Method for oxygen delignification.

摘要

Cellulosic pulp is transported by means of timing screws (24) in essentially plug flow through one or more substantially horizontal reactor tubes (10) in which an oxygen delignification takes place. Oxygen gas is injected into the system at a point adjacent to the pulp inlet (22) and travels concurrently in substantially plug flow with the pulp through the system. In this manner, the pulp is initially exposed to gas of a high oxygen partial pressure while gas vented from the system (38) adjacent the pulp outlet (31) is of low oxygen partial pressure and has a high content of diluent gases. In an alternate embodiment, a countercurrent gas flow process is disclosed. Also provided is a catalytic treatment and recirculation system for the vented gas which permits efficient use of oxygen within the system.