Medium consistency ozone bleaching
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
May 2, 1995
Issued Date -
N/A
app pub date -
Jun 7, 1991
filing date -
Apr 30, 1991
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
In a method of bleaching medium consistency pulp with ozone using a mixer, ozone containing gas and about 6-15% consistency pulp are fed to the mixer, and then discharged in a first, preferably vertical, path. The mixture of pulp and ozone moves in a first part of the vertical path a time period of about 1-5 seconds at a velocity of about 1-5 m/s so that the gas and pulp do not separate during movement in this first part, and the vast majority of the pulp brightening reaction between the ozone and pulp takes place. This is preferably accomplished by passing the mixture upwardly in a small diameter conduit having a height of about 3-20 meters. Then the velocity of the pulp is slowed while still moving in the first path, preferably by feeding it directly to a much larger diameter (e. g. 1.5-10 times) conduit, so the height of the unit may be kept under 100 feet. The pulp flows in the large diameter conduit for about 0.5-5 minutes so that residual reactions take place.
First Claim
Other Claims data not available