Kraft Pulping Process Model Derived from Relationship of the Residual Alkali Concentration on Cooking Time or H-Factor, 1994 Pulping Conference Proceedings

V. Masura

Consumption of active alkali was studied during initial, bulk and residual phases of kraft delignification of spruce wood. The respective amounts of lignin extracted from 1 t of wood into black liquor in individual delignification phases were: 47 kg, 170 kg and 50 kg, totally 267 kg. The respective consumption of AA for the extraction of these amounts of lignin in individual delignification phases were 4.2 kg, 19.2 kg and 7.0 kg Na2O, totally 30.4 kg Na2O.

The respective amounts of carbohydrates degraded by the peeling off reaction in the initial, bulk and residual phases of delignification were 154 kg, 53 kg, and 40 kg, totally 247 kg. The respective consumption of AA for degrading carbohydrates in individual delignification phases were 58.8 kg, 15.8 kg and 20 kg Na2O, totally 94.6 kg Na2O. The overall consumption of AA was 125 kg Na2O and the amount of residual alkali was 35 kg Na2O from the overall input 160 kg Na2O per 1 t o.d.wood.