Pulping potential of young eucalypts: a comparative study of wood - PowerPoint PPT Presentation

Pulping potential of young eucalypts: a comparative study of wood and pulp properties of 12 eucalypt species Duarte Miranda Neiva 1 ,Luís Fernandes 2 , Solange Araújo 1 , Ana Lourenço 1 , Jorge Gominho 1 , Rogério Simões 2 , Helena Pereira 1 1: Centro de Estudos Florestais, Instituto Superior de Agronomia; Universidade de Lisboa 2: Unidade de Materiais Tẽ xteis e Papeleiros, Universidade da Beira Interior 7 th ICEP – International Colloquium on Eucalyptus Pulp, May 26-29 2015 Vitória, Espirito Santo, Brazil

Outline • Wood chemical composition  Ashes, Extractives, Lignin, Holocellulose • Kraft pulping  Yield, kappa number, residual alkali, SWC • Fibers morphological characteristics  Fiber population, length, coarseness • Pulp and Handsheet properties  °SR, WRV, bulk, air permeability … • Possible end uses  High density papers, high porous papers, printing and writing papers

Wood chemical analysis Extractives Ashes E. camaldulensis E. camaldulensis E. rudis E. rudis E. resinifera E. resinifera E. propinqua E. propinqua E. sideroxylon E. sideroxylon E. botryoides E. botryoides E. viminalis E. viminalis E. maculata E. maculata E. saligna E. saligna E. grandis E. grandis E. ovata E. ovata E. globulus E. globulus 0 5 10 15 20 0.0 1.0 2.0 3.0 Ash content- [0.4-2.2%] Extractives content- [6.1-18.9%]

Wood chemical analysis Lignin Holocellulose E. camaldulensis E. camaldulensis E. rudis E. rudis E. resinifera E. resinifera E. propinqua E. propinqua E. sideroxylon E. sideroxylon E. botryoides E. botryoides E. viminalis E. viminalis E. maculata E. maculata E. saligna E. saligna E. grandis E. grandis E. ovata E. ovata E. globulus E. globulus 20 24 28 32 55 59 63 67 71 Lignin content- [22-31%] Holocellulose content- [55-70%]

Kraft pulping conditions • Microdisgestors ( ca. 100ml) • 10 g o.d. wood • 4:1 liquor to wood ratio • 22% active alkalinity (as Na 2 O) • 30% sulfidity (as Na 2 O) • 165 °C reaction temperature • 5 min to achieve maximum temperature • 60 min at isothermal conditions

Kraft results Kappa Yield Residual alkali number (%) (% of inicial EA) 39 20 7 E. camaldulensis 41 19 9 E. rudis 42 17 10 E. resinifera 42 20 12 E. propinqua 43 15 12 E. sideroxylon 44 17 9 E. botryoides 44 15 12 E. viminalis 44 24 14 E. maculata 45 14 13 E. saligna 46 14 13 E. grandis 49 13 14 E. ovata 50 12 16 E. globulus • Pulp yield correlates with holocellulose (R 2 =0.84) • Kappa number correlates with holocellulose (-) and wood density (+) (R 2 =0.71) • For some species the initial chemical charge was almost depleted during pulping. Ex: E. camaldulensis

Specific wood consumption 6 800 700 5 (m 3 wood / ton pulp) Wood density 600 4 SWC (kg/m 3 ) 500 3 400 2 300 SWC Wood Density • Higher wood density decreases wood volume needed to produce a certain amount of pulp • Digester size and wood transportation cost increases with SWC • Although having an average pulp yield E. maculata presented a lowest SWC than E. globulus

Fiber morphological properties Fibers Length Coarseness (millions/g) (µm, weighted in length) (mg/ 100m) E. camaldulensis 29 569 68 E. rudis 30 626 60 E. resinifera 32 629 57 E. propinqua 24 614 76 E. sideroxylon 33 568 59 E. botryoides 26 719 63 E. viminalis 41 598 46 E. maculata 18 748 84 E. saligna 25 708 66 E. grandis 25 759 61 E. ovata 32 608 59 E. globulus 24 727 67 • Coarser fibers are considered to be less conformable than fine fibers and do not bond as readily • Coarseness correlates with Fibers (-) and wood density (+) (R 2 =0.89)

Pulp and Handsheets • Previously dried pulp • Unbleached and unbeaten pulp • Handsheets with 60 g.m 2 basic weight

Pulp Properties 28 Schopper Riegler (°SR) 26 24 22 20 18 16 14 • °SR - rate of drainage of diluted pulp suspension. • ° SR for eucalypt pulps should be between 16-24 [13]

