Endre søk
Begrens søket
12 1 - 50 of 67
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Arrhenius, Karine
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor.
    Podien, Doris
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Yaghooby, Haleh
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Smajovic, Nijaz
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Optimization of an Analytical Method for the Measurement of Oil Carryover from a Compressor in Compressed Natural Gas Refueling Stations2015Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 29, nr 4, s. 2416-2421Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aims of the study were to determine the best method for extracting oil absorbed on coalescing filters at compressed natural gas (CNG) refueling stations and to compare the mass spectrometer (MS) and flame ionization detector (FID) for the quantification of the oil recovered in the extracts. Dichloromethane and heptane as solvents gave slightly higher recovery yields than pentane. The preferred extraction method with regard to time and solvent consumption consisted of an ultrasonic extraction, followed by removal of the remaining solvent under a stream of nitrogen. The FID and MS were found to be equally suitable for quantifying oil carryover, if the sample only contained the target oil when the instruments of analysis have been properly calibrated. If the sample is contaminated by compounds other than the target oil, MS and FID will provide different valuable information: MS may give information on the structure of the contaminants, while FID will give a more reliable quantification without proper calibration. The work discusses issues with the reusability of the filters and how to handle the memory effects.

  • 2.
    Atongka Tchoffor, Placid
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi, Förbrännings- och aerosolteknik. Chalmers University of Technology, Sweden.
    Davidsson, Kent
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi, Förbrännings- och aerosolteknik.
    Thunman, Henrik
    Chalmers University of Technology, Sweden.
    Effects of Steam on the Release of Potassium, Chlorine, and Sulfur during Char Conversion, Investigated under Dual Fluidized Bed Gasification Conditions2014Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, nr 11, s. 6953-6965Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The corrosion and fouling of heat-transfer surfaces and the agglomeration of bed materials in fluidized beds are some of the ash-related problems caused by the transformation and release to the gas phase of ash-forming elements from biomass during thermochemical conversion processes. The magnitudes of these problems are largely dependent upon the release of potassium (K), chlorine (Cl), and sulfur (S) from the biomass. We investigated the effects of steam on the release of K, Cl, and S during char conversion, under conditions relevant for dual-fluidized-bed gasification (DFBG). The study was carried out with wheat straw in a laboratory-scale bubbling fluidized-bed reactor in the temperature range of 800-900 °C. The release of K, Cl, and S from wheat straw during devolatilization, char gasification, and char combustion was quantified with a mass balance that linked the masses of these elements in the wheat straw to the mass of the solid residue obtained at the end of each experiment. To facilitate analyses of the experimental results, leaching and the Brunauer-Emmett-Teller surface area measurement of the wheat straw and some of the solid residues were carried out. The results show that, during devolatilization, the release of volatile salts, e.g., KCl, is significantly limited by intraparticle diffusion resistance, owing to a compact char matrix (i.e., negligible porosity). However, during char gasification, steam renders the char less compact by expanding and/or creating new pores in the char. As a result, intraparticle diffusion resistance decreases, thereby facilitating the evaporation of volatile salts of K and S from the char matrix. The conversion of the char is also conducive to the release of char-bound K and S, especially at 900 °C. At temperatures of >800 °C, the relative proportions of the elements released and char gasified indicate that the release of K can somewhat be decoupled from the release of S and Cl by maximizing the extent of char conversion in the gasification chamber. The results also show that, during char combustion, the proportions of the char that can be combusted and the extent of the release of the elements are influenced by the extent to which the char is gasified in the gasification chamber.

  • 3.
    Atongka Tchoffor, Placid
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi, Förbrännings- och aerosolteknik. Chalmers University of Technology, Sweden.
    Davidsson, Kent
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi, Förbrännings- och aerosolteknik.
    Thunman, Henrik
    Chalmers University of Technology, Sweden.
    Transformation and Release of Potassium, Chlorine, and Sulfur from Wheat Straw under Conditions Relevant to Dual Fluidized Bed Gasification2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 12, s. 7510-7520Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The release and transformation of potassium (K), chlorine (Cl), and sulfur (S) from biomass during thermochemical conversion processes may lead to problems, such as the corrosion and fouling of heat transfer surfaces, agglomeration of bed material, and the poisoning of catalysts used in the downstream processes of gasifiers. To predict and to mitigate effectively these problems, information regarding the quantity and mechanism of the release of these elements under relevant operating conditions is required. In the present work, the release of K, Cl, and S from wheat straw under conditions relevant to dual fluidized bed gasification were quantified in a laboratory-scale bubbling fluidized bed reactor. During the pyrolysis step, the bed temperature ranged from 550 to 900 C, while the residence time for the fuel in the reactor was fixed at 3 min. The char samples obtained from the pyrolysis step were partially combusted at the same temperature at which they were produced for an additional 3 min. The fractions of the elements released from the fuel were quantified by chemical analysis of the char/residual ash obtained in each experiment and a mass balance across the system. Overall, 75%-62% of the Cl, 59%-67% of the S, and 14%-31% of the K in the virgin wheat straw were released during pyrolysis conducted within the investigated temperature range. The char obtained from the pyrolysis process contained significantly higher amounts of K, Cl, and S than the virgin fuel. Furthermore, the ash content of the char was about 5-fold higher than that of the virgin fuel. This suggests that at combustion-relevant temperatures, complete combustion of the char is more likely to result in severe ash-related problems than combustion of the virgin fuel. Partial combustion of the char resulted in additional release of K, Cl, and S. In addition to the experimental results, the transformation and release of the elements during this process are discussed with the aid of chemical thermodynamic equilibrium modeling and leaching.

  • 4.
    Bergvall, Niklas
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Molinder, Roger
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Johansson, Ann-Christine
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Sandström, Linda
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Continuous Slurry Hydrocracking of Biobased Fast Pyrolysis Oil2021Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 35, nr 3, s. 2303-2312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Co-refining of fast pyrolysis bio-oil together with fossil oil in existing refinery infrastructure is an attractive and cost-efficient route to conversion of lignocellulosic biomass to transportation fuel. However, due to large differences in properties between the two oils, special notice is needed to reduce process-related issues. Here, fast pyrolysis bio-oil produced from lignocellulosic biomass was co-refined with vacuum gas oil at a 20:80 weight ratio in continuous operation in a pilot-scale slurry hydrocracker in order to investigate the impact of process parameters on product quality and process performance. Mass balances together with product characterization were used to investigate product yields, product composition, and hydrodeoxygenation. Best conversion and hydrodeoxygenation of the fast pyrolysis bio-oil was achieved using an unsupported catalyst loading of 900 ppm Mo with either a low temperature (410 °C) and long residence time (2 h) or higher temperature (435 °C) and shorter residence time (1 h). These settings resulted in about 94% hydrodeoxygenation but also led to highest yield of biogenic carbon to gas phase (40-43 wt %) and lowest yield of biogenic carbon to oil fractions (53-56 wt %) as well as the water fraction (3-5 wt %). Successfully, coke yield remained low at around 0.07-0.10 wt % for all performed runs, which was comparable to the insoluble particle content in the feed due to the presence of particles in the untreated fast pyrolysis bio-oil. Co-processing pyrolysis oil with fossil oil in a slurry hydrocracker seems to be a robust process with regard to coke formation, which should lead to reduced plugging issues compared to fixed bed hydrotreaters. Although this study gives a brief understanding of the effect of process parameters on the processing of fast pyrolysis bio-oil, further research is required to find optimal process parameters and to fully comprehend the possibilities and limitations for production of transportation fuels from fast pyrolysis bio-oil using this technology.

