Optimization Based Control and Estimation in Fed-Batch Processes

• Author / Creator

  Abdollahi, Javad

• There are varieties of time-varying processes in chemical engineering industrial applications. These processes are abundant among lumped and distributed parameter systems and in batch systems they involve time-dependent change of parameters and/or geometry within lumped and/or distributed parameter systems settings. The focus of this thesis is on optimal state estimation and tracking regulation of two fed-batch processes with time-varying parameters and geometry. The first process is nonlinear time-varying microalgae growth and lipid production. An optimal reference trajectory is identified for maximum lipid production and moving horizon estimator along with model predictive control is realized for reference trajectory tracking of lipid production model. The second process is Czochralski crystal growth process which has moving boundary parabolic partial deferential equation describing heat transfer as dynamic model coupled with a lumped parameter model of pulling dynamics. Galerkin's method is used to reduce the distributed parameter model's order and an observer is developed to reconstruct temperature distribution evolution over the entire crystal domain during growth process. The performance of the observer is examined by implementing the observer on finite element model of the heat transfer in crystal. Furthermore, finite element model of the heat transfer along with finite element model of anisotropic thermal stresses in growing crystal are utilized to identify an optimal trajectory and develop a model predictive reference trajectory tracking controller for temperature distribution in the Czochralski crystal growth process to maximize the crystal cooling while maintaining the thermally induced stresses below the critical value in order to improve the quality of the grown crystal.

• Subjects / Keywords

  • Temperature distribution estimation
  • Nonlinear programming
  • Microalgae production
  • Distributed parameter systems
  • Thermal stress
  • Czochralski crystal growth

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3DN4043W

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.