Visible and near-infrared optical properties of ceria ceramics

Ganesan, Krithiga; Dombrovsky, Leonid A.; Lipiński, Wojciech

doi:10.1016/j.infrared.2012.12.040

Cited by 58 publications

(26 citation statements)

References 33 publications

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“…Though this value, 330 m À 1 , is an order of magnitude smaller than the mean extinction coefficient measured for fibrous alumina with fiber diameters of 1-9 μm (Zhang et al, 2008) (similar to the length scale of the fibers in the ceria particles), it is reasonable to anticipate the extinction coefficient of a packed bed of ceria fibers to be much lower than that of the individual particles. The scattering albedo for the baseline case is 1, which is in agreement with room temperature radiative property measurements on porous ceria structures (Ganesan and Lipinśki, 2011;Ganesan et al, 2013). For this case, thermal radiation is attenuated only by scattering.…”

Section: Reactor Modelsupporting

confidence: 82%

Model of transport and chemical kinetics in a solar thermochemical reactor to split carbon dioxide

Chandran

Davidson

2016

Chemical Engineering Science

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A 3-D model of a solar reactor for the isothermal ceria redox cycle is presented. Reaction rate parameters are extracted for the redox reactions at 1773 K. Recovery of 90% of the sensible heat of the gases is achieved. For CO 2 splitting, CO is produced at 3.6×10 -4 mol s -1 for a 4.2 kW solar input. a b s t r a c t Solar thermochemical reactors to carry out the nonstoichiometric reduction and oxidation of cerium dioxide (ceria) to split water and carbon dioxide provide a pathway to store sunlight in a chemical fuel. One of the challenges in the design of these reactors is understanding the complex coupling of heat and mass transfer and redox chemistry. To elucidate this coupling, we present a three-dimensional, transient model of a recently developed prototype solar reactor that implements an isothermal, pressure-swing ceria redox cycle. Radiative transport is modeled by a hybrid Monte Carlo/finite volume approach and paired with the transport and chemical processes within a fixed bed of porous ceria particles. Morphology specific reaction rate coefficients for the gas-solid reactions in ceria are extracted for the first time from global rate measurements in a bench-top reactor at 1773 K. Results demonstrate the interdependent spatial and temporal variations in temperature, species concentration and reaction rates, and provide insight on the effects of optical properties on reactor performance. For a solar input of 4.2 kW, the reactor achieves nearly isothermal cycling at 1791 K with carbon monoxide produced continuously at 3.6 Â 10 À 4 mol s À 1 . At this temperature, global reaction rates are driven by advective mass transport rates and the intrinsic material thermodynamics. Predicted surface temperatures and fuel production rates compare favorably to measured data.

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Section: Reactor Modelsupporting

confidence: 82%

Model of transport and chemical kinetics in a solar thermochemical reactor to split carbon dioxide

Chandran

Davidson

2016

Chemical Engineering Science

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“…Thus, the use of the radiative transport equation in porous media, may not be well-founded. However, while it is a dramatic geometrical approximation, it has been shown to agree well with experimental data when characterising porous ceria for STRS applications (Dombrovsky et al, 2012;Ganesan et al, 2013a). Simulations of effective radiative transfer (isolated from mass, momentum and other forms of energy transfer) motivated by STRS design have been carried out in conjunction with spectrophotometry set-ups to obtain effective radiative properties for packed beds and porous materials made of ceria (Dombrovsky et al, 2012;Ganesan et al, 2013a,b), zinc oxide (Coray et al, 2009;Schunk et al, 2009b), and a mixture of particles (Jäger et al, 2009).…”

Section: Radiative Properties-experimental and First Principle Studiesmentioning

confidence: 64%

Modelling of solar thermochemical reaction systems

et al. 2017

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a b s t r a c tThis article reviews the progress, challenges and opportunities in numerical modelling of thermal transport, thermochemical reactions and thermomechanics in high-temperature solar thermochemical systems. Continuum-scale models are presented in mathematical detail while highlighting the literature that uses them. The discussion is enhanced by selected examples of numerical studies of solar thermochemical systems for solar fuels and commodity material production. Property predictions necessary for the modelling of solar thermochemical reaction systems are covered.

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“…Ceria, the material of choice in our study, showed only considerable bulk material absorption coefficients for wavelengths smaller than 500 nm [48], corresponding to 25% of the solar irradiation spectrum. For larger wavelengths ceria should be considered semitransparent and a more complete set of effective radiative properties will be needed [31].…”

Section: Problem Statement and Assumptionsmentioning

confidence: 87%

Pore-level engineering of macroporous media for increased performance of solar-driven thermochemical fuel processing

Suter

Steinfeld

Haussener

2014

International Journal of Heat and Mass Transfer

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a b s t r a c tThe performance of high-temperature solar reactors incorporating porous ceramic materials that serve as radiative absorbers and chemical reaction sites can be improved significantly by tailoring their pore structure. We investigated the changes in their effective heat and mass transport properties with increasing mass loading of porous ceramics fabricated by the replica method. We applied a methodology consisting of the experimental characterization of the structure via 3D tomographic techniques coupled to pore-level direct numerical simulations for the determination of the effective transport properties. This approach was extended by using digital image processing on the structure data to allow for artificial changes in the morphological characteristics -corresponding to actual variations in the fabrication process. We derived transport correlations of porous ceria foam with varying mass loading, i.e. reticulate to dense foams with porosity from 0.85 to 0.45. We observed that the correlations proposed in literature do not accurately describe the behavior of low-porosity foams. The numerical findings of this study provide guidance for pore-level engineering of materials used in solar reactors and other high-temperature heat and mass transfer applications.

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Visible and near-infrared optical properties of ceria ceramics

Cited by 58 publications

References 33 publications

Model of transport and chemical kinetics in a solar thermochemical reactor to split carbon dioxide

Model of transport and chemical kinetics in a solar thermochemical reactor to split carbon dioxide

Modelling of solar thermochemical reaction systems

Pore-level engineering of macroporous media for increased performance of solar-driven thermochemical fuel processing

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