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  • 1.
    Basile, Francesco
    et al.
    University of Bologna.
    Albertazzi, Simone
    University of Bologna.
    Barbera, David
    University of Bologna.
    Benito, Patricia
    University of Bologna.
    Einvall, Jessica
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Brandin, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Fornasari, G.
    University of Bologna.
    Trifiro, Ferrucio
    University of Bologna.
    Vaccari, A.
    University of Bologna.
    Steam reforming of hot gas from gasified wood types and miscanthus biomass2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no Supplement 1, p. S116-S122Article in journal (Refereed)
    Abstract [en]

    The reforming of hot gas generated from biomass gasification and high temperature gas filtration was studied in order to reach the goal of the CHRISGAS project: a 60% of synthesis gas (as x(H2)+ x(CO) on a N2 and dry basis) in the exit gas, which can be converted either into H2 or fuels. A Ni-MgAl2O4 commercial-like catalyst was tested downstream the gasification of clean wood made of saw dust, waste wood and miscanthus as herbaceous biomass. The effect of the temperature and contact time on the hydrocarbon conversion as well as the characterization of the used catalysts was studied. Low (<600 °C), medium (750°C–900 °C) and high temperature (900°C–1050 °C) tests were carried out in order to study, respectively, the tar cracking, the lowest operating reformer temperature for clean biomass, the methane conversion achievable as function of the temperature and the catalyst deactivation. The results demonstrate the possibility to produce an enriched syngas by the upgrading of the gasification stream of woody biomass with low sulphur content. However, for miscanthusthe development of catalysts with an enhanced resistance to sulphur poison will be the key point in the process development.

  • 2.
    Bengtsson, Sune
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    The CHRISGAS Project2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no S1, p. S2-S7Article in journal (Refereed)
  • 3.
    Bengtsson, Sune
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    VVBGC demonstration plant activities in Värnamo2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no S1, p. S16-S20Article in journal (Refereed)
  • 4.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Liliedahl, Truls
    Royal Institute of Technology.
    Unit operations for production of clean hydrogen-rich synthesis gas from gasified biomass2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no Supplement 1, p. S8-S15Article in journal (Refereed)
    Abstract [en]

    The rebuild of the Växjö Värnamo Biomass Gasification Center (VVBGC) integrated gasification combined cycle (IGCC) plant into a plant for production of a clean hydrogen rich synthesis gas requires an extensive adaptation of conventional techniques to the special chemical and physical needs found in a gasified biomass environment. The CHRISGAS project has, in a multitude of areas, been responsible for the research and development activities associated with the rebuild. In this paper the present status and some of the issues concerning the upgrading of the product gas from gasified biomass into synthesis gas are addressed. The purpose is to serve as an introduction to the scientific papers written by the partners in the consortium concerning the unit operations of the process.

  • 5. Börjesson, Pål
    et al.
    Gustavsson, Leif
    Christersson, L
    Linder, S
    Future Production and Utilisation of Biomass in Sweden: potentials and CO~2 mitigation1997In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 13, no 6, p. 399-412Article in journal (Refereed)
  • 6.
    Einvall, Jessica
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Parsland, Charlotte
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Benito, Patricia
    University of Bologna.
    Basile, Francesco
    University of Bologna.
    Brandin, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    High temperature water-gas shift step in the production of clean hydrogen rich synthesis gas from gasified biomass2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no Supplement 1, p. S123-S131Article in journal (Refereed)
    Abstract [en]

    The possibility of using the water-gas shift (WGS) step for tuning the H2/CO-ratio in synthesis gas produced from gasified biomass has been investigated in the CHRISGAS (Clean Hydrogen Rich Synthesis Gas) project. The synthesis gas produced will contain contaminants such as H2S, NH3 and chloride components. As the most promising candidate FeCr catalyst, prepared in the laboratory, was tested. One part of the work was conducted in a laboratory set up with simulated gases and another part in real gases in the 100 kW Circulating Fluidized Bed (CFB) gasifier at Delft University of Technology. Used catalysts from both tests have been characterized by XRD and N2 adsoption/desorption at −196 °C.

