Optimization of In-Refiner Brightening with H2O2 for Production of High Brightness Mechanical Printing Paper, 1995 Pulping Conference Proceedings

Stan Heimburger

Heimburger & Company, Inc.

Valerie Simard

Finlay Forest Industries Inc.

Dale Lamoureux

Finlay Forest Industries Inc.

Finlay Forest Industries [FFI] produces 500 ADTPD of standard newsprint and high brightness mechanical printing paper grades. The principle source of fiber for this paper comes from on-site production of RMP. There are three lines of two-stage RMP including seven primary refiners and three secondary refiners. As well, refiner rejects are refined in a single-stage atmospheric refiner. Varying brightness demand by grade of paper produced is accomplished by injecting an alkaline hydrogen peroxide solution [bleach liquor] onto chips just ahead of primary refining. In addition, for high brightness paper grades, bleach liquor is added to thickened rejects ahead of the rejects refiner. A bleach cost minimization program began in August, 1994 and is ongoing. Phase 1 of the program, which will be discussed in detail during this paper, has reduced bleaching costs by 25-35% depending on paper brightness requirements. At the same time, brightness variability of bleached RMP has been decreased. Positive results from the program resulted from a systematic evaluation of key operating variables during actual production runs, incorporation of improvements in subsequent runs and re-evaluation of parameters until an optimal set of conditions was found. Throughout the program, the use of a DCS which controlled bleach liquor preparation and distribution and the empowerment of operators after thoroughly communicating results of all studies were maintained.