Mathematical modeling of CO2 removal using carbonation with CaO: The grain model

Abstract

CaO carbonation with CO 2 is potentially a very important reaction for CO 2 removal from exhaust gas produced in power plants and other metallurgical plants and for hydrogen production by promoting water gas shift reaction in fossil fuel gasification. A mathematical model based on the grain model was applied for modeling of this reaction. Diffusion of gaseous phase through the product layer and structural change of the grains were considered in the model. The modeling results show that ignoring the reaction kinetics controlling regime in the early stage of the reaction and replacing it with a regime considering both the reaction kinetics and diffusion can generate good simulation results. The frequency factor of the reaction rate equation and the diffusivity of CO 2 through the CaCO 3 layer were justified to get the best fit at different temperature range from 400 to 750 o C with respect to experimental data in the literature. The mathematical model switches to a pure diffusion controlling regime at final stage of reaction.

Investigation of CaO–CO2 reaction kinetics by in-situ XRD using synchrotron radiation

“…The chemical reaction CaO (s) þCO 2(g) 2CaCO 3(s) is reversible and hence this technology is based on cyclic stages of carbonation and of calcination and offers a number of advantages including a high sorption capacity for CO 2 at high temperatures, a low cost of sorbent manufacturing and regeneration, and the abundance of its natural precursor. Even though attention has been paid in literature to the carbonation reaction and to its kinetics (Bathia and Perlmutter, 1983;Kyaw et al, 1996Kyaw et al, , 1998Lee, 2004;Sun et al, 2008a;Grasa et al, 2009;Khoshandam et al, 2010;Li et al, 2012;Yu et al, 2012b;Wu and Lan, 2012;Rouchon et al, 2013;Zhou et al, 2013), several aspects of the carbonation reaction are still not clearly understood.…”

Enhanced cyclic stability of CO2 adsorption capacity of CaO-based sorbents using La2O3 or Ca12Al14O33 as additives

“…One potential approach is the capture of CO 2 from flue gas followed by its sequestration in geological formations or perhaps ocean storage [1][2][3][4]. The purpose of CO 2 capture is to produce a concentrated stream of CO 2 suitable for compression and piping to a storage site.…”

Kinetic study of CO2 reaction with CaO by a modified random pore model

“…Their model also considers diffusion and transport effects, including the buildup of product layer. Khoshandam et al developed a grain model to predict the carbonation reaction behavior 8 . Sun et al used grain model to obtain kinetic constants for calcined limestone and dolomite…”