Modelling and simulation of counter-current and confined jet reactors for hydrothermal synthesis of nano-materials

Cai, Yang; Chen, Man; Wang, Xue Z.

doi:10.1016/j.ces.2014.01.006

Cited by 23 publications

(22 citation statements)

References 45 publications

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“…(1) The model is a quasi-steady process which is based on the cylindrical channels without considering the dirt covered on wall and erosion of acid which causes the uneven shape of channel, there is a flow layer which closes the wall, and the dust particles of it are not affected by strong turbulence, pulsation [13], etc.…”

Section: Integrated Technology and Model Hypothesismentioning

confidence: 99%

“…Subsequently, the particulate separation efficiency equations could be rewritten by using vapor condensation mass flux n w as basic parameters followed by (1)- (12): (13) Furthermore, based on the above assumptions, as for an infinite expanding turbulent boundary layer, the correlation of velocity boundary layer thickness δ, thermophoresis temperature boundary layer thickness δ t , and the concentration of the wet (swim) boundary layer thickness δ c can be defined as [12] :…”

Section: Pm 25 Removal Efficiency Of Liquid Film On the Surface Of Tmentioning

confidence: 99%

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Modeling of the Flue Gas Condensation for the PM2.5 Removal Efficiency of a Integrated Technology

Liu

Cheng

2015

Arab J Sci Eng

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A combined pseudo-homogeneous and fractal geometry model was developed to simulate the process of a integrated technology. The technology was proposed to replace heat pipes and WFGD, which is based on the theory that liquid membrane and droplets grow in size by vapor heterogeneous condensation with they acting as nucleation centers and then the grown droplets are removed efficiently by using integrated diverse combinations of condenser pipes and a highly efficient scrubber. The model has been approached useful for both analyzing results and aiding in design of the technology by conducting a twodimensional steady-state model by means of infinitesimal analysis, incorporating with the models of whole fine particles absorption efficiency of a regularly arranged liquid membrane and droplets column group, and the models of geometric classifications for liquid and solid based on the fractal dimension identified by different structural of radius of gyration of liquid-solid interface transition zone. The predicted values were also compared with the experimental results, and they are in excellent agreement. The results showed that: When the fractal dimension d f is 0.3, the calculation result is the most closer to actual experiment parameter. The PM 2.5 diffusion volume flux value V w ranges from 22 and 45 mm/s. List of SymbolsAbbreviations R e Reynolds number of flow gas P r Prandtl number of flow gas S c Schmidt number of water vapor S h Sherwood number F Fanning friction factor K th Thermophoretic coefficient ∇T Temperature gradient of the fluid symbols K th Thermophoresis coefficient C Constant number, C = 0.75, or, C = 0.5 α, γ , p, q Fractal ratio (%) β Blockage, % ε fiber porosity (%) r Circular radius of heat exchange tube (m) W j The width of a single liquid dropletss column (m) r f , The vertical axle line distance of two droplets (m) l Characteristic length of channel (m) d Qualitative dimension size of the channel (m) D f Diameter of PM 2.5 separation of droplets (m) δ Thickness of the temperature boundary layer (m) δ t Vapor concentration boundary layer (m) δ c PM 2.5 concentration boundary layer, respectively (m) δ p Boundary layer thickness of PM 2.5 concentration (m) k Flow gas thermal conductivity [w/(m k)] k w Convective mass transfer coefficient of water vapor (m/s) u Particulate axial velocity (m/s) u j Average air velocity corresponding with W j (m/s) 123 Arab J Sci Eng V w Vapor diffusion volume flux of boundary layer (m/s) V d Particulate migration velocity (m/s) v th Thermophoretic velocity, respectively (m/s) v θ Horizontal direction of gas flow velocity (m/s) v r Perpendicular direction of gas flow velocity (m/s) v d Dust particle velocity (m/s) v p Droplets velocity (m/s) υ g Gas kinematic viscosity (m 2 /s) μ g PM 2.5 dynamic viscosity (m 2 /s) D M Virtual membrane mass transfer coefficient (m 2 /s) D p PM 2.5 diffusion coefficient (m 2 /s) D w Water vapor-air diffusion coefficient, respectively (m 2 /s) n w Water vapor condensation mass flux (kg/(m 2 s)) c p Mass concentration of PM 2.5 compone...

