Summary of latest developments regarding pulp bleaching with Ozone.

1. Achievements in Industrial Ozone Bleaching
Alexis Métais - 5th ICEP, 11/05/2011

2. Introduction
Modernizing or building their pulp mills, several
pulp producers still consider the 30 years old
ECF bleaching as the only option.
But, considering the very good and reliable
results achieved by industrial ozone bleaching,
such a conservative attitude can not be justified
any longer.

3. Introduction
First industrial production of ozone bleached pulp
started in 1992.
At the beginning, ozone bleaching development
was linked to the increasing environmental
pressure.

4. Introduction
Today the choice of ozone is mostly justified by
the economical savings resulting from chemicals
costs cut-off.
In May 2011, 22 mills worldwide use ozone
bleaching and deliver a pulp quality similar or
better than conventional ECF bleaching would do.

6. Ozone Generation
Ozone production requires only Oxygen & Energy.
It is a pure on-site technology needing neither delivery nor storage
Producing 1 kg ozone requires:
- 10 kWh (all included)
- 8.3 kg of pure oxygen
At the generator’s outlet,
the gas mixture contains
7.3 kg oxygen and 1 kg ozone
(concentration of 12 % by weight)

7. Ozone Generation
• Since 2000, ITT WEDECO has developed Z-Compact system which
is an ozone plant completely pre-assembled at factory offering the
following advantages:
• Complete test run before shipment
• Solution “plug & play”
• Fully protected from ambient
conditions
• Minimal foundation work & foot print
Modularity combining “on site” chemical production & supply is
today a key success factor for ozone production .
Example : Fibria Jacarei with 4 Z-Compact systems in operation
• Nominal ozone production on site : 750 kg/h (18 tons/day ozone)
• Peak capacity : 1 ton/h (24 tons/day ozone)

8. Ozone Generation - Availability
Example in Brazil
Contract was 98% on monthly base.
What are the numbers ?
Availability
01.-08. 2010 2009 2008 2007 2006 2005
Total (without
99.9% 99.9% 99.9% 99.9% 99,40% 98,80%
Oxygen plant)
Container 99.7% 99.5% 99.0% 99.0% 99% 98%
Oxygen compressor 99.0% 99.0% 99.0% 100% 99% 98%
Chiller 99.5% 99.4% 99.0% 99.9% 99% 99%
Destructor 100% 100% 100% 100% 100% 99%
MCC 100% 100% 100% 100% 100% 100%
Oxygen plant 98% 98% 98% 99% 98% 98%

9. Z-stage – High Consistency
C-Free® ZeTracTM
HC ozonation is carried out at atmospheric pressure in 1 min.
Ozonated pulp is then sent without intermediate washing to a 5-10
minutes long extraction stage.
Such a solution allows to recycle the E filtrate back to the furnace
and lower the total bleaching effluent to 4-8 m3/adt.

10. Z-stage – Medium Consistency
In 2004, Lenzing upgraded its 2 bleaching lines with modern
mixers: it resulted in a 2.5 ISO brightness points increase for the
same ozone dose.

11. Z-stage – Operating Parameters for HW
Initially Z-stages were operated at 40-45°C.
In Mondi Ruzomberok increased temperatures improve ozone
bleaching efficiency but do not impact mechanical properties:
Temp in Z 43°C 43°C 58°C 61°C
Kappa number after Z(EO) 4.1 4.0 4.0 3.8
ClO2 charge, kg/adt (DCS data) 24.5 23.5 24.7 24.4
Brightness, % ISO 85.9 85.2 86.6 87.7
Reverted Brightness, % ISO 81.8 82.2 83.9 85.9
A similar study made Domtar Espanola operating the Z-stage at
70°C.
Today most of the HW Z-stages operate in the 55-70°C range.

