Modeling of Alkali Impregnation of Eucalyptus Wood

Inalbon, María Cristina; Mussati, Miguel C.; Mocchiutti, Paulina; Zanuttini, Miguel Angel Mario

doi:10.1021/ie1019408

Cited by 11 publications

(15 citation statements)

References 10 publications

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“…For Eucalyptus wood, a model was derived that includes all these aspects of the kraft impregnation process. The predicted concentration profiles were quite close to those of the experimental results (Inalbon et al 2009(Inalbon et al , 2011.…”

Section: Introduction Background and Goalssupporting

confidence: 82%

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Profiles of alkali concentration and galactoglucomannan degradation in kraft impregnation of Scots pine wood: Experimental observations and modeling

Montagna

Nieminen²,

Inalbon

et al. 2015

Holzforschung

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A deep understanding of alkali impregnation including the profiles of alkali concentration and hemicellulose degradation is necessary to analyze the optimization of current and innovative processes. In this paper, the impregnation of Scots pine (Pinus sylvestris L.) wood is analyzed and modeled under consideration of deacetylation, reactions of acidic group, and galactoglucomannan (GGM) degradation. The immobile anionic groups activated by the ionization of lignin-derived OH groups are also considered for the assessment of the Donnan effect. Predicted profiles of sodium and hydroxide ions and acetyl group concentrations are compared to experimental results. The balance between impregnation and hemicellulose degradation levels is discussed based on the developed models. Expectedly, higher concentrations and temperatures speed up the impregnation process. Nevertheless, a higher OH -concentration has two benefits for the same impregnation front position -the alkali charge inside the chip is higher and the GGM degradation is lower.

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Section: Introduction Background and Goalssupporting

confidence: 82%

“…A model for the 1D isothermal alkali impregnation process of eucalyptus chips is already described (Inalbon et al 2011). Briefly, Na + , OH -, and SH -ions and acetate groups were considered as mobile ions, and acetyl and acid groups of wood were considered as immobile.…”

Section: Departing Modelmentioning

confidence: 99%

Profiles of alkali concentration and galactoglucomannan degradation in kraft impregnation of Scots pine wood: Experimental observations and modeling

Montagna

Nieminen²,

Inalbon

et al. 2015

Holzforschung

Self Cite

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“…The diffusion rate of alkali into the chip is determined by paths available for ion transport, concentration of ions, and temperature. However, diffusion of alkali affects the ion transport properties of wood by swelling the fibre wall and the alkali concentration is affected by the reactions with wood components (Inalbon et al 2011). Swelling of wood improves ion mobility, and it can be assumed that diffusion is not restricted in the swollen shell (Inalbon and Zanuttini 2008;Inalbon et al 2009a).…”

Section: Defibration Pointmentioning

confidence: 99%

The limits of delignification in kraft cooking

Brännvall¹

2017

BioRes

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The perspective of the article is to explore kraft cooking at the limits of delignification, i.e. what degree of delignification is needed to obtain fibre liberation and what is the maximum degree of delignification possible in the kraft pulping stage. The reasons for the quite narrow boundaries for sufficient and maximum delignification are explained, and the differences between the behaviour of hardwood and softwood kraft pulping are clarified.

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“…In kraft pulping, chemical penetration times vary in relation to chip size, thickness and uniformity. Uniform chips lead to more uniform pulping conditions and higher pulp recovery (Pulkki 1991;Broderick et al 1998;Ding et al 2005;True 2006;Färlin 2008;Inalbon et al 2011;Cáceres et al 2016a).…”

Section: Chip Quality and Chip Recovery Ratementioning

confidence: 99%

The impact of log surface damage caused by harvesterEucalyptusdebarking on pulp value recovery

Merwe

Pulkki

Ackerman

et al. 2017

Southern Forests: a Journal of Forest Science

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Mechanised harvesting operations are growing in popularity in South Africa, as motor-manual and manual harvesting operations pose significant health and safety risks to workers. Potential damage inflicted by singlegrip harvester feed rollers and delimbing knives on the log surface during debranching and debarking of eucalypts may affect chip size distributions during chip production. Chip size is important as it influences pulp quality and recovery in the kraft pulping process. The study investigated the influence of two mechanised debarking treatments in eucalypts (three feed roller passes and five feed roller passes along the stem surface) with feed-roller-induced log surface damage on pulp value recovery. The two mechanised treatments were compared against chips produced from manually debarked logs with no surface damage. In addition, the effect of two log drying periods (one week and two weeks) and three log classes (base, middle and top logs) on chip quality were also analysed. An economic evaluation was conducted to quantify potential recoverable pulp value losses associated with debarking treatments and log drying periods. Logs subject to manual debarking produced significantly less undesired sized chips than both three-pass and five-pass mechanically debarked logs and therefore had significantly greater pulp value recovery. Mechanically debarked logs had a projected pulp value recovery of R62, R86 and R123 less per bone dry tonne of chips produced from base, middle and top logs, respectively, when compared with manually debarked logs with no log surface damage after a one-week log drying period. Mechanically debarked logs also had a projected pulp value recovery of R77, R40 and R59 less per bone dry tonne of chips produced from base, middle and top logs, respectively, when compared with manually debarked logs with no log surface damage after a two-week log drying period. Logs dried for two weeks also produced significantly less under-sized chips than chips produced from one-week-dried logs and therefore had greater pulp value recovery. However, two-week-dried logs produced wood chips with significantly more over-thick chips than logs dried for one week. The volume of undesirable-sized chips produced during chipping increased with decreasing log size.

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Modeling of Alkali Impregnation of Eucalyptus Wood

Cited by 11 publications

References 10 publications

Profiles of alkali concentration and galactoglucomannan degradation in kraft impregnation of Scots pine wood: Experimental observations and modeling

Profiles of alkali concentration and galactoglucomannan degradation in kraft impregnation of Scots pine wood: Experimental observations and modeling

The limits of delignification in kraft cooking

The impact of log surface damage caused by harvesterEucalyptusdebarking on pulp value recovery

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