  • 5.
    Bergvall, Niklas
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Sandström, Linda
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Cheah, Y. W.
    Chalmers University of Technology, Sweden.
    Öhrman, Olov
    Preem Ab, Sweden.
    Slurry Hydroconversion of Solid Kraft Lignin to Liquid Products Using Molybdenum- and Iron-Based Catalysts2022Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 36, nr 17, s. 10226-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Kraft lignin is an abundantly available and largely underutilized renewable material with potential for production of biobased fuels and chemicals. This study reports the results of a series of slurry hydroprocessing experiments with the aim of converting solid Kraft lignin to liquid products suitable for downstream refining in more conventional reactors. Experiments reported in this study were conducted by feeding a lignin slurry to an already hot, liquid-filled reactor to provide momentaneous heating of the lignin to the reaction temperature. This modified batch procedure provided superior results compared to the regular batch experiments, likely since unwanted repolymerization and condensation reactions of the lignin during the heating phase was avoided, and was therefore used for most of the experiments reported. Experiments were performed using both an unsupported Mo-sulfide catalyst and Fe-based catalysts (bauxite and hematite) at varied reaction temperatures, pressures, and catalyst loadings. The use of Mo-sulfide (0.1% Mo of the entire feed mass) at 425 °C and 50 bar resulted in complete conversion of the Kraft lignin to nonsolid products. Very high conversions (>95%) could also be achieved with both sulfided bauxite or hematite at the same temperature and pressure, but this required much higher catalyst loadings (6.25% bauxite or 4.3% hematite of the total feed mass), and around 99% conversion could be achieved at higher temperatures but at the expense of much higher gas yields. Although requiring much higher loadings, the results in this study suggest that comparatively nonexpensive Fe-based catalysts may be an attractive alternative for a slurry-based process aimed at the hydroconversion of solid lignin to liquid products. Possible implementation strategies for a slurry-based hydroconversion process are proposed and discussed. © 2022 The Authors.

    Fulltekst (pdf)
    fulltext
  • 6.
    Bergvall, Niklas
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Sandström, Linda
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Weiland, Fredrik
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Öhrman, Olov G. W.
    Preem AB, Sweden.
    Corefining of Fast Pyrolysis Bio-Oil with Vacuum Residue and Vacuum Gas Oil in a Continuous Slurry Hydrocracking Process2020Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 7, s. 8452-8465Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Integration of renewable raw materials in existing refineries is most likely the shortest way for the successful, large-scale introduction of biofuels in the transport sector in the short term and medium term. One possible renewable raw material for this application is fast pyrolysis bio-oil (FPBO), which in this study has been coprocessed (at 0 and 20 wt %) with vacuum residue (VR, 50 wt %) and vacuum gas oil (VGO, balance) in a continuous, as well as a semibatch, slurry hydrocracking process. Experiments both with and without FPBO were performed at 450°C and 150 bar with a continuous hydrogen flow through the reactor. Oil-soluble molybdenum hexacarbonyl and molybdenum 2-ethylhexanoate were used as catalyst precursors, to be sulfided in situ. The continuous trials resulted in reactor walls completely free of coking, and they resulted in a low overall coke yield (about 1 wt %). The hydrodeoxygenation reached almost 92%, and the total acid number was reduced by nearly 99% in the FPBO experiment A mass balance of the renewable carbon from FPBO, based on the performed experiments, showed that the fossil CO2 emissions can be lowered by 1.35 kg per kg of processed FPBO if all renewable carbon in gaseous and liquid hydrocarbons is used to replace its fossil counterparts, and all methane formed from FPBO is used to produce hydrogen. Semibatch experiments gave less successful results when upgrading FPBO-containing feedstock, with a high coke yield (8 wt %) as well as a high gas yield (24 wt %). The results of this study demonstrate that FPBO can be successfully coprocessed with heavy fossil oils in a continuous slurry hydrocracking process without neg. affecting the processing of the fossil components of the feed and that a continuous process is preferred over batch or semibatch processes when studying coprocessing of bio-oils.

  • 7. Boman, Christoffer
    et al.
    Pettersson, Esbjörn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Westerholm, R.
    Bostrom, D.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Stove performance and emission characteristics in residential wood log and pellet combustion: Part 1: Pellet stoves2011Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, nr 1, s. 307-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Stove performance, characteristics, and quantities of gaseous and particulate emissions were determined for two different pellet stoves, varying fuel load, pellet diameter, and chimney draft. This approach aimed at covering variations in emissions from stoves in use today. The extensive measurement campaign included CO, NOx, organic gaseous carbon, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions, and inorganic composition. At high load, most emissions were similar. For stove B, operating at high residual oxygen and solely with primary air, the emissions of PMtot and particle numbers were higher while the particles were smaller. Lowering the fuel load, the emissions of CO and hydrocarbons increased dramatically for stove A, which operated continuously also at lower fuel loads. On the other hand for stove B, which had intermittent operation at lower fuel loads, the emissions of hydrocarbons increased only slightly lowering the fuel load, while CO emissions increased sharply, due to high emissions at the end of the combustion cycle. Beside methane, dominating VOCs were ethene, acetylene, and benzene and the emissions of VOC varied in the range 1.1-42 mg/MJfuel. PAH emissions (2-340 μg/MJfuel) were generally dominated by phenanthrene, fluoranthene and pyrene. The PM tot values (15-45 mg/MJfuel) were in all cases dominated by fine particles with mass median diameters in the range 100-200 nm, peak mobility diameters of 50-85 nm, and number concentrations in the range 4 × 1013 to 3 × 1014 particles/MJfuel. During high load conditions, the particulate matter was totally dominated by inorganic particles at 15-25 mg/MJfuel consisting of potassium, sodium, sulfur, and chlorine, in the form of K2SO4, K 3Na(SO4)2, and KCl. The study shows that differences in operation and modulation principles for the tested pellet stoves, relevant for appliances in use today, will affect the performance and emissions significantly, although with lower scattering in the present study compared to compiled literature data. © 2011 American Chemical Society.

  • 8. Brus, E.
    et al.
    Ohman, M.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Bostrom, D.
    Hedman, Henry
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Eklund, A.
    Bed agglomeration characteristics of biomass fuels using blast-furnace slag as bed material2004Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 18, nr 4, s. 1187-1193Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Agglomeration of bed material may cause severe operating problems during fluidized bed combustion. The attack or coating layers that are formed on the bed particles during combustion play an important role in the agglomeration process. To reduce bed agglomeration tendencies, alternative bed materials may be used. In this paper, bed agglomeration characteristics during the combustion of biomass fuels using a relatively new bed material (iron blast-furnace slag) as well as ordinary quartz sand were determined. Controlled agglomeration tests lasting 40 h, using five representative biomass fuels (bark, olive residue, peat, straw, and reed canary grass) were conducted in a bench-scale fluidized bed. The bed materials and agglomerates were analyzed using SEM/EDS and X-ray diffraction. Chemical equilibrium calculations were performed to interpret the experimental findings. The results showed that blast-furnace slag had a lower tendency to agglomerate than quartz sand for most of the fuels. The quartz particles showed an inner attack layer more often than did the blast-furnace slag. The blast-furnace slag had a lower tendency to react with elements from the fuel. The outer coating layer had similar characteristics and thickness for both bed materials when the same fuel was combusted. However, the inner attack layer thickness was larger for quartz particles. SEM/EDS analyses of the agglomerates showed that the inner Ca-K-silicate-rich attack layer was responsible for the agglomeration of quartz sand. The composition of blast-furnace slag agglomerate was similar to the outer coating layer. Chemical equilibrium calculations showed that the original composition of the blast-furnace slag was close to the equilibrium composition, and hence there was no major driving force for reactions between that bed material and K and Ca from the fuel. The homogeneous silica-rich attack layer (with a low melting temperature) was not formed to the same extent for blast-furnace slag, thus explaining the lower bed agglomeration tendency. © 2004 American Chemical Society.

