On the modeling of the co<sub>2</sub>‐catalyzed sintering of calcium oxide

Maya, Juan C.; Bhatia, Suresh K.

doi:10.1002/aic.15696

Cited by 19 publications

(17 citation statements)

References 36 publications

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“…A macroscopic description of the pore size evolution in sintering green bodies can be obtained by statistical considerations. While most constitutive sintering models simplify pores as spherical structures, generalized statistical expressions for distribution of cylindrically shaped pore have been presented in the studies Fierro et al and Maya et al Both studies investigated the simultaneous calcination and sintering of calcium oxide ceramics under an atmosphere with CO 2 .…”

Section: Conversion Of Highly Filled Papers Into Paper‐derived Sintermentioning

confidence: 99%

Highly Filled Papers, on their Manufacturing, Processing, and Applications

et al. 2019

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Since more than a decade ago, the research on highly filled papers, as well as paper-derived inorganic materials, has greatly intensified. As presented in this review, highly filled papers as preforms allow for the design of porous or dense, multilayered, and geometrically complex structures. These paperderived ceramic-or metal-based materials are generated by the heattreatment of highly filled papers. Paper-derived materials are potential materials of choice for applications in transportation, energy-generation, environmental conservation, support structures, medical uses, and electronic components. Due to the adjustability of the filler content and the good machinability of highly filled papers, paper-derived sheets or multilayers may include intricate structures and tailored gradients in phase structure or porosity. Paper-derived multilayers also may contain cast ceramic tapes or other functionalized layers, as presented in some examples. Computer-aided manufacturing processes for paper-derived materials can be supplemented by prediction models for the sintering shrinkage in order to identify optimal post-processing steps, stacking orders and orientations for highly filled paper layers within multilayer green bodies. The accuracy of established component-level sintering models can be significantly increased by microstructure models of the highly filled paper. ParameterName Unit α Mismatch parameter for fiber cross-sections, Equation (5) Dimensionless α p Layer position in viscoelastic paper structure model, Equation (2) Dimensionless A 0 Initial amplitude of perturbation, Equations (15) 10 À6 m A(f) Parameter for evolution of instantaneous carbon conversion rate, Equation (7) Dimensionless A diff Source controlled diffusion parameter, Equations (9) 10 À7 N A match Modeling parameter, Equations (8) Dimensionless a Inter-particle contact-area radius, Equations (19) 10 À8 m a Local average pore area, Equation (4) 10 À6 m 2 b Pore geometry constant, Equation (20) Dimensionless ß evo , m evo Empirical constants for grain evolution in SOVS model, Equation (8) Dimensionless ß r(c)p Proportionality constant for bimodal packing fraction determination, Equation (18) Dimensionless C Modeling constant for debindering pressure calculation, Equation (7) 10 À6 (m 2 Á s)/K C 1 , C 2 , C 3 , C 4 , C 5 Parameters in the Riedel model that are determined by the dihedral angle, Equations (9) Dimensionless c glue Heat capacity of the adhesive layers, Equation (3) 10 À6 s c L , c s Volume fraction of larger-sized/smaller-sized particles in a multimodal mixture of particles, Equation (17)and (18) 10 0 vol% c vol Volume concentration of pulp fibers, Equation (4) 10 0 vol% γ, γ 0 Strain relaxation rate of calendered paper with initial value, Equation (2) Dimensionless γ B Grain boundary energy density, Equation (13) 10 0 J m À2 γ b Specific energy for grain boundary diffusion, Equation (9) 10 3 J mol À1 γ S Material surface energy, Equation (8, 11, and 13) 10 0 J m À2 Δ Half of the inter-particle boundary thickness, Equation (19) 10 À8...

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Section: Conversion Of Highly Filled Papers Into Paper‐derived Sintermentioning

confidence: 99%

Highly Filled Papers, on their Manufacturing, Processing, and Applications

et al. 2019

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“…This phenomenon leads to changes in porosity, pore‐radius distribution, and consequently in the effective diffusivity of CO 2 passing through the CaO product layer. Respecting to the CaO sintering under inert atmosphere, there is a consensus among several authors with regard to the mechanism controlling sintering. They stablished using different methods that the solid mass transport by lattice diffusion, which is a densifying mechanism, dominates the CaO sintering under inert atmosphere in the temperature range 700–1400°C.…”

