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

Abstract

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.

Effects of Tryptophan on the Polymorphic Transformation of Calcium Carbonate: Central Composite Design, Characterization, Kinetics, and Thermodynamics

“…As shown in Table 2, the ac-tivation energies were between 56.6 and 442.6 kJ/mol, which was consistent with the results of previous studies. 35,36 The pre-exponential factors were in the range of 3.08 × 10 1 to 6.11 × 10 20 min −1 , in good agreement with the literature. 36 Linear adjustment using the different reaction mechanisms as shown in Table 1 was applied to estimate the reaction mechanism for the thermal degradation of CaCO 3 .…”

“…2 that the thermal degradation of CaCO 3 predicted by the geometric spherical shrinkage mechanism (the R 3 type model) fitted the experimental data best, which was consistent with previous research. 35,36 The regression coefficients ranged between 0.9630 and 0.9954 depending on the applied kinetic model. The R 3 type model presented the highest accuracy (R 2 = 0.9954) of the 11 models studied.…”

Carbonation Kinetics of Fine CaO Particles in a Sound-Assisted Fluidized Bed for Thermochemical Energy Storage

“…In particular, at a fixed CO 2 partial pressure, , i.e. the thermodynamic pressure driving force; therefore, as typical of exothermic reactions, the carbonation reaction has the tendency to become thermodynamically unfavored with increasing temperatures (Fedunik-Hofman et al, 2019b;Sedghkerdar et al, 2015;Sun P. et al, 2008;Yin et al, 2014). In other words, increasing the temperature at fixed P CO 2 , the reverse reaction (calcination) tends to be favored thermodynamically as the equilibrium temperature is approached (870 °C) (Fedunik-Hofman et al, 2019b;Sedghkerdar et al, 2015;Sun P. et al, 2008;Yin et al, 2014).…”

CO2 Capture for Dry Reforming of Natural Gas: Performance and Process Modeling of Calcium Carbonate Looping Using Acid Based CaCO3 Sorbent

“…In this study, the carbonation-calcination cycles in a TGA were simulated by isothermal concentration swings (switching between CO 2 and N 2 ) at 750°C. The isothermal cycles were used to implement the generalized methods of kinetic analysis (Fedunik-Hofman et al, 2019). Then, the performance of the synthetic sorbent such as cyclic CO 2 uptake capacity over 100 cycles of carbon capture, sorbent attrition rate and reaction kinetics were investigated using the batch bubbling fluidized bed reactor as shown in Figure 3.…”

“…Therefore, a more feasible method was performed, which was isothermal cycles at 750°C, by using 15% CO 2 as the simulated flue gas and N 2 for calcination. This method has been widely adopted in the existing pieces of literature for examining the cyclic stability of Ca-based sorbents (Stendardo et al, 2013;Ramezani et al, 2017;Fedunik-Hofman et al, 2019). The sorbent particles, after the cycling experiment, was recovered by sieving and weighed again to determine the extent of attrition.…”