12. Z-stage – Operating Parameters for HW
As a result of an increased
temperature, steam requirements
can be 75% lower when ozone
bleaching is implemented:
(industrial figures)

13. Green Bleaching
Green Bleaching consists in maximizing the use of
green chemicals and their by-products.
Example of Celtejo (Portugal):
Pulp production: 720 adt/d (Eucalyptus, Pine)
Brightness: 90 % ISO
Flexible bleaching process: (OO)ZeDD, (OO)ZeDP & (OO)ZePP
Total bleach plant effluent volume:
6-8 m3/adt for light-ECF
4-6 m3/adt for TCF

14. Green Bleaching
Oxygen
34 t/day O2 30 t/day O2 + Applications
4 t/day O3
Ozone
17.5 t/day 02
Generator Gas
scrubber 30 t/day 02
available Oxygen
Delignif.
Compressor
Pulp in
Oxygen 12.5 t/day 02
Plant
Oxygen
TOWL
Back-up
Z-Stage
LOX
tank Pulp out Ozone Destruction
System
ambient
air

15. 1998: Domtar Espanola (Canada)
Pulp production: 800 adt/d (Birch, Aspen, Maple)
Brightness: 93 % ISO
In 1998, Domtar Espanola switched from O-A-D-E-DnD to O-A-ZD-E-DnD.
It was noticed:
1. no impact on viscosity or mechanical strength
2. a replacement ratio from 2.2 to 3.5
3. a bleaching costs reduction of 10%

16. Mondi Ruzomberok (Slovakia)
D PO PO
Pulp production: 480,000 adt/y (HW and SW)
Brightness: 89+ % ISO
PFI 28 SR - HW: PFI 28 SR - SW:
Breaking length (km) 7.8 - 8.5 Breaking length (km) 11 - 12
Tear index (mNm2/g) 5.8 - 6.5 Tear index (mNm2/g) 9.5 - 10.5
Stiffness (mN) 125 - 135 Stiffness (mN) 125 - 135
Viscosity (cm3/g) 650 - 700 Viscosity (cm3/g) 550 - 600
In 2005, the mill set a new world record for copy paper production at 1500 m/min.
The paper machine is still today the 3rd fastest worldwide for such a production

17. ITC Bhadrachalam (India)
Line 2
Pulp production: 500 adt/d (Eucalyptus, Subabul and Casurina)
Brightness: 89+ % ISO
ITC’s feedback concerning ozone bleaching is the following:
1. overall strength properties improved by 5%
2. about Rs 450 per MT saving in bleached pulp cost of production
Savings of 7.25 €/adt
3. 1 kg of Ozone replaces 5-6 kg ClO2 as active Cl2

18. Fibria Jacarei (Brazil)
Line C
Eucalyptus pulp production: - 1,200 adt/d on line B
- 2,500 adt/d on line C
Brightness: 90+ % ISO
Producing 1,300,000 adt/y, Fibria Jacarei is the biggest mill using ozone bleaching.
The mill just contracted a new Z-Compact-System
to increase capacity on line B.

19. Oji Paper Nantong (China)
Pulp production: 1600 adt/d (Eucalyptus and Acacia)
Brightness: 90+ % ISO
Start-up: 2012
The Oji Paper mill in Nantong will be
the first Greenfield mill built with an ozone stage

20. In the near Future…
Results presented by Metso - Zetrac forum
April 27– 28, 2011, Pousada do Crato, Flor da Rosa, Portugal

21. In the near Future…
… an A(Ze)(PO) bleaching sequence would allow to bleach
eucalyptus pulp to 92% ISO with 3.3 kg/adt O3 and 8 kg/adt H2O2!

22. Conclusions
Ozone bleaching technology has improved a lot in the last 20 years. It
is today: - a well proven technology
- a reliable on site chemical production
- a safe, stable and flexible process
- used by some reference pulp mills worldwide.
Ozone bleaching allows to reach those 4 targets at once:
1. Lower the effluents amount combined
2.Improve effluents quality
3. Produce pulp with similar or better strength properties,
4. Lower bleaching chemical costs by at least 20%

23. Sustainable development is your ambition…
Ozone Bleaching is our solution!
Fibria Jacarei, Brazil
MUITO OBRIGADO PELA VOSSA ATENÇÃO !