Method and apparatus for controlled addition of alkaline chemicals to an oxygen delignification reaction

摘要

Good temperature and pH control as well as uniform mixing of pulp or other fibrous materials is achieved in a medium consistency oxygen delignification method and system. Alkaline chemicals are sprayed, optionally using oxygen gas as the atomizing agent, into the gas space above the level of pulp maintained in one or more substantially horizontal tubular reaction vessels. At least a part of the steam requirement of the reaction is added only after the major portion of alkaline chemicals has been added to the system. In other embodiments of the invention, alkaline chemicals may be injected into the substantially vertical conduit connecting two reaction vessels or two different alkaline chemicals may be injected at different points in the system.