Comparison of Feedback Control Strategies for Operation of Granulation Loops


  • Ludmila Vesjolaja University of South-Eastern Norway
  • Bjørn Glemmestad Digital Production Department, Yara International ASA, Norway
  • Bernt Lie Department of Electrical Engineering, IT and Cybernetics, University of South-Eastern Norway



Granulation is a particle enlargement process during which fine particles or atomizable liquids are converted into granules via a series of complex granulation mechanisms. In this paper, two feedback control strategies are implemented to make granulation loop processes more steady to operate, i.e., to suppress oscillatory behavior in the produced granule sizes. In the first control strategy, a classical proportional-integral (PI) controller is used, while in the second, a double-loop control strategy is used to control the median diameter of the granules leaving the granulator. The simulation results showed that using the proposed control design for the granulation loop can eliminate the oscillatory behaviour in the produced granule median diameter and make granulation loop processes more steady to operate. A comparison between the two proposed control strategies showed that it is preferable to use the double-loop control strategy.