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  • 1.
    Borén, Eleonora
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Kajsa, Werner
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nordin, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Pommer, Linda
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Defining the temperature regime of gaseous degradation products of Norway spruce2013Ingår i: 21nd European Biomass Conference and Exhibition, Copenhagen, June, 2013, ETA Florens Renewable Energies, 2013, 2013Konferensbidrag (Övrigt vetenskapligt)
  • 2.
    Skoglund, Nils
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Energy Engineering, Department of Engineering Sciences & Mathematics, Luleå University of Technology, Luleå, Sweden.
    Werner, Kajsa
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nylund, Göran M.
    University of Gothenburg, Department of Marine Sciences - Tjärnö.
    Pavia, Henrik
    University of Gothenburg, Department of Marine Sciences - Tjärnö.
    Albers, Eva
    Chalmers University of Technology, Department of Biology and Biological Engineering, Division Industrial Biotechnology.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Combustion of seaweed: a fuel design strategy2017Ingår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 165, s. 155-161Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The high ash content and varying ash composition in algal biomass is often mentioned as problematic if to beused for thermal energy conversion. This paper suggests an approach where detailed information on ash compositionand predicted ash formation reactions are basis for successful remedies enabling the use of fuels consideredto be difficult. The procedure is demonstrated on seaweed (Saccharina latissima) cultivated for biorefinery purposes. The ash composition of the seaweed was found suitable for co-combustion with Miscanthus x giganteus, an energy crop high in alkali and silicon. Fuel mixtures were combusted in a bubbling fluidized bed reactorand ash samples were analyzed by SEM-EDS and XRD. The results showed that Ca from the seaweed was veryreactive and thus efficient in solving the silicatemelting problems. The fuel design approach was proven successfuland the potential for using otherwise difficult seaweed fuels in synergetic co-combustion was demonstrated.

  • 3.
    Werner, Kajsa
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Borén, Eleonora
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Pommer, Linda
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Comprehensive study of the thermal decomposition of different hemicelluloses2013Ingår i: European Biomass Conference and Exhibition Proceedings: 21nd European Biomass Conference and Exhibition, ETA-Florens Renewable Energies , 2013, s. 944-946Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Carbohydrates (cellulose and hemicellulose) constitute the main fraction of plant cell walls and detailed knowledge about their thermal decomposition are therefore of great importance for understanding pyrolytic degradation properties of biomass. Hemicellulose is a diverse group of non-cellulosic polysaccharides and is composed of chains of different monomeric sugar units (pentoses, hexoses and hexuronic acids). The heterogeneous structures of hemicelluloses should be considered when evaluating the decomposition behavior. Nevertheless, thermal analysis of hemicellulose often uses the commercially available xylan as a model compound of hemicelluloses. In contrast to previous work several polysaccharides (xylan arabinogalactan, galactomannan, xyloglucan, and cellulose) were thoroughly investigated in the current study by thermogravimetric analysis, differential scanning calorimetry and pyrolysis-gas chromatography/mass spectrometry during heating in inert atmosphere. The results gave new insights into hemicellulose decomposition and demonstrated that different hemicelluloses have different decompoition behavior.

  • 4.
    Werner, Kajsa
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nils, Skoglund
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Albers, Eva
    Chalmers University of Technology.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Co-combustion of Miscanthus and Calcium Rich Brown Macroalgae2016Ingår i: 22nd International Conference of Impacts of Fuel Quality on Power Production, Prague, Czech Republic, September 19-23, 2016, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    The high ash content and varying ash composition from aquatic biomass is often mentioned as problematic if used for thermal energy conversion. This paper suggests a fuel design approach where detailed information on ash composition is the starting point for mixing and using fuels considered to be difficult. The procedure is demonstrated on brown macroalgae grown for biorefinery purposes in sea water. The fuel fingerprint (concentrations of the main ash forming elements) showed an interesting profile with very high Ca content together with significant amounts of Mg, K, Na, Cl, S, and also some minor contributions from Si and P. After careful considerations, it was concluded that this specific alga would be suitable for co-combustion with a silicone rich biofuel that would typically require some additive to avoid ash melting. One such fuel is Miscanthus. The aim of this study was to evaluate and compare algae as a renewable source of Ca with mineral CaCO3 to reduce the risk of alkali silicate melt formation in combustion of the energy crop Miscanthus. The Miscanthus was co-pelletized with algal biomass and CaCO3, both at Ca/(K+Na) molar ratios of 1.5 and 3.0, and combusted in a bubbling fluidized bed. in. The ash reactions were assessed by analyzing samples from bed, deposit probe, cyclone, and particulate matter with SEM-EDS and P-XRD. The results showed that Ca from the algae reacted with the Miscanthus ash, forming less problematic silicate ash fractions. At the low combustion temperatures used (< 720°C) stable CaSO4 was formed, capturing some of the S that would otherwise have been available for alkali sulfation. Comparing the Ca rich algae with adding pure CaCO3 to the Miscanthus pellets indicated that the Ca in the algae ash was more prone to react with the K-silicate, and thereby more efficiently preventing ash melting.

  • 5.
    Werner, Kajsa
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Piotrowska, Patrycja
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Gentili, Francesco
    Swedish University of Agricultural Sciences.
    Holmlund, Mattias
    Swedish University of Agricultural Sciences, SLU.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Characterization of Thermochemical Fuel Properties of Microalgae and Cyanobacteria2014Konferensbidrag (Övrigt vetenskapligt)
  • 6.
    Werner, Kajsa
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Pommer, Linda
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Thermal decomposition of hemicelluloses2014Ingår i: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 110, s. 130-137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Decomposition modeling of biomass often uses commercially available xylan as model compound representing hemicelluloses, not taking in account the heterogeneous nature of that group of carbohydrates. In this study, the thermal decomposition behavior of seven different hemicelluloses (beta-glucan, arabinogalactan, arabinoxylan, galactomannan, glucomannan, xyloglucan, and xylan) were investigated in inert atmosphere using (i) thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, (ii) differential scanning calorimetry, and (iii) pyrolysis-gas chromatography/mass spectroscopy. Results on decomposition characteristics (mass loss rate, reaction heat and evolving gas composition) were compared and summarized for the different hemicelluloses and for comparison also crystalline cellulose was included in the study. The mass loss rate characteristics differed between the polysaccharides, with cellulose and glucan-based hemicelluloses as the thermally most stable and xylan as the least stable sample. The heat flow during slow heating in nitrogen flow showed a much more exothermal decomposition of xylan compared with the other hemicelluloses. The composition of off-gases during heating showed large differences between the samples. During decomposition of xylan high levels of CO2 and lower levels of other components were formed, whereas also CO, methanol, methane, furfural, 5-hydroxymethylfurfural and anhydrosugars were formed in substantial amounts from the other polysaccharides. The formation of anhydrosugar was correlated to the monosaccharide composition of the polysaccharide chain. The results from the current study contribute to new knowledge concerning thermochemical behavior of different hemicelluloses.

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