Patent ID: 6153300
Filing Date: 2000-11-28
Classification: D21C,Y02W,Y10T

Abstract:
A bleached cellulose pulp produced from comminuted cellulosic fibrous material having cleanliness which varies significantly over time, by practicing the steps of:(a) sensing at least one of the brightness, color, or lignin content of the comminuted cellulosic fibrous material prior to treatment in the first bleaching stage;(b) controlling the quantity of first bleaching chemical added to the first stage in response to the sensing from step (a) to achieve a target brightness increase for treatment of the material in the first stage;(c) sensing at least one of the brightness, color, or lignin content of the comminuted cellulosic fibrous material after treatment in the first bleaching stage and before treatment in the second stage; and(d) controlling the quantity of second bleaching chemical added to the second stage in response to the sensing from step (c) to achieve a target brightness increase for treatment of the material in the second stage.