Solid-Fluid Operations


In this course several classical unit operations in the chemical/biochemical industries involving fluids and solids will be studied. Examples of such unit operations are filtration, centrifugation, gas cleaning, settling and  fluidization. The course will focus on the phenomelogical understanding of such processes, on mathematical modelling and  process optimization and process design. 


General characterization





Responsible teacher

Rui Manuel Freitas Oliveira


Weekly - 4

Total - 91

Teaching language





  • J.M. Coulson and J.F. Richardson, Chemical Engineering, II Vol., 2ª Ed., 1965, Pergamon Press, London
  • J. P. K. Seville, U. Tüzün and R. Clift, Processing particulate solids, 1ª Ed., 1997, Blackie Academic & Professional, London, UK, ISBN: 0751403768
  • Philip A Schweitzer, Handbook of Separation Techniques for Chemical Engineers, 3ª Ed, 1996, McGraw-Hill, New York, NY, ISBN: 0070570612
  • Albert Rushton, Anthony S. Ward, Richard G. Holdich, Solid-Liquid Filtration and Separation Technology (Hardcover), 2ª Ed, 2000, Wiley-VCH, Germany

Teaching method

In this course the theoretical matters are given in two lessons  a week of 1 hour each. In the practial lessons (1 lesson a week of 2,5 hours) and tutorial (2 hours/week) the study is problem-oriented.

Evaluation method


A - Serão efectuados 3 testes

        Nota final testes = média aritmética dos 3 testes

        Para aproveitamento o mínimo da nota final testes é 9,5 e a nota mínima do teste 1 é 7,5

Nota final

      Nota final "avaliação contínua" =  A (nota final testes)


B - Nota de exame final

       Para aproveitamento a nota mínima de exame final é 9,5

Nota final

       Nota final por "exame final" = B (Nota de exame final) 

Subject matter

  1. Particle characterization: size distributions based on weight, number and surface area. Averages based on number or weight data. Effect of shape. Methods for particle size measurement.
  2. Size reduction of solids: Mechanisms for size reduction.  Dynamics of size distribution. Energy for size reduction. Equipment for size reduction.
  3. Motion of particles in a fluid. Characterization of flow around a sphere: laminar and turbulent flow, Stokes law, skin and form drag friction, terminal settling velocities. Extension to non-spherical particles. Transient motion of particles: vertical acceleration under gravity.
  4. Sedimentation: free and hindered settling, the thickening process, settlers sizing.
  5. Flow in packed columns. Characterization of flow in packed columns. Characterization of packings. Calculation of friction factors and pressure drop. Extension to vacuum columns. Economical design of packed bed columns. Heat and mass transfer.
  6. Fluidization: description of fluidization phenomena; Gas and liquid fluidization, Bubbling behavior, Elutriation, Calculation of minimum fluidizing velocity, Calculation of bed expansion, Estimation of required heat transfer surface area.
  7. Centrifugation: Types of centrifuges. Mechanical design. Fluid pressure and liquid surface form. Separation of two liquids. Separation between suspension solids and liquids. Filtration using centrifuges. Prediction of separation efficiency.
  8. Filtration: Filtration theory The general filtration equation. Cake and filter resistance. Compressible and incompressive cakes. Filtration equipment. Design of plate and frame filters and design of rotary vacuum filters
  9. Gas cleaning: Cyclone design.  The theoretical cut model. Recovery efficiency. Pressure drop in cyclones. Electrostatic separators.


Programs where the course is taught: