IMPROVING BLEACHING PERFORMANCE OF SULPHITE DISSOLVING PULPS XXII TECNICELPA – International Forest, Pulp and Paper Conference - 2013 IMPROVING BLEACHING PERFORMANCE OF SULPHITE DISSOLVING PULPS Leonardo Lourenço de Jesus (CICECO-UA) Professor Dmitry V. Evtyugin (CICECO-UA) Engineer António F. d. S. Prates (CAIMA S.A.) Tomar, 3th October 2013

2 CONTENTS Introduction; Objectives; Experimental methodology; Results and discussions; Main conclusions

3 INTRODUCTION Cellulose (Beyond paper) Main applications: Textiles; Cellophane; Rayon; Composites; Films; Varnish; Plastics Produced from: Cotton; Dissolving pulp of wood species Main cellulosic derivatives: Viscose; Cellulose acetates

4 INTRODUCTION Source: textileworld.com Source: apparel.edgl.com Source: Indexmundi

5 INTRODUCTION To be considered as dissolving pulps, cellulosic pulps must satisfy these requisites: High α-cellulose content (≥ 91%); Less Kappa number (≈ 1); Moderate intrinsic viscosity ([450-550] cm3/g) Low amount of hemicelluloses and extractives compounds; High reactivity (> 60%)

6 INTRODUCTION At CAIMA S.A: Where: Cooking process: Acid sulphite with Mg base Bleaching sequence: EOPEP Where: EOP Stage : Delignification and bleaching action; Actually works as unique delignificant stage; EP Stage: Bleaching action

7 INTRODUCTION Table 1- Characteristics of conventionally EOPEP bleached sulphite pulp   Stage EOP Stage EP IK 9,1 8,5 [η] (cm3/g) 1150 1120 Pentosans (%) Not applicable 5,8 Lignin (%) 1,6 Brightness ISO (%) 80,4 87,2 This E. globulus pulp obtained from TCF sulphite pulp cannot be classified as dissolving pulp.

8 OBJECTIVES Study the modification of CAIMA’s bleaching sequence to obtain dissolving pulp as final product (EEOPEP vs EOEP); Characterize this pulp to study the ability for cellulosic derivatives production (namely viscose and cellulose acetate)

EXPERIMENTAL METHODOLOGY 9 EXPERIMENTAL METHODOLOGY Parameter caractherized Significance Standard/Test Moisture Determination of moisture on different pulps TAPPI T 412 om-06 Consistency Determination of pulp’s consistency TAPPI T 240 om-07 Neutral sugars Amount of neutral sugars Analysis of neutral sugars by acid hydrolisis Kappa number Extension of pulp’s delignification TAPPI T 236 om-09 Intrinsic viscosity Extension of pulp’s degradation SCAN-CM 15:88 Hemicelluloses Determination of maximum percentage of solubilized cellulose and hemicelluloses (R10); Determination of total percentage of solubilized hemicelluloses (R18) TAPPI T 235 cm-00 Chemical oxygen demand Degree of organic compounds oxidation ASTM D 1252-00 (reflux method) α-cellulose Determination of α-cellulose amount on final pulps (R17,5) TAPPI T203 cm-99 Reactivity Ability of reaction of final pulps with CS2 Fock method Brightness Degree of cromophores compounds elimination ISO 2470:1999 Pentosans Determination of pentosans by bromite-bromade method TAPPI T223 cm-10 Extractives Determination of extractive compounds with acetone TAPPI T207 cm-97

RESULTS AND DISCUSSION 10 RESULTS AND DISCUSSION Characterization of Pulp 1 and Pulp 2 Table 3- Results of Pulp 1 and Pulp 2 characterizations Parameter caractherized Pulp 1 Pulp 2 Kappa number 11,0 6,6 Intrinsic viscosity (cm3/g) 740 585

RESULTS AND DISCUSSION Intrinsic viscosity (cm3/g) 11 RESULTS AND DISCUSSION E stage optimization (EEOPEP vs EOEP) Table 5- Results on Pulp 1 after treatment in E stage Table 6- Results on Pulp 2 after treatment in E stage Table 4- Operation parameters applied in E stage Temperature (⁰C) Alkali charge (% odp) Yield (%) Kappa number Intrinsic viscosity (cm3/g) R10 (%) R18 (%) COD (mg O2/ Kg odp) 70 2 97.5 5.7 730 89.5 90.0 20500 3 5.2 725 90.2 91.6 21500 80 5.5 90.5 92.1 25500 96.0 5.1 715 89.7 92.3 4 92.5 710 90.8 93.4 31500 5 700 89.2 90.9 46500 90 5.8 720 90.7 87.7 Temperature (⁰C) Alkali charge (% odp) Yield (%) Kappa number Intrinsic viscosity (cm3/g) R10 (%) R18 (%) 90 4 89.0 2.4 675 91.9 94.7 6 85.0 2.3 690 92.1 94.8 110 77.5 710 95.8 75.0 2.7 730 94.0 95.9 Sample Temperature (⁰C) Alkali charge (% odp) Pulp 1 70; 80; 90 2-5 Pulp 2 90;110 4.0; 6.0 Criteria to choose optimal conditions: High yield; Low Kappa number; High R10 and R18; Low intrinsic viscosity

