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  • 1.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Melting Characteristics and Morphology of Bottom Ash and Filter Ash of the Circulating Fluidized Bed Boiler2013In: 21st European Biomass Conference and Exhibition, Copenhagen, Danmark, 3rd-7th June, 2013, ETA-Florence Renewable Energies , 2013, p. 1189-1191Conference paper (Refereed)
    Abstract [en]

    The aim of this work was to investigate the melting characteristics and morphology of filter ash and bottom ash with and without 7% of peat addition to the fuel of the circulating fluidized bed boiler. The samples were characterized by simultaneous thermal analysis (STA) and scanning electron microscope (SEM). The STA results indicate that the filter ash melts at 1140oC with 10 wt% of the mass loss and Bottom ash partially melts at 1170oC with below 2 wt% of the mass loss. The low melting point of the filter ash is due to the high concentration of the alkali metals in the filter ash. Similar trends were observed in the case of fly ash and bottom ash with peat admixture to the fuel. Furthermore the elementary analysis via scanning electron microscopy, coupled with energy-dispersive X-ray analysis showed that 7% of peat addition to the fuel does not significantly effect on the ash composition.

  • 2.
    Andersson, Sven
    et al.
    SP.
    Bäfver, Linda
    SP.
    Davidsson, Kent
    SP.
    Pettersson, Jens
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Schmidt, Hans
    SP.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Yngvesson, Johan
    SP.
    Skrubberintegrerat vått elfilter, WESP2012Report (Other academic)
  • 3.
    Biollaz, S.
    et al.
    PSI.
    Calbry-Muzyka, A.
    PSI.
    Rodriguez, S.
    PSI.
    Sárossy, Z.
    DTU.
    Ravenni, G.
    DTU.
    Fateev, A.
    DTU.
    Seiser, R.
    UCSD.
    Eberhard, M.
    KIT.
    Kolb, T.
    KIT.
    Heikkinen, N.
    VTT.
    Reinikainen, M.
    VTT.
    Brown, R.C.
    Iowa State University, USA.
    Johnston, P.A.
    Iowa State University, USA.
    Nau, P.
    DLR.
    Geigle, K.P.
    DLR.
    Kutne, P.
    DLR.
    Işık-Gülsaç, I.
    TÜBİTAK Mam.
    Aksoy, P.
    TÜBİTAK Mam.
    Çetin, Y.
    TÜBİTAK Mam.
    Sarıoğlan, A.
    TÜBİTAK Mam.
    Tsekos, C.
    Delft University of Technology, The Netherlands.
    de Jong, W.
    Delft University of Technology, The Netherlands.
    Benedikt, F.
    TU Wien, Austria.
    Hofbauer, H.
    TU Wien, Austria.
    Waldheim, L.
    SFC.
    Engvall, K.
    Royal Institute of Technology.
    Neubauer, Y.
    Technical University of Berlin, Germany.
    Funcia, I.
    CENER.
    Gil, J.
    CENER.
    del Campo, I.
    CENER.
    Wilson, I.
    University of Glasgow, UK.
    Khan, Z.
    University of Glasgow, UK.
    Gall, D.
    Gothenburg University.
    Gómez-Barea, A.
    University of Seville, Spain.
    Schmidt, F.
    Umeå University.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Anca-Couce, A.
    Graz University of Technology, Austria.
    von Berg, L.
    Graz University of Technology, Austria.
    Larsson, A.
    GoBiGas.
    Sánchez Hervás, J.M.
    CIEMAT.
    van Egmond, B.F.
    ECN part of TNO.
    Geusebroek, M.
    ECN part of TNO.
    Toonen, A.
    ECN part of TNO.
    Kuipers, J.
    ECN part of TNO.
    Cieplik, M.
    ECN part of TNO.
    Boymans, E.H.
    ECN part of TNO.
    Grootjes, A.J.
    ECN part of TNO.
    Fischer, F.
    TUM.
    Schmid, M.
    University of Stuttgart, Germany.
    Maric, J.
    Chalmers University of Technology.
    Defoort, F.
    CEA.
    Ravel, S.
    CEA.
    Thiery, S.
    CEA.
    Balland, M.
    CEA.
    Kienzl, N.
    Bioenergy 2020+.
    Martini, S.
    Bioenergy 2020+.
    Loipersböck, J.
    Bioenergy 2020+.
    Basset, E.
    ENGIE Lab CRIGEN.
    Barba, A.
    ENGIE Lab CRIGEN.
    Willeboer, W.
    RWE-Essent.
    Venderbosch, R.
    BTG.
    Carpenter, D.
    NREL.
    Pinto, F.
    LNEG.
    Barisano, D.
    ENEA.
    Baratieri, M.
    UNIBZ.
    Ballesteros, R.
    UCLM.
    Mourao Vilela, C. (Editor)
    ECN part of TNO.
    Vreugdenhil, B.J. (Editor)
    ECN part of TNO.
    Gas analysis in gasification of biomass and waste: Guideline report: Document 12018Report (Refereed)
    Abstract [en]

    Gasification is generally acknowledged as one of the technologies that will enable the large-scale production of biofuels and chemicals from biomass and waste. One of the main technical challenges associated to the deployment of biomass gasification as a commercial technology is the cleaning and upgrading of the product gas. The contaminants of product gas from biomass/waste gasification include dust, tars, alkali metals, BTX, sulphur-, nitrogen- and chlorine compounds, and heavy metals. Proper measurement of the components and contaminants of the product gas is essential for the monitoring of gasification-based plants (efficiency, product quality, by-products), as well as for the proper design of the downstream gas cleaning train (for example, scrubbers, sorbents, etc.). In practice, a trade-off between reliability, accuracy and cost has to be reached when selecting the proper analysis technique for a specific application. The deployment and implementation of inexpensive yet accurate gas analysis techniques to monitor the fate of gas contaminants might play an important role in the commercialization of biomass and waste gasification processes.

    This special report commissioned by the IEA Bioenergy Task 33 group compiles a representative part of the extensive work developed in the last years by relevant actors in the field of gas analysis applied to(biomass and waste) gasification. The approach of this report has been based on the creation of a team of contributing partners who have supplied material to the report. This networking approach has been complemented with a literature review. The report is composed of a set of 2 documents. Document 1(the present report) describes the available analysis techniques (both commercial and underdevelopment) for the measurement of different compounds of interest present in gasification gas. The objective is to help the reader to properly select the analysis technique most suitable to the target compounds and the intended application. Document 1 also describes some examples of application of gas analysis at commercial-, pilot- and research gasification plants, as well as examples of recent and current joint research activities in the field. The information contained in Document 1 is complemented with a book of factsheets on gas analysis techniques in Document 2, and a collection of video blogs which illustrate some of the analysis techniques described in Documents 1 and 2.

    This guideline report would like to become a platform for the reinforcement of the network of partners working on the development and application of gas analysis, thus fostering collaboration and exchange of knowledge. As such, this report should become a living document which incorporates in future coming progress and developments in the field.

