YIELD GAINS FROM LO-SOLIDS PULPING OF EUCALYPTUS.pdf

N E W Z E A L A N D FACTORS RESPONSIBLE FOR YIELD GAINS FROM LO-SOLIDS? PULPING OF EUCALYPTUS SPECIES JIAN ER JIANG ROBERT W. ALLISON JOHN A. LLOYD N E W Z E A L A N D Lo-Solids? Features ?More uniform temperature and cooking chemicals profiles ?Minimal cooking temperature ? Lower dissolved solids ?Minimal lignin at end of cook ?Extraction/make-up/dilution N E W Z E A L A N D Conversion to Lo-Solids? 100% WL White Liquor Washer Filtrate 45% WL N E W Z E A L A N D Lo-Solids? Benefits ?Better pulp strength ? Improved washing ?Better bleachability ? Increased extraction capacity ? Improved temperature distribution ?Higher yield? N E W Z E A L A N D AIM ?Confirm pulp yield increase for eucalypts ?Examine the effects of alkali profiling in Lo-Solids cooking of eucalypts N E W Z E A L A N D Study No. 1 ?Mixed eucalypts from New Zealand ?Pulping liquors from ITC? digester ? Laboratory pulps ? Batch (CK) ?Conventional continuous (CCK) ?Lo-Solids? (LSC) N E W Z E A L A N D Batch Cook (CK) Conditions ? 20% EA charge (as NaOH) ? 30% Sulphidity ? 4:1 liquor to wood ? 90 minutes to 165oC ? ~900 H-factors N E W Z E A L A N D Laboratory System N E W Z E A L A N D Temperature - CCK LSC 0 40 80 120 160 0 100 200 300 Pulping Time, minutes T e m p , o C CCK LSCImp HU Cook Cook/Wash W N E W Z E A L A N D 0 10 20 30 40 50 60 70 0 100 200 300 Pulping Time, minutes [E A ], g /L ( N a O H ) CCK LSC Liquor [EA] - CCK LSC N E W Z E A L A N D Pulp Details ID Pulp Type Kappa Yield No. (%) CK Batch 15.5 49.3 CCK Conventional continuous 17.0 49.8 LSC Lo-Solids 18.6 51.0 Mean levels N E W Z E A L A N D Lignin-free Yield 46 47 48 49 50 CK CCK LSC L ig n in -f re e Y ie ld , % 48.1 48.5 49.6 N E W Z E A L A N D Carbohydrate Retention Pulp Kappa Yield, % of Wood Glucan Xylan CK 15.5 35.7 6.9 CCK 17.0 36.9 7.0 LSC 18.6 38.2 7.4 Mean levels N E W Z E A L A N D Selectivity 0 20 40 60 80 12 14 16 18 20