Finding The Sweet Spot for Oxygen Delignification Yunqiao Pu, Rallming Yang, Lucian Lucia, Art Ragauskas Institute of Paper Science and Technology Hasan Jameel - North Carolina State University
Sweet Spot The place on a bat, club, or racket where it is most effective to hit a ball $$$$$$$$$$$$$$$$ We conclude that the sweet spot--or, in scientific terms, the centre of percussion of a uniform baseball bat lies two-thirds of the way down the bat from the batter's end.,,,
Finding The Sweet Spot for Oxygen Delignification Where is O or OO Sweet Spot? 160 140 120 100 80 60 40 20 0 Chemical Usage of North American Bleach Plants 1983 1986 1994 2000 Chlorine Chlorine Dioxide O Delign. Driven largely by environmental issues
Finding The Sweet Spot for Oxygen Delignification Yield on Wood, % 50 48 46 44 42 40 38 50(OO)DED 30DEDED 30ODED 50(OO) Pulping 0 10 20 30 40 50 60 Kappa Number O Sweet Spot: Identifying pulping conditions that optimize O and OO performance to - Enhanced yield - Improved bleachability - Improved selectivity - Improved physical pulp properties
Delignification Pulping Conditions Low AA Med. AA High AA Active Alkali 15.0 17.0 19.0 H-Factor* 1650 1400 1050 Kappa # 50.0 50.0 48.0 Viscosity/cP 36.8 34.1 29.0 Yield 48.5 48.5 47.0 *25% sulfidity
Delignification O and OO Delignification Conditions: Pulp: Low AA, Medium AA, High AA Temperature: 70-90 110 o C NaOH: 1.0 5.0% O 2 : 40 psi Csc: 10% Time: 60 min.
Delignification: O and OO Conditions Pulp NaOH% Temp./ o C Kappa # LAA 3.0 73 35.5 1.6 77 40.3 4.4 77 34.9 1.0 92 41.0 3.0 92 30.0 5.0 92 26.0 1.6 102 34.0 4.4 105 20.0 3.0 111 24.0 3.0 92 30.0 3.0 92 30.0 HAA 3.0 72 32.3 1.6 78 33.1 4.4 77 28.3 1.0 89 36.2 3.0 89 27.2 5.0 92 21.8 1.6 102 28.4 4.4 104 19.7 3.0 108 21.7 3.0 92 25.0 3.0 89 27.0 Pulp Active Alkali, % Temp./ C Kappa # LAAO 3.0 90 30.0 LAAOO1 3.0 72 23.0 LAAOO2 1.6 78 24.2 LAAOO3 4.4 78 22.0 LAAOO7 1.6 105 19.3 LAAOO8 4.4 105 14.9 LAAOO9 3.0 110 14.3 HAAO 3.0 80 31.0 HAAOO1 3.0 70 26.0 HAAOO2 1.6 75 24.7 HAAOO3 4.4 75 23.6 HAAOO4 1.0 90 24.0 HAAOO6 5.0 90 20.3 HAAOO7 1.6 102 20.0 HAAOO8 4.4 102 17.3 HAAOO9 3.0 110 14.8
Delignification O-Delignification - 1% NaOH Kappa 50 45 40 35 30 25 20 15 70 75 80 85 90 95 100 105 110 115 Temperature ( C) Medium High Low HAA most bleachable LAA least
Delignification O-Delignification - 3% NaOH 46 41 HAA most bleachable LAA least Kappa 36 31 26 21 16 70 75 80 85 90 95 100 105 110 115 Tem perature(c) Medium High Low
Delignification Viscosity Selectivity - 3% NaOH VISCOSITY 28 26 24 22 20 18 16 14 12 10 HAA lowest viscosity 20 25 30 35 40 KAPPA MEDIUM HIGH LOW
Delignification Kappa Reduction- 100 o C 40 35 HAA most bleachable LAA least Kappa 30 25 20 15 0 1 2 3 4 5 6 NaOH % Medium High Low
Delignification Yield Selectivity - 3% NaOH 51 50 49 48 47 YIELD 46 45 44 43 42 41 LAA best yield HAA poorest 40 18 20 22 24 26 28 30 32 34 36 38 40 KAPPA MEDIUM HIGH LOW
Delignification Models for Low AA 50 Kappa 15%AA KAPPA= 30.1123 7.06581*((NaOH-3)/2) 6.77534*((Temp-90)/20) + 3.70607*((NaOH-3)/2) 2 YIELD= 48.90639 0.91451*((NaOH-3)/2) 1.1175*((Temp-90)/2) VISCOSITY= 21.84217 4.673034*((NaOH-3)2) 4.67303*((Temp-90)/20) + 1.73915*((NaOH-3)/2) 2
Delignification Models for High AA 50 Kappa 19%AA KAPPA=26.46762 5.71586*((NaOH-3)/2) 4.97502*((Temp-90)/20) 2.39037*((NaOH-3)/2) 2 YIELD=45.21542 0.77563*((NaOH-3)/2) 0.85754*((Temp-90)/20 VISCOSITY= 17.33038 4.61892*((NaOH-3)/2) 1.73502*((Temp-90)/20) 2.65152*((NaOH-3)/2) 2 -comparable results found from MAA
Delignification 50 kappa for oxygen The higher alkali charge in pulping resulted in lower yield at the same kappa number 15% AA 48.5 % yield 19% AA 47.0 % yield The pulps produced with the LAA were slightly more difficult to delignify as compared to the high AA pulps The O-yield and viscosity selectivity was higher for LAA pulp with improvements of 3% yield and 6 cp in viscosity
Delignification Yield on Wood, % Yield Kappa Relationships 50 48 46 44 42 40 50(OO) 50(OO)DED 30ODED Pulping Low AA 38 0 10 20 30 40 50 60 Kappa Number
Finding The Sweet Spot For Oxygen Delignification Fundamentals
Delignification: Fundamental Properties Procedure Isolate lignin from: LAA and HAA Brownstocks LAAO and HAAO, 3% NaOH kappa #30.0, 31.0, respectively LAAOO1, LAAOO2, LAAOO3, LAAOO7, LAAOO8, LAAOO9 Kappa# 23.0 24.2 22.0 19.3 14.9 14.3 HAAOO1, HAAOO2, HAAOO3, HAAOO4, HAAOO6, HAAOO7, HAAOO8, HAAOO9 Kappa # 26.0 24.7 23.6 24.0 20.3 20.0 17.3 14.8 Establish lignin structure using advanced NMR techniques.
