The chemical composition of lipophilic extractives from process waters throughout a totally chlorine free (TCF) bleaching sequence after kraft pulping of eucalypt wood has been studied. These compounds are among the most problematic wood constituents for both TCF and zero liquid effluent (ZLE) processes, since they tend to accumulate in circuits resulting in the formation of the so-called pitch...

The combined production of the most abundant agricultural residues in Spain (viz. cereal straw, sunflower stalks, vine shoots, cotton stalks, olive, orange and peach tree prunings, and horticultural and related residues) amounts to over 50 million tons per year, more than 20% of which is generated by Andalusia alone. Agricultural residues must be disposed of for various reasons including the fa...

Untreated and hot-water-extracted (HWE) Norway spruce (Picea abies) sawdust was cooked using the sulfur-free oxygen-alkali (OA) method under the following conditions: temperature, 170 °C; liquor-to-wood ratio, 5:1 L/kg; and NaOH charge, 19% on the oven-dry sawdust. In comparison with earlier studies conducted with birch sawdust, the spruce cooking yield data, together with the amount of the pul...

The main objective of this thesis was to improve the understanding of some aspects on wood and fibre mechanics related to conditions in the thermomechanical pulping process. Another objective was to measure the power distribution between the rotating plates in a refiner. The thesis comprises the following parts: – A literature review aimed at describing fracture in wood and fibres as related to...

The production of singleand mixed-sugar streams and their conversion to bioproducts were studied using sulfite pulping streams as feedstocks. Sulfite pulp, sludge, and spent sulfite liquor (SSL) were utilized because they are concurrently generated alongside of bleached pulp, and because the pulping process renders pretreatment unnecessary. SSL, comprised of mostly monomeric hexose and pentose ...

Hesperaloe funifera was characterized in terms of its contents of holocellulose, α-cellulose, and lignin (74.1, 52.3, and 7.9%, respectively). Also, an experimental factor design was used to examine the influence of operational variables in the diethanolamine pulping of this material (viz. diethanolamine concentration (50-80%), cooking temperature (155-185 oC), and time (30-90 minutes)) on the ...

Abstract Mass transport of liberated lignin fragments from pits and fiber walls into black liquor is considered a determining step in the delignification process. However, our current understanding diffusion through cellulose influential parameter on this process very limited. A comprehensive detailed study mass cellulosic materials is, therefore, great importance. In study, cell methodology im...