  • 4.
    Biollaz, S.
    et al.
    PSI.
    Calbry-Muzyka, A.
    PSI.
    Rodriguez, S.
    PSI.
    Sárossy, Z.
    DTU.
    Ravenni, G.
    DTU.
    Fateev, A.
    DTU.
    Seiser, R.
    UCSD.
    Eberhard, M.
    KIT.
    Kolb, T.
    KIT.
    Heikkinen, N.
    VTT.
    Reinikainen, M.
    VTT.
    Brown, R.C.
    Iowa State University, USA.
    Johnston, P.A.
    Iowa State University, USA.
    Nau, P.
    DLR.
    Geigle, K.P.
    DLR.
    Kutne, P.
    DLR.
    Işık-Gülsaç, I.
    TÜBİTAK Mam.
    Aksoy, P.
    TÜBİTAK Mam.
    Çetin, Y.
    TÜBİTAK Mam.
    Sarıoğlan, A.
    TÜBİTAK Mam.
    Tsekos, C.
    Delft University of Technology, The Netherlands.
    de Jong, W.
    Delft University of Technology, The Netherlands.
    Benedikt, F.
    TU Wien, Austria.
    Hofbauer, H.
    TU Wien, Austria.
    Waldheim, L.
    SFC.
    Engvall, K.
    Royal Institute of Technology.
    Neubauer, Y.
    Technical University of Berlin, Germany.
    Funcia, I.
    CENER.
    Gil, J.
    CENER.
    del Campo, I.
    CENER.
    Wilson, I.
    University of Glasgow, UK.
    Khan, Z.
    University of Glasgow, UK.
    Gall, D.
    Gothenburg University.
    Gómez-Barea, A.
    University of Seville, Spain.
    Schmidt, F.
    Umeå University.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Anca-Couce, A.
    Graz University of Technology, Austria.
    von Berg, L.
    Graz University of Technology, Austria.
    Larsson, A.
    GoBiGas.
    Sánchez Hervás, J.M.
    CIEMAT.
    van Egmond, B.F.
    ECN part of TNO.
    Geusebroek, M.
    ECN part of TNO.
    Toonen, A.
    ECN part of TNO.
    Kuipers, J.
    ECN part of TNO.
    Cieplik, M.
    ECN part of TNO.
    Boymans, E.H.
    ECN part of TNO.
    Grootjes, A.J.
    ECN part of TNO.
    Fischer, F.
    TUM.
    Schmid, M.
    University of Stuttgart, Germany.
    Maric, J.
    Chalmers University of Technology.
    Defoort, F.
    CEA.
    Ravel, S.
    CEA.
    Thiery, S.
    CEA.
    Balland, M.
    CEA.
    Kienzl, N.
    Bioenergy 2020+.
    Martini, S.
    Bioenergy 2020+.
    Loipersböck, J.
    Bioenergy 2020+.
    Basset, E.
    ENGIE Lab CRIGEN.
    Barba, A.
    ENGIE Lab CRIGEN.
    Willeboer, W.
    RWE-Essent.
    Venderbosch, R.
    BTG.
    Carpenter, D.
    NREL.
    Pinto, F.
    LNEG.
    Barisano, D.
    ENEA.
    Baratieri, M.
    UNIBZ.
    Ballesteros, R.
    UCLM.
    Mourao Vilela, C. (Editor)
    ECN part of TNO.
    Vreugdenhil, B.J. (Editor)
    ECN part of TNO.
    Gas analysis in gasification of biomass and waste: Guideline report: Document 2 - Factsheets on gas analysis techniques2018Report (Refereed)
    Abstract [en]

    Gasification is generally acknowledged as one of the technologies that will enable the large-scale production of biofuels and chemicals from biomass and waste. One of the main technical challenges associated to the deployment of biomass gasification as a commercial technology is the cleaning and upgrading of the product gas. The contaminants of product gas from biomass/waste gasification include dust, tars, alkali metals, BTX, sulphur-, nitrogen- and chlorine compounds, and heavy metals. Proper measurement of the components and contaminants of the product gas is essential for the monitoring of gasification-based plants (efficiency, product quality, by-products), as well as for the proper design of the downstream gas cleaning train (for example, scrubbers, sorbents, etc.). The deployment and implementation of inexpensive yet accurate gas analysis techniques to monitor the fate of gas contaminants might play an important role in the commercialization of biomass and waste gasification processes.

    This special report commissioned by the IEA Bioenergy Task 33 group compiles a representative part of the extensive work developed in the last years by relevant actors in the field of gas analysis applied to (biomass and waste) gasification. The approach of this report has been based on the creation of a team of contributing partners who have supplied material to the report. This networking approach has been complemented with a literature review. This guideline report would like to become a platform for the reinforcement of the network of partners working on the development and application of gas analysis, thus fostering collaboration and exchange of knowledge. As such, this report should become a living document which incorporates in future coming progress and developments in the field.

  • 5.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Aerosolkatalysatorer för industriell gasrening2016Report (Refereed)
    Abstract [en]

    Aerosol catalysts – small particles (with aerodynamic diameter up to 100 m) of catalytically active material suspended in gas – were examined for the intended use of NOx reduction with ammonia (SCR) in smaller industrial plants and boilers as an alternative to SNCR. The aerosol particles are intended to be injected into the flue gas at high temperature, together with ammonia/urea, and then separated on a particulate filter (bag‐type filter) at low temperature. The NOx reduction can occur during the pneumatic transport in the boiler or/and on the catalytically active filter cake. The catalysts must have sufficiently high activity in order to keep down their consumption, they must be cheap enough to be used as a consumable item, and must be harmless to humans and the environment. Two materials were developed during the work as possible candidates: natural zeolites and a FeSO4/activated carbon‐based catalyst. Cost estimates, for a hypothetical 1 MWth plant, shows that a NOx reduction close to 50% economically justify the introduction of SNCR for small plants (<25 GWh, NOx reductions levels between 30‐50% and 2 in stoichiometric ratio), both for the use of urea and liquid anhydrous ammonia with the percent NOx fee of 50 SEK/kg. The result is modest, at best 15‐20% cost reduction compared to no action. Raised tariffs to 60 SEK/kg NOx will improved the situation, but the results are still modest. When the aerosol catalysts was used in the cost estimate, and an assumed NOx reduction degree of 85% was supposed to be reached, good results were obtained at low catalyst costs (0.5‐2 SEK/kg). However the plant can handle at most a cost of 4 SEK/kg. Estimated cost for the aerosol catalyst is in the range of 10 SEK/kg. In order to be economically attractive, the catalyst should be recycled, thereby lowering the cost of catalyst consumption.

  • 6. Bäck, Andreas
    et al.
    Grubbström, Jörgen
    Ecke, Holger
    Pettersson, Jens
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Operation of an Electroctrostatic Precipitator at a 30 MWth oxyfuel plant2011Conference paper (Other academic)
    Abstract [en]

    The performance of a full-scale ESP was studied at the Vattenfall AB oxyfuel pilot plant in SchwarzePumpe. The lignite-fired boiler has a 30 MWth top-mounted pulverized coal burner and was operated under conventional air combustion as well as oxyfuel combustion. The ESP was operated with varying numbers of fields in service and at different current/voltage settings. Particle number size distributionsdownstream the ESP were established on-line in the size range 0.015-10 μm, using an electrical mobility spectrometer and an aerodynamic particle sizer. The particle size distribution at oxyfuel operation was qualitatively very similar to the results obtained for air-firing. Gravimetric measurementsof total fly ash concentration showed outlet emissions below 5 mg/Nm3 when the ESP was operatedwith two fields in service at oxyfuel conditions.

  • 7.
    Bäck, Andreas
    et al.
    Alstom Power Sweden AB.
    Grubbström, Jörgen
    Alstom Power Sweden AB.
    Ecke, Holger
    Vattenfall Research and Development.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Pettersson, Jens
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Operation of an Electrostatic Precipitator at a 30 MWth Oxyfuel Plant2011In: International Journal of Plasma Environmental Science and Technology, ISSN 1881-8692, Vol. 5, no 2, p. 141-145Article in journal (Refereed)
    Abstract [en]

    The performance of a full-scale ESP was studied at the Vattenfall AB oxyfuel pilot plant in Schwarze Pumpe. The lignite-fired boiler has a 30 MWth top-mounted pulverized coal burner and was operated under conventional air combustion as well as oxyfuel combustion. The ESP was operated with varying numbers of fields in service and at different current/voltage settings. Particle number size distributions downstream the ESP were established on-line in the size range 0.015-10 m, using an electrical mobility spectrometer and an aerodynamic particle sizer. The particle size distribution at oxyfuel operation was qualitatively very similar to the results obtained for air-firing. Gravimetric measurements of total fly ash concentration showed outlet emissions below 5 mg/Nm3 when the ESP was operated with two fields in service at oxyfuel conditions.

