An improved kinetic model structure for softwood kraft cooking

Andersson, Niklas; Wilson, D.I.; Germgård, Ulf

doi:10.3183/npprj-2003-18-02-p200-209

Cited by 33 publications

(24 citation statements)

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“…The concept of using transition points as a function of the cooking conditions in the distribution model is quite similar to Gustafson's model. This results in a total of 12 pseudocomponents representing the wood substance [44]. The component dissolution is expressed by Equation 13: Using multivariable curve fitting, the authors derived Equation 14for intersection level L * that represents the cooking stage when the intermediate (L2) and slow reacting lignin (L3) amounts are equal.…”

Section: The Andersson Model Was Developed By Andersson At Karlstad Umentioning

confidence: 99%

A Review on the Modeling, Control and Diagnostics of Continuous Pulp Digesters

2020

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Being at the heart of modern pulp mills, continuous pulp digesters have attracted much attention from the research community. In this article, a comprehensive review in the area of modeling, control and diagnostics of continuous pulp digesters is conducted. The evolution of research focus within these areas is followed and discussed. Particular effort has been devoted to identifying the state-of-the-art and the research gap in a summarized way. Finally, the current and future research directions in the areas have been analyzed and discussed. To date, digester modeling following the Purdue approach, Kappa number control using model predictive controllers and health index-based diagnostic approaches by utilizing different statistical methods have dominated the field. While the rising research interest within the field is evident, we anticipate further developments in advanced sensors and integration of these sensors for improving model prediction and controller performance; and the exploration of different AI-based approaches will be at the core of future research.

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Section: The Andersson Model Was Developed By Andersson At Karlstad Umentioning

confidence: 99%

A Review on the Modeling, Control and Diagnostics of Continuous Pulp Digesters

2020

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“…This work was later extended by Pu 8 . Also, several other dynamic models have been developed to describe the pulping process with respect to distinctive operating conditions such as digester type, pulping method and fed wood species 9‐11 . Andersson et al 11 and Sixta et al 12 performed comparative analysis on the accuracy of these kinetic models, and concluded that the Purdue model has the best structure in both incorporating the process complexity and optimizing the computational efficiency.…”

Section: Introductionmentioning

confidence: 99%

Multiscale modeling and multiobjective control of wood fiber morphology in batch pulp digester

Choi

Kwon

2020

AIChE Journal

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Even though it is widely known that mechanical properties of papers are dependent upon fiber morphology such as fiber length and cell wall thickness, existing macroscopic models are limited in describing the microscopic traits of pulp. Thus, we proposed a multiscale model by integrating a macroscopic model (i.e., Purdue model) and a microscopic model (i.e., kinetic Monte Carlo algorithm) to capture the dynamic evolution of the fiber morphology as well as conventional pulp quality index such as Kappa number. Then, a reduced‐order model is identified to handle the computational requirement of the multiscale model, and implemented to a model‐based controller to regulate both the fiber length and the Kappa number which are expressed in the forms of conflicting objective functions. The epsilon‐constraint method is employed to find the Pareto optimal sets to provide decision makers with the degree of freedom to choose one according to their preferred end‐use paper properties.

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“…Several models describing the digester process dynamics have been developed. The model developed by Andersson et al 5 described the delignification process by dividing the lignin and carbohydrate components into three subgroups, resulting in a total of 12 pseudocomponents. The model developed by Gustafson et al 6 described delignification kinetics with two components, lignin and carbohydrates, in three different cooking zones, which are initial, bulk, and residual.…”

Section: Introductionmentioning

confidence: 99%

Multiscale modeling and control of Kappa number and porosity in a batch‐type pulp digester

Choi¹,

Kwon²

2019

AIChE Journal

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This work proposes a multiscale modeling and model-based feedback control framework for the delignification process in a batch-type pulp digester. Specifically, we focus on a hardwood chip in the digester and develop a multiscale model capturing both the evolution of microscopic properties such as the pore size and shape distributions in the solid phase and the dynamic changes in the temperature and component concentrations in the liquor phase. While the macroscopic model adopts the continuum hypothesis based on the Purdue model, a novel microscopic model is developed using a kinetic Monte Carlo algorithm, accounting for the dissolution of lignin, cellulose, and hemicellulose contacting the liquor phase. A reduced-order model was built to design a Luenberger observer for state estimation, which is then used to develop a model-based control system. The simulation results demonstrated that the proposed methodology was able to regulate both the Kappa number and porosity to desired values.

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An improved kinetic model structure for softwood kraft cooking

Cited by 33 publications

References 0 publications

A Review on the Modeling, Control and Diagnostics of Continuous Pulp Digesters

A Review on the Modeling, Control and Diagnostics of Continuous Pulp Digesters

Multiscale modeling and multiobjective control of wood fiber morphology in batch pulp digester

Multiscale modeling and control of Kappa number and porosity in a batch‐type pulp digester

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