  • 9.
    Bulsink, Philip
    et al.
    Natural Resources Canada, Canada.
    De Miguel Mercader, Ferran
    Scion, New Zealand.
    Sandström, Linda
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Van De Beld, Bert
    BTG Biomass Technology Group BV, Netherlands.
    Preto, Fernando
    Natural Resources Canada, Canada.
    Zacher, Alan H.
    Pacific Northwest National Laboratory, USA.
    Oasmaa, Anja
    VTT Technical Research Centre of Finland, Finland.
    Dahmen, Nicolaus
    Karlsruhe Institute of Technology, Germany.
    Funke, Axel
    Karlsruhe Institute of Technology, Germany.
    Bronson, Benjamin
    Natural Resources Canada, Canada.
    Results of the International Energy Agency Bioenergy Round Robin on the Analysis of Heteroatoms in Biomass Liquefaction Oils2020Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A round robin study evaluating the analysis of biomass liquefaction oils (BLOs) from fast pyrolysis and hydrothermal liquefaction (HTL) was performed, receiving data from 14 laboratories in seven countries in order to assess the current status of analytical techniques for the determination of nitrogen, sulfur, and chlorine content in BLOs and to evaluate potential differences in origin (i.e., fast pyrolysis versus HTL). The BLOs were produced from a range of feedstocks including pine, mixed softwoods, forest residues, microalgae, miscanthus, and wheat straw to cover a variety in nitrogen, sulfur, and chlorine content and speciation. Nine samples were distributed, comprised of eight separate BLOs and one blind duplicate produced by five producers. The samples were analyzed for water, carbon, hydrogen, nitrogen, sulfur, and chlorine content. No analytical test method was mandated; laboratories were encouraged to utilize whichever method they determined would be most applicable, relying on the existing body of BLO literature as a guide. The results of this round robin study are presented in this paper. The results of the carbon, hydrogen, and water measurements as reference analyses had relative standard deviations (2.9, 3.5, and 5.6%, respectively) that were comparable to those found in past round robin studies on fast pyrolysis bio-oil. The analysis of nitrogen, sulfur, and chlorine showed higher levels of variability. Laboratories mostly chose the same method for water, carbon, hydrogen, and nitrogen determination, whereas there were a variety of methods chosen for sulfur and chlorine determination. The results suggest that specific analytical methods for the determination of nitrogen, sulfur, and chlorine should be further refined to ensure reproducible and accurate results for BLO analysis due to their importance in emissions, material selection, and catalyst activity.

  • 10.
    Carlsson, Per
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Iisa, K
    Gebart, Rikard
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Computational fluid dynamics simulations of raw gas composition from a black liquor Gasifier: Comparison with experiments2011Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, nr 9, s. 4122-4128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pressurized entrained flow high temperature black liquor gasification can be used as a complement or a substitute to the Tomlinson boiler used in the chemical recovery process at kraft pulp mills. The technology has been proven on the development scale, but there are still no full scale plants. This work is intended to aid in the development by providing computational tools that can be used in scale up of the existing technology. In this work, an existing computational fluid dynamics (CFD) model describing the gasification reactor is refined. First, one-dimensional (1D) plug flow reactor calculations with a comprehensive reaction mechanism are performed to judge the validity of the global homogeneous reaction mechanism used in the CFD simulations in the temperature range considered. On the basis of the results from the comparison, an extinction temperature modification of the steam-methane reforming reaction was introduced in the CFD model. An extinction temperature of 1400 K was determined to give the best overall agreement between the two models. Next, the results from simulations of the flow in a 3 MW pilot gasifier with the updated CFD model are compared to experimental results in which pressure, oxygen to black liquor equivalence ratio, and residence time have been varied. The results show that the updated CFD model can predict the main gas components (H 2, CO, CO2) within an absolute error of 2.5 mol %. CH 4 can be predicted within an absolute error of 1 mol %, and most of the trends when process conditions are varied are captured by the model. © 2011 American Chemical Society.

  • 11.
    Carlsson, Per
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center. SINTEF Energy Research AS, Norway.
    Ma, Charlie
    Luleå University of Technology, Sweden.
    Molinder, Roger
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Weiland, Fredrik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center. Luleå University of Technology, Sweden.
    Wiinikka, Henrik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center. Luleå University of Technology, Sweden.
    Öhman, Marcus
    Luleå University of Technology, Sweden.
    Öhrman, Olov .G.W
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Slag formation during oxygen-blown entrained-flow gasification of stem wood2014Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, nr 11, s. 6941-6952Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Stem wood powders were fired in a mullite-lined pilot-scale oxygen-blown pressurized entrained-flow gasifier. During repeated campaigns involving increases in fuel load and process temperature, slag formations that eventuated in the blockage of the gasifier outlet were observed. These slags were retrieved for visual and chemical characterization. It was found that the slags had very high contents of Al and, in particular, high Al/Si ratios that suggest likely dissolution of the mullite-based refractory of the gasifier lining due to interactions with the fuel ash. Possible causes for the slag formation and behavior are proposed, and practical implications for the design of future stem wood entrained-flow gasifiers are also discussed.

  • 12.
    Cea, B.
    et al.
    Institut National de l'Environnement Industriel et des Risques, France.
    Fraboulet, I.
    Institut National de l'Environnement Industriel et des Risques, France.
    Feuger, O.
    Institut National de l'Environnement Industriel et des Risques, France.
    Hugony, F.
    ENEA, Italy.
    Morreale, C.
    Innovhub Stazioni Sperimentali per l'Industria S.r.l, Italy.
    Migliavacca, G.
    Innovhub Stazioni Sperimentali per l'Industria S.r.l, Italy.
    Andersen, J. S.
    DTI Danish Technological Institute, Denmark.
    Warming-Jespersen, M. G.
    DTI Danish Technological Institute, Denmark.
    Bäckström, Daniel
    RISE Research Institutes of Sweden.
    Janhäll, Sara
    RISE Research Institutes of Sweden, Samhällsbyggnad, Energi och resurser.
    Development and Evaluation of an Innovative Method Based on Dilution to Sample Solid and Condensable Fractions of Particles Emitted by Residential Wood Combustion2021Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 35, nr 23, s. 19705-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An innovative and simple method based on dilution, named as the dilution chamber (DC), allowing the measurement of solid and condensable fractions of particulate matter emitted by residential wood combustion appliances has been developed, and its performances have been evaluated. The DC method was then tested by five European institutes (Ineris, ISSI/ENEA, DTI, and RISE) on advanced residential wood log/pellet stoves, under nominal output and low output combustion conditions and using different fuel types. The aim of the study was to evaluate the capability of the DC method to collect the condensable fraction. The DC method was compared with another manual method used to collect the solid and condensable fractions at the same time, the dilution tunnel (DT), on four sampling platforms. A third method, a combining heated filter and impinger filled in with isopropanol collection (SPC-IPA), was also used by Ineris only for comparison with the DC method. PM measurements based on the DC method globally showed a linear correlation with PM measurements based on DT (R2 ranged between 0.81 and 0.99, p < 0.05) specifically for the residential wood stoves under low output conditions when the condensable fraction contributes the most. An analysis and quantification of PAHs related to the total mass of PM of samples taken by the DC method and performed by ENEA/ISSI showed that it produces a condensation effect of semivolatile species comparable or even greater than the DT method. PM emission factors calculated from PM measurements based on the DC method were (i) about 2- to 20-fold higher for the residential wood stoves (EF ranged between 201 to 2420 g GJ-1) compared to those obtained for the residential pellet stoves (EF ranged between 108 to 556 g GJ-1) and (ii) of the same magnitude of PM emission factors from the literature or the EMEP/EEA air pollutant emission inventory guidebook.

  • 13.
    Elliott, Douglas C.
    et al.
    Pacific Northwest National Laboratory, USA.
    Meier, Dietrich
    Thünen Institute of Wood Research, Germany.
    Oasmaa, Anja
    VTT Technical Research Center of Finland, Finland.
    van De Beld, Bert
    BTG Biomass Technology Group BV, The Netherlands.
    Bridgwater, Anthony V.
    Aston University, UK.
    Marklund, Magnus
    RISE - Research Institutes of Sweden, Bioekonomi, ETC Energy Technology Center.
    Results of the International Energy Agency Round Robin on Fast Pyrolysis Bio-oil Production2017Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, nr 5, s. 5111-5119Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An international round robin study of the production of fast pyrolysis bio-oil was undertaken. A total of 15 institutions in six countries contributed. Three biomass samples were distributed to the laboratories for processing in fast pyrolysis reactors. Samples of the bio-oil produced were transported to a central analytical laboratory for analysis. The round robin was focused on validating the pyrolysis community understanding of production of fast pyrolysis bio-oil by providing a common feedstock for bio-oil preparation. The round robin included: distribution of three feedstock samples, hybrid poplar, wheat straw, and a blend of lignocellulosic biomasses, from a common source to each participating laboratory, preparation of fast pyrolysis bio-oil in each laboratory with the three feedstocks provided, and return of the three bio-oil products (minimum of 500 mL) with operational description to a central analytical laboratory for bio-oil property determination. The analyses of interest were CHN, S, trace element analysis, water, ash, solids, pyrolytic lignin, density, viscosity, carboxylic acid number, and accelerated aging of bio-oil. In addition, an effort was made to compare the bio-oil components to the products of analytical pyrolysis through gas chromatography/mass spectrometry (GC/MS) analysis. The results showed that clear differences can occur in fast pyrolysis bio-oil properties by applying different process configurations and reactor designs in small scale. The comparison to the analytical pyrolysis method suggested that pyrolysis (Py)-GC/MS could serve as a rapid qualitative screening method for bio-oil composition when produced in small-scale fluid-bed reactors. Gel permeation chromatography was also applied to determine molecular weight information. Furthermore, hot vapor filtration generally resulted in the most favorable bio-oil product, with respect to water, solids, viscosity, and carboxylic acid number. These results can be helpful in understanding the variation in bio-oil production methods and their effects on bio-oil product composition.