  • 8.
    Finnerman, Oskar
    et al.
    Chalmers University of Technology.
    Razmjoo, Narges
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Guo, Ning
    Chalmers University of Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ström, Henrik
    Chalmers University of Technology.
    Reactor modelling assessment for urea-SNCR applications2017In: International journal of numerical methods for heat & fluid flow, ISSN 0961-5539, E-ISSN 1758-6585, Vol. 27, no 7, p. 1395-1411Article in journal (Refereed)
    Abstract [en]

    Purpose

    This work aims to investigate the effects of neglecting, modelling or partly resolving turbulent fluctuations of velocity, temperature and concentrations on the predicted turbulence-chemistry interaction in urea-selective non-catalytic reduction (SNCR) systems.

    Design/methodology/approach

    Numerical predictions of the NO conversion efficiency in an industrial urea-SNCR system are compared to experimental data. Reactor models of varying complexity are assessed, ranging from one-dimensional ideal reactor models to state-of-the-art computational fluid dynamics simulations based on the detached-eddy simulation (DES) approach. The models use the same reaction mechanism but differ in the degree to which they resolve the turbulent fluctuations of the gas phase. A methodology for handling of unknown experimental data with regard to providing adequate boundary conditions is also proposed.

    Findings

    One-dimensional reactor models may be useful for a first quick assessment of urea-SNCR system performance. It is critical to account for heat losses, if present, due to the significant sensitivity of the overall process to temperature. The most comprehensive DES setup evaluated is associated with approximately two orders of magnitude higher computational cost than the conventional Reynolds-averaged Navier–Stokes-based simulations. For studies that require a large number of simulations (e.g. optimizations or handling of incomplete experimental data), the less costly approaches may be favored with a tolerable loss of accuracy.

    Originality/value

    Novel numerical and experimental results are presented to elucidate the role of turbulent fluctuations on the performance of a complex, turbulent, reacting multiphase flow.

  • 9.
    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.
    Seemann, Martin C.
    Rodin, Jennie
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Characterization of Particulate Matter in the Hot Product Gas from Indirect Steam Bubbling Fluidized Bed Gasification of Wood Pellets2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 4, p. 1781-1789Article in journal (Refereed)
    Abstract [en]

    This study characterized the particulate matter (PM) formed during the indirect steam bubbling fluidized bed gasification of wood pellets at atmospheric pressure. A system including a dilution probe, a bed of granular activated carbon, and a thermodenuder was used to sample the PM at high temperature with the aim of separating it from condensing inorganic vapors and tars. The particle mass size distribution was bimodal with a fine mode in the <0.5-μm size range and a dominating coarse mode in the >0.5-μm size range. The coarse mode was representatively characterized while condensing inorganic vapors and tars complicated the evaluation of the results for the fine-mode PM. Morphological analysis of the PM indicated that the char content was low. The inorganic fraction was dominated by potassium and chlorine for fine-mode PM and calcium and silicon for coarse-mode PM.

  • 10.
    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.
    Characteristics of aerosol particles from steam and oxygen gasification of various biofuels2010In: 18th European Biomass Conference and Exhibition: From resarch to industry and markets, ETA Renewable Energies and WIP Renewable Energies , 2010, p. 900-902Conference paper (Refereed)
    Abstract [en]

    The present study investigated how the characteristics of the particulate matter (PM) from steam and oxygen gasification of biomass were affected by the biofuel used. The results show that the biofuel had a large impact on the fine mode PM generated during the gasification, both on the particle size distribution and on the elementary composition. When using miscanthus as fuel, high concentrations of ultrafine particles consisting of potassium chloride were formed compared to when using high- and low-quality wood (wood A and wood B) as fuels. The impact of the biofuel on the coarse mode PM was less in this study. Large amounts of bed material dominated the coarse fraction. However, heavy metals were detected in the coarse mode PM when using wood B, constituting treated wood, as fuel.

  • 11.
    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 from a Circulating Fluidized Bed Gasifier Using Different Types of BiomassManuscript (preprint) (Other academic)
    Abstract [en]

    This study characterized the particulate matter (PM) formed during gasification of different types of biomass in a circulating fluidized bed gasifier at atmospheric pressure. Two systems were used to sample the PM, and both on- and offline analysis techniques were used to characterize the PM. Four different instruments were used to measure the particle mass size distribution and concentration in the size range 0.01–30 µm. The agreement between the instruments was good, and the particle mass size distributions upstream of any cleaning device were bimodal, dominated by the coarse mode (>0.5 µm). The particle mass concentration of the fine mode (<0.5 µm) varied, depending on which biomass was used. The variation in particle mass concentration of the coarse mode was less, and was due to different loads of bed material and various ash contents in the biomass. The morphological analysis of the PM showed that the char content was low and that the PM was dominated by ash and bed material. The coarse-mode PM was rich in magnesium and calcium, while potassium and chlorine were prevalent in the fine-mode PM. The elementary composition of the PM varied between the different types of biomass used and heavy metals, that is, zinc and lead, were detected in low concentrations when using demolition wood as fuel.

  • 12.
    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.

  • 13.
    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.
    Simeone, Eleonora
    Technical University of Delft.
    de Jong, Wiebren
    Technical University of Delft.
    Müller, Michael
    Forschungszentrum Jülich.
    Porbatzki, Dirk
    Forschungszentrum Jülich.
    Report of Particle Size and Composition Classificationduring Atmospheric Pressure Gasification2010Report (Other academic)
  • 14.
    Gustafsson, Eva
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Bioenergiteknik.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Further development and testing of a method for characterization of particles from biomass gasification using a laboratory scale gasifier2008In: 16th European Biomass Conference & Exhibition: From research to industry and markets, 2008, p. 1037-1040Conference paper (Refereed)
    Abstract [en]

    In the present study, a laboratory scale gasifier was used to further develop and test a method for characterization of particles from biomass gasification. It was found that when an inlet temperature to the bed of activated carbon, used for tar adsorption, of 200ºC was used, particles with low volatility were produced since they vaporized when heated to 300ºC, indicating condensation of tars. When an inlet temperature of 300ºC was used, the particles were stable when heated to 300ºC. This indicates that the tars had been kept in vapour phase and been adsorbed in the carbon bed. The particles were further heated in steps of 100ºC to 700ºC in order to study the change in particle size distribution and total concentration. The particles were stable up to 400ºC, indicating low tar content. The total particle concentration decreased between 400-700ºC probably due to oxidation of carbonaceous material, for example soot, or volatilisation of alkali chlorides. The particles present after heating to 700ºC were most likely inorganic ash. The concentration of fine particles decreased more than the concentration of coarse particles when heated to 700ºC. This could be due to a higher content of carbonaceous material in the fine particles and more ash-rich coarse particles.

  • 15.
    Gustafsson, Eva
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Method for High-Temperature Particle Sampling in Tar-Rich Gases from the Thermochemical Conversion of Biomass2010In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 24, no 3, p. 2042-2051Article in journal (Refereed)
    Abstract [en]

    The thermochemical conversion of biomass produces compounds in both gas and particle phases that may be regarded as contaminants. These contaminants include both particulate matter (e.g., fly ash, soot, and fragmented nonvolatilized material) and volatilized metals and tars that condense and form particulate matter during cooling. In this study a method for high-temperature particle sampling in tar-rich gases from the thermochemical conversion of biomass was developed and tested. Both a bed of granular activated carbon and a denuder were used for tar adsorption. First, the transport efficiency of particles was determined both theoretically and experimentally using a K2SO4 reference aerosol, and the losses were found to be smaller in the denuder than in the bed of granular activated carbon. The adsorption capacity was then tested using a model aerosol of K2SO4 and diethyl-hexyl-sebacate (DEL-IS). The adsorption capacity of the bed of granular activated carbon was found to be higher than that of the denuder. The adsorption capacity was also tested using a model aerosol of K2SO4 particles and tar-rich gas from a laboratory-scale gasifier. As for DEHS, the result indicated that the capacity of the bed of granular activated carbon was higher than that of the denuder; it was also found that the adsorption was incomplete when the tar concentrations increased. In addition, the bed of granular activated carbon was successfully tested during experiments using a 100 kW circulating fluidized bed gasifier. The results indicate that the tar adsorption capacity is dependent not only on the total tar concentration but also on the tar composition

