Influence of added potassium and sodium carbonates on CO2 reactivity of the char from a demineralized inertinite rich bituminous coal

• Published in: Journal of analytical and applied pyrolysis Vol. 96; pp. 188 - 195
• Main Authors: Klopper, L., Strydom, C.A., Bunt, J.R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2012
• Subjects: carbon dioxide; catalysts; Catalytic gasification; coal; heat treatment; Inertinite rich bituminous coal; nitrogen; potassium; Potassium carbonate; potassium chloride; pyrolysis; sodium; Sodium carbonate; sodium chloride; surface area; Thermal treatment; X-ray diffraction; Catalytic gasification; Sodium carbonate; Inertinite rich bituminous coal; Potassium carbonate; Thermal treatment
• ISSN: 0165-2370; 1873-250X
• DOI: 10.1016/j.jaap.2012.04.005

► The paper describes the influence of potassium and sodium carbonates on the CO2 (gasification processes) reactivity of an inertinite rich South African coal. ► Addition of K2CO3, Na2CO3 and their mixture showed an increase in the CO2 reactivity of the char prepared from the demineralized coal at 900°C in nitrogen. ► Addition of the catalysts to the coal before preparing the char resulted in better CO2 conversion than addition of the catalysts to the prepared char.
The addition of K2CO3, Na2CO3 and a mixture of the two catalysts showed an increase in the CO2 reactivity of the char prepared from the demineralized inertinite rich bitumious coal at 900°C in nitrogen. The CO2 reactivity of the char is higher when the catalysts are added to the coal before preparing the char in comparison to addition of the catalyst to the prepared char. The distribution of the catalyst on the char particles thus seems to be better upon addition of the catalyst to the coal (before charring). An added effect could be the evolution of CO2 during charring that may increase the surface area of the produced char. The surface area values of the chars (>400m2/g) were higher than the values for the demineralized coal samples (approximately 150m2/g) and the values for the char prepared from the coal with added catalysts increased from 413 to 445m2/g. XRF, XRD and QEMSCAN analyses were performed to determine the species of K2CO3 and Na2CO3 formed during thermal treatment of the samples. KCl, NaCl, K2O and Na2O are some of the species that were detected.