PULP BLEACHING

摘要

"PULP BLEACHING" A method of reacting oxygen with a cellulose pulp slurry having a consistency from 8% to 16% to effect delignification or bleaching. The slurry is dosed with oxygen incrementally by feeding a stream of it under pressure through a reaction path made up of a plurality of stages. In each stage the stream is first confined to a cross-section at which it has a velocity such as to provide turbulent liquid flow and is then expanded to a cross-section at which it has a velocity such as to provide plug flow. In each stage oxygen is introduced into the liquid flow under pressure in the form of a mass of minute bubbles to disperse them throughout so that the oxygen is brought into intimate contact to react with the pulp in the plug flow. The treated slurry is recovered from the final stage.