  • 16.
    Gustafsson, Eva
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Strand, Michael
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Sampling of particles from biomass gasification: a method for testing the tar adsorption capacity of a bed ofgranular activated carbon2009In: Book of Proceedings- Bioenergy 2009: Sustainable Bioenergy Business4th International Bioenergy Conference / [ed] Mia Savolainen, Jyväskylä: FINBIO , 2009, p. 645-649Conference paper (Refereed)
    Abstract [en]

    In the present study, a method was developed for testing of the tar adsorption capacity of a bed of granular activated carbon for the application of sampling particles from biomass gasification at high temperature. A laboratory scale gasifier was used to produce a tar-rich gas and sampling was performed using a dilution probe, diluting the gas with either pure nitrogen or nitrogen containing K2SO4 particles. It was found that when using pure nitrogen for dilution; particles were formed using all tested primary dilution ratios; however the concentration decreased when the primary dilution ratio increased. When using nitrogen containing K2SO4 particles for dilution the particle number and volume size distributions were identical with the reference when higher primary dilution ratios were used while particle formation took place when the primary dilution ratio was lower, indicating incomplete tar adsorption. The conclusion of the study was that the method could be used for testing of the tar adsorption capacity of a bed of granular activated carbon for the application of sampling particles from biomass gasification at high temperature and that it is advantageous to use nitrogen containing K2SO4 particles instead of pure nitrogen for dilution in order to facilitate theevaluation of results.

  • 17.
    Gustafsson, Eva
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Bioenergi.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sanati, Mehri
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Bioenergi.
    Measurement of Aerosol Particles from Steam and Oxygen Blown Gasification of Wood Pellets in a 20 kW Atmospheric Bubbling Fluidised Bed (ABFB) Gasifier2007In: 15th European Biomass Conference & Exhibition: From Research to Market Deployment, ETA-Renewable Energies and WIP-Renewable Energies , 2007, p. 1128-1130Conference paper (Refereed)
    Abstract [en]

    In the present study, the particle number and mass size distributions from two measurements on steam and oxygen blown atmospheric bubbling fluidised bed (ABFB) gasification (20 kW) of wood pellets are presented. The total particle number concentration determined using a scanning mobility particle sizer (SMPS) varied between 5.1x10^5-6.6x10^6 particles/cm3 (mobility equivalent diameter (dB) 10-670 nm), with the largest variation for particles with dB<100 nm. The particle number size distributions were bimodal with modes at 20-30 nm and at 260-410 nm. The particle mass concentrations determined using a low pressure impactor (LPI) varied between 60-310 mg/m3 for particles with aerodynamic diameter (dae)<5 µm, with modes at 0.2-0.3 µm and at 2-3 µm.

  • 18.
    Gustafsson, Eva
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Bioenergi.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sanati, Mehri
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Bioenergi.
    Physical and Chemical Characterization of Aerosol Particles Formed during the Thermochemical Conversion of Wood Pellets Using a Bubbling Fluidized Bed Gasifier2007In: Energy Fuels, ISSN 0887-0624, Vol. 21, no 6, p. 3660-3667Article in journal (Refereed)
    Abstract [en]

    Product gas obtained through biomass gasification can be upgraded to hydrogen-rich synthesis gas. The synthesis gas can be further converted to liquid or gaseous fuels. However, the raw product gas contains both gas- and particle-phase impurities that can negatively affect both catalysts and hot-gas filters used for upgrading and cleaning. The present study aimed to characterize, both physically and chemically, aerosol particles formed during the steam- and oxygen-blown biomass gasification of wood pellets in an atmospheric 20 kW bubbling fluidized bed (BFB) gasifier. The product gas from the gasifier was sampled upstream from the cyclone at 500 °C. The particle number size distribution determined using a scanning mobility particle sizer (SMPS) was bimodal, with modes at 20–30 and 400 nm, mobility equivalent diameters (dB). The total mean number concentration of particles with dB = 15–670 nm was approximately 7 × 10^5 particles/cm3; however, the concentration of particles with dB < 80 nm fluctuated. The particle mass size distribution determined using a low-pressure impactor (LPI) was bimodal, and the total mass concentration of particles with aerodynamic diameters (dae) < 5 µm was 310 mg/m3. Microscopy analysis of particulate matter on the lower LPI stages, expected to sample particles with dae < 0.4 µm, revealed structures approximately 10 µm in diameter. In addition, the mass concentration of particles with dae < 0.5 µm determined using a LPI was higher than that estimated using a SMPS, possibly because of the bounce-off or re-entrainment of coarser particles from higher LPI stages. Elementary analysis of the particulate matter indicated that it was dominated by carbon. The collected particulate matter was stable when heated in nitrogen to 500 °C, indicating that the carbon was not present as volatile tars but more likely as char or soot. The particulate matter collected on all LPI stages contained a small percentage of ash (noncarbonaceous inorganic material), with calcium as the dominant element.

  • 19.
    Hermansson, Sven
    et al.
    SP.
    Backéus, Sofia
    Bohman, Christoffer
    Gulliksson, Hans
    Larsson, Sylvia
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Öhman, Marcu
    Testbädd Mellanskalig Biorbränsleförbränning - en förstudie2014Report (Other academic)
    Abstract [en]

    Conversion of biomass to heat and power plays an important role in the transition of the Swedish energy system from fossil based to renewables. For manufacturers and users of medium scale combustion plants (0.5 – approx. 15 MWth), a spectrum of challenges are accounted with both today’s and future flexible use of modern biomass fuels. Such challenges are e.g. fuel handling and processing together with combustion instabilities caused by new fuels with resulting ware-and-tear and elevated emission levels. However, the possibilities to test and try out new innovations is very limited, which is why a Test Bed has the potential to significantly contribute to the innovation growth within the sector. The purpose of this feasibility study therefore to investigate the prerequisites for the establishment of a Test Bed for Medium Scale Biomass Combustion. The fundament of the feasibility study is a survey of the existing infrastructure for testing and innovation development of medium scale biomass combustion, which could be further developed and interconnected. Furthermore, a broad inquiry has been performed among market actors, focusing on the present and future need together with existing conditions for taking part in the development of a test bed. These first two steps has then been synthesized into recommendations on how a test bed should be developed and exploited by relevant actors. The major conclusions and recommendations of the feasibility study are:  A cost efficient and innovative Test Bed system for medium scale biomass combustion could be developed by enhanced cooperation between passive test-bed like plants and systems, industrial testing plants and research activities,  Development of a test bed system is hindered by the fact that there is no clear receiver of such system on the market. Stake holder cooperation is today weak, which makes common investments and financing impossible  There is no economic support for the erection of new, dedicated test bed facilities for medium scale biomass combustion,  Pre-treatment of biomass raw material with the purpose of enhancing fuel quality simultaneously refining products from the biomass has been found to show good potential for further development of test beds. This study therefore recommends that such investigation should be taken under consideration.

  • 20.
    Karlsson, Stefan
    et al.
    Glafo ; University of Jena, Germany .
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Limbach, Renè
    University of Jena, Germany.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Wondraczek, Lothar
    University of Jena, Germany.
    Alkali salt vapour deposition and in-line ion exchange on flat glass surfaces2015In: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 56, no 6, p. 203-213Article in journal (Refereed)
    Abstract [en]

    This study suggests a different route for the modification of flat/float glass surfaces; i.e. exchange of ionic species originatingfrom in-line vapour deposition of salt as compared to the conventional route of immersing the glass in a molten saltbath. The aim of this work is to develop a more flexible and, eventually, more rapid process for improving the mechanicalstrength of flat glass by introducing external material into the surface. We discuss how chemical strengthening can beperformed through the application of potassium chloride on the glass surface by vapour deposition, and in-line thermallyactivated ion exchange. The method presented here has the potential to be up-scaled and to be used in in-line productionin the future, which would make it possible to produce large quantities of chemically strengthened flat glass at aconsiderably lower cost.