    In the first part of the laboratory investigation a laboratory set up was built. The main gas mixture consisted of CO, CO2, H2, H2O and N2 with the possibility to add gas or water-soluble contaminants, like H2S, NH3 and HCl, in low concentration (0–3 dm3 m−3). The set up can be operated up to 2 MPa pressure at 200–600 °C and run un-attendant for 100 h or more. For the second part of the work a catalytic probe was developed that allowed exposure of the catalyst by inserting the probe into the flowing gas from gasified biomass.

    The catalyst deactivates by two different causes. The initial deactivation is caused by the growth of the crystals in the active phase (magnetite) and the higher crystallinity the lower specific surface area. The second deactivation is caused by the presence of catalytic poisons in the gas, such as H2S, NH3 and chloride that block the active surface.

    The catalyst subjected to sulphur poisoning shows decreased but stable activity. The activity shows strong decrease for the ammonia and HCl poisoned catalysts. It seems important to investigate the levels of these compounds before putting a FeCr based shift step in industrial operation. The activity also decreased after the catalysts had been exposed to gas from gasified biomass. The exposed catalysts are not re-activated by time on stream in the laboratory set up, which indicates that the decrease in CO2-ratio must be attributed to irreversible poisoning from compounds present in the gas from the gasifier.

    It is most likely that the FeCr catalyst is suitable to be used in a high temperature shift step, for industrial production of synthesis gas from gasified biomass if sulphur is the only poison needed to be taken into account. The ammonia should be decomposed in the previous catalytic reformer step but the levels of volatile chloride in the gas at the shift step position are not known.

  • 7.
    Gustafsson, Eva
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Lin, Leteng
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Characterization of particulate matter in the hot product gas from atmospheric fluidized bed biomass gasifiers2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no Supplement 1, p. 71-78Article in journal (Refereed)
    Abstract [en]

    This study compares the characteristics of particulate matter (PM) in the hot product gas from three different atmospheric fluidized bed biomass gasifiers: a bubbling fluidized bed (BFB) gasifier, a circulating fluidized bed (CFB) gasifier, and an indirect BFB gasifier (the latter integrated with a CFB boiler). All gasifiers displayed a bimodal particle mass size distribution with a fine mode in the <0.5 μm size range and a coarse mode in the >0.5 μm size range. Compared with the mass concentration of the coarse mode the mass concentration of the fine mode was low in all gasifiers. For both the BFB and CFB gasifiers the fine-mode PM had a similar inorganic composition, indicating an origin from the ash and the magnesite bed material used in both gasifiers. In the indirect BFB gasifier the fine-mode PM was instead dominated by potassium and chlorine, and the tar fraction properties evoked tar condensation in the sampling system that affected mainly the fine-mode PM. The coarse-mode PM in the BFB gasifier was dominated by char fragments abraded from the pyrolyzed wood pellets. In the CFB gasifier the coarse-mode PM was mainly ash and magnesite bed material that passed through the process cyclone. In the indirect BFB gasifier the coarse-mode PM was mainly ash, probably originating both from the BFB gasifier and the CFB boiler.

  • 8.
    Haus, Sylvia
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Sathre, Roger
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Climate mitigation comparison of woody biomass systems with the inclusion of land-use in the reference fossil system2014In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 65, p. 136-144Article in journal (Refereed)
    Abstract [en]

    While issues of land-use have been considered in many direct analyses of biomass systems, little attention has heretofore been paid to land-use in reference fossil systems. Here we address this limitation by comparing forest biomass systems to reference fossil systems with explicit consideration of land-use in both systems. We estimate and compare the time profiles of greenhouse gas (GHG) emission and cumulative radiative forcing (CRF) of woody biomass systems and reference fossil systems. A life cycle perspective is used that includes all significant elements of both systems, including GHG emissions along the full material and energy chains. We consider the growth dynamics of forests under different management regimes, as well as energy and material substitution effects of harvested biomass. We determine the annual net emissions of CO2, N2O and CH4 for each system over a 240-year period, and then calculate time profiles of cRF as a proxy measurement of climate change impact. The results show greatest potential for climate change mitigation when intensive forest management is applied in the woody biomass system. This methodological framework provides a tool to help determine optimal strategies for managing forests so as to minimize climate change impacts. The inclusion of land-use in the reference system improves the accuracy of quantitative projections of climate benefits of biomass-based systems. (c) 2014 Elsevier Ltd. All rights reserved.

