Modeling and optimization of emulsification

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Modeling and optimization of emulsification

• Researcher Martijn Stork
• Supervisors Okko Bosgra
• Jan Wieringa and Ardjan Krijgsman (Unilever
  RD Vlaardingen)
• Date May 23, 2003

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Outline

• Introduction
• Objectives
• Approach
• Modeling Experiments
• Future work

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Emulsions

• An emulsion is a dispersion of drops of one
  liquid in another one with which it is
  incompletely miscible
• Dressings, mayonnaises, skin creams, sauces and
  ice cream ingredients.

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Equipment
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Current manufacturing

• Manufacturing according to traditional methods
  and fixed recipes it is not clear if the process
  is operated in an optimal way
• No feedback during manufacturing (no disturbance
  rejection)
• Process time 5-10 minutes.

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Objectives

• Gaining insight in the dynamic behavior of
  emulsification
• Model-based optimization of the operation
  procedure of emulsification
• The tools used should be applicable (without too
  much experimental effort) for a wide range of
  emulsions and equipment scales.

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Approach

• Development of a theoretical model
• Parameter estimation and model validation
• Development of an optimization approach
• Implementation of optimal input trajectories on
  the plant.

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Model

• Reactor model (4 compartments, 1 population
  balance equation per compartment)
• Drop model (breakage condition, breakage
  frequency, number and sizes of daughter drops)
• Pump model
• Viscosity model

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Compartments

• Laminar compartment small volume round stirrer
  with drop breakage
• Bulk compartment no breakage
• Colloid mill compartment drop breakage
• Piping compartment no breakage

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Population balance equations

• Bulk compartment
• Laminar compartment

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Modeling of net birth rate

• Sink term
• Source term

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Drop model

• Capillary number
• Breakage as capillary number exceeds certain
  critical value.

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Drop model

• Break freq.
• Number
• Size

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Ncm35, Volfrac0.5
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Model adaptations

• Break freq.
• Sizes
• Model contains 4
  fit parameters
  

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Ncm35, Volfrac0.5
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Ncm50, Volfrac0.5
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Discussion

• Drop model predicts trends well
• DSD shifts to the left
• Peak value decreases for higher volume fractions
• Peak value decreases for higher rotor speeds
• Drop model does not predict the shape of the DSD
  correctly

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Future work

• Optimization studies
• Implementation of optimal trajectories on small
  scale plant