manufacturing of dissolving hardwood and softwood pulp with

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Manufacturing of dissolving hardwood and softwood pulp with continuous cooking and novel fiberline technology

6th International Colloquium on Eucalyptus PulpNov 24-27 Colonia UY Janne Vehmaa

Content

• Dissolving pulp overview• Dissolving pulp cooking• Dissolving Pulp bleaching• Pre hydrolysis kraft mill• Conclusions

6th International Colloquium on Eucalyptus PulpNov.24-27 Colonia UY. Vehmaa


Annual Production Tons

Oil Based Synthetic Fiber 40,000,000Cotton 25,000,000Viscose Fiber 4,000,000Wool and other Animal Fiber 1,000,000

Total Fiber 70,000,0002008 Data from CIRFS

Viscose fiber is the key alternate fiber for replacement of lost cotton production

Dissolving pulp overvievGlobal Textile Fiber Production


0

1

2

3

4

5

6

7

1990 1995 2000 2005 2010 2015 2020 2025

Million tons

Forecast

Rest of Asia

North America

Western Europe

Japan

China

Rest of the World

The trend in dissolving pulp demand has turned from a rapid decline into modestgrowth. The world demand for dissolving pulp is expected to grow from 4.1 millionADt/a in 2008 to 6.3 million ADt/a by 2025 (CAGR 2.5%/a). Demand is expected togrow fastest in China and the rest of Asia.

Consumption of DP by Region – Average ForecastDissolving pulp overviev

Source: Poyry (2009)


Dissolving pulp overviev

+MoistureTemperature (155 – 170 C)Time (45 – 90 minutes)

Cellulose, lignin and some remaining hemicellulosestill in Chip Form

+ Sugar Fragments from hemicelluloses as: monomers and oligomers

+ Acetic Acid

+ Smaller amounts of:levulinic, syringic, formic and aldobiuronic acids

+ Acid Lignin fragments

+ Gases (CO, CO2…..)

End pH in the range of 3.3 – 3.7Auto buffering

Auto-Hydrolysis of Wood

Pre-hydrolysis kraft process has been known over 60 years


Brightness, % (ISO) 88-92Viscosity, ml/g 450-550Alpha cellulose, % 93-95R10, % >92R18, % >95Kappa number <0.5Ash content, % <0.1

Dissolving pulp overvievTypical bleached pulp parametersQuality parameters are same for SW and HW

Content

• Dissolving pulp overviev• Dissolving pulp cooking• Dissolving Pulp bleaching• Pre hydrolysis kraft mill• Conclusions



EffFibre – Dissolving Pulp Mill ConceptWood consumption balance – reference vs. dissolving pulp

Reference

Dissolving pulpUnit: OD kg/ADMT


Traditional technology solutionsDissolving Pulp Cooking

160 C40 minpH 4

165 C30 minpH 13

Variable pH interface location led to scale formation on screens and digester walls: solved in mill by converting to paper grade for 2 – 4 days

Traditional equipment cause imprecise chip volume fed to digester, making pH adjustment and interface location uncontrollable


Technology updatesDissolving Pulp Cooking

Chip feed technologyenable acid feed system

Heat recovery with reboiler;Clean steam to chip feedStabile pH controll

Stem vapor phase in bothvessels;Stabile feed and retention time.

Water displacement enablehydrolysate recovery and decrease alkali charge


Andritz DP ResultsLab / Mill

South American DP Producer Eucalyptus Specifications

Species Eucalyptus Eucalyptus Standard Special High Grade

Viscosity 400 - 550 520 350 - 599 250 - 599 500 - 599

Brightness 91+ 90.2 88 - 90 89 - 92 > 90.5

S18 1.4 – 2.8 3.3 – 3.8 3.0 – 4.0 2.3 – 3.0 < 2.3

S10 2.1 – 3.8 4.7 – 6.4 ~7 4.0 – 7.0 4.0 – 5.5

Ash 0.11 – 0.14 0.13 0.03 – 0.12 0.03 – 0.10 0.03 – 0.08

Extractives < 0.20 < 0.20 < 0.15 < 0.10

Alpha 94.5 – 97.4 94.7 94.5 – 96.0 95.0 – 96.0 95.5 – 96.5

R18 97.2 – 98.6 96.2 96.5 – 97.0 96.5 – 98.0 >97.2

R10 96.2 – 97.9 93.6 ~93 93 – 95 ~95

Pentosans 3.0 – 4.0 3.0 3.0 – 4.0 2.5 – 3.5 1.5 – 2.5

Dissolving Pulp CookingDissolving Pulp Properties

Mill results from startup operation has been improved, today’s optimized result: (pentosan < 2.5%, alpha-cellulose 95 – 97%)

Content




Selecting the bleaching technology

Dissolving pulpbleaching

Process enable viscositycontrollMeet brightness targetOptimized marerials whenTCFShort sequence options:

TCF/light ECFNo hexa removalMetal removal in bleaching

Flexible bleachingFor dissolving pulpand paper grade

• Process conditions enableviscosity controll and visco protection

• Meet brightness targetwith both grades

• Typically 3-4 washersequence:

• ECF with or withoutozone

• Hexa removal option• Metal removal in bleaching

Flexibility

Cost optimization

Technology between pulp grades is different

Dissolving Pulp bleaching


MethodsDissolving Pulp bleaching

• Eucalyptus chips were collected from various orgins from South America

• SW chips are from various sources in

• The HW prehydrolysis and cooking was done in PITC USA. P-factorand cooking parameters were fixed according to kappa target.

