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US 8,273,382 B2Granted
Suppressing microbial growth in pulp and paper
AssigneeNalco Company
InventorsLaura E. Rice, Andrew J. Cooper, Robert L. Wetegrove, Michael V. Enzien
Life of this patent
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Abstract
A composition for anti-microbial effect in a water system such as a pulp and paper processing line with an aqueous slurry. The composition comprises a free chlorine-generating biocide comprising a chlorine source, urea, and an alkali in a concentration sufficient to provide a pH greater than 10, and typically at least pH 11.
Claims14
A method for stabilizing chlorine for use as a water treatment biocide in a papermaking process system, comprising the steps of:
- adding, with mixing, a free chlorine source to a point in a stream of the papermaking process system;
- adding, with mixing, urea to a point in the stream of the papermaking process system;
- and
- adding, with mixing, an alkali to a point in the stream of the papermaking process system, to cause mixing of the alkali with the chlorine source and the urea;
- wherein the result of the additions causes to be formed for a period of time within the papermaking process stream a composition, the composition comprising:
- a free chlorine-generating biocide comprising a chlorine source;
- urea;
- and an alkali in a concentration sufficient to provide a pH of from 12 to 13.5 for said composition, and wherein the composition does not comprise stabilized bromine.
5 more elements
Dependencies are inferred from the claim text.