Comparison of Feedback Control Strategies for Operation of Granulation Loops

Ludmila Vesjolaja,Bernt Lie,Bjørn Glemmestad

doi:10.5755/j01.itc.50.4.28104

Ludmila Vesjolaja, Bernt Lie + Show 1 more

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https://doi.org/10.5755/j01.itc.50.4.28104

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Abstract

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.

Highlights

Granulation is a particle design technique during which fine particles are converted into larger particles called granules
This paper focuses on damping and elimination of oscillatory behavior seen on granulation loop plants
Stabilization of the oscillatory behavior is performed by recycling some of the product-sized particles back to the granulator

Summary

Introduction

Granulation is a particle design technique during which fine particles are converted into larger particles called granules. As a result of granulation process, granules with the desired properties are produced. The desired granule properties depend on the product quality requirements. Some of the common granule properties of interest are particle size, moisture content, porosity, compressibility and etc. Granule formation and their properties depends on granulation mechanisms. According to Iveson et al [8], there are three main granulation mechanisms: (i) particle nucleation that is the initial stage of particle formation, (ii) particle growth that can occur due to various mechanisms such as particle layering and and particle agglomeration, and (iii) particle breakage, e.g., particle surface attrition due to particle collision [8], [3]

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