Abstract
Botswana coal found within the Karoo Basin has received little attention primarily due to limited data on its properties. Several previous researches have been conducted using data for South African coal. However, coal is a heterogeneous material with properties varying not only across different geographic sites but also in iso-seams. Thus, it is important to conduct a study on Botswana coal to determine its combustion characteristics and reactivity. Thermogravimetric analysis was used to study thermal decomposition and determine coal kinetic parameters of coals from the Morupule, Mmamabula and Mabesekwa coalfields. Coal samples were subjected to non-isothermal heating at a heating rate of 25 °C/min in an oxygen atmosphere until a maximum temperature of 1000 °C was reached. Different combustion parameters such as combustion temperatures, and maximum combustion rate were determined from thermogravimetric analysis/derivative thermogravimetric curves. Also determined were the five comprehensive combustion indices for further appreciation of the samples’ combustion traits. Furthermore, the samples were classified based on the chemical composition of the ash. Combustion temperatures were found to be 512.93 ± 3.53 °C to 532.571.36 ± °C ignition temperature, 524.431.17 ± °C to 689.40.56 ± °C peak maximum temperature and 662.771.42 ± °C to 749.73 ± 0.86 °C burnout temperature. Basic oxides in ash could be used to establish the similarities between the coal ash samples via principal component analysis. Proximate-ultimate properties were used to characterize the coal samples into high volatile bituminous and lignite coal. Coal kinetics calculated using pseudo-first-order Arrhenius method yielded activation energies between 42.31 and 60.11 kJ mol−1.
Similar content being viewed by others
References
Aich, S., Behera, D., Nandi, B. K., & Bhattacharya, S. (2020). Relationship between proximate analysis parameters and combustion behaviour of high ash Indian coal. International Journal of Coal Science & Technology, 7(4), 766–777.
Aich, S., Nandi, B. K., & Bhattacharya, S. (2019). Utilization of sal leaves and sal leaves char to improve the combustion performance of reject coal. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 41(19), 2299–2312.
AUDA-NEPAD. (2016). Rapid assessment and gap analysis: Botswana. https://www.se4all-africa.org/fileadmin/uploads/se4all/Documents/Country_RAGAs/Botswana-Rapid-assessment-Gap-Analysis-Final.p
Behera, D., Nandi, B. K., & Bhattacharya, S. (2019). Chemical properties and combustion behavior of constituent relative density fraction of a thermal coal. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 41(6), 654–664.
Bodily, D. M., Wann, J.-P., Chen, W., Zhu, X., Hu, W., & Wadsworth, M. E. (1991). Characterization of mineral and coal pyrite (B. T.-1991 I. C. on C. S. P. International Energy Agency Coal Research Ltd (ed.); pp. 973–976). Butterworth-Heinemann. https://doi.org/10.1016/B978-0-7506-0387-4.50246-1
Chen, Y., Mori, S., & Pan, W.-P. (1995). Estimating the combustibility of various coals by TG-DTA. Energy and Fuels, 9(1), 71–74.
da Silva Filho, C. G., & Milioli, F. E. (2008). A thermogravimetric analysis of the combustion of a Brazilian mineral coal. Química Nova, 31(1), 98–103.
Engin, B., & Atakül, H. (2018). Air and oxy-fuel combustion kinetics of low rank lignites. Journal of the Energy Institute, 91(2), 311–322.
Falcon, R., & Ham, A. J. (1988). The characteristics of Southern African coals. Journal of the South African Institute of Mining and Metallurgy, 88, 145–161.
Guo, L., Zhai, M., Wang, Z., Zhang, Y., & Dong, P. (2018). Comparison of bituminous coal and lignite during combustion: Combustion performance, coking and slagging characteristics. Journal of the Energy Institute, 92(3), 802–812.
Huangfu, W., You, F., Shao, Y., Wang, Z., & Zhu, Y. (2018). Effects of oxygen concentrations and heating rates on non-isothermal combustion properties of jet coal in East China. Procedia Engineering, 211, 262–270.
IRENA. (2021). Renewables readiness assessment: Botswana. www.irena.org/publications
Janković, B., Manić, N., Stojiljković, D., & Jovanović, V. (2020). The assessment of spontaneous ignition potential of coals using TGA–DTG technique. Combustion and Flame, 211, 32–43.
Jolliffe, I. T. (2002). Principal component analysis. Springer-Verlag. https://doi.org/10.1007/0-387-22440-8_1
Kaymakçi, E., & Didari, V. (2002). Relations between coal properties and spontaneous combustion parameters. Turkish Journal of Engineering and Environmental Sciences, 26, 59–64.
Ketlogetswe, C., Mothudi, T. H., & Mothibi, J. (2007). Effectiveness of Botswana’s policy on rural electrification. Energy Policy, 35, 1330–1337.
