing biomaterial extracts to remove/reduce metal oxides from coal and the need to regulate the silica-to-alumina ratio in coal composition, for resolving the issue of clinker formation. The investigation demonstrates the bio extract's efficacy in leaching alumina, iron oxide, and alkali/alkaline earth metal oxides from coal, significantly reducing ash content. Consequently, there is a remarkable increase in coal's gross calorific value post bio-beneficiation, accompanied by a significant reduction in sulfur content in addition to the decrease in tendency of clinker formation of coal during combustion. This study is a significant contribution to the field of environmentally friendly coal beneficiation and to reduce the tendency of clinker formation during combustion.