  • 9.
    Joelsson, Jonas M.
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Reduction of CO2 emission and oil dependency with biomass-based polygeneration2010In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 34, no 7, p. 967-984Article in journal (Refereed)
    Abstract [en]

    We compare different options for the use of lignocellulosic biomass to reduce CO2 emission and oil use, focusing on polygeneration of biomass-based motor fuels and electricity, and discuss methodological issues related to such comparisons. The use of biomass can significantly reduce CO2 emission and oil use, but there is a trade-off between the reductions in CO2 emission and oil use. Bioelectricity from stand-alone plants replacing coal-based electricity reduced CO2 emission by 99 kg per GJ biomass input but gave no oil use reduction. Stand-alone produced methanol replacing diesel reduced the CO2 emission with 38 kg and the oil use with 0.67 GJ per GJ biomass, indicating that a potential CO2 emission reduction of 90 kg is lost per GJ oil reduced. CO2 emission and oil use reduction for alternatives co-producing fuel and electricity fall between the stand-alone alternatives. Plug-in hybrid-electric vehicles using bioelectricity reduced CO2 emission by 75–88 kg and oil use by 0.99–1.2 GJ, per GJ biomass input. Biomass can also reduce CO2 emission and/or oil use more efficiently if fossil-fuel-fired boilers or electric heating is replaced by district heating from biomass-based combined heat and power generation. This is also true if electricity or motor fuel is produced from black liquor gasification in pulp mills or if wood is used instead of concrete in building construction. Biomass gasification is an important technology to achieve large reductions, irrespective of whether CO2 emission or oil use reduction is prioritised.

     

  • 10.
    Nilsson, Bengt
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Blom, Åsa
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    The influence of two different handling methods on the moisture content and composition of logging residuals2013In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 52, p. 34-42Article in journal (Refereed)
    Abstract [en]

    The most frequently used handling method in Sweden for the extraction of forest fuels is one in which logging residues are piled in harvester heaps to dry within the clear-cutting area before stacking into larger windrows. This handling method, however, requires multiple stages and the amount of handling involved results in a significant loss of biomass that could have been used for energy. This study compares two handling methods for the extraction of logging residues in stands dominated by Norway spruce. The traditional “dried-stacked” method was compared to the “fresh-stacked” method in which logging residues are collected simultaneously during normal logging operations and stacked in windrows at or near the roadside to dry. Determination of fraction composition and moisture content was carried out on the biomass provided to the energy-converting industry shortly after comminuting the logging residues. The results show that the fresh-stacked logging residues contained a higher amount of needles (8%), compared to 4% for the dried-stacked logging residues. However, the amount of needles was considered to be low in both handling methods. Both handling methods were proven to provide adequate drying with moisture content levels at approximately 36% for fresh-stacked and 31% for dried-stacked logging residues. These results indicate that weather and forest conditions have a greater impact on the moisture content than handling method. An acceptance of fresh-stacked logging residues, preferably connected to ash recycling, would afford the energy-converting industries the opportunity to use new technologies, reduce costs and extract a greater biomass total.

  • 11.
    Näslund Eriksson, Lisa
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Biofuels from stumps and small roundwood - Costs and CO2 benefits2008In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 32, no 10, p. 897-902Article in journal (Refereed)
    Abstract [en]

    In this study, we analysed and compared costs, primary energy use and CO2 benefits of recovering stumps and small roundwood from thinnings, together with logging residues. Small roundwood, chipped at a terminal or end-user, has a cost comparable to the chip system and a primary energy use comparable to the bundle system used for recovery of logging residues. The small roundwood system with roadside chipping is more expensive. As productivity in the cutting process improves, the small roundwood alternatives become more cost-effective. The stump system has costs in the same range as or lower than the chip and bundle systems. Forestry operations for stump and small roundwood recovery require considerable primary energy, but net recovery per hectare is much greater than for the chip and bundle systems, which means that more fossil fuel can be displaced per hectare of clearcut than with a chip or a bundle system. Stumps and small roundwood from thinnings can become as cost-effective as logging residues in the near future. Furthermore, when stumps and small roundwood from thinnings are also used to replace fossil fuels, the potential CO2 reduction will be about four times as great as when only logging residues are used with a traditional chip system.