  • 14. Eriksson, G.
    et al.
    Hedman, Henry
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Bostrom, D.
    Pettersson, Esbjörn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Backman, Rainier
    Ohman, M.
    Combustion characterization of rapeseed meal and possible combustion applications2009Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, nr 8, s. 3990-3939Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A future shortage of biomass fuel can be foreseen. The production of rapeseed oil for a number of purposesis increasing, among others, for biodiesel production. A yproduct from the oil extraction process is rapeseed meal (RM), presently used as animal feed. Further increases in supply will make fuel use an option. Several energy companies have shown interest but have been cautious because of the scarcity of data on fuel properties, which led to the present study. Combustion-relevant properties of RM from several producers have been determined. The volatile fraction (74 ± .06%wt ds) is comparable to wood; the moisture content (6.2-11.8%wt) is low; and the ash content (7.41 ± 0.286%wt ds) is high compared to most other biomass fuels. The lower heating value is 18.2 ± 0.3 MJ/kg (dry basis). In comparison to other biomass fuels, the chlorine content is low (0.02-0.05%wt ds) and the sulfur content is high (0.67-0.74%wt ds). RM has high contents of nitrogen (5.0-6.4%wt ds), phosphorus (1.12-1.23%wt ds), and potassium (1.2-1.4%wt ds). Fuel-specific combustion properties of typical RM were determined through combustion tests, with an emphasis on gas emissions, ash formation, and potential ash-related operational problems. Softwood bark was chosen as a suitable and representative co-combustion (woody) fuel. RM was added to the bark at two levels: 10 and 30%wt ds. These mixtures were pelletized, and so was RM without bark (for durability mixed with cutter shavings, contributing 1%wt of the ash). Each of these fuels was combusted in a 5 kWfluidized bed and an underfed pellet burner (to simulate grate combustion). Pure RM was combusted in a powder burner. Emissions of NO and SO2 were high for all combustion tests, requiring applications with flue gas cleaning, economically viable only at large scale. Emissions of HCl were relatively low. Temperatures for initial bed agglomeration in the fluidized-bed tests were high for RM compared to many other agricultural fuels, thereby indicating that RM could be an attractive fuel from a bed agglomeration point of view. The results of grate combustion suggest that slagging is not likely to be severe for RM, pure or mixed with other fuels. Fine-mode particles from fluidized-bed combustion and grate combustion mainly contained sulfates of potassium, suggesting that the risk of problems caused by deposit formation should be moderate. The chlorine concentration of the particles was reduced when RM was added to bark, potentially lowering the risk of high-temperature corrosion. Particle emissions from powder combustion of RM were 17 times higher than for wood powder, and the fine-mode fraction contained mainly K-phosphates known to cause deposits, suggesting that powder combustion of RM should be used with caution. A possible use of RM is as a sulfur-containing additive to biomass fuels rich in Cl and K for avoiding ash-related operational problems in fluidized beds and grate combustors originated from high KCl concentrations in the flue gases © 2009 American Chemical Society.

  • 15.
    Furusjö, Erik
    et al.
    Luleå University of Technology, Sweden.
    Pettersson, Esbjörn
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, ETC Energy Technology Center.
    Mixing of Fast Pyrolysis Oil and Black Liquor: Preparing an Improved Gasification Feedstock2016Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, nr 12, s. 10575-10582Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Co-gasification of fast pyrolysis oil and black liquor can be used to increase the size and improve profitability of pulp mill integrated biorefineries. The acids present in pyrolysis oil limit the amount that can be mixed into black liquor without causing precipitation of the black liquor dissolved lignin. This work shows that a simple model based on pyrolysis oil total acid number, including weak phenolic acids, can be used to predict the maximum pyrolysis oil fraction in blends. The maximum oil fraction is 20-25% for typical pyrolysis oil but can be increased up to at least 50% mass, corresponding to 70% energy, by addition of base. Thermodynamic equilibrium calculations are used to understand the effects of blend composition, including any added base, on the performance of a commercial scale gasification process. A substantial increase in overall gasification efficiency is observed with increasing pyrolysis oil fraction.

    Fulltekst (pdf)
    fulltext
  • 16.
    Gall, Dan
    et al.
    University of Gothenburg, Sweden.
    Pushp, Mohit
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Safety.
    Davidsson, Kent O.
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Energi och cirkulär ekonomi.
    Pettersson, Jan B. C.
    University of Gothenburg, Sweden.
    Online Measurements of Alkali and Heavy Tar Components in Biomass Gasification2017Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, nr 8, s. 8152-8161Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tar and alkali metal compounds are released during biomass gasification and have a major impact on the operation and performance of gasification processes. Herein we describe a novel method for characterization of alkali and heavy tar compounds in the hot product gas formed during gasification. Gas is continuously extracted, cooled and diluted, which results in condensation of tar and alkali into aerosol particles. The thermal stability of these particles is subsequently evaluated using a volatility tandem differential mobility analyzer (VTDMA) method. The technique is adopted from aerosol science where it is frequently used to characterize the thermal properties of aerosol particles. Laboratory studies show that pure and mixed alkali salts and organic compounds evaporate in well-defined temperature ranges, which can be used to determine the chemical composition of particles. The performance of the VTDMA is demonstrated at a 4 MWth dual fluidized bed gasifier using two different types of online sampling systems. Alkali metal compounds and a wide distribution of heavy tar components with boiling points above 400°C are observed in the product gas. Implications and potential further improvements of the technique are discussed.

  • 17.
    Gall, Dan
    et al.
    University of Gothenburg, Sweden.
    Pushp, Mohit
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Safety.
    Larsson, Anton
    Göteborg Energi AB, Sweden.
    Davidsson, Kent
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Energi och cirkulär ekonomi.
    Pettersson, Jan B. C.
    University of Gothenburg, Sweden.
    Online Measurements of Alkali Metals during Start-up and Operation of an Industrial-Scale Biomass Gasification Plant2018Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, nr 1, s. 532-541Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Alkali metal compounds may have positive influences on biomass gasification by affecting char reactivity and tar reforming but may also disturb the process by formation of deposits and agglomerates. We herein present results from online measurements of alkali compounds and particle concentrations in a dual fluidized bed gasifier with an input of 32 MWth. A surface ionization detector was used to measure alkali concentrations in the product gas, and aerosol particle measurement techniques were employed to study concentrations and properties of condensable components in the gas. Measurements were performed during start-up and steady-state operation of the gasifier. The alkali concentration increased to approximately 200 mg m-3 when fuel was fed to the gasifier and continued to rise during activation of the olivine bed by addition of potassium carbonate, while the alkali concentration was in the range from 20 to 60 mg m-3 during steady-state operation. Addition of fresh bed material and recirculated ash had noticeable effects on the observed alkali concentrations, and K2CO3 additions to improve tar chemistry resulted in increased levels of alkali in the product gas. Addition of elemental sulfur led to reduced concentrations of CH4 and heavy tars, while no clear influence on the alkali concentration was observed. The study shows that alkali concentrations are high in the product gas, which has implications for the fluidized bed process, tar chemistry, and operation of downstream components including coolers, filters, and catalytically active materials used for product gas reforming.