  • 21.
    Karlsson, Stefan
    et al.
    Glafo – the Glass Research Institute.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Chemical strengthening of flat glass by vapour deposition and in-line alkali metal ion exchange2014Report (Refereed)
    Abstract [en]

    Glass is a common material in the everyday life. It is widely used in a variety of applications e.g. architectural, automotive, containers, drinking vessels, displays, insulation and optical fibers due to its universal forming ability, transparency, chemical durability, form stability, hardness and relatively low price. Flat glass is a wide market of the glass industry and generally ninety percent of all flat glass produced worldwide is manufactured using the float forming process. There is a large market strive for thinner and stronger glass in order to reduce costs, save energy, reduce environmental footprint, find new applications and to improve the working environment for labour working with mounting flat glass. This study comprises the modification of flat/float glass surface by a novel route; exchange of ionic species originating from in-line vapour deposition of salt compared to the conventional route of immersing the glass in molten salt baths. The aim of this work is to develop a novel process in order to improve the mechanical strength of flat/float glass by introducing external material to the surface in a process with the obvious potential to be automatic in industrial processes. Chemical strengthening has been performed by applying potassium chloride to the glass surface by vapour deposition and thermally activated ion exchange. The method presented here is anticipated to be used in production in the future and would make it possible to produce larger quantities of chemically strengthened flat glass to a considerably lower cost.

  • 22.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Gustafsson, Eva
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Aerosol-based method for investigating biomass char reactivity at high temperatures2011In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 158, no 7, p. 1426-1437Article in journal (Refereed)
    Abstract [en]

    An aerosol-based method was proposed and developed to characterize particles fragmented from biomass chars during oxidation. The chars were prepared from both wood and miscanthus pellets under various pyrolysis conditions. Char fragments with aerodynamic diameters in the range of 0.5–10 μm were suspended and transported in a reactive gas through an aerosol reactor, which was heated by an electric oven. The oxidation of char particles in the reactor was investigated by determining on-line the particle size distributions before and after passage through the reactor using an aerodynamic particle sizer (APS) spectrometer. The interpretation of APS data was evaluated by both experiments and models in which the fine char particles were assumed to keep either constant density or constant diameter during the oxidation process. The results indicate that the aerosol-based method can be used to determine reaction kinetics of char particles in the high temperature range, where oxidation is normally controlled by diffusion limitation if measuring with the conventional techniques. The application of the aerosol method indicated that high pyrolysis temperature and prolonged retention time will reduce the char reactivity.

  • 23.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Gustafsson, Eva
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    High-temperature Kinetics of Fine Biomass Char Particles in Air and CO22010In: 18th European Biomass Conference and Exhibition: From Research to Industry and Markets, 2010Conference paper (Refereed)
    Abstract [en]

    Knowledge of reliable chemical kinetics of char always plays significant roles in the modelling, design and optimization of processes during biofuel thermochemical conversions.The determination of reaction kinetics of char in the high-temperature range still highly depends on the extrapolation of results from kinetic data determined at lower temperatures due to mass and heat transfer limitations. In this work an aerosol-based method was used to investigate the reactivity of singly-distributed char particles with aerodynamic diameters between 0.5-10 mm. The conversion of char particles in the reactor at varying temperatures and residence time was determined by comparing the particle size distributions before and after passing the reactor, using an aerodynamic particle sizer (APS) spectrometer. The results of char particles reacted with air, CO2 and steam indicate that the aerosol-based method can be used to determine reaction kinetics of char particles in the high temperature range where reaction is controlled by diffusion limitation if using conventional thermogravimetric analysis (TGA). By combining the aerosol-based method and conventional TGA, the oxidation and gasification kinetic parameters of biomass char can be derived in the temperature range of 350-800ºC, and 800-1200ºC respectively. The aerosol-based method shows the potential of on-line measuring the char reactivity.

  • 24.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Morgalla, Mario
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Study on char fragmentation during biomass gasification in bubbling fluidized bed2015In: 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, ETA-Florence Renewable Energies , 2015, p. 652-655Conference paper (Refereed)
    Abstract [en]

    In this work a bench scale bubbling fluidized bed gasifier was built to work with an aerosol sampling and measuring system in order to study char fragmentation phenomenon during biomass gasification process. Both barbeque char and wood pellets were gasified in CO2 (20 vol.%) -N2 mixture and steam (30 vol.%)-N2 mixture, respectively. An aerodynamic particle sizer (APS) was used to measure fragmented char particles during the whole gasification process. For the wood pellet gasification case, major fragmentation was observed during the devolatilization stage, which should be attributed to the combined effect of primary fragmentation and attrition. The aerodynamic diameter of those elutriable particles which can be measured by the current system was in the range of 0.5-8 µm. During the char gasification stage, a distinct mode of char fragments was produced in the size range of 1-7 µm in either case. The total mass concentration of elutriable particles gradually increased when gasification of char started, and then decreased while the reaction approached completion.

  • 25.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Further development and application of aerosol-based method for on-line investigation of char reactivity in steam2013In: Proceedings for 21st European Biomass Conference and Exhibition, ETA-Florence Renewable Energies , 2013, p. 875-878Conference paper (Refereed)
    Abstract [en]

    Wood char was prepared from wood pellets under controlled pyrolysis conditions. The gasification kinetics for wood char in 33 vol% steam was established in the temperature range from 800ºC to 1300ºC by the combination of thermogravimetric analysis (TGA) and a novel aerosol-based method. The aerosol method was further developed and demonstrated successfully for generating, transporting and gasifying the suspended char particles (0.5-10 µm) in the steam atmosphere at high temperature up to 1300ºC. A tapered element oscillating microbalance (TEOM) was used to measure the change of mass concentrations of particles in the carrier gas, before and after gasification. The activation energy was 155 kJ·mol-1 for wood char with the pre-exponential factor of 3.56×104. This method can be potentially applied to on-line measure the reactivity of char particles directly in hot gas from the gasifier.

  • 26.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Investigation of the intrinsic CO2 gasification kinetics of biomass char at medium to high temperatures2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 220-228Article in journal (Refereed)
    Abstract [en]

    In total eight char samples from pelletized wood, miscanthus, and straw were prepared under various pyrolysis conditions. The CO2 gasification kinetics for each sample was established in the temperature range from 800 °C to 1300 °C by the combination of thermogravimetric analysis (TGA) and a novel aerosol-based method. The aerosol-based method was used for the high temperature range between 1100 °C and 1300 °C, by gasifying suspended char particles (0.5–10 μm) in an oxidizing carrier gas. A tapered element oscillating microbalance (TEOM) was used to measure the change of mass concentrations of particles in the carrier gas, before and after gasification. The results showed that the aerosol-based method could be used to investigate the intrinsic gasification kinetics of biomass char, at least up to 1300 °C. All char samples showed similar reactivity in the low temperature range. However, above 1000 °C there were significant differences in reactivity, and at 1300 °C the conversion of the wood was in the order of 10 times faster than that of straw. The general char reactivity order in this study was wood > miscanthus > straw.

