Patent ID: 8784608
Filing Date: 2014-07-22
Classification: D21B,D21C,D21D,D21F,D21H,Y02W

Abstract:
1. A method for treating process water, which comprises: generating cavitation by emitting a fluid jet via a nozzle or an orifice tube; treating process water used in a process for producing pulp and/or paper by the cavitation to strip contaminants deposited on pulp fibers and/or inorganic particles contained in the process water; and then returning the treated process water to the process for producing pulp and/or paper for reuse, wherein the process water contains from 0.1 to 3% by weight of solids and comprises pulp fiber, wherein the process water contains 50% by weight or less, based on total solids, of long pulp fiber fractions, and the long pulp fiber fractions refer to pulp fibers retained on a 150-mesh (φ100 μm) screen, and wherein a jet flow rate of the fluid jet is in the range of 20 m-sec or more and 100 m/sec or less.