  • 18.
    Gogolev, Ivan
    et al.
    Chalmers University of Technology, Sweden.
    Soleimanisalim, Amir H
    Chalmers University of Technology, Sweden.
    Mei, Daofeng
    Chalmers University of Technology, Sweden.
    Lyngfelt, Anders
    Chalmers University of Technology, Sweden.
    Effects of Temperature, Operation Mode, and Steam Concentration on Alkali Release in Chemical Looping Conversion of Biomass-Experimental Investigation in a 10 kWthPilot2022Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 36, nr 17, s. 9551-9570Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Alkali release was studied in a 10 kWthchemical looping pilot operated with a Linz-Donawitz (LD) slag oxygen carrier (OC) and three biomass fuels. Experiments were performed at three temperatures and in three operation modes: chemical looping combustion (CLC), chemical looping gasification (CLG), and oxygen-carrier-aided combustion (OCAC). Gas-phase alkali release was measured with a surface ionization detector (SID). Fuel reactor (FR) gas-phase alkali emissions increased with the temperature. This occurred as a result of increased evaporation of KCl and enhanced decomposition of alkali salts during char conversion. Air reactor (AR) alkali emissions were lower than in the FR and independent of the operating temperature. In comparison of operating modes, CLC and CLG modes resulted in similar gas-phase alkali emissions due to the similar extent of char conversion. In contrast, operation of the reactor system in OCAC mode resulted in significantly lower levels of gas-phase alkalis. The difference in alkali emission was attributed to the steam-rich atmosphere of CLC. The effect of steam was further investigated in CLC and OCAC tests. Lowering steam concentrations in CLC operation resulted in lower gas-phase alkali emissions, while introducing steam to the FR during OCAC operation resulted in higher alkali emissions. It was concluded that steam likely enhances gas-phase K release through a reaction of K2CO3within the fuel char with steam to produce KOH(g). Solid sampling and analysis for K content was used along with SID measurements to develop a K mass balance for the reactor system. Mass balance results for the straw pellet fuel tests showed that LD slag OC absorbs approximately 15-51% of fuel K, 2.2% of fuel K is released to the gas phase, and up to 3.4% of fuel K is captured in the AR fly ash. The residual 40-80% of fuel K was determined to leave the FR as K-rich fly ash. 

  • 19.
    Haugen, N. E. L.
    et al.
    SINTEF Energy Research, Norway.
    Bugge, M.
    SINTEF Energy Research, Norway.
    Mack, A.
    Stuttgart University, Germany.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet. NTNU, Norway.
    Skreiberg, Ø.
    Bed Model for Grate-Fired Furnaces: Computational Fluid Dynamics Modeling and Comparison to Experiments2022Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 36, nr 11, s. 5852-5867Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A detailed but still central processing unit (CPU)-efficient bed model for grate-fired combustion of biomass and waste is developed. Simulations of wood chip combustion are performed, and the results are compared to experiments. The so-called layer model is used to track the development of the thermally thick representative fuel particles in the bed. As an efficient way of handling a large number of physical fuel particles, each representative fuel particle represents a number of physical particles with the exact same properties. The motion of the fuel bed is handled in a way that requires negligible CPU power, while for wastes and other fuels with less defined shapes and structure, it still yields accuracy similar to the much more CPU-intensive collision-based models. In this work, the bed model is coupled with ANSYS Fluent and used to simulate one of the test campaigns performed at the grate-fired pilot unit at the University of Stuttgart. It is found that for the test campaign of interest, burning wood chips, the fuel bed is ignited from below, and it is explained how this is due to the thermal properties of the grate and how important the numerical handling of the grate is for an accurate prediction of the bed behavior.

  • 20.
    Heen Blindheim, Fredrik
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Ruwoldt, Jost
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Lignin-Based Wax Inhibitors2024Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 38, nr 4, s. 2898-2909Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article tested a novel concept for synthesizing green wax inhibitors. Four technical lignins were reacted with stearoyl chloride to produce esterified C18 esterified lignin. The effect of the reaction on the lignin molecular weight, characteristic FTIR spectra, and thermal degradation was surveyed. In addition, wax inhibition testing was performed by rheology on model waxy oils. The grafting reactions increased the mass-average molecular weight of the lignin and in some cases also the polydispersity index. FTIR analysis confirmed the success of esterification reactions as the O-H stretching band decreased, whereas the C-H and C═O stretching bands significantly increased. The thermal degradation was further found to occur at temperatures above 170 °C, indicating that the lignin wax inhibitors were thermally stable enough for crude oil production. The effect on waxy gelation was varied, showing that the low molecular weight waxes benefited more than the high molecular ones. A gelation point reduction of up to 6 °C was found after lignin addition. After the wax type, wax concentration, lignin concentration, and lignin type were varied, it was found that C18 esterified Kraft lignin exhibited the most beneficial effect. The results from viscometry agreed with the observations from the rheometric gelation point. Cross-polarized microscopy was used to map the effect on the wax crystal morphology. A difference was found only in the case of one esterified Kraft lignin, which yielded smaller and more finely dispersed wax crystals. In conclusion, a new wax inhibitor was synthesized by reacting technical lignin with stearoyl chloride. This lignin showed wax inhibitor activity in some of the tested cases. At this point, the length of the pendant alkyl chains (C18) is likely a limiting factor. However, this study attributes the potential for a new concept to synthesize green wax inhibitors. 

    Fulltekst (pdf)
    fulltext
  • 21.
    Janosik, Tomasz
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemiska processer och läkemedel.
    Nilsson, Anders N
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemisk och farmaceutisk toxikologi.
    Hällgren, Anne-Charlotte
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemiska processer och läkemedel.
    Hedberg, Martin
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemiska processer och läkemedel.
    Bernlind, Christian
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemiska processer och läkemedel.
    Rådberg, Henrik
    Preem AB, Sweden.
    Ahlsén, Lovisa
    Preem AB, Sweden.
    Arora, Prakhar
    Preem AB, Sweden.
    Öhrman, Olov
    Preem AB, Sweden.
    Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater2022Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 36, nr 15, s. 8274-8287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In several countries forest-based biofuels are being developed and to some extent also deployed. Fast pyrolysis bio-oil produced from, for example, sawdust, has now been coprocessed in fluid catalytic cracking refinery units in a number of commercial trials. However, this application is limited to about 10% of the total feed, and coprocessing in conventional fixed bed hydrotreaters is necessary to reach the high potential with this feedstock. Feeding and upgrading of fast pyrolysis bio-oil in a fixed bed reactor configuration is still problematic due to the inherent bio-oil properties. Stabilization of reactive compounds in fast pyrolysis bio-oil and mild hydrotreatment in a separate refining unit prior to refinery integration has therefore been developed the past decade. Another approach, presented here, involves complete dewatering of fast pyrolysis bio-oil by azeotropic distillation using mesityl oxide as the solvent, followed by conversion of the abundant hydroxyl compounds via mixed anhydride esterification methodology using an external source of mixed carboxylic acids of different chain lengths originating from renewable tall oil fatty acids, providing a lipophilic feed component. Dewatering and derivatizing were carried out in reactors up to 50 dm3 with a mass ratio of fast pyrolysis bio-oil to tall oil fatty acid of 10:13. The produced lipophilic oils were miscible with a petroleum light gas oil fraction and exhibited superior stability even after accelerated aging at elevated temperature (80 °C). The derivatized oils were thus mixed with light gas oil, with a proportion of 30 wt % derivatized oil in final blends and hydrotreated continuously in pilot fixed bed reactors for 14 days at 4 operating conditions without plugging or excessive exotherms. The test conditions were varied; the reactor pressure was either 55 or 80 bar, temperature 380 or 400 °C, and liquid hourly space velocity either 1 or 2 h-1 during the hydrotreatment. Successful hydrodeoxygenation and desulfurization were accomplished, whereas an increasing nitrogen concentration could be observed in the liquid products with the particular catalyst and reaction conditions employed. The observed hydrogen consumption (15-20 g/kg feed) was compared with the stoichiometric consumption for direct deoxygenation and with typical consumptions for industrial hydrotreated vegetable oil processing. The measured biogenic carbon content in hydrotreated liquid products (26.7%) agreed extremely well with the calculated biogenic carbon content in the hydrotreating feed (26.6%) that consisted of the blend of derivatized oil and petroleum light gas oil. The overall results are very promising since simple unit operations can be used to produce derivatized fast pyrolysis bio-oils that do not need additional standalone hydrotreating units but can be coprocessed in existing ones

