Conditions to Extend Kraft Cooking Successfully, 1992 Pulping Conference Proceedings
The chemical pulping industry has been striving for extended kraft cooking ever since realizing the must to decrease the amount of residual lignin entering bleaching processes. The task has not been easy. Stubbornly, the softwood cooking kappa number has defied most of reduction attempts. At best it has been possible to achieve 25 - 30 % reduction. Based on various studies made on continuous and discontinuous kraft cooking, new understanding of the fundamentals in cooking technology has unveiled new factors limiting our efforts to prolong delignification. The present paper discusses the prerequisites for far extended cooking and evaluates currently available principles and technology. Development trends, realized installations and on-going low kappa projects are reviewed.
Conditions to Extend Kraft Cooking Successfully, 1992 Pulping Conference Proceedings