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Oxygen Delignification Kinetics And Selectivity Improvement, Steven M. Violette
Oxygen Delignification Kinetics And Selectivity Improvement, Steven M. Violette
Electronic Theses and Dissertations
Pulp strength loss during oxygen delignification is caused by cellulose chain cleavage resulting fiom attack by oxygen-based radicals generated through reactions with lignin. The objective of this research was to improve the lignin-to-cellulose selectivity during oxygen delignification by using radical-scavenging polymeric additives that adsorb on the cellulose surfaces where protection fiom radicals is needed. Among the polymers evaluated were starch, carboxymethyl-cellulose, galactomannan, xylan, and glucomannan. Oxygen delignification experiments were conducted on Northeast softwood Kraft pulps at different temperatures, sodium hydroxide charges, reaction times, and pretreatments. The effect of polymer additives on the selectivity and kinetics was studied. Polymer adsorption on …
Relationship Between Alkaline Pulp Yield And The Mass Fraction And Degree Of Polymerization Of Cellulose In Pulp, Mehmet Sefik Tunc
Relationship Between Alkaline Pulp Yield And The Mass Fraction And Degree Of Polymerization Of Cellulose In Pulp, Mehmet Sefik Tunc
Electronic Theses and Dissertations
Wood as a raw material is generally the dominant cost factor for the production of chemical pulp. Therefore, an increase in pulp yield has a major impact on the competitiveness of a mill. In order to optimize pulp yield, for example by changing operating conditions, a mill must be able to monitor the yield accurately. However, an accurate "real-time" pulp yield measurement method is not available at the present time. Pulping yield is presently measured from the amount of pulp produced from a given quantity of wood consumed over a 3 to 6 month time frame. This method is obviously …