  • 22.
    Jones, Frida
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi, Förbrännings- och aerosolteknik. Åbo Akademi Process Chemistry Centre, Finland.
    Tran, Honghi
    University of Toronto, Canada.
    Lindberg, Daniel K.
    Åbo Akademi Process Chemistry Centre, Finland.
    Zhao, Liming
    University of Toronto, Canada.
    Hupa, Mikko
    Åbo Akademi Process Chemistry Centre, Finland.
    Thermal Stability of Zinc Compounds2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 10, s. 5663-5669Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zn and Cl have been found in deposits in municipal solid waste (MSW) boilers and industrial boilers. This leads to the general belief that ZnCl 2 may play a role in corrosion of heat-transfer tubes, owing to its low melting temperature and high corrosivity. In this study, the thermal stability of the compounds ZnCl2, ZnSO4, and ZnO as well as mixtures of ZnCl2 and NaCl/KCl was investigated by means of thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). The reactions of the Zn compounds with SO2/SO3 and HCl were also investigated. The results obtained show that ZnCl2 melts at 320 C. Above 400 C, ZnCl2 vaporizes and is partly oxidized to ZnO. ZnSO4 is stable up to 680 C, at which it decomposes and, subsequently, forms ZnO above 900 C. ZnO is stable at a much higher temperatures but can be chlorinated to ZnCl2 in the presence of HCl at temperatures around 300 C. In the presence of a large amount of NaCl/KCl, which is typically the case in actual boilers, ZnCl2 reacts with NaCl/KCl to form 2NaCl·ZnCl2 and 2KCl·ZnCl2, respectively. These compounds melt at temperatures lower than NaCl and KCl but higher than ZnCl2. The findings show the significance of understanding the thermal stability of various zinc compounds, how they interact with one another, and whether they react with alkali chlorides and other compounds in the deposits to assess the role of Zn in deposit formation and corrosion in boilers burning Zn-containing fuels.

  • 23.
    Jonsson, Carrie Y.C.
    et al.
    Luleå University of Technology, Sweden.
    Stjernberg, Jesper
    Luleå University of Technology, Sweden.
    Wiinikka, Henrik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center. Luleå University of Technology, Sweden.
    Lindblom, Bo
    Luleå University of Technology, Sweden; LKAB, Sweden.
    Boström, Dan
    Umeå University, Sweden.
    Öhman, Marcus
    Luleå University of Technology, Sweden.
    Deposit formation in a grate-kiln plant for iron-ore pellet production.: Part 1: Characterization of process gas particles2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 10, s. 6159-6170Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Slag formation in the grate-kiln process is a major problem for iron-ore pellet producers. It is therefore important to understand the slag formation mechanism in the grate-kiln production plant. This study initiated the investigation by in situ sampling and identifying particles in the flue gas from a full-scale 40 MW grate-kiln production plant for iron-ore pelletizing. Particles were sampled from two cases of combustion with pulverized coal and heavy fuel oil. The sampling location was at the transfer chute that was situated between the traveling grate and the rotary kiln. The particle-sampling system was set up with a water-cooled particle probe equipped with nitrogen gas dilution, cyclone, and low-pressure impactor. Sub-micrometer and fine particles were size-segregated in the impactor, while coarse particles (>6 μm) were separated with a cyclone before the impactor. Characterization of these particles was carried out with environmental scanning electron microscopy (ESEM), and the morphology of sub-micrometer particles was studied with transmission electron microscopy (TEM). The results showed that particles in the flue gas consisted principally of fragments from iron-ore pellets and secondarily of ashes from pulverized coal and heavy fuel oil combustions. Three categories of particle modes were identified: (1) sub-micrometer mode, (2) first fragmentation mode, and (3) second fragmentation mode. The sub-micrometer mode consisted of vaporized and condensed species; relatively high concentrations of Na and K were observed for both combustion cases, with higher concentrations of Cl and S from heavy fuel oil combustion but higher concentrations of Si and Fe and minor P, Ca, and Al from coal combustion. The first fragmentation mode consisted of both iron-ore pellet fines and fly ash particles; a significant increment of Fe (>65 wt %) was observed, with higher concentrations of Ca and Si during heavy fuel oil combustion but higher concentrations of Si and Al during coal combustion. The second fragmentation mode consisted almost entirely of coarse iron-ore pellet fines, predominantly of Fe (∼90 wt %). The particles in the flue gas were dominantly iron-ore fines because the second fragmentation mode contributed >96 wt % of the total mass of collected particles.

  • 24.
    Kaombe, Divina D.
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Lenes, Marianne
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Toven, Kai
    RISE., Innventia, PFI – Paper and Fiber Research Institute.
    Glomm, Wilhelm Robert
    NTNU Norwegian University of Science and Technology, Norway.
    Turbiscan as a tool for studying the phase separation tendency of pyrolysis oil2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 3, s. 1446-1452Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the main obstacles in using pyrolysis oils in heat and power applications is their instability upon storage, which leads to unacceptable quality, from the end user's point of view. Because of the opaque nature of pyrolysis oils, there are presently many challenges associated with determining their stability. Thus, techniques are needed for the characterization of the phase separation of pyrolysis oils, as well as determining the underlying mechanisms of their instability. Here, we present the application of the Turbiscan technique for the evaluation of phase separation tendency of pyrolysis oils over a period of 24 h at various temperatures, compared to the Karl Fischer method. A well-stored pyrolysis oil from poplar wood and fresh pyrolysis oil from forest residue were used for the investigation. For each of the oils, one batch was diluted with water in order to force phase separation, and a second batch was used without dilution. The study reveals that the Turbiscan technique makes it possible to study several aspects of phase separation in a single experiment; such as sedimentation, clarification, migration velocity and phase fraction. The advantages and potential limitation of the Turbiscan technique are discussed.

  • 25. Lindstrom, E.
    et al.
    Sandstrom, M.
    Bostrom, D.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Ohman, M.
    Slagging characteristics during combustion of cereal grains rich in phosphorus2007Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 21, nr 2, s. 710-717Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A residential cereal burner (20 kW) was used study the slagging characteristics of cereal grains with and without lime addition. The deposited bottom ash and slag were analyzed using X-ray diffraction (XRD), to identify the crystalline phases, and environmental scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy (ESEM/EDS), to study the morphology and elemental composition. Phase-diagram information was utilized to extract qualitative information about the behavior of cereal grain ashes under combustion conditions. Chemical equilibrium model calculations were used to interpret the experimental results. In addition, investigations of the melting behavior of the produced slags were conducted. The results showed significant differences in slagging characteristics between the fuels that were used. The slags consisted of high-temperature melting crystalline phases (calcium/magnesium potassium phosphates) and a potassium-rich phosphate melt for all cereal grains. For oat and barley, cristobalite was also identified in the slag. Furthermore, in these cases, the slags most probably contained a potassium-rich silica melt. The differences in the melting behaviors of the slags had a considerable effect on the performance of the burner. The addition of lime reduced the formation of slag for barley and totally eliminated it for rye and wheat. This occurs because lime contributes to the formation of high-temperature melting calcium potassium phosphates. © 2007 American Chemical Society.

  • 26.
    Liu, Zengjian
    et al.
    University of Science and Technology Beijing, China.
    Wang, Guangwei
    University of Science and Technology Beijing, China.
    Zhang, Jianliang
    University of Science and Technology Beijing, China.
    Lee, Jui-Yuan
    National Taipei University of Technology, Taiwan.
    Wang, Haiyang
    University of Science and Technology Beijing, China.
    Sun, Mimmin
    University of Science and Technology Beijing, China.
    Wang, Chuan
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS AB. Åbo Akademi University, Finland.
    Study on CO2 Gasification Reactivity and Structure Characteristics of Carbonaceous Materials from the Corex Furnace2018Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, nr 5, s. 6155-6166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The gasification reactivities of four pretreated carbonaceous materials from the Corex furnace, including one coal char, two metallurgical cokes, and one recycling dust, were investigated by a thermogravimetric analyzer, in which the recycling dust came mainly from two metallurgical cokes and accounted for a mass fraction of 71.3%. The physicochemical properties of the different samples were tested systematically. The results showed that the recycling dust had a gasification reactivity similar to the coal char, of which the value was higher than those of the two metallurgical cokes. The structure analysis ascertained that the main factor that affected the gasification reactivity was the carbonaceous structure. Moreover, to characterize the reactive behavior of the different samples, three nth-order typical gas-solid reaction models were employed in this study. It has been found that the random pore model was the best model. The activation energies of different chars were in the range of 181.1-202.3 kJ/mol.