RESULTS AND DISCUSSION Intrinsic viscosity (cm3/g) 12 RESULTS AND DISCUSSION EOP stage vs O stage (EEOPEP vs EOEP) In order to select the second stage with less modification of actual CAIMA’s bleaching sequence, 2 alternatives were studied with Pulp 1: EOP (Actual delignificant and bleaching stage at current CAIMA’s EOPEP bleaching sequence); O (Alternative stage) Table 8- Results on pulps’ delignification in EOP and O stages Table 7- Operation parameters for EOP and O stages   EOP O Temperature (°C) 80 105 Alkali charge (% NaOH) 2.1 2.5 H2O2 charge (% H2O2) 1.2 Not applicable O2 (bar) 3 6 Time (h) 1 Stage Yield (%) Kappa number Intrinsic viscosity (cm3/g) R10 (%) R18 (%) EOP 87.5 2.7 455 95.3 97.2 O 92.5 2.6 710 95.6 98.7 Due to low intrinsic viscosity, the EOP stage was excluded and the O stage was selectionated as delignificant stage

RESULTS AND DISCUSSION 13 RESULTS AND DISCUSSION Optimization of O stage (EOEP) Table 10- Results on oxygen delignification of Pulp 1 (105 °C) Table 9- Conditions applied in O stage Table 11- Results on oxygen delignification of Pulp 2 (oxygen pressure 5 bar) Time (h) Alkali charge (% odp) Temperature (°C) Yield (%) Kappa number Intrinsic viscosity (cm3/g) R10 (%) R18 (%) 0.5 2.8 95 85.5 1.5 655 93.1 95.2 1.0 80.5 1.2 630 95.1 97.6 105 79.5 1.6 690 93.0 96.0 2.3 76.6 2.1 620 92.4 94.0 Temperature (⁰C) Alkali charge (% odp) O2 pressure (bar) Time (h) Pulp 1 105 2.5; 2.8 6; 8 1; 1.5 Pulp 2 95;105 2.3; 2.8 5 0.5; 1 Time (h) O2 pressure (bar) Alkaline charge (% odp) Yield (%) Kappa number Intrinsic viscosity (cm3/g) R10 (%) R18 (%) 1 6 2.5 92.5 2.6 710 96.6 98.7 2.8 92.0 2.2 680 96.7 98.9 8 90.0 670 89.5 1.6 640 95.4 98.4 1.5 87.5 87.0 570 95.9 98.5 Criteria to choose optimal conditions: High yield; Low Kappa number; High R10 and R18; Low intrinsic viscosity

RESULTS AND DISCUSSION 14 RESULTS AND DISCUSSION Study of EP stage (EOEP) Table 13- Results on the bleaching of Pulp 1 in the last EP stage (H2O2 load of 1.0%) Table 14- Results on the bleaching of Pulp 2 in the last EP stage Table 12- Conditions applied in EP stage H2O2 charge (wH2O2/wodp) Yield (%) Kappa number Intrinsic viscosity (cm3/g) R10 R18 1.0 84.5 1.3 520 91.3 94.5 1.4 77.5 1.1 470 91.8 95.2 Temperature (⁰C) Alkali charge (% odp) H2O2 charge Time (h) 80 1.0 1.0; 1.4 2.5 Yield (%) Kappa number Intrinsic viscosity (cm3/g) R10 R18 89.5 0.9 500 96.7 98.9

RESULTS AND DISCUSSION 15 RESULTS AND DISCUSSION Final pulp characterization Table 15- Results of analysis of pulps bleached by EOEP Fully bleached pulp Pentosans (%) Extractives (%) α-cellulose (%) Brightness (%) Reactivity index Pulp 1 2.0 - 96.8 89.4 72.2 Pulp 2 3.2 0.40 93.2 90.1 68.0

16 CONCLUSIONS For incoming sulfite E. Globulus pulps with Kappa number between 6-11, the bleaching sequence EOEP showed best results than EEOPEP ; At first E stage, the optimal conditions are: Temperature: 80-90°C; Time: 1h; Alkali load: 3-4% On this first stage, ca. 50-60% of residual lignin and cooking-degraded low molecular weight polysaccharides were removed without significative loss of pulp viscosity; On O stage, the optimal conditions for Pulp 1 (T=105 °C, t=1 h, P(O2)=8 bar) were more drastic than Pulp 2 (T=95 °C, t=0,5 h, P(O2)=5 bar); The main consequence was a major delignification on Pulp 1 (ca. 70%) than on Pulp 2 (ca. 40%);

17 CONCLUSIONS At EP stage, the optimal conditions are very similar relatively the conditions that are used on actual CAIMA’s EOPEP bleaching sequence. The optimal conditions are: Temperature= 80°C; Time= 2.5h; Alkali load= 1.0% odp; H2O2 charge= 1.0% odp Both pulps (Pulp 1 and Pulp 2) bleached from EOEP can be classified as dissolving pulps because: Kappa number ≈ 1; Intrinsic viscosty ≈ 500 cm3/g; Brightness ≈ 90 % ISO; Low pentosans content (2-3 %); High amount of α-celulose (93-95 %); Reactivity ≈ 70 %

Thanks for your attention 18 FINALLY… Thanks for your attention