EcoFracSmart: A new stock preparation process for testliner - - PowerPoint PPT Presentation

EcoFracSmart: A new stock preparation process for testliner

Karl-Johan Grundström, Marco Lucisano

STFI-Packforsk AB Box 5604 – SE-11486 Stockholm (Sweden)

turning science into reality

2007-09-24 8th Research Forum on recycling 2007

Bernt Bergström, Annika Bjärestrand

Noss

Eva Larsson

Lyckeby Industrial

Hans-Olof Lindh

Smurfit Kappa Lagamill

Roland Selin

JLR Pulping Systems

Owe Sänneskog

Läckeby Water

Outcome

Introduce a stock preparation process for testliner, based on ecoefficient coarse screening and hydrocyclone fractionation of the furnish for differentiated treatment of the fractions.

Outcome

In an industrial installation:

• 35-40 kWh/t as electricity.
• 130 kWh/t as steam.

In pilot trials: 60% furnish: no upgrade by refining. 60% furnish: excellent papermaking fibres.

The papermaking process

Illustration: CEPI Sustainability Report 2005

Recycling in Europe

Strategic goal 2005 Recycling rate 2005 Strategic goal 2010 56% 54.6% 66%

Energy in papermaking

Source: CEPI Sustainability Report 2005

Raw materials

Goal of the project

Demonstration of process technology for stock preparation in a recycled paper mill:

– Decreasing energy consumption. – Improving product properties. – Simplifying stock preparation.

EcoFracSmart = EcoSmart + FracSmart

Pulper + Hydration + Multifunctional Screen Hydrocyclone fractionation

• Separate fibre according to end-product properties.
• Limit energy intensive processes.
• Minimize energy consumption in the early steps.
• Separate impurities as early as possible.
• Gentle mechanical treatment of the fibre material.

The project

OCC / Consumer packaging Pulping Screening Hydrocyclone fractionation Cleaning Refining Production of two

• ply testliner
• Addition of starch
• Impulse drying

Refining Cleaning Production of two

• ply testliner

Repulping Screen fractionation Refining Production of two

• ply testliner
• Addition of starch

Pilot Pilot Papermill Papermill

Hydrocyclone trial

OCC / Consumer packaging Pulping Screening

• Refining

Cleaning Production of two

• ply testliner

Repulping Screen fractionation Refining Production of two

• ply testliner
• Reference

trial

Impulse drying

Combines the functions of:

• Defibration,
• Separation of heavy contaminants,
• Coarse screening,
• Fine screening.

Multifunctional screen

Multifunctional screen

• A modified pressure screen:

– Lower defibration energy in the pulper. – Hydration between the pulper and the screen. – The feed flow is hydrated but poorly defibrated material. – The rotor has a defibration action in the entrance section of the screen.

• Simplification of the process flow.

Multifunctional screen

FS FF Disp

PM

Curved screen

PM

Pulper Pulper PM Broke

PM

Disp

Original installation

Water Pulper Press

Original reject system

Chests Refining Cleaners To PM Pulper Chest Chest Multifunctional Screen Water

With multifunctional screen

• 121

Fractionating Screen

• 375

Dispersion 219

• Multifunctional Screen

219 520 Total

• 24

Fractionating Screen Multifunctional Screen Standard [kW]

• 301 kW

Installed power

Stock preparation energy

280±40 450±40 Energy consumption (including dispersion) [kWh/t] 280±40 320±40 Energy consumption (excluding dispersion) [kWh/t] EcoSmart Trad

Effect of the new process

• Lower energy consumption.
• Simplified process layout.
• Good papermachine runnability.
• Lower contaminants better surface.
• Higher ash content somewhat lower

strength properties.

250 um

250 μm Micrograph Phase contrast microscopy

Raw material – OCC

OCC / Consumer packaging Pulping Screening Hydrocyclone fractionation Cleaning Refining Production of two

• ply testliner
• Addition of starch
• Impulse drying

Refining Cleaning Production of two

• ply testliner

Repulping Screen fractionation Refining Production of two

• ply testliner
• Addition of starch

Pilot Pilot Papermill Papermill

Hydrocyclone trial

OCC / Consumer packaging Pulping Screening

• Refining

Cleaning Production of two

• ply testliner

Repulping Screen fractionation Refining Production of two

• ply testliner
• Reference

trial

Impulse drying

Hydrocyclone fractionation

Fractionating hydrocyclones Cleaners Filtrate Coarse fraction C = 3.0% P = 2.5 kg/min 14°SR Fine fraction C = 3.3% P = 3.7 kg/min 72°SR Sand Heavy reject Q = 34 l/min C = 1.3% P = 0.44 kg/min Q = 1400 l/min C = 0.66% P = 9.2 kg/min Q = 950 l/min C = 0.38% P = 3.6 kg/min 39°SR

60% 40%

Reference: screen fractionation

Short fibre fraction C = 3.9% P = 6 kg/min 59°SR Long fibre fraction C = 4.1% P = 8 kg/min 19°SR Q = 700 l/min C = 1.3% C = 0.39% C = 0.028% Q = 700 l/min C = 0.9% Q = 1400 l/min C = 1.1% P = 14 kg/min 34°SR

48% 52%

Fractionation, Impurities

Feed Fine fraction Unrefined 70 kWh/t 120 kWh/t

Impurities [%]

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 Coarse fraction

Hydrocyclones Screen

Tensile index

Feed Fine fraction Unrefined 70 kWh/t 120 kWh/t

Tensile index [Nm/g]

10 20 30 40 50 60 Coarse fraction

Hydrocyclones Screen

Surface roughness

Feed Fine fraction Unrefined 70 kWh/t 120 kWh/t

Surface roughness [ml/min]

200 400 600 800 1000 Coarse fraction

Pilot scale papermaking

• Two-ply testliner:

– Twin-wire: 50 g/m2 (fine/short fraction) – Fourdrinier: 75 g/m2

Fourdrinier table Twin-wire former Shoe presses Roll press

SCT index

120 kWh/t 70 kWh/t 70 kWh/t 70 kWh/t 120 kWh/t 120 kWh/t No starch Starch X Starch A Commercial testliner

SCT index [Nm/g]

5 10 15 20 25 30

Hydrocyclones Screen Impulse drying

Surface roughness

Surface roughness [ml/min]

200 400 600 800 1000 1200 1400 1600 1800 120 kWh/t 70 kWh/t 70 kWh/t 70 kWh/t 120 kWh/t 120 kWh/t No starch Starch X Starch A Commercial testliner

Impulse drying

Results and conclusions

• New screening section installed and tested:

– -35-40 kWh/t electricity. – -130 kWh/t steam.

• Hydrocyclone fractionation tested successfully:

– Testliner from OCC: energy saving > 20 kWh/t. – All properties unaffected or improved. – Synergy with selective dosage of starch.

• Process integration assessed on testliner from OCC:

– No technically unsolvable open issues. – Large optimization window.

Acknowledgements

Financial support from STEM, The Swedish Energy Agency, is gratefully acknowledged.