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Control of continuous digester kappa number using generalized model predictive control, TAPPI Journal September 2024
ABSTRACT: Kappa number variability at the digester impacts pulp yield, physical strength properties, and lignin content for downstream delignification processing. Regulation of the digester kappa number is therefore of great importance to the pulp and paper industry. In this work, an industrial application of model-based predictive control (MPC), based on generalized prediction control, was developed for kappa number feedback control and applied to a dual vessel continuous digester located in Western Canada. The problem was complicated by the need to apply heat at multiple locations in the cook. In this study, the problem was reduced from a multiple to a single input system by identifying three potential single variable permutations for temperature adjustment. In the end, a coordinated approach to the heaters was adopted. The process was perturbed and modeled as a simple first order plus dead time model and implemented in generalized predictive control (GPC). The GPC was then configured to be equivalent to Dahlin’s controller, which reduced tuning parameterization to a single closed loop time constant. The controller was then tuned based on robustness towards a worst-case dead time mismatch of 50%. The control held the mean value of the kappa number close to the setpoint, and a 40% reduction in the kappa number’s standard deviation was achieved. Different kappa number trials were run, and the average fiberline yield for each period was evaluated. Trial results suggested yield gains of 0.3%•0.5% were possible for each 1 kappa number target increase.
Extremely Water Absorbent Nonwovens Produced with Hydrophilic Water Based Emulsion Polymer, 2011 Innovative Nonwovens Conference
Extremely Water Absorbent Nonwovens Produced with Hydrophilic Water Based Emulsion Polymer, 2011 Innovative Nonwovens Conference
Conference papers
Moisture management and optimization from headbox to reel in papermaking process, 19PaperCon
Moisture management and optimization from headbox to reel in papermaking process, 19PaperCon
Conference papers
Micro Characterization of z-resistance of papers, 19PaperCon
Micro Characterization of z-resistance of papers, 19PaperCon
Conference papers
The Role of Gas Dispersion in the Oxygen Delignification Process, 19PEERS
The Role of Gas Dispersion in the Oxygen Delignification Process, 19PEERS
Conference papers
Quality Improvement from the Wet End for Board and Packaging Grades, 18PaperCon
Quality Improvement from the Wet End for Board and Packaging Grades, 18PaperCon
Conference papers
On Optimization of Paper Machines using Economic Model Predictive Control, 18PaperCon
On Optimization of Paper Machines using Economic Model Predictive Control, 18PaperCon
Conference papers
Mathematical Modeling and Simulation of Initial and Mechanical Dewatering of Paper Web in Paper Machine Sections, 18PaperCon
Mathematical Modeling and Simulation of Initial and Mechanical Dewatering of Paper Web in Paper Machine Sections, 18PaperCon
Acoustic Emission From Paper Machine Components Without Excessive Stress, 2008 Engineering, Pulping and Environmental Conference
Acoustic Emission From Paper Machine Components Without Excessive Stress, 2008 Engineering, Pulping and Environmental Conference
Alternative Fuel Impact on Lime Reburning Kiln Performance, 2008 Engineering, Pulping and Environmental Conference
Alternative Fuel Impact on Lime Reburning Kiln Performance, 2008 Engineering, Pulping and Environmental Conference