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Investigation of Transport Phenomena in Clarification of Beer by Membrane Using CFD Method

Kazemi, Mohammad Amin | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42436 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Soltanieh, Mohammad
  7. Abstract:
  8. During the brewing process, beer alternately goes through different chemical and biochemical reactions and solid–liquid separation stages. The clarification at the final step of brewing is a highly critical stage when it comes to producing a clear and bright beer. Recently, membrane technology has been successfully used in beer clarification, wherein Kieselguhr (diatomaceous earth) filtration is replaced by cross-flow microfiltration. The most important disadvantages of using microfiltration in clarification of beer is the fouling and flux decline during the process. The phenomenology of fouling mechanisms is still undefined and selection of an appropriate technique for flux enhancement in crossflow microfiltration of beer requires a detailed understanding of the causes of membrane fouling and also the contribution of each cause. In this investigation, crossflow microfiltration of non-alcoholic beer is investigated numerically and it has been verified by experimental data. Due to the presence of particles with different sizes in feed suspension, a modified combination of three mechanisms of particle back-diffusion is developed to predict particle deposition and cake layer buildup during the process. The simulation results show that smaller particles are the main contributor to the cake layer due to a minimum in back transport and are the main reason of the flux decline. On the other hand, larger particles are swept away along the membrane during the filtration process and move toward the membrane exit due to the crossflow. Therefore, the cake enriches with finer particles as the permeate flux decreases. The specific cake resistance was determined experimentally and Carman-Kozeny equation fails to provide a complete theoretical perspective of specific resistance of irregular, non-uniformly sized particles that formed the cake layer. The results of numerical simulation with consideration of particle size distribution are in better agreement with observed data compared to considering a mean diameter for all particle classes
  9. Keywords:
  10. Modeling ; Particle Distribution ; Clarification ; Cross Flow Microfiltration ; Cake Formation ; Flux Decline

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