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Applied Biochemistry and Biotechnology

, Volume 98, Issue 1–9, pp 1187–1206 | Cite as

Molecular distillation

Rigorous modeling and simulation for recovering vitamin E from vegetal oils
  • C. B. Batistella
  • E. B. Moraes
  • R. Maciel Filho
  • M. R. Wolf MacielEmail author
Article

Abstract

In this work, important results from simulations are presented, showing the potentiality of the molecular distillation process for recovering vitamin E from vegetal oils. Two types of molecular distillators are considered: falling film and centrifugal. The results emphasize the degree of recovery and factors that influence substantially the performance of the molecular distillators, such as feed flow rate, residence time, and process temperature. Moreover, they show that each type of molecular distillator enables one to operate under specific residence time and temperature. Therefore, a careful analysis must be made in order to determine the best equipment and operating conditions for obtaining products with high quality and concentration, and reduced problems of material thermal decomposition. Vitamin E (tocopherols) from vegetal oils, more specifically, from the deodorizer distillate of soya oil, was the studied case.

Index Entries

Molecular distillation vegetal oils vitamin E soya oil 

Nomenclature

C

Concentration, in mole fraction

Cs

Surface concentration, in mole fraction

d

Molecular diameter (m)

Di

Diffusion coefficient (m2/s)

dt

Time interval (s)

E

Evaporation rate (kg/m2·s)

Ea

Evaporation rate, (molecules/m2·s)

F

Surface ratio

fi

Distribution function

g

Gravitational acceleration (m/s2), molecular relative velocity in the vapor phase (m/s)

h

Distance between evaporator and condenser surfaces (m)

Jij

Integral of the collision

k

Anisotropy of vapor (equation 1), Boltzman constant (vapor phase)

L

Evaporator length (m)

m

Mass flow rate (kg/s)

Mi

Molar mass (kg/kg·mol)

Mm

Molecular mass (kg)

n

Number of components in the liquid mixture, number of molecules (vapor phase)

Nav

Avogadro’s number

Nc

Number of collisions

Nm

Number of molecules

P

System pressure (Pa)

Pisat

Vapor pressure (Pa)

r

Radial coordinate (m)

R

Outer radius of condenser (m)

Rg

Universal gas constant, (J/kmol·K)

S

Film thickness (m)

T

Temperature (K)

Ts

Surface temperature (K)

u

Velocity in x direction, liquid film or molecules (vapor phase) (m/s)

v

Velocity in y direction, liquid film or molecules (vapor phase) (m/s)

w

Velocity of the molecules in z direction (m/s)

Wz

Velocity in z (m/s)

x

Distance along rotor surface (m)

y

Distance perpendicular to rotor surface (m)

z

Axial coordinate (m)

Greek Symbols

α

Thermal diffusivity (m2/s)

β

Mean path of vapor molecule (m)

ΔH

Evaporation enthalpy (J/kg)

ø

Cone half-angle (rad)

λ

Thermal conductivity (W/m(K)

η

Viscosity (Pa(s)

μ

Cinematic viscosity (m2/s)

ρ

Density (kg/m3)

Ω

Rotor speed (rad/s)

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References

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Copyright information

© Humana Press Inc. 2002

Authors and Affiliations

  • C. B. Batistella
    • 1
  • E. B. Moraes
    • 1
  • R. Maciel Filho
    • 1
  • M. R. Wolf Maciel
    • 1
    Email author
  1. 1.Separation Process Development Laboratory (LDPS). Faculty of Chemical EngineeringState University of Campinas, (UNICAMP)Campinas-SPBrazil

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