Skip to Main content Skip to Navigation
Theses

Évaluation d'un nouveau procédé de blanchiment par le dioxyde de chlore en réacteur à déplacement de liqueur et comparaison avec les procédés batch conventionnels ou non conventionnels

Abstract : Chlorine dioxide is the most common bleaching agent for chemical pulps. In batch process approximately 50% of oxidizing capacity of ClO2 is consumed in useless reactions with the primary reaction products. The reaction of ClO2 with model compounds and kraft pulp confirms that approximately 5 to 6 electrons of oxidation per C9 unit of lignin is sufficient for the complete reaction. The more ClO2 applied is consumed in secondary reactions which become more significant after degradation of the phenolic rings. The results also showed that the muconic acid structures react with ClO2. The reactivity depends on the temperature and the concentration. Dimethyl muconic acid reacts more rapidly with an exchange of 2 to 4 electrons according to the ClO2 charge. The rate of its reaction is similar to that of the non-phenolic rings reaction rate. Displacement bleaching makes it possible to limit secondary reactions due to separation of reaction products from the reaction zone. The hydrodynamic study made it possible to optimize the principal parameters of the formation of the fibre fixed bed and the efficiency of elimination of the reaction products by the flow. The results of the pulp delignification by displacement showed that this process does not more effective because of the chlorate formation, in spite of elimination the reaction products. However, delignification in system multi-batch, with a low charge at the first stage with an intermediate alkali extraction stage lead to reduce up to 40% the ClO2 consumption.
Document type :
Theses
Complete list of metadatas

Cited literature [150 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00010856
Contributor : Emmanuelle Belgacem <>
Submitted on : Thursday, November 3, 2005 - 2:54:10 PM
Last modification on : Thursday, November 19, 2020 - 12:59:26 PM
Long-term archiving on: : Friday, April 2, 2010 - 11:06:15 PM

Identifiers

  • HAL Id : tel-00010856, version 1

Collections

CNRS | LGP2 | UGA

Citation

Yahya Hamzeh. Évaluation d'un nouveau procédé de blanchiment par le dioxyde de chlore en réacteur à déplacement de liqueur et comparaison avec les procédés batch conventionnels ou non conventionnels. Matériaux. Institut National Polytechnique de Grenoble - INPG, 2005. Français. ⟨tel-00010856⟩

Share

Metrics

Record views

483

Files downloads

2062