Case Study # 261
1. Headline: Using ozone, oxygen and peroxide to bleach
chemical pulp instead of chlorine in a French pulp and
paper plant
2. Background: The paper industry is searching for a way to
get rid of the chlorinated products for bleaching the
chemical pulp. Bisulfate pulp without chlorine, having a
whiteness of 85 % is proposed at a very high cost price.
Saint-Gobain Papier-Bois has developed a way to bleach
kraft pulps without chlorinated derivatives, ensuring a
whiteness of 86.5 %. This case study was conducted in
1992.
3. Cleaner Production Principle: Material substitution
4. Description of Cleaner Production Application:
Information about the process and wastes
The kraft pulp manufactured in the plant in Condat stems
from broad - leaved trees. The lignin is dissolved under
the action of chemicals (soda), the temperature and the
pressure. The raw fibers obtained are bleached by means of
oxidizing agents. Condat plants use a standard process
with chlorine, hypochlorite and chlorine bioxyde,
generating organo-chlorinated substances in the effluents
and the pulp.
The new bleaching technique, exploiting the results of the
pilot-plants, uses neither chlorine nor chlorinated
derivatives and uses ozone, oxygen and peroxide.
After standard wood heating, the process is as follows :
Lignin removal using oxygen: Washing a filter, injection
of oxygen into the mixing chamber and reaction, washing a
filter.
Chelating phase: Treatment using sulfuric acid and a
chelating agent, washing a filter.
High consistency ozone phase: Increase in the consistency
of up to 35 % on filter press, ozonation, washing a
filter.
Peroxide-oxygen phase: Soda injection : injection of steam
at 80C, introduction of peroxide, injection of oxygen and
reaction in a tower, washing a filter.
High consistency peroxide phase: Increase in the
consistency of up to 40 % on filter press, treatment using
peroxide, washing a filter.
Pilot experiment conclusive on 20 tons/day: Dimensioning
realized for 200 tons/day at Condat, but realization
postponed because of cessation of pulp production in 1994.
Level of marketing: Patents registered in France and in
Europe.
5. Economics:
Cost of direct investment: Assessment at 165 000 000 FF
(1992) for a unit of 200 tons/day.
Operation and maintenance costs: Increase in the cost
price by 12 % due to the price of ozone and peroxide.
6. Advantages:
Total suppression of chlorine in the process.
Decrease by 97 % in the effluents color.
Reduction in the malodorous discharges into the air from
lower sulphide ratio of the pulp.
Whiteness of the kraft pulp without chlorine is on par
with the processes using chlorine.
All the effluents, free from chlorine, can be reused in a
recovery boiler.
Possibility of building a plant with a closed water
circuit.
7. Constraints: Decrease in the capacity of producing pulp
by about 2.5 % because of the capacity limit of the
recovery boiler.
8. Contacts:
Direction RÆgionale de l'Industrie et de la
Recherche
M. DELMONT
TEL: 33 56.00.04.00
Saint-Gobain Papier Bois
353 boulevard du PrÆsident Wilson
33200 BORDEAUX, France
TEL: 33 56.42.45.30
FAX: 33 56.02.37.01
M. POMMIER
Centre de Recherche de SGPB
Talence
TEL: 33 56.84.64.00
FAX: 33 56.84.64.13
M. Maton
M. Chatenet
Office International de l'Eau
Direction de la Formation et des Etudes
rue Edouard Chamberland
87065 Limoges Cedex, France
TEL: 33 55114770
FAX: 33 55777115
9. Keywords: France, ISIC 3411, pulp and paper, bleaching,
material substitution, ozone, peroxide, chlorine, kraft,
chelating, acid, filtration
10. This case study was submitted to UNEP IE in 1994 by the
French Office International de l'Eau. It has not undergone
a formal technical review.