Finding The Sweet Spot for Oxygen Delignification: HAA 1.2 1 OCH 3 0.8 OH 0.6 0.4 mmol/gr lignin 0.2 0 R OH OCH 3 HAA HAAO HAAOO1 C5 Condensed Phenolics C5 Noncondensed Phenolics HAAOO2 HAAOO4 HAAOO3 5,5' PhOH HAAOO6 HAAOO7 HAAOO8 HAAOO9 1.00:0.96 1.00:1.10 1.00: 1.15
Delignification: LAA 1.40 1.20 1.00 mmol/gr lignin 0.80 0.60 0.40 OH OCH 3 0.20 0.00 LAA LAAO LAAOO2 LAAOO1 LAAOO3 LAAOO7 LAAOO8 LAAOO9 C5 Condensed PhOH C5 Noncondensed PhOH 5,5' PhOH R OCH 3 OH 1.00:1.05 1.00:1.13 1.00:1.26
Delignification 2.50 2.50 2.00 OH mmol gr/lignin 2.00 mmol gr/lignin 1.50 1.00 1.50 1.00 O HO OCH 3 0.50 OCH 3 0.00 0.50 OH HAA 0.00 HAAO HAAOO1 HAA HAAOO2 HAAO HAAOO4 HAAOO3 HAAOO1 HAAOO6 HAAOO2 HAAOO7 HAAOO4 HAAOO8 HAAOO9 HAAOO3 HAAOO6 Aliphatic Hydroxyl Acids HAAOO7 HAAOO8 HAAOO9 Aliphatic Hydroxyl Acids LAA similar pattern, little indication of side chain oxidation, remaining lignin only slightly oxidized
Delignification OH LAA, LAAO, LAAOO1 LAAOO9: 0.09 ±0.01 mmol/gr lignin HAA, HAAO, HAAOO1 HAAOO9: 0.10 ±0.01 OH O HO OCH 3 LAA LAAO, LAAOO1 LAAOO9: 3.3% ±0.1 %/C6 aromatic unit HAA, HAAO, HAAOO1 HAAOO9: 3.6% ±0.1 OH OCH 3
Delignification A 0.50 0.4 0.3 0.2 0.1 0.0-0.10 HO OH OCH 3 UV/Vis Ionization Difference Spectroscopy LAAO LAA LAAOO7 LAAOO3 LAAOO9 LAAOO1 OH 230.0 300 350 400 450 500.0 NM O OCH 3 1. λ max 250 and 300 nm are assigned to unconjugated phenolics, decreases with aggressive O-stages conditions is consistent with the 31P NMR data. 2. Lignin samples appear to be relatively free of phenolic stilbenes (λmax375 nm). 3. λ max 350 nm has been attributed to phenolic α-carbonyl groups
Delignification: Carbohydrates % Pulp Carbohydrate Profiles: Arabinan, Galactan, Mannan no significant variation from LAA LAOO9 & HAA HAOO9 LAA LAAO LAAOO1 LAAOO3 LAAOO7 LAAOO9 Xylan 9.0 9.1 8.8 9.0 8.7 9.1 Glucan 75.3 78.0 77.8 77.1 77.7 79.9 HAA HAAO HAAO1 HAAOO4 HAAOO6 HAAOO8 Xylan 7.5 7.7 7.3 7.5 7.4 7.7 Glucan 75.3 77.2 78.0 78.5 79.5 81.7
Conclusions
Delignification: Conclusions The results show there is tremendous potential for improving the yield, pulp properties and oxygen bleaching performance by optimizing the pulping and oxygen bleaching together: Pulping/OO performance is predictable Modeling performance is supported by fundamental properties Bleachability vs. selectivity in competition
Delignification: Conclusions HAA lignin differs from LAA, latter had higher amounts of condensed phenolics (pulping control). For HAA and LAA p-hydroxylphenyl groups unreactive to O chemistry (bio control) Very little side chain oxidation of lignin bioploymer during O and OO Difference in bleachability not due to hexenuronic acid LAA and O pulps had higher amounts of xylans It is possible to find a sweet spot for O and OO
Acknowledgements IPST Member Companies U.S. Department of Energy arthur.ragauskas@ipst.gatech.edu