Journal of the Southern African Institute of Mining and Metallurgy
On-line version ISSN 2411-9717
BADA, S.O.; FALCON, R.M.S.; FALCON, L.M. and MAKHULA, M.J.. Thermogravimetric investigation of macadamia nut shell, coal, and anthracite in different combustion atmospheres. J. S. Afr. Inst. Min. Metall. [online]. 2015, vol.115, n.8, pp. 741-746. ISSN 2411-9717. http://dx.doi.org/10.17159/2411-9717/2015/V115N8A10.
The combustion and co-combustion behaviour of macadamia nut shell, high-ash coal, and anthracite, along with their blends was studied using thermogravimetry. The reactivities of all samples were analysed in air, oxygen, and CO2 atmospheres and at different heating rates from 10 to 40°C/min. Macadamia shell was found to have a lower ash content, 0.36%, than coal with 27.49% ash. The calorific values were similar, 19.64 MJ/kg and 19.44 MJ/kg respectively. The differential thermogravimetric results indicate that as the heating rates increase the ignition, peak, and burnout temperatures increase significantly, leading to high combustion rates. The interaction between the fuels was evaluated using the weighted average model, and the results indicated that there is more synergetic interaction between 20% macadamia plus 80% coal under oxygen than in air and CO2 atmospheres. The results of the investigation provide the combustion and co-combustion characteristics of various samples and their blends and indicate their combustion compatibilities.
Keywords : anthracite; blending; coal; macadamia shell; combustion.