Kinetic study of CO<sub>2</sub> reaction with CaO by a modified random pore model

Nouri, Seyed Mohammad Mahdi; Ebrahim, H. Ale

doi:10.1515/pjct-2016-0014

Cited by 14 publications

(7 citation statements)

References 22 publications

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“…This confirms that a complex model is not necessarily required to obtain reaction kinetics in this instance. This values also agrees well with Nouri and Ebrahim 34 (46 kJ mol -1 ) as well as Dedman and Owen 35 (39 kJ mol -1 ). However, this activation energy differs from the activation energies obtained by other authors.…”

Section: Temperaturesupporting

confidence: 91%

Two-Phase Fluidized Bed Model for Pressurized Carbonation Kinetics of Calcium Oxide

Yao

Zhang

Sceats³

et al. 2017

Energy Fuels

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A two-phase reactor model has been developed using a system of ordinary differential equations in MATLAB to model the carbonation reaction and therefore determine the kinetics of calcium oxide in a pressurised fluidised bed reactor as part of the calcium looping cycle. The model assumes that the particulate and bubble phases are modelled as a CSTR and a PFR respectively. The random pore model developed by Bhatia and Perlmutter1 is incorporated into the system of equations to predict the rate of carbonation for pressures up to 5 bara total, and CO2 partial pressures up to 150 kPa. The surface rate constant and product layer diffusivity in the random pore model expression were obtained by fitting the model to experimental data for a range of pressures, CO2 concentrations and temperatures by minimization of the resid-ual sum of squares. The surface rate constants were found to be between 3.05 and 12.9 x 10-10 m4 mol-1 s-1 for a temper-ature range of 550 to 750 °C. The product layer diffusivities were found to be between 0.06 and 23.6 x 10-13 m2 s-1 for the same temperature range. The surface rate constant and product layer diffusivity activation energy were calculated using the Arrhenius

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Section: Temperaturesupporting

confidence: 91%

Two-Phase Fluidized Bed Model for Pressurized Carbonation Kinetics of Calcium Oxide

Yao

Zhang

Sceats³

et al. 2017

Energy Fuels

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“…A further study obtained the kinetic parameters under recarbonation conditions [101]. A simplified RPM was used by Nouri et al to model carbonation of limestone [102], which showed a similar relationship between reaction order and pCO 2 to Bhatia and Perlmutter [86], although E a in the kinetic control region was larger(~47 kJ mol −1 ). Values of E a in the diffusion region were calculated to be~140 kJ mol −1 [102].…”

Section: Pore Models Homogeneous Particle Models and Rate Equation Tmentioning

confidence: 99%

“…There is some disagreement regarding the reaction order for the kinetic control region. Some studies find the reaction to be F1 up to a pCO 2 of 10 kPa [59,86,102]. However, Grasa et al report that the carbonation reaction is F1 up to 100 kPa, before transitioning to F0 at higher CO 2 partial pressures [35] For diffusion, E a values range between~100 [57] and~270 kJ mol −1 [57] for CaO and natural limestones.…”

Section: Comparison Of Carbonation Kinetic Analysismentioning

confidence: 99%

Kinetics of Solid-Gas Reactions and Their Application to Carbonate Looping Systems

2019

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Reaction kinetics is an important field of study in chemical engineering to translate laboratory-scale studies to large-scale reactor conditions. The procedures used to determine kinetic parameters (activation energy, pre-exponential factor and the reaction model) include model-fitting, model-free and generalized methods, which have been extensively used in published literature to model solid-gas reactions. A comprehensive review of kinetic analysis methods will be presented using the example of carbonate looping, an important process applied to thermochemical energy storage and carbon capture technologies. The kinetic parameters obtained by different methods for both the calcination and carbonation reactions are compared. The experimental conditions, material properties and the kinetic method are found to strongly influence the kinetic parameters and recommendations are provided for the analysis of both reactions. Of the methods, isoconversional techniques are encouraged to arrive at non-mechanistic parameters for calcination, while for carbonation, material characterization is recommended before choosing a specific kinetic analysis method.

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“…For the initial kinetic control region of carbonation, typical values of E a are 19-29 kJ mol −1 in synthetic CaO or natural lime [30], although slightly larger values (i.e., [39][40][41][42][43][44][45][46] [38,39] and 72 kJ mol −1 [37]) have been reported. In the kinetic control region, E a has been reported to be independent of material properties and morphology (although variation in kinetic parameters for synthetic CaO and natural lime may suggest otherwise [30]), while morphological effects have a greater influence in the diffusion control region, leading to a greater disparity in diffusion activation energies [28].…”

Section: Introductionmentioning

confidence: 98%

Comparative Kinetic Analysis of CaCO3/CaO Reaction System for Energy Storage and Carbon Capture

2019

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The calcium carbonate looping cycle is an important reaction system for processes such as thermochemical energy storage and carbon capture technologies, which can be used to lower greenhouse gas emissions associated with the energy industry. Kinetic analysis of the reactions involved (calcination and carbonation) can be used to determine kinetic parameters (activation energy, pre-exponential factor, and the reaction model), which is useful to translate laboratory-scale studies to large-scale reactor conditions. A variety of methods are available and there is a lack of consensus on the kinetic parameters in published literature. In this paper, the calcination of synthesized CaCO3 is modeled using model-fitting methods under two different experimental atmospheres, including 100% CO2, which realistically reflects reactor conditions and is relatively unstudied kinetically. Results are compared with similar studies and model-free methods using a detailed, comparative methodology that has not been carried out previously. Under N2, an activation energy of 204 kJ mol-1 is obtained with the R2 (contracting area) geometric model, which is consistent with various model-fitting and isoconversional analyses. For experiments under CO2, much higher activation energies (up to 1220 kJ mol-1 with a first-order reaction model) are obtained, which has also been observed previously. The carbonation of synthesized CaO is modeled using an intrinsic chemical reaction rate model and an apparent model. Activation energies of 17.45 kJ mol-1 and 59.95 kJ mol-1 are obtained for the kinetic and diffusion control regions, respectively, which are on the lower bounds of literature results. The experimental conditions, material properties, and the kinetic method are found to strongly influence the kinetic parameters, and recommendations are provided for the analysis of both reactions.

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

Cited by 14 publications

References 22 publications

Two-Phase Fluidized Bed Model for Pressurized Carbonation Kinetics of Calcium Oxide

Two-Phase Fluidized Bed Model for Pressurized Carbonation Kinetics of Calcium Oxide

Kinetics of Solid-Gas Reactions and Their Application to Carbonate Looping Systems

Comparative Kinetic Analysis of CaCO3/CaO Reaction System for Energy Storage and Carbon Capture

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

Cited by 14 publications

References 22 publications

Two-Phase Fluidized Bed Model for Pressurized Carbonation Kinetics of Calcium Oxide

Two-Phase Fluidized Bed Model for Pressurized Carbonation Kinetics of Calcium Oxide

Kinetics of Solid-Gas Reactions and Their Application to Carbonate Looping Systems

Comparative Kinetic Analysis of CaCO3/CaO Reaction System for Energy Storage and Carbon Capture

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