Pulp Properties Water Retention Value 140 130 120 110 100 90 • Combined effect of physical/chemical properties measuring pulp water affinity • For eucalypt pulps (previously dried) should be between 100-130% [13]

Handsheet Properties Bulk 2.2 2.0 cm 3 .g -1 1.8 1.6 1.4 1.2 • Influences almost all physical and mechanical properties. • Lower bulk - denser paper and normally higher fiber collapsibility • Bulk correlates with coarseness (+) and wood density (+) (R 2 =80)

Handsheet Properties 3000 Air permeability 2500 mL.min -1 2000 1500 1000 500 0 • Structural property related to sheet pores (number, size, shape and distribution) • Gives a general idea on the behavior of the paper to other fluids penetration (such as inks) • Air permeability correlates with bulk (+) (R 2 =0.89)

Handsheet Properties Tear index 14 12 mN.m 2 .g -1 10 8 6 4 2 0 • Measures the mechanical work required to continue a tear in the handsheet • Tear index correlates with bulk (-) (R 2 =0.71)

Handsheet Properties 50 Tensile index 40 N.m.g -1 30 20 10 • Direct indication of durability and performance of paper when receiving tensile stress • Tensile index correlates with bulk (-) (R 2 =0.92)

Handsheet Properties 210 Scott bond 190 170 150 J.m -2 130 110 90 70 50 • Quantifies the paper surface strength (Z direction). • Scott bond correlates with WRV (+) and bulk (-) (R 2 =0.92)

Possible end uses • High density papers (glassine, bible paper) E. viminalis Yield (%) 44 Kappa 15 Fibers (millions/g) 41 Coarseness (mg/100m) 4.6 °SR 24 WRV (%) 126 Bulk (cm 3 /g) 1.4 Air permeability (mL/min) 376 Tear index (mN.m 2 /g) 11 Tensile Index (Nm/g) 43 Scott bond (J/m 2 ) 166 Desired characteristics • High fiber population • Low air permeability • Low coarseness • High paper strength properties • Low bulk

Possible end uses • High porous and tissue paper E. maculata E. propinqua Yield (%) 44 42 Kappa 24 20 Fibers (millions/g) 18 24 Coarseness (mg/100m) 8.4 7.6 °SR 16 20.5 WRV (%) 99 114 Bulk (cm 3 /g) 2.1 2.1 Air permeability (mL/min) 2490 2029 Tear index (mN.m 2 /g) 3 4 Tensile Index (Nm/g) 16 18 Scott bond (J/m 2 ) 63 90 Desired characteristics • Low fiber population • High air permeability • High coarseness • Low paper strength properties • High bulk

Possible end uses • Printing and writing paper E. E. E. E. E. E.globulus botryoides saligna grandis ovata globulus (Portuguese mill) Yield (%) 44 45 46 49 50 - Kappa 17 14 14 13 12 12-17 Fibers (millions/g) 26 25 25 32 24 - Coarseness (mg/100m) 6.3 6.6 6.1 5.9 6.7 - °SR 21 20 22 25 19 18 WRV (%) 127 118 113 133 112 - Bulk (cm 3 /g) 1.6 1.7 1.7 1.6 1.8 - Air permeability 700 1143 1171 350 1500 - (mL/min) Tear index (mN.m 2 /g) 12 9 13 10 9 4.4 Tensile Index (Nm/g) 39 38 36 40 32 32.9 Scott bond (J/m 2 ) 142 103 122 169 116 - Desired characteristics • • Good paper surface strength (Scott bond) Medium/high fiber population • • High paper strength propertjes at low ͦSR Good air permeability

Conclusions • E. maculata and E. propinqua presented fiber and handsheet characteristics desired for highly porous and tissue paper • E. viminalis appears to show good fiber and handsheet qualities for high density papers (glassine, bible) • E. botryoides , E. saligna , E. grandis , E. ovata and E. globulus appear to be the most suited for printing and writing papers • E. globulus presented the best overall combined results in terms of kraft pulping, fiber morphology and handsheet properties • Results suggest that the variability in the Eucalypt genus can be further explored, increasing the number of species to be used by the Pulp and Paper industry

Considerations • Edaphoclimatic conditions influence the growth and quality of the trees, and consequently the pulp produced • Reaction conditions influence the yield and characteristics of the pulp • It is only possible to optimize the reaction conditions for a specific end use • The optimization of the reaction conditions should be different for each species

Thanks! This work as been published in Industrial Crops and Products: “ Chemical composition and kraft pulping potential of 12 eucalypt s pecies” 66: 89-95 (2015) Duarte Miranda Neiva- duarteneiva@isa.ulisboa.pt