b'PULP REFININGThe mill was able to reduce refining energy by 73.8% with strength properties remaining within specification.Figure 4. Overview showing how the combination of substrate, operating conditions, target benefit and enzyme can yield beneficial results.MILL CASE STUDY The trial ran for two days acrossspeed up the machine. ASA usage was The first commercial trial was run250gsm and 300gsm grades. The firstreduced by 50% during the trial period.in an integrated mill with a multi- changes seen during the trial were aTable 1 shows the trial data compared ply Fourdrinier machine. The mill4% decrease in sheet bulk and a 47%to a two-month average baseline.produces Kraftliner. The wet enddecrease in sheet porosity. This wasThe machine refining system consists chemistry program consists of aindicative of better sheet pressing andof three refiners, each ply having a coagulant for charge control, a cationicconsolidation. The mill was able todedicated refiner to refine the mixed polyacrylamide for retention, and areduce refining energy by 73.8% withstock furnish. A total energy reduction GPAM for drainage. The mill also usesstrength properties remaining withinof 73.8% was achieved during the ASA sizing. specification. The machine productionoptimization phase as compared to rate was increased by 10.27% duethe pre-trial levels. Figure 5 shows the This is a three-ply Fourdrinier machineto better drainage and the ability torefining energy reduction.producing linerboard.Top ply (25% of sheet): 100% unbleached softwood (Kappa 70)Middle ply (50% of sheet): 50% unbleached softwood, 30% OCC, 15% broke, 5% sludge from clarifierBottom ply (25% of sheet): 85% unbleached softwood, 15% brokeThe paper machine pH is 6.8-7.2 and typical conductivity is 2500-3800 uS/cm. The goals of the trial were to:1.Reduce refining energy.2.Maintain / improve strength properties.3.Reduce steam usage.4.Increase production rate. Table 1. 20 WORLD PULP&PAPER'