Effect of soda-ethanol cooking with caustic extraction prior to bleaching on the properties of hardwood pulp

Pulping using organic solvents is an alternative to kraft pulping and can reduce environmental pollutants. Ethanol is a potential cooking liquor, as it improves the penetration of the cooking chemical due to its low surface tension, and it can be recovered via distillation. The chemical structure an...

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Bibliographic Details
Published in:Bioresources 2022-05, Vol.17 (2), p.2884-2895
Main Authors: Lee, Tai-Ju, Gwon, Jaegyoung, Youe, Won-Jae, Oh, Yu-jin, Ahn, Byeong-Jun, Seo, Jin-Ho
Format: Article
Language:English
Subjects:
Alcohol
Alkalies
Bleaching
Cellulose
Chlorine
Chlorine dioxide
Cooking
Distillation
Drinking water
Energy consumption
Ethanol
Hardwoods
Hemicellulose
Hydrogen peroxide
Kraft pulp
Lignin
Liquor
Organic solvents
Pollutants
Pollution control
Pulp
Pulping
Slurries
Sodium hydroxide
Surface tension
Xylan
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Summary:Pulping using organic solvents is an alternative to kraft pulping and can reduce environmental pollutants. Ethanol is a potential cooking liquor, as it improves the penetration of the cooking chemical due to its low surface tension, and it can be recovered via distillation. The chemical structure and alpha-cellulose content need to be controlled during cooking and bleaching processes to prepare dissolving pulp. Therefore, the effect of ethanol on the cooking efficiency and caustic extraction prior to sequential bleaching on the alpha-cellulose content of the pulp were analyzed. The cooking yield was 50.2% in cooking liquor with 20% NaOH and 50% ethanol at 160 °C for 120 min. The delignification extent was 83.2%, which was better than that of kraft cooking. Caustic extraction was effective in removing the hemicellulose content, and the removal rate of xylan was 61.1% with 10% NaOH added to 1.5% pulp slurry and reacted at 60 °C for 90 min. The alpha-cellulose of bleached pulp could be improved to over 94% by a sequential bleaching process consisting of chlorine dioxide, sodium hydroxide, and hydrogen peroxide.
ISSN:1930-2126
1930-2126
DOI:10.15376/biores.17.2.2884-2895