Double-Loop Control Structure for Rotary Drum Granulation Loop

Abstract

The operation of granulation plants on an industrial scale is challenging. Periodic instability associated with the operation of the granulation loop causes the particle size distribution of the particles flowing out from the granulator to oscillate, thus making it difficult to maintain the desired product quality. To address this problem, two control strategies are proposed in this paper, including a novel approach, where product-sized particles are recycled back to maintain a stable granulation loop process. A dynamic model of the process that is based on a population balance equation is used to represent the process dynamics. Both of the control strategies utilize a double-loop control structure that is suitable for highly oscillatory systems. The simulation results show that both control strategies, including the novel approach, are able to remove the oscillating behaviour and stabilize the granulation plant loop.

Comparison of Feedback Control Strategies for Operation of Granulation Loops

“…This paper is the extension of our previous studies reported in. In this paper, the authors extend the previous study [29] by comparing two feedback control strategies with the objective to eliminate the oscillatory behaviour in the the produced particle sizes. Thus, the main contribution of this paper is the comparison of the double-loop control strategy [29] with the classical PI controller.…”

“…In this paper, the authors extend the previous study [29] by comparing two feedback control strategies with the objective to eliminate the oscillatory behaviour in the the produced particle sizes. Thus, the main contribution of this paper is the comparison of the double-loop control strategy [29] with the classical PI controller. Another contribution of this paper is the analysis of the system dynamics using a bifurcation analysis.…”

“…The recent studies regarding stabilization of the continuous granulation loop process in the fluidized bed are reported in [17], [18]. Similarly to fluidized bed granulators, granulation loop processes using drum granulators also show oscillatory behavior of particle sizes and particle flow rates [29], [30]. Studies regarding the control of the granulation processes where the rotary drums are used as the granulators are given in [5], [24], [29], [33], [32].…”

“…where ( , , ) m d z t is the mass density function [29], [30], [31]. Equation ( 1) is formed by assuming the two granulation mechanisms, particle growth due to layering and particle agglomeration.…”

“…Model expressions for the screens and the crusher in Figure 3 Table 2 Simulation parameters [29] Parameter Value…”