Bctmp filtrate recycling system and method

Abstract

A process for making bleached pulp comprises contacting an unbleached pulp mixture with a first recycled filtrate obtained from a first location of a first recycled filtrate loop, to obtain a first pulp mixture having a first consistency; bleaching the pulp mixture, to obtain a first bleached pulp mixture; pressing or dewatering the bleached pulp mixture, to obtain a first pressed bleached pulp mixture and a second filtrate; sending a portion of the second filtrate to a second location of the first recycled filtrate loop, wherein the second location is downstream of and in fluid communication with the first location; contacting the pressed bleached pulp mixture with a second recycled filtrate obtained from a third location of the first recycled filtrate loop, to obtain a second pulp mixture having a second consistency, wherein the second consistency is greater than the first consistency, and wherein the third location is downstream of and in fluid communication with the second location; bleaching the second pulp mixture, to obtain a second bleached pulp mixture; pressing or dewatering the second bleached pulp mixture, to obtain a second pressed bleached pulp mixture and a third filtrate; sending a portion of the third filtrate to a fourth location of the first recycled filtrate loop, wherein the fourth location is downstream of and in fluid communication with the third location; and recycling a portion of the third filtrate in the first recycled filtrate loop to the first location.