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- DeGeyter, S, et al.
(author)
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Agglomeration characteristics using alternative bed materials for combustion of biomass
- 2005
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In: Biomass for energy, industry and climate protection. - Florence : ETA - Renewable Energies. - 8889407077 ; , s. 1343-1346
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Conference paper (peer-reviewed)abstract
- The objective of the work was to evaluate differences in agglomeration characteristics between commercially available alternative bed materials and quartz-based bed materials, commonly used in fluidised bed combustion. Pure quartz bed materials. Magnesium oxide and foundry sand (natural sand with a clay coating) were used as alternative bed aterials. Carefully controlled bench-scale fluidised bed agglomeration experiments were performed, using calcium-rich bark and potassium-rich olive residue as model fuels with significantly different ash compositions, typical for forestry and griculture residues respectively. The resulting bed material particles and agglomerates were analysed with SEM/EDS. Analysis of bed material and agglomerates suggested that Mg and Al in the bed materials affect the agglomeration temperature positively for calcium-rich fuels. Al-rich foundry sand was found to decrease the agglomeration temperature in (Si, K)-rich systems. For combustion of olive residue in MgO bed, no attack layer was formed and agglomeration probably occurred via direct adhesion by partly melted alkali-silicates. The results suggest that the choice of bed material should take the intended fuel use into consideration.
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- Holmberg, Jonas, 1976-, et al.
(author)
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Efficient wood use - a comparison between chemical and mechanical pulping
- 2005
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In: Biomass for energy, industry and climate protection. - [Florence] : ETA-Renewable Energies. - 8889407077
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Book chapter (other academic/artistic)abstract
- The pulp and paper industry is energy intensive and consumes large amounts of wood. Here, the total biomass use is estimated for the production of one tonne paper in a cradle-to-factory gate scope, assuming that all energy, including electricity and motor fuels, are produced from forest biomass. We consider the production of newsprint made from mechanical pulp; lightweight coated paper from a mixture of mechanical and chemical pulp; and fine paper from chemical pulp, under Swedish conditions. The results indicate that chemical pulp papers require less biomass resources per tonne of paper produced than do mechanical pulp papers. For mechanical pulp papers, external electricity requires the largest part of the biomass. Motor fuel production accounts in no case for more than 10%. Between 27% and 38% of the total biomass used is embodied in the paper product, indicating that waste paper recovery options are important.
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- Lindström, E, et al.
(author)
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Effect of kaolin and limestone addition on slag formation during combustion of woody biomass pellets
- 2005
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In: Biomass for energy, industry and climate protection. - Florence : ETA - Renewable Energies. - 8889407077 ; , s. 1319-1322
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Conference paper (peer-reviewed)abstract
- Limited availability of sawdust and cutter shavings and an increasing demand for wood pellets in Sweden are pushing the market towards new, more problematic, raw materials with higher ash content. Examples of such raw materials are bark, logging residues and whole tree assortments. The objectives of the present work were to determine the effects of kaolin and limestone addition on the slagging tendencies of some problematic woody biomass pellets during combustion in a typical residential pellet burner and also to contribute to the understanding of the role of kaolin and limestone in preventing slagging. This was accomplished by studying the bottom ash and the slag composition after 19 suspension with additive-to-fuel ratio of 1 wt %d.s. to the severely contaminated bark and cleaning assortment ignificantly reduced the slagging tendencies. Significantly higher Ca- and Al-concentrations in the slag were observed for limestone and kaolin addition, respectively. These changes resulted in a more favorable melting behavior (i.e. a igher solid phase to melt ratio).
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- Persson, Tobias, et al.
(author)
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Fractionation of hemicelluloses by membrane filtration
- 2005
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In: Proceedings of the 14th European Biomass Conference. - 8889407077 ; , s. 1693-1696
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Conference paper (other academic/artistic)abstract
- Hemicellulosic materials are among the most abundant renewable resources on earth, but have not yet found any broad application. However, if a cost effective extraction method is developed, hemicelluloses have the potential to be utilized to a much larger extent in the future. Ultrafiltration (UF) is a low energy demanding separation process that can be used to concentrate and purify hemicelluloses from industrial process water. In this investigation the performance of six UF membranes was studied, when treating process water from thermo-mechanical pulping (TMP) of spruce. Four membranes were hydrophobic and two hydrophilic and the cut-off was 1-5 kDa. The hydrophobic membranes were subject to severe fouling problems and had a much lower flux than the hydrophilic membranes. The hydrophilic membrane C005F, from Microdyn Nadir GmbH with cut-off 5 kDa, had the highest flux and showed the best separation capability with respect to hemicelluloses and contaminants (salts and monosaccharides). The flux was 140 l/m2.h at 0.8 MPa and 40°C. The retention of hemicelluloses was 90% and the retention of monosaccharides 3%. High flux and efficient separation of product and contaminants reduce the investment costs of a hemicellulose extraction plant.
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