Sökning: "high kappa number pulp"
Visar resultat 1 - 5 av 18 avhandlingar innehållade orden high kappa number pulp.
1. Aspects of extended impregnation kraft cooking for high-yield pulping of hardwood
Sammanfattning : The long-term trend regarding wood is an increase in price. Because wood contributes to a large part of production costs, the efficient utilisation of wood is greatly desired to reduce production costs for kraft pulp producers. During the 1990s, the development of improved modified kraft cooking began, which led to higher yields. LÄS MER
2. Extended impregnation kraft cooking of softwood : Effects on reject, yield, pulping uniformity, and physical properties
Sammanfattning : Converting wood into paper is a complex process involving many different stages, one of which is pulping. Pulping involves liberating the wood fibres from each other, which can be done either chemically or mechanically. LÄS MER
3. Optimization of Pretreatment of Kraft Pulp with Nitrogen Oxides
Sammanfattning : Modified kraft pulp subjected to oxygen bleaching following pretreatment with 2% nitrogen dioxide for 140 min with the addition of oxygen resulted in low selectivity after subsequent oxygen bleaching. In contrast, pretreatment in the absence of oxygen removed more than 80% of the lignin after oxygen bleaching and still maintained high selectivity (kappa number less than 5 at viscosity 950 dm3/kg). LÄS MER
4. On the importance of oxidizable structures in bleached kraft pulps
Sammanfattning : After cooking, kraft pulps always contain not only residual lignin but also significant amounts of hexenuronic acid and other non-lignin structures oxidizable by permanganate under the standard kappa number determination conditions. These here referred to as false lignin. LÄS MER
5. Pulp strength enhancement by oxygen delignification
Sammanfattning : Oxygen delignification is widely used in the pulp and paper industry as a part of delignification process between the kraft cook and bleaching. However, its potential has not been fully utilized. LÄS MER