Kok, M. V. (2003). Fossil fuels: Application of thermal analysis techniques. In M. E. Brown & P. K. Gallagher (Eds.), Applications to inorganic and miscellaneous materials (pp. 371–395). Elsiver.
Lima, A. T., Kirkelund, G. M., Ntuli, F., & Ottosen, L. M. (2022). Screening dilute sources of rare earth elements for their circular recovery. Journal of Geochemical Exploration, 238, 107000.
Liu, Y., Wang, C., & Che, D. (2012). Ignition and kinetics analysis of coal combustion in low oxygen concentration. Energy Sources Part A-Recovery Utilization and Environmental Effects, 34, 810–819.
Maledi, N. B. (2017). Characterisation of mineral matter in South African coals using micro-raman spectroscopy and other techniques [University of the Witwatersrand, Johannesburg]. https://hdl.handle.net/10539/24090
Onifade, M., & Genc, B. (2018). Prediction of the spontaneous combustion liability of coals and coal shales using statistical analysis. Journal of the Southern African Institute of Mining and Metallurgy, 118, 799–808.
Orem, W. H., & Finkelman, R. B. (2003). Coal formation and geochemistry. In F. T. Mackenzie (Ed.), Sediments, diagenesis, and sedimentary rocks: Treatise on geochemistry (Vol. 7, pp. 191–222). Elsevier-Pergamon.
Paya, B. (2011). The coal road map pitso-An overview of Botswana’s resources and future plans.
Qi, X., Li, Q., Zhang, H., & Xin, H. (2017). Thermodynamic characteristics of coal reaction under low oxygen concentration conditions. Journal of the Energy Institute, 90(4), 544–555.
Rosenvold, R. J., Dubow, J. B., & Rajeshwar, K. (1982). Thermal analyses of Ohio bituminous coals. Thermochimica Acta, 53(3), 321–332.
Saloojee, F. (2011). Kinetics of pyrolysis and combustion of a South African coal using the distributed activation energy model. University of the Witwatersrand.
Song, C.-Z., Wen, J.-H., Li, Y.-Y., Dan, H., Shi, X.-Y., & Xin, S. (2017). Thermogravimetric assessment of combustion characteristics of blends of lignite coals with coal gangue. In Proceedings of the 3rd annual international conference on mechanics and mechanical engineering (MME 2016), 490–495.
Speight, J. G. (2015). Handbook of coal analysis: Proximate analysis. https://doi.org/10.1002/9781119037699.ch5
Strezov, V., Lucas, J. A., Evans, T., & Strezov, L. (2004). Effect of heating rate on the thermal properties and devolatilisation of coal. Journal of Thermal Analysis and Calorimetry, 78, 385–397.
Suarez-Ruiz, I. (2012). Organic petrology: An overview. In A. Al-Juboury (Ed.), Petrology—new perspectives and applications (pp. 199–224). Intech. https://doi.org/10.5772/23431
Wang, C., Wang, C., Jia, X., Gao, X., Wang, P., Feng, Q., & Che, D. (2021). Experimental investigation on combustion characteristics and kinetics during co-firing bituminous coal with ultra-low volatile carbon-based solid fuels. Journal of the Energy Institute, 95, 87–100.
Wang, J.-H., Chang, L.-P., Li, F., & Xie, K.-C. (2010). A study on the combustion properties of western chinese coals. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 32(11), 1040–1051.
Wang, Y., Song, Y., Keduan, Z., Li, Y., Teng, Y., He, R., & Liu, Q. (2016). Combustion kinetics of Chinese Shenhua raw coal and its pyrolysis carbocoal. Journal of the Energy Institute, 90, 624–633.
Zhang, H., Dou, B., Li, J., Zhao, L., & Wu, K. (2020). Thermogravimetric kinetics on catalytic combustion of bituminous coal. Journal of the Energy Institute, 93(6), 2526–2535.
Zhang, Q., Luo, M., Yan, L., Yang, A., & Hui, X. (2019). Kinetic analysis of low-rank coal pyrolysis by model-free and model-fitting methods. Journal of Chemistry, 2019, 9075862.
Zhou, P. P. (2016). Development and energy in Africa(DEA)project: A case study for Botswana-Rural Electrification by Grid Electrification.
Acknowledgments
The authors would like to thank the management of Botswana International University of Science and Technology for financing this research.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of Interest
A declaration is made that no competing financial interests nor personal relationships exist that could have appeared to influence the work reported in this paper.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Keboletse, K.P., Ntuli, F., Oladijo, O.P. et al. Comprehensive Analysis of Coal Combustion Characteristics and Kinetic Parameters of Botswana Coal, Morupule, Mmamabula and Mabesekwa Coalfields. Nat Resour Res 32, 2805–2819 (2023). https://doi.org/10.1007/s11053-023-10254-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11053-023-10254-9