• The SW prehydrolysis and cooking was Done in Aalto universityFinland. P-factor and cooking parameters were fixed according to kappa target.

• Oxygen stage and pressurized alkaline stages was done oil bathautoclaves

• Ozone stage were done in Mark IV mixer

• Other bleaching stages were done in polyethylene bags and water bath


Initial PulpDissolving Pulp Bleaching

Initial pulp HW, Euca SWKappa Number 7,8 20,7Viscosity, mL/g 1211 1024ISO Brightness, % 44,4 26,2R10, % 97,2 93,7R18, % 98 95,1


O Stage HW, Euca SWTemperature, °C 105 95Time, min 75 60Pressure, bar 5,5 5,5NaOH, % 1,2 2Final pH 11 12,1Kappa Number 2,8 9,7Viscosity, mL/g 997 734ISO Brightness, % 67,5 37,1

Dissolving Pulp BleachingPulp after oxygen stage


Dissolving Pulp bleachingTCF bleaching performance, Euca

Z/Q‐P

ZQ Stage: Temperature, °C 75Time, min (D‐stage) 15O3, % 0,4DTPA, % 0,15H2SO4, % 0,23NaOH, % 0,27Final pH 2.7/5.6

ISO Brightness, % 86,1Viscosity, mL/g 708

P Stage: 90°C, 90 min.Temperature, °C 90Time, min 90H2O2, % 0,7NaOH, % 0,9Final pH 10,8H2O2, Consumed, % 0,48ISO Brightnesss, % 92,2Viscosity mL/g 517R10, % 93,5R18, % 97,2


Light ECF bleachingEuca

Dissolving Pulp bleaching

Z/D‐Eop‐(D)

ZD Stage:Temperature, °C 70Time, min (D‐stage) 15O3, % 0,5ClO2, % 0,1H2SO4, % 0,2Final pH 2.8/2.7Brightness, % ISO 89,2

Eop Stage:Temperature, °C 100Time, min 90Pressure, bar 2,4NaOH, % 0,8

H2O2, % 0,34Final pH 10,0H2O2 Consumed % 0,33Kappa Number 0,3Viscosity, mL/g 493ISO Brightness, % 92,1R 10 92,9R 18 96,1


ECF bleachingDissolving Pulp bleaching

Do‐Eop‐D‐P

Do Stage: HW, euca SW

Temperature, °C 75 60Time, min 20 40H2SO4, % 0,16 0,22ClO2, % 0,25 0,92ISO Brightness, % 80,1 56,9Viscosity, mL/g 848 696

Eop Stage: HW, euca SW

Temperature, °C 95 95Time, min 90 90Pressure, bar 2,4 2,5NaOH, % 0,9 1,2H2O2, % 0,4 0,4Kappa Number 0,9 1,19Viscosity, mL/g 680 541ISO Brightness, % 86,7 77


ECF bleachingDissolving Pulp bleaching

Do‐Eop‐D‐P

D1 Stage:HW, euca SW

Temperature, °C 75 70Time, min 120 120H2SO4, % 0,02 0,12ClO2, % 0,4 0,27ISO Brightness, % 91,7 86,6

P Stage: HW, euca SW

Temperature, °C 85 85Time, min 90 90NaOH, % 0,5 1H2O2, % 0,1 0,5Viscosity mL/g 615 489ISO Brightness, % 91,9 89,3R10, % 95,7 94R18, % 97,7 96,5


Dissolving Pulp bleachingBleaching Results Conclusions

• Pre hydrolysis HW Euca kraft pulp done with continuous cooking method is veryeasy to bleach

• Pre hydrolysis SW kraft pulp has good dissolving properties and reasonablechemical consumption in bleaching

• Two washer bleaching appplications are very attractive solutions, if the millproduce only viscose pulp

• TCF bleaching with ozone is competitive and flexible, if the mill produce onlyviscose pulp

• The flexible bleaching solution for kraft- and viscose pulp require 3-4 washersolution

• MC-ozone is extremenly efficient in hardwood viscose pulp bleaching and provide good solution for kraft paper pulp also

• Eucalyptus competitive raw material for viscose pulp production

Content




Pre hydrolysis kraft millDissolving Grade Kraft Pulp Fiberline


For a Pre-Hydrolysis Kraft Pulp Mill Fiberline

Hydrolysate handling α cellulose content , 92…96 (adjustable) Viscosity control to target:

P-factor Cooking and oxygen kappa High temperature alkali stages; O2, EO, EOP, P Ozone technology

Metal control and efficient metal washing A-stage role in metal management

State of art screening system Transition pulp, storage management in swing line

Pre hydrolysis kraft millMill Design Considerations

1st ozone mixer

Flow stabilator 1 Second ozone mixer

Flow stabilator 2

Ozone Reactor

Lay-Out and mill installation

Pre hydrolysis kraft millMC-ozone technology


Conclusions• Continuous cooking technology is good excellent solution to produce dissolving

pulp from HW and SW.• Existing fiberline can easily modified to produce doissolving pulp and it can

operate as swing line• The dissolving bleaching for HW can be done with two washer application• When ozone is used, the total cemical consumption is extremely low for HW• TCF is attractive option to produce Euca dissolving pulp• Modern fiberline applications in cooking and bleaching provide lot of benefits in

dissolving pulp production.


Thank You!

Questions?


We accept the challenge!www.andritz.com

Fiber Technologies DivisionAny questions?

For further informationplease contact:ANDRITZ Oy – Finland+358 20 450 5555

[email protected]

manufacturing of dissolving hardwood and softwood pulp with

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