Breakage and coalescence of drops in a batch stirred vessel—II comparison of model and experiments

Sovová, Helena

doi:10.1016/0009-2509(81)85117-2

Cited by 125 publications

(77 citation statements)

References 26 publications

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“…Various generalized phenomenological breakage models have been proposed in the literature in order to relate the drop-size distribution with the basic hydrodynamics and physical properties of the system (Coulaloglou and Tavlarides, 1977;Narsimhan et al, 1979;Sovova, 1981;Chatzi et al, 1989;Chatzi and Kiparissides, 1992).…”

Section: Breakage Interaction Frequencymentioning

confidence: 99%

Steady‐state drop‐size distributions in high holup fraction dispersion systems

Chatzi

Kiparssides

1995

AIChE Journal

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Section: Breakage Interaction Frequencymentioning

confidence: 99%

Steady‐state drop‐size distributions in high holup fraction dispersion systems

Chatzi

Kiparssides

1995

AIChE Journal

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“…Population balance equation (PBE) models have been successfully used to predict size distributions for other particulate processing devices including liquid-liquid dispersers (Alopaeus et al, 1999(Alopaeus et al, , 2002(Alopaeus et al, , 2003Coulaloglou and Tavlarides, 1977;Kostoglou and Karabelas, 2001;Sovova, 1981;Sovova and Prochazka, 1981), liquid-liquid extractors (Ruiz et al, 2002;Ruiz and Padilla, 2004;Simon et al, 2003), and high pressure homogenizers (Hakansson et al, 2009a,b). We have developed a series of increasingly sophisticated PBE models for high pressure homogenizers that account for both breakage and coalescence (Raikar et al, 2009(Raikar et al, , 2010.…”

Section: Introductionmentioning

confidence: 99%

Prediction of emulsion drop size distributions in colloid mills

Maindarkar

Dubbelboer

Meuldijk

et al. 2014

Chemical Engineering Science

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Developed a population balance equation model for emulsification in colloid mill. Derived the function for drop breakage frequency in simple shear flow. Proposed a new daughter drop distribution function for capillary drop breakage. Used a viscosity model to predict the emulsion viscosity at high shear rates. Demonstrated good agreement between measured and predicted drop size distributions. Colloid mills are the most common emulsification devices used in industry for products with high oil content. Drop breakage occurs when the emulsion is flowed through a small gap between rotor and stator under laminar shear conditions. In this paper, we have developed the first full population balance equation (PBE) model for colloid mills and used the model to better understand the relevant drop breakage mechanisms. The PBE model accounted for both drop breakage and coalescence and generated predictions of the drop size distribution after each pass of the emulsion through the colloid mill. Drops were assumed to break due to capillary instability with the distribution of drop sizes resulting from each breakage event studied in detail. A viscosity model was developed to predict the emulsion viscosity as function of the oil fraction and the high shear rates commonly used. Nonlinear optimization was used to estimate adjustable parameters in the breakage and coalescence functions to minimize the least-squares difference between predicted and measured drop size distributions for high oil-to-surfactant emulsions. We concluded that experimentally observed drop volume distributions could not be predicted with daughter drop distribution functions reported in the literature. Improved predictions were obtained using a new bimodal distribution function which captured drop breakage into multiple, nearly uniform daughter drops with a large number of small satellite drops. We also investigated model extensibility for changes in the oil fraction, emulsion flow rate and rotor speed.Published by Elsevier Ltd.

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“…(A17)). The models: Coulaloglou & Tavlarides [11], Sovova [51], Tsouris & Tavlarides [64] are developed based on a phenomenological approach and the model of Laso et al [52] is strictly empirical. The phenomenological models are based on the film drainage theory using the statistic collision rate and the coalescence efficiency:…”

Section: The Coalescence Frequencymentioning

confidence: 99%

“…The model of Sovova [51] consists of an additional energy term to account for the boundary interfacial energy. The model of the coalescence efficiency ( , ') h d d between two droplets is an analogue to the stochastic collision probability of two gas molecules as defined in the kinetic theory of gases.…”

Section: The Coalescence Frequencymentioning

confidence: 99%

See 1 more Smart Citation

LLECMOD: A Bivariate Population Balance Simulation Tool for Liquid- Liquid Extraction Columns

Attarakih¹,

Bart²,

Steinmetz³

et al. 2008

TOCENGJ

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Abstract:The population balance equation finds many applications in modelling poly-dispersed systems arising in many engineering applications such as aerosols dynamics, crystallization, precipitation, granulation, liquid-liquid, gas-liquid, combustion processes and microbial systems. The population balance lays down a modern approach for modelling the complex discrete behaviour of such systems. Due to the industrial importance of liquid-liquid extraction columns for the separation of many chemicals that are not amenable for separation by distillation, a Windows based program called LLECMOD is developed. Due to the multivariate nature of the population of droplets in liquid -liquid extraction columns (with respect to size and solute concentration), a spatially distributed population balance equation is developed. The basis of LLECMOD depends on modern numerical algorithms that couples the computational fluid dynamics and population balances. To avoid the solution of the momentum balance equations (for the continuous and discrete phases), experimental correlations are used for the estimation of the turbulent energy dissipation and the slip velocities of the moving droplets along with interaction frequencies of breakage and coalescence. The design of LLECMOD is flexible in such a way that allows the user to define droplet terminal velocity, energy dissipation, axial dispersion, breakage and coalescence frequencies and the other internal geometrical details of the column. The user input dialog makes the LLECMOD a user-friendly program that enables the user to select the simulation parameters and functions easily. The program is reinforced by a parameter estimation package for the droplet coalescence models. The scale-up and simulation of agitated extraction columns based on the populations balanced model leads to the main application of the simulation tool.

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Breakage and coalescence of drops in a batch stirred vessel—II comparison of model and experiments

Cited by 125 publications

References 26 publications

Steady‐state drop‐size distributions in high holup fraction dispersion systems

Steady‐state drop‐size distributions in high holup fraction dispersion systems

Prediction of emulsion drop size distributions in colloid mills

LLECMOD: A Bivariate Population Balance Simulation Tool for Liquid- Liquid Extraction Columns

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