  • 27.
    Lin, Leteng
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Strand, Michael
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Investigation on the oxidation kinetics of biomass char particles2009In: Book of Proceeding-Bioenergy 2009: Sustainable Bioenergy Business4th International Bioenergy Conference / [ed] Mia Savolainen, Jyväskylä: FINBIO , 2009, p. 933-939Conference paper (Refereed)
    Abstract [en]

    One specific type of wood pellets were pyrolyzed with both low and high heating rate in nitrogen atmosphere at 800-900°C. The pulverized chars were oxidized by thermo gravimetric analysis (TGA) in an atmosphere of nitrogen with 3%-21% of oxygen admixture. Three pore models reported in the literature were tested against the experimental data. In order to investigate the reactivity of singly distributed particles, char samples were fragmented and suspended into a gas using a shaking device. A fraction of suspended particles with an aerodynamic diameter between 0.5-10 um were then fed into a tubular reactor heated by an electric oven. The oxidation of char particles in the reactor at different temperatures was investigated by measuring the particle size distribution before and after passing the reactor, using an aerodynamic particle sizer (APS) spectrometer. This method made it possible to investigate the oxidation kinetics of char particles at high temperature area which is hard to realize in TGA due to the mass transportation limitation.

  • 28.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Online investigation of steam gasification kinetics of biomass chars up to high temperatures2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 1, p. 607-613Article in journal (Refereed)
    Abstract [en]

    In this study, a novel aerosol-based method has been further developed and applied for on-line investigating of steam gasification kinetics of suspended biomass char particles. By combining the aerosol method with thermogravimetric analysis, the gasification kinetics were established in steam (33 vol%)-N2 atmosphere from 800°C to 1300°C for char samples produced from pelletized wood, straw, and miscanthus. The aerosol method includes steps for generating, suspending, and gasifying char particles. The conversion of the char particles was established by measuring the change in particle size distributions and mass concentrations using an aerodynamic particle sizer (APS) spectrometer and a tapered element oscillating microbalance (TEOM), respectively. The reactivity of three char samples could be ranked as wood > miscanthus > straw. The activation energy was 155 kJ·mol-1 for wood char, 199 kJ·mol-1 for miscanthus char, and 222 kJ·mol-1 for straw char. Results interpreted from TEOM and APS measurements indicated that the effective density of char particles initially decreased until a certain level of conversion was reached, and then remained constant. 

  • 29.
    Lutic, Doina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sanati, Mehri
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Bioenergiteknik.
    Catalytic properties of oxide nanoparticles applied in gas sensors2007In: TOPICS IN CATALYSIS, ISSN 1022-5528, Vol. 45, no 1-4, p. 105-109Article in journal (Refereed)
    Abstract [en]

    A series of gas sensing layers based on indium oxide doped with gold were prepared by using the aerosol technology for deposition as the active contact layer in a metal oxide semiconductor capacitive device. The interaction between the measured species and the insulator surface was quantified as the voltage changes at a constant capacitance of the device. The sensor properties were investigated in the presence of H2, CO, NH3, NO, NO2 and C3H6 at temperatures between 100–400 °C. Significant differences in the morphology of the layer and its sensitivity were noted for different preparation methods and different gas environments.

  • 30.
    Morgalla, Mario
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Seemann, Martin
    Chalmers.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Characterization of particulate matter formed during wood pellet gasification in an indirect bubbling fluidized bed gasifier using aerosol measurement techniques2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 138, p. 578-587Article in journal (Refereed)
    Abstract [en]

    This study characterizes particulate matter, organic compounds, and inorganic compounds formed in an atmospheric indirect bubbling fluidized bed gasifier at two different steam-to-fuel ratios using wood pellets as fuel. The sampling and conditioning system consisted of a high-temperature dilution probe to quench aerosol dynamics and condense inorganic vapors, a primary thermodenuder to adsorb tar components, and a secondary thermodenuder to investigate the volatility/thermal stability of the remaining aerosol. Both online and offline instruments were used to characterize the aerosol in terms of number size distribution, mass size distribution, particle mass concentration, particle number concentration, morphology, and elemental analysis. Size distributions with three distinct modes were established. The fine and intermediate modes were mainly formed by tar and alkali vapors that had condensed in the sampling and conditioning systems. The coarse mode mainly consisted of the original particles, which are char, fly ash, and fragmented bed material. At the higher steam-to-fuel ratio, tar components seem to be reduced and more coarse-mode particles emitted compared to the low steam case. Furthermore, a possibility for online monitoring of heavy tar is suggested. (C) 2015 Elsevier B.V. All rights reserved.

  • 31.
    Morgalla, Mario
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Benzene Conversion in a Packed Alumina Bed Continuously Fed with Woody Char Particles2018In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 7, p. 7670-7677Article in journal (Refereed)
    Abstract [en]

    This Article investigates the decomposition of benzene (as a model tar) over finely dispersed char particles continuously distributed into a packed bed. Fragmented char particles and benzene plus a gasification agent (H2O or CO2) were supplied into a ceramic reactor that was heated electrically. The supplied char particles were retained in the reactor by a bed of alumina grains. Woody char as well as iron-doped and potassium-doped woody char were used. The influence of the gasification agent, char concentration, char weight time (proportional to the instant char mass present in the bed), and bed temperature (600-1050 degrees C) was investigated. Increasing the char concentration and char weight time increased benzene conversions for all tested chars. At similar char weight times, the benzene conversion increased with temperature, whereas the iron- and potassium doped char did not affect the specific conversion. At similar char concentrations, changing the gasification agent from CO2 to steam as well as using doped char led to decreased benzene conversions. This can be explained by accelerated char gasification reactions and thus a diminished char mass in the packed bed. Furthermore, benzene conversion rates were enhanced in the presence of CO2 as compared to steam. As the temperature was increased from 950 to 1050 degrees C, the benzene conversions were slightly reduced. This was interpreted as a combined effect of the enhanced benzene conversion rates and reduced char weight times. The highest benzene conversions achieved in the experiments were approximately 80% at 950-1000 degrees C using CO2 as gasification agent and supplying approximately 20-30 g N m(-3) undoped woody char.

  • 32.
    Morgalla, Mario
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Benzene conversion in a packed bed loaded with biomass char particles2018In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 1, p. 554-560Article in journal (Refereed)
    Abstract [en]

    This study investigates the conversion of benzene in a packed bed containing fine char particles. Benzene and steam were simultaneously supplied to a tubular ceramic reactor that was heated electrically. Fragmented char particles were suspended and continuously supplied via a separate supply line. A packed bed of crushed alumina balls was positioned in the reactor to retain the char particles. The benzene conversion in the hot char bed was investigated by varying the bed temperature (900–1100 °C), steam concentration (0–27 vol %), and char concentration (5–50 g Nm–3). The highest conversions achieved in the experiments were approximately 75%. At comparable char concentrations, similar benzene conversions occurred at 900 and 1000 °C. Increasing the temperature to 1100 °C or increasing the steam concentration reduced the benzene conversion. The results indicate that the reduced conversion was due to enhanced char gasification reactions at elevated temperatures and steam concentrations and thus to reduced char mass in the packed bed.

  • 33.
    Morgalla, Mario
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Characterization Of Particulate Matter In Biomass Gasification2015In: Proceedings for the 23rd European Biomass Conference and Exhibition / [ed] I. Obernberger, D. Baxter, A.Grassi, P.Helm, ETA-Florence Renewable Energies , 2015, p. 664-667Conference paper (Refereed)
    Abstract [en]

    The purpose of this work is to examine the potential of monitoring heavy tar compounds contained in the product gas of a biomass gasifier. The hot product gas from atmospheric indirect bubbling fluidized bed gasification of wood pellets was extracted. The sampling and conditioning system consisted of a high-temperature dilution probe, a primary thermodenuder and a secondary thermodenuder. Online and semi-online instruments were used to characterize the aerosol in terms of number size distribution and particle mass concentration. The fine mode (mobility equivalent diameter db < 150 nm) was found to mainly consist of heavy tar compounds. An Electrical low­pressure impactor (ELPI) was used to measure this mode with a time resolution of 1 second and thus showed the potential for online measurements of heavy tar.

