Control scheme for rapid pulp delignification and bleaching
AssigneeUnion Camp Patent Holding, Inc.
InventorsGeorge Pangalos, Ronald A. Falcone, Jr., William L. Mayo, Gregory J. Bosch
Life of this patent
Estimating the term…
Abstract
A process control for adjusting bleaching agent application in response to the pulp brightness and/or K number is realized by utilizing a coupled control feedforward and/or feedback control system or combination thereof wherein brightness measurements are made between successive K number measurements and adjustments made to the bleaching agent application in response to a comparison value.
Claims16
A coupled control method for controlling a continuous ozone bleaching process for paper pulp to a desired degree of bleaching, which comprises:
- (a) adding feed ozone at a desired amount to the pulp;
- (b) passing the pulp continuously into and out of a bleaching reactor;
- (c) measuring ingoing pulp brightness between successive ingoing pulp K number measurements;
- and
- (d) adjusting the quantity of feed ozone required to reach a desired degree of bleaching in response to the measured brightness and K number values.
A coupled control method for controlling a continuous ozone bleaching process for paper pulp to a desired degree of bleaching, which comprises:
- (a) adding feed ozone at a desired amount to the pulp;
- (b) passing the pulp continuously into and out of a bleaching reactor;
- (c) measuring the brightness value of the pulp between successive K number measurements;
- and
- (d) adjusting the quantity of feed ozone required to reach a desired degree of bleaching in response to the measured brightness and K number values;
- wherein the measured pulp property is an ingoing pulp property;
- and
- the adjusting step comprises:
- (e) periodically measuring the K number of the incoming pulp as it passes into the reactor and adjusting the amount of feed ozone to obtain the desired degree of bleaching;
- (f) measuring the pulp brightness between periodic K number measurements, and making a moving average of several pulp brightness measurements;
- (g) comparing the moving average brightness measurement with the brightness representing the K number for that period prior to the next K number measurement to initiate a change in feed ozone;
- and
- (h) adjusting the quantity of feed ozone in response to the comparison value.
Dependencies are inferred from the claim text.