The effect of alkali charge on Eucalyptus spp. kraft pulping, 2006 Engineering, Pulping, and Environmental Conference

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The objective of this study was to evaluate the behavior of the pulping process in industrial Eucalyptus spp chips under different alkali charges. The alkali charge applied varied between 10 and 20%, at 1%intervals. The parameters analyzed were: total yield, screened yield, kappa number, pH, viscosity, lignin content in the pulp and hexenuronic acid content. For all these parameters variations in the results were noticed as the alkali charge was changed. For total yield the values varied between 65.4 and 50.6%. For screened yield the values varied between 9.2 and 54.5%. The high total yield and the very low screened yield can be explained by the high content of rejects in some of the pulping conditions, indicating that during the pulping process there was a lack of alkali. The reject content was high for the lowest alkali charges, but by the 13%alkali charge it reached values of around zero. For the kappa number, the values varied from 82.4 to 13.4. For viscosity the results varied from 807 up to 1225cm3/g, and for lignin content in the pulp from 12.7 up to 3.02%. The hexenuronic acid formed varied between 23.0 and 65.7.