  • 34.
    Morgalla, Mario
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Decomposition of benzene using char aerosol particles dispersed in a high-temperature filter2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 118, p. 1345-1352Article in journal (Refereed)
    Abstract [en]

    In this study the tar-removal suitability of char particles finely dispersed in a high-temperature filter was investigated. Benzene was selected as the model tar. An aerosol-based method was designed and used to investigate the benzene decomposition behaviour. Two types of char were used: commercially available activated charcoal and pine char prepared in the laboratory. The conversion behaviour of both chars was investigated in the temperature range between 750 and 900 °C using steam as the gasification medium. During the experiments, different benzene concentrations, amounts of deposited char and gas residence times were tested. The results indicate that both activated carbon and pine char reduced the benzene concentration. Activated carbon generally produced higher and more stable benzene conversions compared to the pine char particles. Decreasing the benzene concentration or increasing the gas residence time or char mass improved the benzene conversion. It was concluded that the char gasification rate became slower while benzene was simultaneously converted. The aerosol-based method was also used to investigate benzene decomposition behaviour while continuously supplying fresh char particles together with steam at 1000 °C. In that way, the deactivated and gasified char particles were steadily replaced, preventing the benzene conversion from decreasing over time.

  • 35.
    Parsland, Charlotte
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Catalytic Cracking of Biomass Tars: a Model-Study of Naphtalene Cracking with Mineral Based Catalysts2010In: 18th European Biomass Conference & Exhibition: From Research to Industry and Market, ETA Renewable Energies and WIP Renewable Energies , 2010Conference paper (Refereed)
    Abstract [en]

    In the production of syngas from biomass gasification the resulting raw gas needs to be low in both tar and particulates but also optimized in its composition. Different bed materials have been studied in the purpose of catalytically reducing tars. The set-up has been in lab-scale and naphtalene has been used as a model substance. One problem that can occur when using porous and active bed materials is abrasion of the solids which causes formation of fine particles that can not be recirculated in the process cyclone. Other limiting factors are poor catalytic effectiveness and high costs for the new materials. The objective of this study is to investigate potentially cost-efficient, mechanically stable and catalytically active bed-materials.

  • 36.
    Pettersson, Jens
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Cost Efficient Precipitation of Sub Micron Particles in Flue Gases Formed by Thecombustion of Solid Biofuel2010In: 18th European Biomass Conference: From Research to Industry and Markets, ETA Renewable Energies and WIP Renewable Energies , 2010, p. 1296-1300Conference paper (Other academic)
    Abstract [en]

    This research considers three stage Electrostatic precipitators, diffusion charging and other novel techniques. Electrostatic Precipitators have shown to be both efficient and reliable on larger plants, however too costly to be an option for smaller plants. More stringent requirements on exposure of humans to particulate matter,especially fine particles, has put a pressure also on small plants to apply additional, costly filter technologies, to prevent emission of fine particulate matter. These more stringent requirements on small biofuel plants counteract the rational use of unrefined biomass resources. This research aims to investigate new principles to better adopt the Electrostatic precipitator technology to suit the specific fine particulate matter characteristic for biofuels, thus promoting the use of biofuel, simultaneously fulfilling more stringent emission requirements.

  • 37.
    Pettersson, Jens
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Lin, Leteng
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Charging- and removal efficiency of an ESP in a 250 kW biomass boiler2011In: International Conference on Electrostatic Precipitation XII, ICESP Nürnberg 2011, 2011Conference paper (Refereed)
    Abstract [en]

    The combustion of biomass creates ultra fine particulate matter which is not precipitated by traditional multi cyclone technique, usually adopted on small scale plants. In Sweden the number of small bio fuelled plants is increasing and there is a need for cost effective means to precipitate the ultra fine particles formed. One such technique may be electrostatic precipitation, but the economy of scale is a constraining factor for systems commercially available today. This paper describes field tests of a low cost electrostatic precipitator, ESP, including not only investigation of collection efficiency, but also measurement of charging effectiveness. The aim of the tests was to determine the potential for the low cost ESP design to form part of an electrostatic precipitation system for use on bio fuelled plants in the megawatt scale. The charges acquired by the particles have been measured using a low pressure cascade impactor, ELPI. Measurements of charges were carried out on particles escaping from the ESP. The results of the measurements of particle charges indicates that the method may correctly reflect the mean charge levels of particles of the different sizes usually found within the fine particle mode of flue gases from biomass combustion.

  • 38.
    Pettersson, Jens
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Lin, Leteng
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Kostnadseffektiv partikelavskiljning i mindre närvärmeanläggningar2011Report (Other academic)
    Abstract [sv]

    Avsliljningstekniker för mindre biobränsleanläggningar, i storlek under 10 megawatt, har undersökts. Experiment i laboratorium och fältförsök har utförsts avseende elektrostatiska filter.

  • 39.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hermansson, Sven
    RISE Research Institutes of Sweden.
    Morgalla, Mario
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Study of the transient release of water vapor from a fuel bed of wet biomass in a reciprocating-grate furnace2018In: Journal of the Energy Institute, ISSN 1743-9671Article in journal (Refereed)
    Abstract [en]

    The present study investigates how sudden changes in fuel moisture affected the combustion characteristics of the fuel bed in a 4-MW reciprocating-grate furnace. The moisture content of the fuel fed to the furnace was monitored online using a near-infrared spectroscopy device, and the water vapor concentration in the flue gas was measured continuously. To obtain experimental data on fuel-bed conditions, the temperature and gas composition in the bed were measured using a probe. A simplified drying model was developed using the measured gas composition values as inputs. The model was then used to estimate the drying rate and to simulate the extent of the drying zone along the grate. Measurements indicated that a change in the moisture content of the fuel fed to the furnace was detected as a change in water vapor concentration in the flue gas with a delay of about 2 h. The model predicted that a portion of wet fuel would need about 2 h to become dry, in line with the measured time delay of the water vapor concentration change in the flue gas. Overall, there was good alignment between the measured and simulated results, supporting the validity of the model and the assumed mechanisms.

  • 40.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hermansson, Sven
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Characterization of the fuel bed combustion of wood residues in a 4 MW grate boiler2015In: European Biomass Conference and Exhibition Proceedings, 2015, p. 741-744Conference paper (Refereed)
    Abstract [en]

    Information about distributions of temperature and gas species within the fuel bed is of great importance in studying the formation of pollutants in an industrial-scale biomass boiler. The main objective of this study was to investigate the gas composition and temperature in some available sections of the fuel bed of a 4 MW reciprocating grate boiler, burning mixture of fresh pine wood chips, bark, and sawdust with two significantly different moisture content levels. The averageCO, CO2,CH4, and O2 concentrations measured during the combustion of the more moist fuel (about 60 mass %) were about 12, 12, 2, and 4 vol. %, respectively, whereas the corresponding values for the less moist fuel (about 45 mass %) were about15, 10, 2.5, and 5 vol. %, respectively. Higher concentration of CO and lower concentration of CO2 for the less moist fuel could originate either from the char conversion process or from the reactions of the devolatilizationgas products.

  • 41.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Sefidari, Hamid
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Characterization of hot gas in a 4 MW reciprocating grate boiler2014In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 124, p. 21-27Article in journal (Refereed)
    Abstract [en]

    The gas concentration and temperature information from the combustion of biomass offer significant advantages to enhance the understanding of an industrial-scale biomass heating plant. The main objective of this study was to investigate the gas composition and temperature in a 4 MW reciprocating grate boiler. An extensive series of measurements was carried out, and the samples, which were drawn through different ports by means of a water-cooled stainless steel suction pyrometer, were analyzed for temperature and for O2, CO, and NO concentrations. The results showed that the averaged NO, CO, and O2 concentrations in the gas phase during fuel combustion in the primary chamber were 40 ppm, 3.5 and 6.5 vol.%, respectively, while the values were 80 ppm, 1.1 and 6 vol.% in the secondary chamber. Detailed gas species and temperature distributions are discussed, which provide good possibilities for the control of emissions.