  • 27.
    Ma, Charlie
    et al.
    Luleå University of Technology, Sweden.
    Weiland, Fredrik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center. Luleå University of Technology, Sweden.
    Hedman, Henry
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Boström, Dan
    Umeå University, Sweden.
    Backman, Rainier V.
    Umeå University, Sweden.
    Öhman, Marcus
    KTH Royal Institute of Technology, Sweden.
    Characterization of reactor ash deposits from pilot-scale pressurized entrained-flow gasification of woody biomass2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 11, s. 6801-6814Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pressurized entrained-flow gasification of renewable forest residues has the potential to produce high-quality syngas suitable for the synthesis of transport fuels and chemicals. The ash transformation behavior during gasification is critical to the overall production process and necessitates a level of understanding to implement appropriate control measures. Toward this end, ash deposits were collected from inside the reactor of a pilot-scale O 2-blown pressurized entrained-flow gasifier firing stem wood, bark, and pulp mill debarking residue (PMDR) in separate campaigns. These deposits were characterized with environmental scanning electron microscopy equipped with energy-dispersive X-ray spectrometry and X-ray diffractometry. The stem wood deposit contained high levels of calcium and was comparatively insubstantial. The bark and PMDR fuels contained contaminant sand and feldspar particles that were subsequently evident in each respective deposit. The bark deposit consisted of lightly sintered ash aggregates comprising presumably a silicate melt that enveloped particles of quartz and, to a lesser degree, feldspars. Discontinuous layers likely to be composed of alkaline-earth metal silicates were found upon the aggregate peripheries. The PMDR deposit consisted of a continuous slag that contained quartz and feldspar particles dispersed within a silicate melt. Significant levels of alkaline-earth and alkali metals constituted the silicate melts of both the bark and PMDR deposits. Overall, the results suggest that fuel contaminants (i.e., quartz and feldspars) play a significant role in the slag formation process during pressurized entrained-flow gasification of these woody biomasses.

  • 28.
    Molinder, Roger
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Sandström, Linda
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Characteristics of Particles in Pyrolysis Oil2016Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, nr 11, s. 9456-9462Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Particles filtered out of pyrolysis oil produced through fast pyrolysis of stem wood, willow, reed canary grass, bark, and forest residue were characterized using scanning electron microscopy and energy-dispersive spectroscopy with the aim of identifying particle categories and discussing transport mechanisms of particles and inorganics into the oil. Particles filtered out of both the condensed and the aerosol fractions of the oil displayed three types of morphology: (i) char-like structures (1-15 μm), (ii) spheres (100 nm to 1 μm), and (iii) irregularly shaped residue (50-500 nm). The char-like structures were identified as char. The spheres and irregularly shaped residue shared morphology and composition with tar balls and organic particles with inorganic inclusions. These particles could have formed either during the fast pyrolysis stage or through precipitation from the oil during storage. All particles consisted mainly of C and O but also small amounts of inorganics. The particles from the aerosol fraction of the oil had higher inorganics content than the particles from the condensed fraction. The results were discussed, and suggested transport mechanisms of inorganics into particles were presented.

  • 29.
    Mousavi, S. M.
    et al.
    Lund University, Sweden.
    Thorin, E.
    Umeå University, Sweden.
    Schmidt, F. M.
    Umeå University, Sweden.
    Sepman, Alexey
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Bai, X S
    Lund University, Sweden.
    Fatehi, H
    Lund University, Sweden.
    Numerical Study and Experimental Verification of Biomass Conversion and Potassium Release in a 140 kW Entrained Flow Gasifier2023Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 37, nr 2, s. 1116-1130Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, a Eulerian-Lagrangian model is used to study biomass gasification and release of potassium species in a 140 kW atmospheric entrained flow gasifier (EFG). Experimental measurements of water concentration and temperature inside the reactor, together with the gas composition at the gasifier outlet, are used to validate the model. For the first time, a detailed K-release model is used to predict the concentrations of gas-phase K species inside the gasifier, and the results are compared with experimental measurements from an optical port in the EFG. The prediction errors for atomic potassium (K), potassium chloride (KCl), potassium hydroxide (KOH), and total potassium are 1.4%, 9.8%, 5.5%, and 5.7%, respectively, which are within the uncertainty limits of the measurements. The numerical model is used to identify and study the main phenomena that occur in different zones of the gasifier. Five zones are identified in which drying, pyrolysis, combustion, recirculation, and gasification are active. The model was then used to study the transformation and release of different K species from biomass particles. It was found that, for the forest residue fuel that was used in the present study, the organic part of K is released at the shortest residence time, followed by the release of inorganic K at higher residence times. The release of inorganic salts starts by evaporation of KCl and continues by dissociation of K2CO3 and K2SO4, which forms gas-phase KOH. The major fraction of K is released around the combustion zone (around 0.7-1.3 m downstream of the inlet) due to the high H2O concentration and temperature. These conditions lead to rapid dissociation of K2CO3 and K2SO4, which increases the total K concentration from 336 to 510 ppm in the combustion zone. The dissociation of the inorganic salts and KOH formation continues in the gasification zone at a lower rate; hence, the total K concentration slowly increases from 510 ppm at 1.3 m to 561 ppm at the outlet. © 2023 The Authors. 

  • 30.
    Netzer, Corinna
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Säkerhetsforskning. NTNU Norwegian University of Science and Technology, Norway.
    Løvås, Terese
    NTNU Norwegian University of Science and Technology, Norway.
    Surrogate Reaction Mechanism for Waste Incineration and Pollutant Formation2021Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 35, nr 9, s. 7030-7049Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The incineration of municipal solid waste (MSW) is an attractive technology to generate thermal energy and reduce landfill waste volume. To optimize primary measures to ensure low emission formation during combustion, numerical models that account for varying waste streams and their impact on nitrogen oxide (NOx) formation are needed. In this work, the representation of the fuel by surrogate species is adopted from liquid fuel and biomass combustion and applied to solid waste devolatilization and combustion. A surrogate formulation including biomass components, protein, inorganics, and plastic species is proposed, and a comprehensive description of the heterogeneous and homogeneous reactions is developed. The presented work combines and extends available schemes from the literature for woody and algae biomass, coal, and plastic pyrolysis. The focus is set on the prediction of fuel NOx and its precursors, including cyclic nitrogen-containing hydrocarbons. Additionally, the interaction of NOx with sulfur and chloride species is accounted for, which are typically released during the devolatilization of MSW. The model allows for predicting thermogravimetric analysis measurement of waste fractions and different waste mixtures. The proposed kinetic mechanism well reproduces NOx formation from ammonia and hydrogen cyanide and its reduction under selective non-catalytic reduction conditions. The chemical model is successfully applied to predict the released gas composition along a grate-fired fuel bed using a stochastic reactor network. © 2021 The Authors.

