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Evaluating the Effects of Operating Conditions on Particle Size and Molecular Weight Distributions in Emulsion Polymerization of Styrene

Vafa, Ehsan | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39222 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Shahrokhi, Mohammad
  7. Abstract:
  8. In this work, a comprehensive dynamic model has been used for styrene emulsion polymerization in a semi-batch reactor to predict the evolution of product particle size and molecular weight distributions under non-isothermal condition. Method of moments has been applied for solving the population balance equations and the results are compared with the results obtained from finite-volume method as a precise technique. A sensitivity analysis respect to perturbation in initial values of various reagents, species and the reactor temperature has been performed to identify suitable manipulated variables for closed-loop control of the reactor. The detailed model is used to generate optimal feed rates of surfactant and chain transfer agent to attain target PSD and MWD, using the Patternsearch algorithm as an optimization tool. For on-line inferential feedback control of PSD and MWD, it was assumed that continuous measurement of conductivity is possible and measurement of unreacted CTA is available every 5 minutes, using GC instrument. The amount of unreacted CTA between sampling times was estimated, using an open-loop observer based on reaction calorimetery. Having the optimal trajectories of conductivity and unreacted CTA as set points, a new inferential closed-loop strategy has been proposed for controlling PSD and MWD simultaneously. It was shown that the proposed control scheme has a better performance compared to open-loop control of PSD and MWD
  9. Keywords:
  10. Emulsion Polymerization ; Particles Size Distribution ; Molecular Mass Distribution ; Simulation ; Control ; Sensitivity Analysis

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