| 1. |
- Jansson, Mikael, et al.
(författare)
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Second generation ethanol through alkaline fractionation of pine and aspen wood
- 2010
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 44:1-3, s. 47-52
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Tidskriftsartikel (refereegranskat)abstract
- Pre-treatment studies on pine and aspen wood with alkaline fractionation were performed, the experimental results obtained being used as input for assessing the conversion of an existing pulp mill to ethanol and lignin production. By the LignoBoost process, the extracted lignin could be used in the lime kiln to replace fuel oil, while the lignin not needed in the lime kiln could be sold as a by-product. In addition to fuel applications, lignin could be used in a wide range of bio-based product applications, which would increase the value of the extracted lignin and increase the total revenues. A WinGEMS model was used to calculate mass and energy balances, and the results were used for an economic evaluation of the concept. The assessment indicated that the proposed alkaline concept would have reasonable production costs from both pine and aspen wood, comparable with the bioethanol produced from grain in Northern Europe today, i.e. about 0.45 ε/L ethanol (∌5 SEK/L). The production rate of a typical mill producing 1000 tonnes of pulp per day before conversion would be in the order of 140 000 m 3 of ethanol per year, as depending on the raw wood material. The corresponding lignin production would range from 25 000 to 63 000 tonnes per year. The use of alkaline delignification to produce a substrate with low lignin content for the enzymatic hydrolysis builds entirely on known and well-proven technology, yet it needs to be further developed. The process chain from enzymatic hydrolysis to ethanol is very similar to that used today for grain ethanol. Altogether, the technical risk should therefore be low.
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| 2. |
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| 3. |
- Olm, Leelo, et al.
(författare)
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High sulphidity kraft pulping
- 2009
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 24:4, s. 433-439
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Tidskriftsartikel (refereegranskat)abstract
- The object of this project was to evaluate the effect of high sulphidity on the performance of the kraft cooking process. Softwood (SW) mix (50/50 of spruce, Picea abies, and pine, Pinus sylvestris) and a hardwood (HW: birch, Betula pendula) have been explored as wood raw material. The reference kraft cook was carried out at 35% sulphidity. The laboratory kraft cooking trials showed that the rate of delignification in kraft cooking increases with increasing sulphidity for both these raw materials. An increase in sulphidity from 35% to 80% increases the apparent delignification rate by a factor of almost two. The faster delignification rate could be exploited as an increase in production and/or as a reduction in EA charge (2%-units for both raw materials) and/or as a decrease in cooking temperature (5°C for SW) at the same production. The yield of softwood kraft pulp at a given kappa number was not affected by the increase in sulphidity. For hardwood, the combination of high sulphidity and reduced effective alkali charge gave an increase in pulp yield of one %-unit. The pulp viscosity at a given kappa number was increased. The high sulphidity in SW kraft cooking (at a given EAcharge) led to a slightly better bleachability in an OD(E+P)DD bleaching sequence. The fully bleached SW kraft pulp at 80% sulphidity had a slightly higher tear index and higher fibre strength than the corresponding reference kraft pulp at 35% sulphidity. The other strength properties were virtually unchanged. The fully bleached HW kraft pulp at 80% sulphidity showed better optical properties, light scattering and opacity, which are, in fact, the critical properties for fully bleached hardwood pulps.
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| 4. |
- Tormund, Disa, et al.
(författare)
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Delignification and bleaching response of earlywood and latewood
- 2006
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Ingår i: Journal of wood chemistry and technology. - : Informa UK Limited. - 0277-3813 .- 1532-2319. ; 26:4, s. 325-337
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Tidskriftsartikel (refereegranskat)abstract
- The delignification response in cooking and the impact of bleaching on earlywood and latewood were studied. Spruce earlywood and latewood chips were pulped by the kraft process and subsequently treated with one bleaching chemical at a time. In cooking, latewood required a higher alkali charge to reach the same kappa number. No difference in the light absorption coefficient between the different fiber types was observed. After oxygen delignification the earlywood fibers had a higher light absorption coefficient at the same kappa number. The difference in light absorbing material was maintained when bleaching was performed with chlorine dioxide, ozone, and peracetic acid. Hydrogen peroxide decreased the light absorbing structures in the earlywood to the same level as for latewood. The earlywood pulp had a higher brightness at a given kappa number than the latewood. The higher brightness remained through all bleaching operations and was primarily due to a higher light scattering ability.
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