Theoretical model of the kraft pulping process

Gustafson, Richard; Sleicher, C. A.; Mckean, W. T.; Finlayson, Bruce A.

doi:10.1021/i200020a016

Cited by 137 publications

(118 citation statements)

References 5 publications

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“…The residual phase is characterized by slow delignification, increased carbohydrate degradation, and increased consumption of alkali (Gustafson et al 1983). In a study of E. globulus wood, Miranda and Pereira (2002) found that the rate of delignification is approximately 10 times slower in the residual phase than in the bulk phase.…”

Section: Response Surfacementioning

confidence: 99%

Modeling and Optimization of Eucalyptus globulus Bark and Wood Delignification using Response Surface Methodology

Neiva¹,

Gominho²,

Pereira³

2014

BioResources

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Statistical models and optimization of Eucalyptus globulus Labill. wood and bark delignification were achieved using response surface methodology (RSM). A central composite design was outlined to model the simultaneous influence of active alkali (AA), reaction temperature (T), and reaction time (t) on pulp yield (η) and kappa number (k) during the kraft pulping of wood and bark. Experimental results were fitted to a second-order polynomial with linear interaction of factors. The statistical models showed high coefficients of determination for both wood (R . Using these models, the optimum conditions to attain a pulp with the highest yield at an acceptable kappa number (below 17) were determined. For wood, the pulp yield was 51.6% (51.5% predicted) and the kappa number was 16.1 (16.9 predicted) under optimized conditions (AA = 21%, T = 151 ºC, and t = 118 min). For bark, the pulp yield was 51.3% (51.0% predicted) and the kappa number was 19.4 (16.9 predicted) under optimized conditions (AA = 15%, T = 166 ºC, and t = 114 min). The degree of polymerization (DP) of the carbohydrates for the optimized pulps, 1430 and 1151 for wood and bark, respectively, suggests low levels of polysaccharide degradation. The bark delignification showed similar behavior to wood.

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Section: Response Surfacementioning

confidence: 99%

Modeling and Optimization of Eucalyptus globulus Bark and Wood Delignification using Response Surface Methodology

Neiva¹,

Gominho²,

Pereira³

2014

BioResources

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“…In the Gustafson model (M G ), the cooking time is divided into the initial, bulk and residual stages, according to the amount of remaining lignin in the pulp (Gustafson et al 1983 ). The lignin level that marks the transition from the initial to the bulk stage is set at 22.5 % of lignin in softwood and the transition level from the bulk stage to residual stage at 2.2 % .…”

Section: Model 1: Gustafson Model (M G )mentioning

confidence: 99%

Comparative evaluation of different kinetic models for batch cooking: A review

Nieminen

Sixta

2012

Holzforschung

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The purpose of this study was to review some of the existing models for delignifi cation in kraft cooking. Data and results from earlier studies were utilized to evaluate the performance of the models of Gustafson (M G ), Purdue (M P ), Andersson (M A ) and Bogren ' s method " continuous distribution of reactivity " (M Bcdr ) in terms of their ability to give a realistic description for delignifi cation of softwood and hardwood. The M G , M P and M Bcdr were tested on lignin data obtained from cooks of Eucalyptus globulus . In this case, M P seemed to perform best, whereas the M Bcdr failed in the range of low residual lignins. M A considers the lignin subunits with various reaction speeds, and this feature improves the performance in the case of low residual lignins and helps to refl ect sudden changes in cooking conditions, but the difference to the ordinary M P is moderate.

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“…In the last few decades, physical model studies of a continuous paper pulp digester have been frequently reported [5,[11][12][13][14][15][16][17]. A fundamental model proposed by Bhartiya [17], 2003, is chosen as process model of the studied digester.…”

Section: Model Selection and Simplificationmentioning

confidence: 99%

Model parameter estimation of simplified linear models for a continuous paper pulp digester

Ding

Gustafsson

Johansson

2007

Journal of Process Control

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A physical model of a continuous paper pulp digester is simplified and two subprocesses selected from the digester are modelled by coupled linear partial differential equations. This study focuses on the parameter identification of the simplified linear models. Finitedimensional approximation of the model is made and a software package developed for identification of distributed parameter processes is applied. This identification system is developed for flexibility to allow identification for different choices of subprocesses and process variables. Unknown parameters of the subprocess models are estimated and the results are illustrated by process simulation and model validation.

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Theoretical model of the kraft pulping process

Cited by 137 publications

References 5 publications

Modeling and Optimization of Eucalyptus globulus Bark and Wood Delignification using Response Surface Methodology

Modeling and Optimization of Eucalyptus globulus Bark and Wood Delignification using Response Surface Methodology

Comparative evaluation of different kinetic models for batch cooking: A review

Model parameter estimation of simplified linear models for a continuous paper pulp digester

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