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- Deshpande, Raghe, et al.
(författare)
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Initial phase of sodium bisulphite pulping of spruce. Part I
- 2016
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Ingår i: Cellulose Chemistry and Technology. - : Editura Academiei Romane. - 0576-9787. ; 50:2, s. 293-300
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Tidskriftsartikel (refereegranskat)abstract
- A sodium bisulphite cooking study has been performed on spruce chips with the aim of monitoring the impregnation and the initial phase of such a cook performed at pH 4.5. Both pulp and liquor analyses have been carried out and the experiments have been done with a laboratory-prepared cooking acid, in comparison with a mill cooking acid. The pulping experiments have been performed down to a total pulp yield of 60%. The objective was to verify and extend the current knowledge of bisulphite pulping with a focus on the initial phase of the cook. With the help of a kinetic model that has been developed in the project, the pulp composition during the cook with respect to cellulose, lignin, glucomannan and xylan can now be predicted. The side reactions with respect to thiosulphate formation were also analyzed in this study.
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- Deshpande, Roghe, et al.
(författare)
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Some process aspects on single-stage bisulfite pulping of pine
- 2016
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Ingår i: Nordic Pulp & Paper Research Journal. - : SPCI. - 0283-2631 .- 2000-0669. ; 31:3, s. 379-385
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Tidskriftsartikel (refereegranskat)abstract
- Sulfite pulping of pine is well-known to be a risky process because problematic lignin conden-sation reactions can occur resulting in poor pulp quality. However, sulfite pulping of pine is interesting of economic reasons as pine wood is cheaper than spruce. Therefore it has become interesting to investigate sulfite pulping again to determine if old data are still valid. Thus sodium bisulfite pulping of pine was carried out to investigate the influence of time, temperature and cooking acid quality. A small comparison of spruce pulping was also included. By using different cooking temperatures the activation energies for delignification and for degradation of cellulose and hemicelluloses could be determined. The results showed no lignin condensation reactions, thus it was not problematic to carry out these pine cooking experiments. It was found that glucomannan had higher activation energy than xylan and the activation energies of these hemicelluloses were lower than the corresponding value for the lignin degradation. It was found that the activation energy for bisulfite pulping of pine was slightly lower than the activation energy for bisulfite pulping of spruce.
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