Abstract
This study aimed to evaluate the influence of white liquor sulfidity on the efficiency of the kraft pulping process. For this study, Eucalyptus spp. chips were used. Laboratory cooking with variable sulfidity levels (0 to 40% at 5% intervals) was conducted under previously optimized conditions, aiming to obtain pulp with a Kappa number of 18 ± 0.9 and residual effective alkali between 9 and 12 gL-1. At the end of each cook, Kappa number, solids generation, specific wood, and alkali consumption were evaluated. The sulfidity variation in white liquor influenced all analyzed parameters, and concerning the specific wood consumption, a distinct behavior was observed for the low sulfidity (S ≤ 19.52%) and high sulfidity regions (S ˃ 19.52%). Based on the obtained results, the production of eucalyptus kraft pulp with white liquor sulfidity of approximately 20% is recommended.
Highlights
Contact information: Laboratory of Chemistry, Pulp and Energy, Forest Science Department, School of Agriculture “Luiz de Queiroz,” University of São Paulo, Av
The results obtained in this study developed with Eucalyptus spp. wood (Table 2), were similar to those obtained by Rosli et al (2009), which when evaluating the pulping condition effects in Acacia mangium wood, obtained pulp with kappa number 18 ± 0.9 while using 15 and 30% sulfidity
In treatments where sulfidity levels below 20% were used, the highest specific wood consumption (4.08 m3.od t-1) was obtained in the treatment with no addition of sodium sulfide in white liquor (S = 0%)
Summary
Contact information: Laboratory of Chemistry, Pulp and Energy, Forest Science Department, School of Agriculture “Luiz de Queiroz,” University of São Paulo, Av. The basic objective is the production of pulps with the dissolution of lignin, with the lowest possible damage to carbohydrates and to the process yield (Gomide 1979). Such processes are classified according to the pH and may be acidic or alkaline. The kraft process is the most used by the pulp industry since the 1930s According to Rydholm (1965), in the kraft process, sodium sulfide is obtained by the transformation of sodium sulfate in the recovery boiler. At the end of cooking, almost all of the S2- has been hydrolyzed to hydrosulfide (HS-) and hydroxyl (OH-)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
