Optimizing the Bleaching of Georgia’s SW Thinning Kraft Pulp Resource Program Review Art J. Ragauskas Institute of Paper Science and Technology
Optimizing the Pulping and Bleaching of Georgia’s SW Thinning Wood Resource: Background • Georgia has the highest collection of non-industrial private forest landowners (NIPF) in the nation • NIPF are a primary source of wood for many of Georgia’s pulp mills. • NIPF owners have begun to utilize short-rotation management options to improve the feasibility, profitability, and cash flow of production forestry enterprises. • A valuable component in forestry management approaches is to cut immature trees to stimulate growth/yield of the remaining trees • University of Georgia have demonstrated that thinning loblolly and slash pine stands increased internal rate of return for NIPF landowners by 1½% (slash) to 2% (loblolly) over unthinned stands. • Hence economical factors will increase the availability of pine thinnings for kraft pulping operations • Potential cost savings of 15 – 30%
Optimizing the Pulping and Bleaching of Georgia’s SW Thinning Wood Resource: Background • The performance of Georgia’s pine thinnings for bleached kraft pulps have not been reported. • Literature results document differences in kraft pulping for thinnings versus mature wood for: – Black, norway, radiate pine, red and white spruce – FY 2002 – 2003 GA TIP3 documented for GA SW Kraft – Wood (M:T) • Density: 1.00:1.04, Klason Lignin: 1:00:1.04, Glucose: 1:04:1:1.00 – Kraft Pulp (M vs.T) • Yield: 45.63 - 44.63, Kappa #: 24.2 – 27.4 • Tensile Index: 88.2 – 89.6, Tear Index: 16.8 – 13.6 (after 4000 PFI rev) • Differences greater than some northern species • Experimental results between 40:60 and 60:40 blends of Thinning and Mature are very small and would most likely not be observed in commercial practice • Need to quantify results after bleaching
Optimizing the Pulping and Bleaching of Georgia’s SW Thinning Wood Resource: Program/GA Mill Objectives Research Program Objective: Assess the impact of SW thinnings for the production of bleached kraft pulp for Georgia’s pulp mill operations. FY 2002 – 03: Examined SW kraft pulps FY 2003 – 04: Examine ECF bleached SW kraft pulps This program will provide Georgia’s pulp mills with valuable operational information so that they can manufacture a high-value, quality product at the lowest cost possible using the states pine wood thinnings at the completion of FY 2003 – 04 studies
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Program/GA Mill Objectives Experimental Objectives: • Kraft Cooking Process Ratio of Thinnings:Mature Wood Employed • Conventional batch 100:0, 80:20, 40:60, 0:100 • Simulated ITC 100:0, 60:40, 0:100 The kraft pulps will be bleached to TAPPI brightness ~85 via two bleaching sequences: OD(E+P+O)D D(E+P+O)DED • The partially bleached pulps will be analyzed for kappa number, viscosity, and TAPPI brightness • The fully bleached pulps will be analyzed for optical, chemical, and physical strength properties • Fully bleached pulps will also be PFI refined with 2000, and 4,000 revs and the physical strength properties will be re-assessed at each point of refining
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Experimental Protocol OD(E+P+O)D O-Stage (Incoming brownstock kappa # 24-27) – 60 min, 100 o C, 10% csc, 90 psig O 2 – Caustic charge varied 1.0 – 1.8 • preferred value ~1.5% NaOH to yield post-O kraft pulps with kappa # ~ 10 • D o -Stage • 45 min, 50 o C, 3.5% csc, Kf 0.25, terminal pH 2.1 – 2.3 • (E+P+O)-Stage • 60 min, 75 o C, 10% csc, 0.4% H 2 O 2 , initial O 2 :65 psig 15 min; then vent12 psig/5 min, %NaOH 50% of Kf • D 1 -Stage • 180 min, 75 o C, 10% csc, ClO 2 charge 0.5 – 2.0%, terminal pH 3 • Final TAPPI Brightness Values ~ 87
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results OD(E+P+O)D TAPPI Brightness Properties Conventional ITC Mature 87.6 87.2 Thinning 87.2 87.5 60% Thin/40% Mature 87.4 40% Thin/60% Mature 87.3 80% Thin/20% Mature 87.7
