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2594998 
Journal Article 
CO2 capture from syngas via cyclic carbonation/calcination for a naturally occurring limestone: Modelling and bench-scale testing 
Symonds, RT; Lu, DY; Macchi, A; Hughes, RW; Anthony, EJ 
2009 
Yes 
Chemical Engineering Science
ISSN: 0009-2509 
64 
15 
3536-3543 
WOS:000271298500015 
The intrinsic rate constants of the CaO-CO2 reaction, in the presence of syngas, were studied using a grain model for a naturally occurring calcium oxide-based sorbent using a thermogravimetric analyzer. Over temperatures ranging from 580 to 700 degrees C, it was observed that the presence of CO and H-2 (with steam) during carbonation caused a significant increase in the initial rate of carbonation, which has been attributed to the CaO surface sites catalyzing the water-gas shift reaction, increasing the local CO2 concentration. The water-gas shift reaction was assumed to be responsible for the increase in activation energy from 29.7 to 60.3 kJ/mol for limestone based on the formation of intermediate complexes. Changes in microporosity due to particle sintering during calcination have been credited with the rapid initial decrease in cyclic CaO maximum conversion for limestone particles, whereas the presence of steam during carbonation has been shown to improve the long-term maximum conversion in comparison to previous studies without steam present. (C) 2009 Elsevier Ltd. All rights reserved. 
CO2 capture; Gasification syngas; Ca-sorbent looping; Calcination-carbonation cycle; Modelling