  • 12.
    Näslund Eriksson, Lisa
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Comparative analysis of wood chips and bundles – Costs, carbon dioxide emissions, dry-matter losses and allergic reactions2010In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 34, no 1, p. 82-90Article in journal (Refereed)
    Abstract [en]

    There are multiple systems for the collection, processing, and transport of forest residues for use as a fuel. We compare two systems in use in Sweden to analyze differences in fuel cost, CO2 emissions, dry-matter loss, and potential for allergic reactions. We compare a bundle system with the traditional Swedish chip system, and then do an in-depth comparison of a Finnish bundle system with the Swedish bundle system. Bundle systems have lower costs, while the allergic reactions do not differ significantly between the systems. The bundle machine is expensive, but results in high productivity and in an overall cost-effective system. The bundle system has higher primary energy use and CO2 emissions, but the lower dry-matter losses in the bundle system chain give CO2 emissions per delivered MWh almost as low as for the chip system. Also, lower dry-matter losses mean that more biomass per hectare can be extracted from the clear-cut area. This leads to a higher possible substitution of fossil fuels per hectare with the bundle system, and that more CO2 emissions from fossil fuel can be avoided per hectare than in the chip system. The Finnish bundle system with its more effective compressing and forwarding is more cost- and energy-effective than the Swedish bundle system, but Swedish bundle systems can be adapted to be more effective in both aspects.

     

  • 13.
    Näslund Eriksson, Lisa
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Costs, CO2- and primary energy balances of forest-fuel recovery systems at different forest productivity2010In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 34, no 5, p. 610-619Article in journal (Refereed)
    Abstract [en]

    Here we examine the cost, primary energy use, and net carbon emissions associated with removal and use of forest residues for energy, considering different recovery systems, terrain, forwarding distance and forest productivity. We show the potential recovery of forest fuel for Sweden, its costs and net carbon emissions from primary energy use and avoided fossil carbon emissions. The potential annual net recovery of forest fuel is about 66 TWh, which would cost one billion 2005 to recover and would reduce fossil emissions by 6.9 Mt carbon if coal were replaced. Of the forest fuel, 56% is situated in normal terrain with productivity of >30 t dry-matter ha (-1) and of this, 65% has a forwarding distance of <400 m. In normal terrain with >30 t dry-matter ha (1) the cost increase for the recovery of forest fuel, excluding stumps, is around 4-6% and 8-11% for medium and longer forwarding distances, respectively. The stump and small roundwood systems are less cost-effective at lower forest fuel intensity per area. For systems where loose material is forwarded, less dry-matter per hectare increases costs by 6-7%, while a difficult terrain increases costs by 3-4%. Still, these systems are quite cost-effective. The cost of spreading ash is around 40 2005 ha (-1), while primary energy use for spreading ash in areas where logging residues, stumps, and small roundwood are recovered is about 0.025% of the recovered bioenergy.

  • 14.
    Poudel, Bishnu Chandra
    et al.
    Mid Sweden University.
    Sathre, Roger
    Linnaeus University, Faculty of Science and Engineering, School of Engineering. Mid Sweden University.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bergh, Johan
    Mid Sweden University.
    Lundström, Anders
    Swedish University of Agricultural Sciences.
    Hyvönen, Riitta
    Swedish University of Agricultural Sciences.
    Effects of climate change on biomass production and substitution in north-central Sweden2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no 10, p. 4340-4355Article in journal (Refereed)
    Abstract [en]

    In this study we estimate the effects of climate change on forest production in north-central Sweden, as well as the potential climate change mitigation feedback effects of the resulting increased carbon stock and forest product use. Our results show that an average regional temperature rise of 4 °C over the next 100 years may increase annual forest production by 33% and potential annual harvest by 32%, compared to a reference case without climate change. This increased biomass production, if used to substitute fossil fuels and energy-intensive materials, can result in a significant net carbon emission reduction. We find that carbon stock in forest biomass, forest soils, and wood products also increase, but this effect is less significant than biomass substitution. A total net reduction in carbon emissions of up to 104 Tg of carbon can occur over 100 years, depending on harvest level and reference fossil fuel.