Section: Introductionmentioning

confidence: 99%

“…The former is related to the fact that CO 2 partial pressure is the thermodynamic driving force for calcination; thus, as CO 2 partial pressure approaches its equilibrium value, the reaction rate is slower. Concerning the CO 2 ‐catalyzed sintering of the CaO product layer, it has been established that this gas catalyzes the CaO sintering by surface diffusion and grain‐boundary diffusion . The first step of this catalytic process is the chemisorption of CO 2 on the CaO surface to form

{CO}_{3}^{2 -}

, which catalyzes the mass transport by surface diffusion.…”

Section: Introductionmentioning

confidence: 99%

“…However, these sintering models do not take into account the nonuniformity of microstructure and consider the CO 2 effect in a completely empirical way, making it impossible to understand the physical phenomena involved in the process. In addition, in the aforementioned calcination models with simultaneous sintering, it is usually assumed that the change in surface area is proportional to the change in porosity, which does not occur in many cases . Conversely, a recent study has modeled the CO 2 ‐catalyzed sintering of CaO taking into account the change of the pore‐size distribution, although for nonreactive systems and under constant CO 2 partial pressures …”

Section: Introductionmentioning

confidence: 99%

“…Hence, the general objective of this article is to develop a mathematical model for the calcination of CaCO 3 under atmospheres containing CO 2 that considers the CO 2 effect on the microstructure of the product CaO. This model couples the SCM with the model of CO 2 ‐catalyzed sintering of CaO developed by Maya et al and is validated with experimental data of the evolution of conversion and pore‐size distribution during the calcination of pure CaCO 3 and limestone. Moreover, the CO 2 hindering effect on rate of calcination under conditions near to equilibrium is also evaluated, as well as the effects of intraparticle mass‐transfer resistance and impurities on the overall calcination rate.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the CaO sintering on the calcination rate of CaCO₃ under atmospheres containing CO₂

et al. 2018

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For the calcination of CaCO3 under CO2‐containing atmospheres, a mathematical model taking into account the CO2‐catalyzed sintering of the CaO product layer is developed. In this model, a modified shrinking core model is coupled with a population balance‐based sintering model. By comparing model predictions with experimental data, it is found that CO2 strongly affects the overall calcination rate both at high temperature and CO2 partial pressure, since under these conditions CaO densification considerably reduces the effective diffusivity of CO2 within product layer. It is observed that for large particles, the CO2‐catalyzed sintering of CaO can produce the “die off” phenomenon, which takes place when the reaction stops due to the blockage of pores within product layer. Finally, it was determined that limestone impurities do not significantly affect the calcination reaction under atmospheres containing CO2, because CO2 causes a much greater increase of the CaO sintering rate than limestone impurities do. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3638–3648, 2018

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Modeling a fluidized bed reactor by integrating various scales: Pore, particle, and reactor

et al. 2021

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This work proposes a novel population‐balance based model for a bubbling fluidized bed reactor. This model considers two continuum phases: bubble and emulsion. The evolution of the bubble size distribution was modeled using a population balance, considering both axial and radial motion. This sub‐model involves a new mathematical form for the aggregation frequency, which predicts the migration of bubbles from the reactor wall toward the reactor center. Additionally, reacting particles were considered as a Lagrangian phase, which exchanges mass with emulsion phases. For each particle, the variation of the pore size distribution was also considered. The model presented here accurately predicted the experimental data for biochar gasification in a lab‐scale bubbling fluidized bed reactor. Finally, the aggregation frequency is shown to serve as a scaling parameter.

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On the modeling of the co₂‐catalyzed sintering of calcium oxide

Cited by 19 publications

References 36 publications

Highly Filled Papers, on their Manufacturing, Processing, and Applications

Highly Filled Papers, on their Manufacturing, Processing, and Applications

Effect of the CaO sintering on the calcination rate of CaCO₃ under atmospheres containing CO₂

Modeling a fluidized bed reactor by integrating various scales: Pore, particle, and reactor

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On the modeling of the co2‐catalyzed sintering of calcium oxide

Cited by 19 publications

References 36 publications

Highly Filled Papers, on their Manufacturing, Processing, and Applications

Highly Filled Papers, on their Manufacturing, Processing, and Applications

Effect of the CaO sintering on the calcination rate of CaCO3 under atmospheres containing CO2

Modeling a fluidized bed reactor by integrating various scales: Pore, particle, and reactor

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Product

Resources

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On the modeling of the co₂‐catalyzed sintering of calcium oxide

Effect of the CaO sintering on the calcination rate of CaCO₃ under atmospheres containing CO₂