CUED Publications database

An investigation of the kinetics of CO2 uptake by a synthetic calcium based sorbent

Liu, W and Dennis, JS and Sultan, DS and Redfern, SAT and Scott, SA (2012) An investigation of the kinetics of CO2 uptake by a synthetic calcium based sorbent. Chemical Engineering Science, 69. pp. 644-658. ISSN 0009-2509

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Abstract

This study examines the kinetics of carbonation by CO2 at temperatures of ca. 750 °C of a synthetic sorbent composed of 15 wt% mayenite (Ca12Al14O33) and CaO, designated HA-85-850, and draws comparisons with the carbonation of a calcined limestone. In-situ XRD has verified the inertness of mayenite, which neither interacts with the active CaO nor does it significantly alter the CaO carbonation–calcination equilibrium. An overlapping grain model was developed to predict the rate and extent of carbonation of HA-85-850 and limestone. In the model, the initial microstructure of the sorbent was defined by a discretised grain size distribution, assuming spherical grains. The initial input to the model – the size distribution of grains – was a fitted parameter, which was in good agreement with measurements made with mercury porosimetry and by the analysis of SEM images of sectioned particles. It was found that the randomly overlapping spherical grain assumption offered great simplicity to the model, despite its approximation to the actual porous structure within a particle. The model was able to predict the performance of the materials well and, particularly, was able to account for changes in rate and extent of reaction as the structure evolved after various numbers of cycles of calcination and carbonation.

Item Type: Article
Uncontrolled Keywords: Absorption Calcium looping diffusion Kinetics Simulation Sorbent
Subjects: UNSPECIFIED
Divisions: Div A > Energy
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 11:25
Last Modified: 13 Oct 2014 01:15
DOI: 10.1016/j.ces.2011.11.036