  • 15.
    Rupar, Katarina
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, Institutionen för biovetenskaper och processteknik.
    Sanati, Mehri
    The Release of Organic Compounds during Biomass Drying depends upon the feedstock and/or altering Drying Heating Medium2003In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 25, no 6, p. 615-622Article in journal (Refereed)
    Abstract [en]

    The release of organic compounds during the drying of biomass is a potential environmental problem, it may contributeto air pollution or eutrophication. In many countries there are legal restrictions on the amounts of terpenes that may bereleased into the atmosphere. When considering bioenergy in future energy systems, it is important that information on theenvironmental e-ects is available. The emissions of organic compounds from di-erent green and dried biofuels that have beendried in hot air and steam medium, were analyzed by using di-erent techniques. Gas chromatography and gas chromatographymass spectrometry have been used to identify the organic matter. The terpene content was signi2cantly a-ected by thefollowing factors: changing of the drying medium and the way the same biomass was handled from di-erent localities inSweden. Comparison between spectra from dried and green fuels reveal that the main compounds emitted during dryingare monoterpene and sesquiterpene hydrocarbons, while the emissions of diterpene hydrocarbons seem to be negligible. Therelative proportionality between emitted monoterpene, diterpene and sesquiterpene change when the drying medium shiftsfrom steam to hot air. The obtained result of this work implies a parameter optimization study of the dryer with regard toenvironmental impact. With assistance of this result it might be foreseen that choice of special drying medium, diversity ofbiomass and low temperature reduce the emissions. A thermo-gravimetric analyzer was used for investigating the biomassdrying rate.

  • 16.
    Rupar-Gadd, Katarina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Forss, Jörgen
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Self-heating properties of softwood samples investigated by using isothermal calorimetry2018In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 111, p. 206-212Article in journal (Refereed)
    Abstract [en]

    The investigation focused on obtaining experimental results from the self-heating properties of different softwood samples during lab-scale storage. The samples investigated were a mixture of dried soft wood sawdust, softwood pellets 8 mm in diameter, and aged softwood sawdust stored outdoors for three months. Isothermal calorimetry was used to measure the heat released from the biomass samples and assess the contribution to self-heating during storage. Softwood samples were stored at 20 °C, 50 °C, 55 °C and 60 °C, and the metals manganese, copper and iron were added as a water solution to investigate if the presence of metals would increase the risk of self-heating. For most sample series, the highest levels of heat release were found after approximately 10 days of storage; sample series stored at 50 °C displayed the highest levels. The addition of copper resulted in levels of heat release 135% higher than samples without metal added.

  • 17.
    Sarenbo, Sirkku
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Wood ash dilemma - reduced quality due to poor combustion performance2009In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 33, no 9, p. 1212-1220Article in journal (Refereed)
    Abstract [en]

    Recycling of wood ash is based on the presumption that moderate concentrations of environmentally harmful elements are a part of the nutrient cycle and do not increase in net concentrations in the forest soil. It is assumed that the same quantities of harmful elements are harvested from the forest and recycled back. This principle does not apply to polycyclic aromatic hydrocarbons (PAHs) since these pollutants are formed during the combustion process, especially when the combustion performance is poor. Additionally, industrial combustors are adjusted in order to reduce NO(x)-emissions, indirectly causing formation of PAHs. This study examined fly ash from combustion of pulverized wood for its elemental and PAH concentrations during a period of 9 weeks. The 16 EPA-PAH concentrations range between 40 and 300 mg kg(-1). Re-burning of the ash reduces the PAH concentrations to 0.24 mg kg(-1) and organic carbon concentration from 40% to 5%, enhancing its composition significantly. It is important to determine the amount and fate of PAHs spread on forest soils with wood ash to ensure the improvement of the health of the forest ecosystem. Maximized energy efficiency of industrial boilers is the key to reducing anthropogenic emissions of greenhouse gases and enabling a sustainable nutrient recycling system. (C) 2009 Elsevier Ltd. All rights reserved.

