Delignification and bleaching of a lignocellulosic pulp slurry with ozone
AssigneeInternational Paper Company
InventorsArthur W. Kempf, Richard B. Phillips
Life of this patent
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Abstract
A process for the delignification and bleaching of a lignocellulosic pulp slurry, having a consistency between about 1% and 10%, by weight of oven-dried pulp, and a pH between about 1 and 7, while at a temperature between about 0.degree. C. and 70.degree. C., with a gaseous mixture selected from the group consisting of ozone/oxygen, ozone/air, and a mixture thereof. The ozone containing gaseous mixture, which has an ozone concentration of from about 0.1% to about 20%, by weight of oxygen or air, is bubbled into the pulp slurry, while agitating the pulp slurry at a rate of about 0.01 to 5.0 horsepower-days per ton of pulp.
Claims15
A process for delignifying and bleaching lignocellulosic pulp, which comprises reacting a lignocellulosic pulp slurry, having a consistency of from about 1% to about 10%, by weight of oven-dried pulp, and a pH within the range of from about 1 to about 7 and a temperature between about 0.degree. C. and about 70.degree. C., with a gaseous mixture selected from the group consisting of ozone/oxygen, ozone/air, and a mixture thereof, in a reaction vessel, said gaseous mixture being in the form of bubbles substantially all of which are about 1/8 inch or less in diameter and having an ozone concentration of from about 0.1% to about 20%, by weight of oxygen or air, while agitating the pulp slurry at a rate of from about 0.01 to about 5.0 horsepower-days per ton of pulp.
Dependencies are inferred from the claim text.