INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

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.