Dissolution kinetics of South African coal fly ash and the development of a semi-empirical model to predict dissolution
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Association of the Chemical Engineers of Serbia AChE
Abstract
Wet flue gas desulphurization (FGD) is a crucial technology which can be used
to abate the emission of sulphur dioxide in coal power plants. The dissolution
of coal fly ash in adipic acid is investigated by varying acid concentration (0.05–
-0.15 M), particle size (45–150 μm), pH (5.5–7.0), temperature (318–363 K) and
solid-to-liquid ratio (5–15 wt.%) over a period of 60 min which is a crucial step
in wet (FGD). Characterization of the sorbent was done using X–ray fluorescence
(XRF), X–ray diffraction (XRD), Furrier transform infrared (FTIR), scanning
electron microscope (SEM) and Branauer-Emmett-Teller (BET) surface
area. BET surface area results showed an increase in the specific surface area
and SEM observation indicated a porous structure was formed after dissolution.
The experimental data was analyzed using the shrinking core model and
the diffusion through the product layer was found to be the rate limiting step.
The activation energy for the process was calculated to be 10.64 kJ/mol.
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Koech, L. et al. 2015. Dissolution kinetics of South African coal fly ash and the development of a semi-empirical model to predict dissolution. Chemical industry & chemical engineering quarterly, 21(2):319-330. [https://doi.org/10.2298/CICEQ140423032K]