Open AccessDissolution kinetics of South African coal fly ash and the development of a semi-empirical model to predict dissolution
Author(s) -
Lawrence Koech,
Raymond C. Everson,
Hein W.J.P. Neomagus,
Hilary Rutto
Publication year - 2014
Publication title -
chemical industry and chemical engineering quarterly
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.189
H-Index - 26
eISSN - 2217-7434
pISSN - 1451-9372
DOI - 10.2298/ciceq140423032k
Subject(s) - dissolution , fly ash , scanning electron microscope , sorbent , bet theory , coal , flue gas desulfurization , fourier transform infrared spectroscopy , materials science , diffusion , specific surface area , chemical engineering , mineralogy , chemistry , adsorption , composite material , organic chemistry , physics , thermodynamics , catalysis , engineering
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 (0.05-0.15M), particle size (45- 150μm), pH (5.5-7.0), temperature (318-363K) and solid to liquid ratio (5-15 wt %.) over a period of 60 minutes 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 10.64kJ/mol
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