Optimal Nonlinear Control of Poly Vinyl Acetate CSTR

Hassanzadeh, Bardia | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39860 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Pishvaie, Mahmoud Reza
  7. Abstract:
  8. Nonlinear nature of polymerization reactors has always attracted great attentions in various scientific areas such as modeling, simulation, dynamical behavior investigation and control engineering as well. Free radical polymerization in continuous reactors, whether in terms of design and startup or in terms of economical concerns, has numerous fans in industrial aspects. In the following thesis, the dynamical behavior of continuous stirred tank reactor of Vinyl Acetate free radical polymerization is examined in an industrial scale. A control system with optimum performance is designed for this CSTR as well. According to the common behavior of this type of reactor, it may demonstrate multiplicities and limit cycles in different districts of steady-state conditions. Occurrence of such unusual behaviors is investigated through bifurcation analysis in detail. Another challenge in the design of the control system is dealing with multi-rate measurements that usually come up along with significant delays in calculation of moments comparing to the fast measurement of reactor temperature. In order to solve this problem a multi-rate nonlinear extended Kalman filter is designed to have an online estimation of the states of the system. This online estimation is not only optimum but also decreases measurement costs noticeably. Robustness of the closed loop response to the model mismatch has shown satisfactory results as well.

  9. Keywords:
  10. Polyvinylacetate ; Polymerization ; Free Radicals Polymerization ; Stirred Tank Reactor ; Bifurcation ; Steady State Multiplicity ; Nonlinear Extended Kalman Filter ; Multirate State Estimation

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