A reduced model approach to estimation and control of a Kamyr digester

Wisnewski, Philip A.; Doyle, Francis J.

doi:10.1016/0098-1354(96)00183-4

Cited by 22 publications

(15 citation statements)

References 5 publications

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“…In fact, as the reactions proceed, the voidage of the chip increases due to the dissolution of the organic material. Wisnewski and Doyle III (1996) and Wisnewski et al (1997) claimed that, through a rede"nition of mass concentrations, it could be possible to overtake some necessary assumptions in earlier Purdue models, namely in calculating the chip porosity. However, this step ahead can be achieved without the inconvenience of having to change the usual industrial basis (mass of wood component per mass of initial oven dry chip)…”

Section: Modelingmentioning

confidence: 99%

Steady-state simulation of a continuous moving bed reactor in the pulp and paper industry

Fernandes

Castro

2000

Chemical Engineering Science

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This paper is concerned with the mathematical modeling and simulation of the steady-state operation of an industrial moving bed heterogeneous reactor for the kraft pulping of Eucalyptus globulus. The cooking takes place in a single-vessel hydraulic digester adapted for isothermal cooking (ITC), a further development of the modi"ed continuous cooking (MCC) process. A heterogeneous model is used to take into account the di!erent phases, each with distinct pro"les of temperature and concentration of organic (lignin, cellulose and hemicellulose) and inorganic (e!ective alkali and sul"de) compounds. The numerical solution of the model is based on a non-uniform discretization strategy to cope with special geometric and operational features of the digester. The decrease in bulk porosity caused by the compaction of the bed and the progressive increase in the voidage of chips as a result of chemical reactions are incorporated into the model as well as the resulting implications in the entrapped and free liquor #ows. The model presented here can be used in optimization studies and has been validated with data from an industrial mill.

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Section: Modelingmentioning

confidence: 99%

Steady-state simulation of a continuous moving bed reactor in the pulp and paper industry

Fernandes

Castro

2000

Chemical Engineering Science

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“…Due to its superiority, researchers have investigated different MPC concepts for continuous pulp digesters. Some of the studies are focused on the linear MPC concept that tackles problems with linear constraints and dynamics [75,78,82]. Both linearization of the physics-based models and subspace identification from the data were adopted.…”

Section: Discussion and Future Research Directions Of Pulp Digesters mentioning

confidence: 99%

“…The author also proposed an online control architecture for online model adaptation and optimal control of pulp digester. Wisnewski and Doyle [78] analyzed the performance of linear MPC and nonlinear MPC for set-point tracking and unmeasured disturbance rejection. The authors used Hankel-norm approximation to obtain a low-order linear model from an extended Purdue model.…”

Section: Kappa Number Controlmentioning

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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“…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. Motivated by the modeling efforts and tight regulations on product quality, the model predictive control (MPC) has been widely used for different types of pulp digesters, 13‐18 and these works have been extended to design plantwide control frameworks 19,20 …”

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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A reduced model approach to estimation and control of a Kamyr digester

Cited by 22 publications

References 5 publications

Steady-state simulation of a continuous moving bed reactor in the pulp and paper industry

Steady-state simulation of a continuous moving bed reactor in the pulp and paper industry

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

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