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results OD(E+O+P)D Fiber Properties: Fiber Length ITC 4.00 FQA Length 3.00 (mm) 2.00 1.00 Weight Weighted 0.00 Length Weighted Mature 60% Thinning Thinning
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results OD(E+O+P)D Fiber Properties: Fiber Length Conventional 4.00 FQA Length (mm) 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 W e i g h t W e i g h t e d Thinning L e n g t h W e i g h t e d 40% Thin 80% Thin. Mature
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results OD(E+O+P)D Fiber Properties: Fines 10.0 % Fines (Arithemetic) 8.0 6.0 4.0 2.0 0.0 ITC:Mature ITC: 60% ITC: Thinning 40% Thin 80% Thin. Mature Thinning Thinning
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results OD(E+O+P)D Fiber Properties: Fiber Charge 0.0300 mmol Acid goup/gr pulp 0.0250 0.0200 0.0150 0.0100 0.0050 0.0000 ITC:Mature ITC: 60% ITC: Thinning 40% Thin 80% Thin. Mature Thinning Thinning
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results O(D+P+O)D Sheet Properties 70 14 60 12 10 Tear Index (mNm2/g) 50 Tensile Index (Nm/g) 8 40 6 30 4 20 ITC: Thin 2 ITC 60% T 4000 10 0 ITC:Mature 1 0 2000 2 Revolutions 2000 0 3 4000 0 ITC:Mature ITC 60% T ITC: Thin
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results Sheet Properties: Conventional Kraft Pulps 80 70 60 50 Tensile Index 40 30 20 10 4000 revs 2000 revs 0 Thin O Revs 80% T 40% T Mature
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results Sheet Properties: Conventional Kraft Pulps 2500 2000 1500 TEA Index 1000 500 4000 Revs 2000 Revs 0 Thin O Revs 80% T 40% T Mature
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results Sheet Properties: Conventional Kraft Pulps 16 14 12 10 Tear Index 8 6 Mature 4 40% T 2 80% T 0 1 Thin 0 2000 2 4000 3
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Experimental Protocol D(E+P+O)DED • D 0 -Stage (Incoming brownstock kappa # 24-27) – K.f.:0.20, 45 min, 50 o C, 3.5% csc, terminal pH: 1.8 • (E+P+O)-Stage • 60 min, 90 o C, 10% csc, 0.4% H 2 O 2 , initial O 2 :35 psig 15 min; then vent 12 psig/5 min, 3.2 %NaOH • D 1 -Stage • 180 min, 75 o C, 10% csc, 1.0% ClO 2, terminal pH 3 • E-Stage • 60 min, 75 o C, 10% csc, 0.5% NaOH, terminal pH 12 • D 2 -Stage • 180 min, 75 o C, 10% csc, 0.2% ClO 2 , terminal pH 3 • Final TAPPI Brightness Values ~ 88
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results D(E+P+O)DED TAPPI Brightness Properties Conventional ITC Mature 87.8 88.1 Thinning 87.8 88.9 60% Thin/40% Mature 88.4 88.8 40% Thin/60% Mature 88.3 80% Thin/20% Mature 88.4
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results Pulp Viscosity Properties (mPa.s) Conventional D(EPO)DED ITC D(EPO)DED Mature 18.7 33.0 Thinning 23.0 21.3 60% Thin/40% Mature 21.6 24.7 40% Thin/60% Mature 22.1 80% Thin/20% Mature 23.1 Physical Strength Properties Evaluated After 0, 2000, and 4000 revs PFI refining
Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: Results D(E+O+P)DED Fiber Properties: Fiber Length 4.50 4.00 3.50 FQA Fiber Length/mm 3.00 2.50 2.00 1.50 1.00 0.50 0.00 g n e i n r u n e i t r h a u e Weight-Weighted T M t r a u e % M % t r Length-Weighted a u 0 s M 0 % t k 0 a 0 o s 1 0 M 1 % o k 2 o 0 C s / % g 4 o k n 0 C C o / g i 6 o n T n C C / n g I i - n T i g h n C n n I i T n - i T h i e n n I % r T n - i u h g 0 i t % h n T a 8 T M i 0 n % 6 n % 0 % i h 4 0 0 T 0 0 1 : e 1 r u t a M f o d n e l B
D(E+O+P)DED Fiber Properties: Tensile Index Thinning Wood Resource: Results Optimizing the Bleaching of Georgia’s SW Tensile Index 100 90 100% Thinning 70 80 50 60 30 40 10 20 0 1. 0 revs. 2. 2,000revs. 3. 4,000revs. 100%-Mature 4. 0 revs. 5. 2,000revs. 80% Thinning/20% Mature 6. 4,000revs. 7. 0 revs. 8. 2,000revs. 60% Thinning/40% Mature 9. 4,000revs. 10. 0 revs. 11. 2,000revs. 40% Thinning/60% Mature 12. 4,000revs. 13. 0 revs. 14. 2,000revs. 15. 4,000revs. 100% Thinning-ITC 16. 0 revs. 17. 2,000revs. 18. 4,000revs. 100% Mature-ITC 16. 0 revs. 17. 2,000revs. 60% Thin/40% Mature ITC 18. 4,000revs. 19. 0 revs. 20. 2,000revs. 21. 4,000revs.
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