The effect of treatments before the first stage with chlorine dioxide in a short sequence

• Grant number: 17/11603-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2017
• End date: June 30, 2018
• Field of knowledge: Agronomical Sciences - Forestry Resources and Forestry Engineering - Technology and Use of Forest Products
• Principal Investigator: Gustavo Ventorim
• Grantee: Iliane Rodrigues de Oliveira
• Host Institution: Universidade Estadual Paulista (UNESP). Campus Experimental de Itapeva. Itapeva , SP, Brazil

Abstract

In the bleaching process it is ideal that the removal of undesirable components present in pulp, such as lignin and HexA's, give an efficient manner, but at low cost in the process. As this removal occurs differently, the sequence used should contain suitable ways for removal of these two chemical compounds. The high temperature of acid hydrolysis (AHT) stage presents adequate conditions for the selective removal of hexenuronic acids, although this acidic pH is not ideal for the removal of lignin. For this reason, it is interesting to use a high temperature acid hydrolysis and /or high temperature alkaline extraction (E) in the bleaching sequence, in order to obtain a higher efficiency in lignin removal, since it is more soluble in alkaline medium. The aim of this project is to evaluate the effect of treatments, including alkaline extraction under the same operating conditions (120 min / 95ºC) as a high temperature acid hydrolysis, in short bleaching sequences. This study uses pre-delignified eucalyptus kraft pulp with oxygen from a pulp company. With this pulp will be performed different bleaching sequences ECF (Elemental Chlorine Free), OD0PD1, OED0P, OAHTD0P, OAHTED0P, in the first mentioned sequence the second stage of dioxide will be included in the sequence only if necessary to achieve the desired final whiteness. The results to be discussed in this work will be: alvura, alvura reversion, bleaching dioxide consumption, pulp viscosity, and evaluation of the alkaline stage inclusion effect in a short sequence. (AU)