  • 18.
    Sathre, Roger
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Time-dependent climate benefits of using forest residues to substitute fossil fuels2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no 7, p. 2506-2516Article in journal (Refereed)
    Abstract [en]

     In this study we analyze and compare the climate impacts from the recovery, transport and combustion of forest residues (harvest slash and stumps), versus the climate impacts that would have occurred if the residues were left in the forest and fossil fuels used instead. We use cumulative radiative forcing (CRF) as an indicator of climate impacts, and we explicitly consider the temporal dynamics of atmospheric carbon dioxide and biomass decomposition. Over a 240-year period, we find that CRF is significantly reduced when forest residues are used instead of fossil fuels. The type of fossil fuel replaced is important, with coal replacement giving the greatest CRF reduction. Replacing oil and fossil gas also gives long-term CRF reduction, although CRF is positive during the first 10-25 years when these fuels are replaced. Biomass productivity is also important, with more productive forests giving greater CRF reduction per hectare. The decay rate for biomass left in the forest is found to be less significant. Fossil energy inputs for biomass recovery and transport have very little impact on CRF. (C) 2011 Elsevier Ltd. All rights reserved.

  • 19.
    Sathre, Roger
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Bergh, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Primary energy and greenhouse gas implications of increasing biomass production through forest fertilization2010In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 34, no 4, p. 572-581Article in journal (Refereed)
    Abstract [en]

    In this study we analyze the primary energy and greenhouse gas (GHG) implications of increasing biomass production by fertilizing 10% of Swedish forest land. We estimate the primary energy use and GHG emissions from forest management including production and application of N and NPK fertilizers. Based on modelled growth response, we then estimate the net primary energy and GHG benefits of using biomaterials and biofuels obtained from the increased forest biomass production. The results show an increased annual biomass harvest of 7.4 million t dry matter, of which 41% is large-diameter stemwood. About 6.9 PJ/year of additional primary energy input is needed for fertilizer production and forest management. Using the additional biomass for fuel and material substitution can reduce fossil primary energy use by 150 or 164 PJ/year if the reference fossil fuel is fossil gas or coal, respectively. About 22% of the reduced fossil energy use is due to material substitution and the remainder is due to fuel substitution. The net annual primary energy benefit corresponds to about 7% of Sweden's total primary energy use. The resulting annual net GHG emission reduction is 11.9 million or 18.1 million tCO2equiv if the reference fossil fuel is fossil gas or coal, respectively, corresponding to 18% or 28% of the total Swedish GHG emissions in 2007. A significant one-time carbon stock increase also occurs in wood products and forest tree biomass. These results suggest that forest fertilization is an attractive option for increasing energy security and reducing net GHG emission.

  • 20. Schlamadinger, B
    et al.
    Apps, M
    Bohlin, F
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik, fysik och matematik.
    Jungmeier, G
    Marland, G
    Pingoud, K
    Savolainen, I
    Towards a Standard Methodology for Greenhouse Gas Balances of Bioenergy Systems in Comparison with Fossil Energy Systems1997In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 13, no 6, p. 359-376Article in journal (Refereed)
  • 21.
    Wollak, Birte
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Forss, Jörgen
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Welander, Ulrika
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Evaluation of blue mussels (Mytilus edulis) as substrate for biogas production in Kalmar County (Sweden)2018In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 111, p. 96-102Article in journal (Refereed)
    Abstract [en]

    The Baltic Sea is an over-fertilized inland sea; the blue mussels have potential to absorb nutrients as well as being a source of renewable energy in the form of biogas. The aim of this study was to evaluate technology to utilize blue mussels for biogas production in a pilot scale. Blue mussels (Mytilus edulis) were anaerobically digested in a two-stage digestion process (430 L), consisting of a percolation bed and an up-flow anaerobic sludge blanket reactor. Frozen mussels with shells were placed in the percolation bed and digestion was performed at 36 oC during 37 days. The methane potential achieved with this technique was 310 L kg-1 volatile solid substances (273.15 K, 101.3 kPa). This result suggests that blue mussels can be efficiently digested in a larger scale and have the potential of contributing to a sustainable energy mix in the Baltic region and at the same time decrease the eutrophication of the Baltic Sea.  No addition of nutrients and no pretreatment of the mussels (peeling) were needed.

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