Diffusion models and scale-up

Boyadjiev, Christo

doi:10.1016/j.ijheatmasstransfer.2005.08.013

Cited by 33 publications

(13 citation statements)

References 5 publications

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“…Under these hydrodynamic conditions, velocity distributions in the gas and liquid phases in the column cannot be obtained. Only a qualitative theoretical analysis of the absorption kinetics can be carried out employing the diffusion type of model 5–9.…”

Section: Physical Absorptionmentioning

confidence: 99%

“…The mathematical model of the process is created by approximations of the mechanics of continua 5. The model is based on the convection‐diffusion equation 5–9, where the convective transfer in the medium elementary volume results from laminar or turbulent (as a result of large‐scale pulsations) flows, the diffusive transfer is molecular or turbulent (as a result of small‐scale pulsations), and the interphase mass transfer is a volume reaction.…”

Section: Physical Absorptionmentioning

confidence: 99%

“…Practically, waste gas purification in thermal power plants is based on absorption methods. Intensification of SO 2 absorption needs a quantitative description of the process by a suitable mathematical model 5–9, which has to be created on the base of a qualitative analysis of the process mechanism. Solutions of these problems are reported for physical and chemical absorption of SO 2 in column apparatuses 10–12, using one‐phase absorbents like water and water solutions of NaOH, Na 2 CO 3 , and NH 4 OH.…”

Section: Introductionmentioning

confidence: 99%

“…Approximations of the boundary layer theory 5 provide the best mathematical description of the physical process, but modeling of the absorption processes in column apparatuses is difficult, because the finding of the velocity distributions in the phases and interphase surface is practically impossible. The interphase mass transfer problem in column apparatuses can be modeled by means of a new approach based on approximations of the mechanics of continua 5–9, where the mathematical point is equivalent to the medium elementary volume, which is sufficiently small with respect to the column volume and at the same time sufficiently large with regard to the intermolecular volumes of the medium.…”

Section: Introductionmentioning

confidence: 99%

“…Application of the convection‐diffusion type of models for a quantitative description of gas absorption in column apparatuses is not possible because the velocity functions in the convection‐diffusion equations are unknown. The problem can be avoided if the average values of the velocity and concentration over the cross‐sectional area of the column are used 5–9, i.e., the medium elementary volume, in the physical approximations of the mechanics of continua, will be equivalent to a small cylinder with real radius and a height, which is sufficiently small with respect to the column height and at the same time sufficiently large with regard to the intermolecular distances in the medium.…”

Section: Introductionmentioning

confidence: 99%

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Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO₂ Nanoparticles

et al. 2015

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After long electrochemical cycles,t he continuous loss in the capacityo fn ickel oxide (NiO) hinders its practical application as anode materialf or lithium-ion batteries. The need to improve the lithium-storage performance of NiO becomes essential for the accomplishment of high-performance lithium-ion batteries. In this respect, an ew form of 3D NiO, which comprises TiO 2 nanoparticles, has been fabricated and used as anode for lithium-ion storage. The as-prepared 3D NiO-TiO 2 nanocomposites achieved areal discharge capacities of 1.49 and 0.78 mAh cm À2 at current densities of 1.0 and 6.0 mA cm À2 , respectively.T he improvement in the lithium-storage properties of the NiO/TiO 2 nanocomposite is attributedt ot he TiO 2 nanoparticles creating rational interfaces with the NiO, which incredibly supports the NiO surfacea nd improves the structural stability.The low capacity of conventional graphite when used as an anode in lithium-ion batteries (LIBs) has made metal oxides become important lithium-ion battery anode materials not only due to their high theoretical capacity,w hich mostly doubles that of graphite, buta lso playasafe role during the electrochemical process because of their high potential around 1.0 V, which could avoid the problem of lithium plating at very low potential.[1] However, the use of metal oxides for LIBs has been limited mainly by their poor electrical conductivity,e asy agglomeration, and poor cyclic performance, resulting from al arge volumec hange during lithium intercalation and de-intercalation.[2] Since NiO is one of the most common metal oxides, considering its abundancy and low cost, it is also ap romising anode material for LIBs.[3] Compared to its theoretical capacity,t he low capacity of NiO obtained after long repeated cycles further limits its application as anode material for LIBs.[4] Enormous efforts have been made to enhancet he capacityo fN iO after cycling and numerousa dvancements have been achieved. These strategies include designing various nanostructured materials with controllable size, [5] crystallinity, [6] and chemical composition, [7] synthesizing porous and mesoporous NiO to increaset he electrode/electrolyte contact area, [8] using ag ood conductive matrix with carbonaceous materials [4a, 9] and combination with other metal oxidest of orm composites.[10]Recent works have demonstratedakind of additional Li storage generated at the interface of nanomaterials, which addresses that the interface of nanoparticleso rn anocrystals in an anocomposite electrode system can accommodate additional Li ions, leading to ar ise of the total Li storage.[11] For example,W ue tal. reported that TiO 2 -B nanodomains embedded in anatase TiO 2 enhances the lithium-storage capacity of TiO 2 due to coherent interfaces.[11b] Also, as uperior lithium-storage property was also exhibited with the generation of small TiO 2 nanocrystals at the interface of the TiO 2 hollow sphere and the nanocrystals.[12] Also, the small size of the nanoparticles (~5nm) has been reported to be ac rucia...

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Section: Physical Absorptionmentioning

confidence: 99%

Section: Physical Absorptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO₂ Nanoparticles

et al. 2015

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Gas Purification from SO₂ in Thermal Power Plants

et al. 2014

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Solid fuel combustion in thermal power plants, which use sulfur-rich fuels, poses the problem of SO 2 removal from waste gases. In addition, purification of huge amounts of gas with low SO 2 concentration is necessary. A maximum absorption rate could decrease the size of required big apparatuses. Gas purification from low-concentrated SO 2 in physical and chemical absorption is analyzed theoretically. A convection-diffusion type of models is applied for creating average concentration models and for quantitative description of the absorption processes. Theoretical analysis of methods and devices for waste gas purification from SO 2 by CaCO 3 suspension indicates that the process is practically physical absorption.

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An Innovative Approach for Adsorption Column Modeling

Boyadjiev

Popova-Krumova

et al. 2015

Chem Eng & Technol

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An new methody for physical and chemical adsorption modeling in column apparatuses is presented. A convection‐diffusion model is obtained in the approximations of the continua mechanics, where the mathematical point is equivalent to the medium elementary volume which is sufficiently small with respect to the column volume and at the same time sufficiently large with respect to the intermolecular volumes of the medium. The created convection‐diffusion type model allows performing qualitative analysis of the process and obtaining the effect of the velocity radial nonuniformity in the column. An average concentration model is applied for quantitative description of physical and chemical adsorption in the column apparatus. The methods for model equation solutions and model parameter identifications are described.

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Diffusion models and scale-up

Cited by 33 publications

References 5 publications

Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO₂ Nanoparticles

Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO₂ Nanoparticles

Gas Purification from SO₂ in Thermal Power Plants

An Innovative Approach for Adsorption Column Modeling

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Diffusion models and scale-up

Cited by 33 publications

References 5 publications

Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO2 Nanoparticles

Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO2 Nanoparticles

Gas Purification from SO2 in Thermal Power Plants

An Innovative Approach for Adsorption Column Modeling

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Resources

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Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO₂ Nanoparticles

Improving the Lithium‐Storage Properties of Self‐Grown Nickel Oxide: A Back‐Up from TiO₂ Nanoparticles

Gas Purification from SO₂ in Thermal Power Plants