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 ...

Kraft wood pulping is the predominant process used in the pulp and paper industry for its versatility and insensitivity to variations of wood supply. In this work, a deterministic model has been developed for a Kraft Pulping Process of Eucalyptus by combining intrinsic kinetic equations (Lignin, Carbohydrates) and it is used to investigate the effects of process conditions on the extent of deli...

Wood-derived cellulosic fibers prepared in different ways were successfully employed to absorb simulated crude oil, demonstrating their possible use as absorbents in the case of oil spills. When dry fibers were used, the highest sorption capacity (six parts of oil per unit mass of fiber) was shown by bleached softwood kraft fibers, compared to hardwood bleached kraft and softwood chemithermomec...

∈∆N ), (1.1) where the convention 0log(0)= 0 is adapted, (see Shannon [19]). Throughout this paper, ∑ will stand for ∑N i=1 unless otherwise stated and logarithms are taken to the baseD (D > 1). Let a finite set of N input symbols X = {x1, x2, . . . ,xN } be encoded using alphabet of D symbols, then it has been shown by Feinstien [6] that there is a uniquely decipherable code with lengths n1,n2...

Laboratory-obtained kraft lignins have been studied via elemental analysis (EA), 1H-NMR, FTIR, GPC to analyse the chemical structure. The kraft lignins were subjected to oxidation with H2O2 using Co(salen) as a biomimetic catalyst at mild condition (80oC, 240 min). The kraft lignins isolated from eucalyptus (EKL) and bamboo (BKL) had a low hydroxyl (oxygen) contents, a low molecular weights (~3...

The influences of pulp type, content of acidic groups (i.e., sulfonic and carboxylic groups) in CTMP, kappa number (i.e., residual lignin content) of unbleached kraft pulp, and beating degree of bleached kraft pulp on the conductivity of polyaniline (PAn)-coated conductive paper were investigated. The amounts of PAn coated on chemical pulps were higher than those coated on high yield pulps, and...

Xylans were selectively removed from paper grade pulps by nitren extraction in order to produce dissolving pulps. The impact of nitren charge on the removal of hemicelluloses was demonstrated for a birch and mixed softwood kraft pulp. The 95% purity level could easily be reached for the birch kraft pulp. Softwood glucomannans were almost insoluble under the investigated extraction conditions ap...