Abstract: A wood pulp slurry is treated with oxygen in a mill with little change to the process or structure of the mill. No special pressure tanks are required. The consistency of the pulp need not be altered for the treatment step. It may be treated at the usual process consistency of the pulp; e.g., it may be treated at the usual consistency of the pulp leaving a washer or the subsequent steam mixer without additional dewatering or additional dilution.The oxygen is added into a closed section of the system so that it cannot immediately vent to the atmosphere. Alkali should also be present when the oxygen is mixed with the slurry. The mixing should occur near to the point of oxygen addition.The oxygen is inserted into the pulp slurry and mixed with the pulp slurry between a pair of washers. The second washer may be a vacuum, pressure or diffusion washer.The mixing occurs in a relatively small mixer that intensively mixes the slurry and gas.

Abstract: A wood pump slurry is treated with oxygen in a mill with little change to the process or structure of the mill. No special pressure tanks are required. The consistency of the pulp need not be altered for the treatment step. It may be treated at the usual process consistency of the pulp; e.g., it may be treated at the usual consistency of the pulp leaving a washer or subsequent steam mixer without additional dewatering or additional dilution.The oxygen is added into a closed section of the system so that it cannot immediately vent to the atmosphere. Alkali should also be present when the oxygen is mixed with the slurry. The mixing should occur near to the point of oxygen addition.The oxygen is inserted into the pulp slurry and mixed with the pulp slurry between a washer and the subsequent storage tank.The mixing occurs in a relatively small mixter that intensively mixes the slurry and gas. The mixer has a mixing zone with a swept area of 10,000 to 1,000,000 square meters per metric ton of oven-dry pulp.

Abstract: Washed wood pulp from a continuous digester is treated with oxygen in the blow line from the digester. Most of the treatment occurs within the mixer. The mixer has a mixing zone with a swept area of 10,000 to 1,000,000 square meters per metric ton of oven-dry pulp. A preferred range is 25,000 to 150,000 square meters per ton of oven-dry pulp and an optimum range is around 65,400 square meters per metric ton of oven-dry pulp. Following mixing, the pulp may be taken to a subsequent process, a diffusion washer, or to a storage tank.