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Pulp Pretreatments For Improved Selectivity And Extended Oxygen Delignification, Zheng Dang
Pulp Pretreatments For Improved Selectivity And Extended Oxygen Delignification, Zheng Dang
Electronic Theses and Dissertations
Oxygen delignification has developed steadily since it was introduced commercially in 1970 in South Africa and virtually all new fiber lines incorporate an oxygen delignification system following the digester prior to the bleach plant. Currently, the degradation of cellulose and consequently the loss of pulp strength limit the drop in kappa number that can be obtained using an oxygen process. Pulp selectivity, given by the selectivity coefficient (α), relates the reduction in the molecular weight of cellulose to the reduction in the ligin content of the pulp when measured by the kappa number. An evaluation of selectivity of deligification data …
Effect Of Kraft Pulping On Oxygen Delignification, Haixuan Zou
Effect Of Kraft Pulping On Oxygen Delignification, Haixuan Zou
Electronic Theses and Dissertations
The objective of the study reported here was to investigate experimentally the effect of the major Kraft pulping variables on the response of brownstock pulps to medium consistency oxygen delignification. Kraft pulping was performed on mixed Northeastern hardwood chips in a laboratory rocking digester. Kraft pulps of kappa number 16 and 20 mL KMnO4 were produced by pulping under a variety of conditions. The effective alkali (EA) charged to the digester was varied over the range of 12 to 21% while the sodium sulfide content of the pulping liquor was varied between 0 to 30% sulfidity. Cooking temperatures of …