An Improved Form of Shrinking Core Model for Prediction of the Conversion during Reduction Process in Chemical Looping Combustion

Chen, Luming; Yang, Xiaogang; Li, Guang; Wen, Conghua; Li, Xia; Snape, Colin E.

doi:10.1021/acs.energyfuels.6b03036

Cited by 12 publications

(13 citation statements)

References 19 publications

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“…At later stages in the development, detailed kinetic data are needed within any type of simulation for scale‐up and refined design. Depending on the background of the investigation, different reaction models can be proposed and applied . When solid‐solid diffusion is predominant, often a shrinking core approach is applied …”

Section: Methodsmentioning

confidence: 99%

“…An implicit analytical solution of Eq. with a constant gas concentration (

C_{{normalH}_{2}} true)

and at a given temperature results in

t (|, {\overset{X}{true}}_{{normalFe}^{3 +}}) = {normalτ}_{k} ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{1}{3}}) + {normalτ}_{D} 3 ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{2}{3}} - \frac{2}{3} {\overset{X}{true}}_{{normalFe}^{3 +}})

where

{normalτ}_{k} = \frac{r_{o}}{a k} \frac{C_{{normalF normale}^{3 +}}^{normalo}}{C_{{normalH}_{2}}}

{normalτ}_{D} = \frac{b r_{o}^{2}}{6 a D} \frac{C_{{normalFe}^{3 +}}^{o}}{C_{{normalH}_{2}}}

…”

Section: Methodsmentioning

confidence: 99%

“…Equation is used to calculate at what time or temperature a certain conversion is obtained. In dimensionless form the equation can be written as

normalθ (|, \overset{X}{true}) = \frac{{normalτ}_{k}}{{normalτ}_{k} + {normalτ}_{D}} ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{1}{3}}) + \frac{{normalτ}_{D}}{{normalτ}_{k} + {normalτ}_{D}} 3 ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{2}{3}} - \frac{2}{3} {\overset{X}{true}}_{{normalFe}^{3 +}})

normalo normalr normala normals normalθ = \frac{t}{{normalτ}_{k} + {normalτ}_{D}}

…”

Section: Methodsmentioning

confidence: 99%

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Insight in kinetics from pre‐edge features using time resolved in situ XAS

et al. 2017

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The kinetics of reduction of a 10 wt %Fe2O3‐MgAl2O4 spinel were investigated using XRD and time resolved Fe‐K QXANES. The Rietveld refinement of the XRD pattern showed the replacement of Al with Fe in the spinel structure and the formation of MgFeAlOx. The XANES pre‐edge feature was employed to study the reduction kinetics during H2‐TPR (Temperature Programmed Reduction) up to 730°C. About 55% of the Fe3+ in MgFeAlOx was reduced to Fe2+. A shrinking core model, which takes into account both solid‐state diffusion via an oxygen diffusion coefficient, and gas‐solid reaction through a reaction rate coefficient, was applied. The activation energy for chemical reaction showed a linear dependence on the conversion, increasing from 104 to 126 kJ/mol over the course of material reduction. The good accordance between the shrinking core model description and the experimental data indicates that XANES pre‐edge features can be used to correlate changes in material structure and reaction kinetics. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1339–1349, 2018

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Section: Methodsmentioning

confidence: 99%

“…An implicit analytical solution of Eq. with a constant gas concentration (

C_{{normalH}_{2}} true)

and at a given temperature results in

t (|, {\overset{X}{true}}_{{normalFe}^{3 +}}) = {normalτ}_{k} ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{1}{3}}) + {normalτ}_{D} 3 ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{2}{3}} - \frac{2}{3} {\overset{X}{true}}_{{normalFe}^{3 +}})

where

{normalτ}_{k} = \frac{r_{o}}{a k} \frac{C_{{normalF normale}^{3 +}}^{normalo}}{C_{{normalH}_{2}}}

{normalτ}_{D} = \frac{b r_{o}^{2}}{6 a D} \frac{C_{{normalFe}^{3 +}}^{o}}{C_{{normalH}_{2}}}

…”

Section: Methodsmentioning

confidence: 99%

“…Equation is used to calculate at what time or temperature a certain conversion is obtained. In dimensionless form the equation can be written as

normalθ (|, \overset{X}{true}) = \frac{{normalτ}_{k}}{{normalτ}_{k} + {normalτ}_{D}} ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{1}{3}}) + \frac{{normalτ}_{D}}{{normalτ}_{k} + {normalτ}_{D}} 3 ([]|, 1 - {(|, 1 - {\overset{X}{true}}_{{normalFe}^{3 +}})}^{\frac{2}{3}} - \frac{2}{3} {\overset{X}{true}}_{{normalFe}^{3 +}})

normalo normalr normala normals normalθ = \frac{t}{{normalτ}_{k} + {normalτ}_{D}}

…”

Section: Methodsmentioning

confidence: 99%

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Insight in kinetics from pre‐edge features using time resolved in situ XAS

et al. 2017

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“…Other authors [49] [44] have proposed variations for the SCM for irregularly shaped particles that include both reaction and internal diffusional resistances as rate controlling aspects.…”

Section: Pellet Model (Pm)mentioning

confidence: 99%

“…With describing the shape factor of the particle or grain and describing the volume of product formed per unit volume of reactant if significant volume changes occur during solid consumption, refer to [49] for detailed explanations of the later. When is equal to 3 the characteristic expression for the SCM is obtained.…”

Section: Pellet Model (Pm)mentioning

confidence: 99%

Development and Particle Scale Modeling of Metal Oxide Oxygen Carriers in Chemical Looping Applications

Riley¹

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Greenhouse gas (GHG) effects and environmental warming due to CO2 emissions have been considered as the main drivers for climate change. Development of near-term reactor and process engineering solutions by combining fossil fuel based energy production with cost effective and energy-efficient carbon capture are of significant importance to address the challenge of environmental protection and energy sustainability. An Advanced combustion concept called Chemical Looping Combustion (CLC) arose as a bridging technology for clean fuel combustion in energy production with inherent CO2 capture, while standing out as prospective cost-effective and efficient alternative. CLC relies on the use of an oxygen carrier (OC) to transfer oxygen to the fuel source. The choice of OC is often crucial to the application, making the carrier an essential component in the success of the technology. Herein, a protocol is presented to determine oxygen carrier viability in CLC systems that utilize circulating fluidized bed designs. Key physical and reaction properties are discussed for a designed OC candidate. CuFeAlO4, copper-ferri-aluminate, was shown to be viable for advancement to pilot scale testing and a promising candidate that could withstand the harsh conditions of CLC.

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Developing Oxygen Carriers for Chemical Looping Biomass Processing: Challenges and Opportunities

Zhou

Luo

et al. 2020

Advanced Sustainable Systems

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of global average temperature to within 2 °C compared to pre-industrial era, [2] it is necessary to rapidly reduce our reliance on fossil fuels. To this end, tremendous efforts have been put in to ramp up the capacities of renewable energy generation, including solar, wind, hydro, geothermal, tidal, etc. [3] However, non-biological renewables are available intermittenty, location-specific, and require costly infra

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An Improved Form of Shrinking Core Model for Prediction of the Conversion during Reduction Process in Chemical Looping Combustion

Cited by 12 publications

References 19 publications

Insight in kinetics from pre‐edge features using time resolved in situ XAS

Insight in kinetics from pre‐edge features using time resolved in situ XAS

Development and Particle Scale Modeling of Metal Oxide Oxygen Carriers in Chemical Looping Applications

Developing Oxygen Carriers for Chemical Looping Biomass Processing: Challenges and Opportunities

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