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Section: Integrated Technology and Model Hypothesismentioning

confidence: 99%

Section: Pm 25 Removal Efficiency Of Liquid Film On the Surface Of Tmentioning

confidence: 99%

Modeling of the Flue Gas Condensation for the PM2.5 Removal Efficiency of a Integrated Technology

Liu

Cheng

2015

Arab J Sci Eng

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“…Adsorption layer theory suggests that particle growth happens on pre‐exist layers of atoms or molecules that adsorbed on crystals faces. For rapid reactive crystallization it was thought that in addition surface growth, aggregation of small particles including nuclei is another factor causing crystal size growth …”

Section: Study On the Reaction Crystal Growth And Flowmentioning

confidence: 99%

Continuous reactive crystallization of pharmaceuticals using impinging jet mixers

et al. 2016

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For reactive crystallization of pharmaceuticals that show rapid reaction rate, low solubility of active pharmaceutical ingredient, hence large supersaturation, it was found in a recent study that a process design that integrates an impinging jet mixer and a batch stirred tank, the former to achieve intensive micromixing prior to reaction and crystal nucleation and the later to immediately disperse the formed nuclei or small particles to minimise aggregation but promote crystal growth, has produced high quality crystals. The current investigation studies the hypothesis that due to the short processing time of reactive crystallization, the impinging jet mixer -stirred tank design can be made to operate in continuous mode. The new design combines an impinging jet mixer for feed introduction and reaction, and a continuous stirred tank reactor (CSTR) and a tubular reactor for crystal growth. Study on reactive crystallization of sodium cefuroxime (an antibiotic), using firstly in a 1L CSTR then scaled to 50L CSTR, found that the new design has produced crystals of higher crystallinity, narrower particle size, and improved product stability, than the conventional batch crystallizer.

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“…As a result, some researchers have questioned the applicability of the traditional crystal interface growth theory, and proposed new mechanisms. For example, some researchers believe that it is the aggregation that dominates the crystal growth process [3,4].…”

Section: Introductionmentioning

confidence: 99%

Novel Impinging Jet and Continuous Crystallizer Design for Rapid Reactive Crystallization of Pharmaceuticals

Liu

Cai

Wang

2015

Procedia Engineering

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Reactive crystallization is an important operation in the pharmaceutical industry for the production of the active pharmaceutical ingredients (APIs), but has not been as widely studied as cooling or anti-solvent crystallization. Reactive crystallization has many unique features that make them different from cooling or anti-solvent crystallization, even leading to some concepts and methods not directly applicable to the former. Literature survey reveals that previous research on reactive crystallization has mainly been conducted for inorganic materials which are known to be simpler than crystallization of organic molecules. The focus of this research project was to carry out research on the process design and optimization of organic reactive crystallization. The objective was to research on novel crystallizer designs that suit and take advantages of the features of reactive crystallization, and on advanced modeling and optimization techniques with the aim of manufacturing high quality products. Process analytical technology was used as a supporting tool to achieve the above stated objectives. The results showed that by using novel impinging jet design, the product had uniform size distribution and superior crystallinity. In addition, continuous process design can achieve a greater amount of product handling and reduce the batch-to-batch variation.

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Modelling and simulation of counter-current and confined jet reactors for hydrothermal synthesis of nano-materials

Cited by 23 publications

References 45 publications

Modeling of the Flue Gas Condensation for the PM2.5 Removal Efficiency of a Integrated Technology

Modeling of the Flue Gas Condensation for the PM2.5 Removal Efficiency of a Integrated Technology

Continuous reactive crystallization of pharmaceuticals using impinging jet mixers

Novel Impinging Jet and Continuous Crystallizer Design for Rapid Reactive Crystallization of Pharmaceuticals

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