  • 42.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Sefidari, Hamid
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Experimental investigation of fuel bed combustion in an industrial grate boiler2015Conference paper (Refereed)
    Abstract [en]

    Information about distributions of temperature and gas species within the fuel bed is of great importance in studying the formation of pollutants in an industrial-scale biomass boiler. The main objective of this study was to investigate the gas composition and temperature in some available sections of the fuel bed of a 4 MW reciprocating grate boiler. The results showed that the temperature profiles of the grate bars and the fuel bed suggest significant temperature gradients versus the height of the fuel bed. The averaged NO, CO, CO2, and O2 concentrations measured in the fuel bed were about 80 ppm, 21, 11 and 1 vol. %, respectively.

  • 43.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Sefidari, Hamid
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Luleå University of Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Measurements of temperature and gas composition within the burning bed of wet woody residues in a 4 MW moving grate boiler2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 152, p. 438-445Article in journal (Refereed)
    Abstract [en]

    Moving grate firing systems are widely used for biomass combustion. The characteristics of the fuel bed combustion in moving grate boilers are of practical interest as they are directly related to the release of pollutants and affect the furnace efficiency. Measurements of temperature and gas species concentrations inside the fuel bed are necessary to improve our understanding of the highly complex processes involved in biomass combustion.There have been few experimental studies of the fuel bed of industrial scale grate furnaces. The present study measured temperature and gas species concentrations within a thick burning bed of wet woody biomass, in a  4 MW reciprocating grate boiler. Measurements were carried out under three different operating conditions through ports located in the wall of the furnace using a stainless steel probe incorporating a thermocouple. Temperatures of about 1000 °C were measured close to the grate, indicating intense combustion at the bottom of the fuel bed. The temperature distribution along the bed height showed that different stages of the combustion process take place in horizontally adjacent layers along the grate. Higher flow rates of the primary air resulted in relatively higher CO and lower CO2 and NO concentrations in the fuel bed.

  • 44.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Sefidari, Hamid
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Yang, Jingjing
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Gas measurements and characterization of wood combustion in a traveling grate boiler2013In: Proceedings for 21st European Biomass Conference and Exhibition, ETA-Florence Renewable Energies , 2013, p. 591-594Conference paper (Refereed)
    Abstract [en]

    Experimental tests have been carried out on a moving grate boiler at a 4 MW heating plant located at a sawing mill in south of Sweden. In order to investigate the performance of the combustion chamber, the local concentrations of O2, NO and CO are determined in the region above the grate using two water-cooled stainless steel probes of different lengths and diameters. The fuel used was sawmill waste consisting of bark, sawdust and shavings. The results of the study provided valuable insights into the combustion process.

  • 45.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    In-bed combustion charachteristics of wet wood chips and sawdust in a full-scale grate boiler2017In: Proceedings 13th International Conference on Energy for a Clean Environment, 2017Conference paper (Refereed)
  • 46.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Investigation of moist fuel bed combustion in grate furnaces2017In: Proceedings of Nordic Flame Days, 10-11 October, 2017, Stockholm, 2017Conference paper (Refereed)
  • 47.
    Sanati, Mehri
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Bioenergiteknik.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Nanocrystalline ruthenium oxide and ruthenium in sensing applications – an experimental and theoretical study2006In: Journal of Nanoparticle Research, ISSN 1388-0764, Vol. 8, no 6, p. 899-910Article in journal (Refereed)
    Abstract [en]

    In this project, we have explored RuO2 and Ru nanoparticles (∼ ∼10 and ∼ ∼5 nm, respectively, estimated from XRD data) to be used as gate material in field effect sensor devices. The particles were synthesized by wet chemical procedure. The capacitance versus voltage characteristics of the studied capacitance shifts to a lower voltage while exposed to reducing gases. The main objectives are to improve the selectivity of the FET sensors by tailoring the dimension and surface chemistry of the nanoparticles and to improve the high temperature stability. The sensors were characterized using capacitance versus voltage measurements, at different frequencies, 500 Hz to 1 MHz, and temperatures at 100–400°C. The sensor response patterns have been found to depend on operating temperature. X-ray photoelectron spectroscopy (XPS) analyses were performed to investigate the oxidation state due to gas exposure. Quantum-chemical computations suggest that heterolytic dissociative adsorption is favored and preliminary computations regarding water formation from adsorbed hydrogen and oxygen was also performed

  • 48.
    Sanati, Mehri
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Strand, Michael
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Nanoparticles for long-term stable, more selective MISiCFET gas sensors2005In: Sensors and Actuators B, ISSN 0925-4005, Vol. 107, no 2, p. 831-838Article in journal (Refereed)
    Abstract [en]

    Synthesis of metal-oxide nanoparticles and utilization of these particles as gate materials for field-effect sensor devices is reported. Improved

    selectivity to specific gases is expected by modulating the size of the oxide nanoparticles or impregnating them with catalytic metals. Another

    objective is to improve the long-term thermal stability of the sensors, since the metal loaded nanoparticles may prevent thermally induced

    restructuring of the gate layer, which is often a problematic issue for the catalytic metal layers. Because of its reasonably high electrical

    conductivity, which is especially important for the capacitive gas sensors, ruthenium dioxide has been identified to be one of the potential

    candidates as gate material for the field-effect sensor devices. Interestingly, this material has been found to change its resistivity in different

    gaseous ambients. When used as a gate material, sensitivity to reducing gases has been observed for the RuO2/SiO2/4H-SiC capacitors.

    Changes in the resistivity of the films due to various gas exposures have also been recorded. Morphological studies of nanoparticles (SiO2

    and Al2O3), loaded or impregnated with catalytic metals (e.g. Pt), have been performed.

  • 49.
    Sanati, Mehri
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    New Materials for Chemical and Biosensors2006In: Material and Manufacturing Processes, ISSN 1042-6914, Vol. 21, no 3, p. 275-278Article in journal (Refereed)
    Abstract [en]

    Wide band gap materials such as SiC, AlN, GaN, ZnO, and diamond have excellent properties such as high operation temperature when

    used as field effect devices and a high resonating frequency of the substrate materials used in piezoelectric resonator devices. Integration of FET

    and resonating sensors on the same chip enables powerful miniaturized devices, which can deliver increased information about a gas mixture or

    complex liquid. Examples of sensor devices based on different wide band gap materials will be given.

  • 50.
    Saqnati, Mehri
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Strand, Michael
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Lillieblad, Lena
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers2005In: Aerosol Science and Technology, ISSN 0278-6826, Vol. 39, no 91, p. 919-930Article in journal (Refereed)
    Abstract [en]

    This study focuses on the hygroscopic properties of submicrometer

    aerosol particles emitted from two small-scale district heating

    combustion plants (1 and 1.5 MW) burning two types of biomass

    fuels (moist forest residue and pellets). The hygroscopic particle

    diameter growth factor (Gf ) was measured when taken from a dehydrated

    to a humidified state for particle diameters between 30–

    350 nm (dry size) using a Hygroscopic Tandem Differential Mobility

    Analyzer (H-TDMA). Particles of a certain dry size all showed

    similar diameter growth and the Gf at RH = 90% for 110/100 nm

    particles was 1.68 in the 1MWboiler, and 1.5 in the 1.5MWboiler.

    These growth factors are considerably higher in comparison to

    other combustion aerosol particles such as diesel exhaust, and are

    the result of the efficient combustion and the high concentration of

    alkali species in the fuel. The observed water uptake could be explained

    using the Zdanovski-Stokes-Robinson (ZSR) mixing rule

    and a chemical composition of potassium salts only, taken from

    ion chromatography analysis of filter and impactor samples (KCl,

    K2SO4, andK2CO3). Agglomerated particles collapsed and became

    more spherical when initially exposed to a moderately high relative

    humidity. When diluted with hot particle-free air, the fractallike

    structures remained intact until humidified in the H-TDMA.

    A method to estimate the fractal dimension of the agglomerated

    combustion aerosol and to convert the measured mobility diameter

    hygroscopic growth to the more useful property volume diameter

    growth is presented. The fractal dimension was estimated to be

    ∼2.5.

12 1 - 50 of 72
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