  • 31.
    Netzer, Corinna
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik. NTNU Norwegian University of Science and Technology, Norway.
    Seidel, Lars
    LOGE Deutschland GmbH, Germany.
    Mauß, Fabian
    Brandenburg University of Technology, Germany.
    Løvås, Terese
    NTNU Norwegian University of Science and Technology, Norway.
    Stochastic reactor-based fuel bed model for grate furnaces2020Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 12, s. 16599-16612Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biomass devolatilization and incineration in grate-fired plants are characterized by heterogeneous fuel mixtures, often incompletely mixed, dynamical processes in the fuel bed and on the particle scale, as well as heterogeneous and homogeneous chemistry. This makes modeling using detailed kinetics favorable but computationally expensive. Therefore, a computationally efficient model based on zero-dimensional stochastic reactors and reduced chemistry schemes, consisting of 83 gas-phase species and 18 species for surface reactions, is developed. Each reactor is enabled to account for the three phases: the solid phase, pore gas surrounding the solid, and the bulk gas. The stochastic reactors are connected to build a reactor network that represents the fuel bed in grate-fired furnaces. The use of stochastic reactors allows us to account for incompletely mixed fuel feeds, distributions of local temperature and local equivalence ratio within each reactor and the fuel bed. This allows us to predict the released gases and emission precursors more accurately than if a homogeneous reactor network approach was employed. The model approach is demonstrated by predicting pyrolysis conditions and two fuel beds of grate-fired plants from the literature. The developed approach can predict global operating parameters, such as the fuel bed length, species release to the freeboard, and species distributions within the fuel bed to a high degree of accuracy when compared to experiments. © 2020 American Chemical Society

  • 32.
    Näzelius, Ida Linn
    et al.
    Luleå University of Technology, Sweden.
    Boström, Dan
    Umeå University, Sweden.
    Boman, Christoffer
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Samuelsson, Robert
    SLU Swedish University of Agricultural Sciences, Sweden.
    Öhman, Marcus
    Luleå University of Technology, Sweden.
    Influence of peat addition to woody biomass pellets on slagging characteristics during combustion2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 7, s. 3997-4006Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Upgraded biofuels such as pellets, briquettes, and powder are today commonly used in small as well as large scale appliances. In order to cover an increasing fuel demand new materials such as bark, whole tree assortments, and peat are introduced. These materials have higher ash content which is why they are potentially more problematic compared with stem wood. In general, few studies can be found regarding cocombustion of peat and biomass and in particular where the slagging tendencies are discussed. The overall objective of this study was therefore to determine the influence of peat addition to woody biomass pellets on slagging characteristics. Two different peat assortments (peat A and B) were copelletized separately in four different dry matter levels (0-5-15-30 wt %) into stem wood and energy wood, respectively. Peat A was a traditional Scandinavian fuel peat, with a high ash and Si content (carex), and peat B had a low ash content and relatively high Ca/Si ratio (sphagnum) chosen for its special characteristics. The produced pellets were combusted in a commercial underfed pellet burner (15 kW) installed in a reference boiler. The collected deposits (bottom ash and slag) from the combustion experiments were chemically characterized by scanning electron microscopy (SEM) combined with energy-dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) regarding the elemental distribution and morphology and phase composition, respectively. In addition, the bottom ashes were characterized according to inductively coupled plasma atomic emission spectroscopy (ICP-AES). To interpret the experimental findings chemical equilibrium model calculations were performed. The slagging tendency increased when adding peat into the woody biomasses. Especially sawdust with its relatively low ash and Ca content was generally more sensitive for the different peat assortments. Cofiring with the relatively Si and ash rich peat A resulted in the most severe slagging tendency. A significant increment of the Si, Al, and Fe content and a significant decrement of the Ca content in the slag could be seen when increasing the content of peat A in both woody biomasses. The slagging tendency increased when adding peat A because high temperature melting Ca-Mg oxides react to form more low temperature melting Ca/Mg-Al-K silicates. The slagging tendency was significantly lower when adding the more ash poor peat B, with relatively high Ca/Si ratio, into the woody biomass fuels compared with the peat A mixtures. The slag from the peat B mixings had a slightly higher Ca content compared with the Si content and a clearly higher content of Ca compared with the peat A mixtures. There were still Ca-Mg oxides left in the bottom ash i.e. a less amount of sticky low temperature melting K-silicate rich melt was formed when peat B was added to the woody biomasses.

  • 33.
    Ohman, M.
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Boman, Christoffer
    Hedman, Henry
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Eklund, R.
    Residential combustion performance of pelletized hydrolysis residue from lignocellulosic ethanol production2006Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 20, nr 3, s. 1298-1304Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As a result of the production of ethanol from lignocellulosic material by acid hydrolysis, a large quantity of non-hydrolyzed material is obtained as a residue, mainly derived from the lignin in the wood. One possible economical use of this hydrolysis residue is as raw material for production of fuel pellets to be used in residential pellet appliances (i.e., stoves and burners). The combustion characteristics of single pellets, as well as combustion results (i.e., ash deposition, maintenance, and emission performance) in residential pellet appliances, were therefore determined for hydrolysis residue pellets and compared with corresponding results using wood pellets. The hydrolysis residue pellets had a lower slagging tendency, as well as a higher heating value and lower ash content, than the wood (stem) pellets. During combustion in residential pellet appliances, relatively similar gaseous emission performance and characteristics were obtained for hydrolysis residue and stem wood pellets. However, the results showed a significant potential for very low emissions of fine particles during combustion of hydrolysis residue pellets because of the low content of volatile inorganic constituents. Tendencies for char-aggregate formation at low temperature (<800 °C) were identified during combustion of hydrolysis residue pellets. A practical implementation of the results in this work, both regarding accessibility and emission performance, is therefore to recommend the use of continuous-feed equipment thereby preserving a high temperature during the whole operation time. Thus, the results show that pelletized hydrolysis residue from lignocellulosic ethanol production could be a very interesting material for future residential pellet appliances designed for this typical biomass fuel. © 2006 American Chemical Society.

  • 34.
    Ohman, M.
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Bostrom, D.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Hedman, Henry
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Effect of kaolin and limestone addition on slag formation during combustion of wood fuels2004Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 18, nr 5, s. 1370-1376Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ash-related problems have more than occasionally been observed in wood-fuel-fired boilers and also recently in wood-pellet burners. These problems can lead to reduced accessibility of the combustion systems as well as bad publicity for the market. The objectives of the present work were, therefore, to determine the effects of kaolin and limestone addition on the slagging propensities of problematic and problem-free wood fuels during combustion in residential pellet appliances (burners), thus contributing to the understanding of the role of kaolin and limestone in preventing slagging on furnace grates. Pellets with additive-to-fuel ratios between 0 and 0.7 wt %d.s. were combusted in three different types of burner constructions (10 kW): over-, horizontal-, and under-feeding of the fuel. The collected slag deposits from the under-fed burner as well as the corresponding deposited fly ash in the boiler were characterized with X-ray diffraction (XRD) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The initial sintering temperatures of the formed slags were also determined. By adding limestone with an additive-to-fuel ratio of 0.5 wt %d.s. to the problematic stemwood raw material (Si-enriched probably because of contamination of sand/soil), the severe slagging of the fuel could totally be eliminated. Adding kaolin to the problematic raw material gave a minor decrease in slagging tendency of the problematic raw material and a major increase in slagging tendency of the problem-free stemwood raw material. When adding limestone to the problematic raw material, the composition of the formed slag was changed from relatively low temperature melting silicates to high temperature melting silicates and oxides. On the other hand, kaolin addition to the problematic raw material changed the content of the slag from mainly Ca-Mg silicates to be dominated by K-Al silicates which have relatively low melting points. When introducing kaolin to the problem-free raw material, the high temperature melting Ca-Mg oxides react to form lower temperature melting Ca-Al-K silicates. Chemical equilibrium model calculations were used to interpret the experimental findings, and generally good qualitative agreements between modeling and experimental results were obtained. © 2004 American Chemical Society.

  • 35.
    Ohman, M.
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    A new method for quantification of fluidized bed agglomeration tendencies: A sensitivity analysis1998Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 12, nr 1, s. 90-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new method for quantification of fluidized bed agglomeration tendencies for different fuels has been developed and evaluated. A bench scale fluidized bed reactor (5 kW), specially designed to obtain a homogeneous isothermal bed temperature, is used. The method is based on controlled increase of the bed temperature by applying external heat to the primary air and to the bed section walls. In addition, temperature homogeneity is secured by switching from normal fuel feeding to a propane precombustor. The initial agglomeration temperature is determined by on-or off-line principal component analysis of the variations in measured bed temperatures (four values) and differential pressures (four). To determine potential effects of all the process related variables, an extensive sensitivity analysis was performed. Experiments were performed according to a statistical experimental design to evaluate the effects of eight different process analytical variables on the determined agglomeration temperature of a biomass fuel. The results showed that for a given fuel, the amount of bed material, heating rate, fluidization velocity, and air to fuel ratio during both "ashing" and heating did not influence the determined agglomeration temperature. Only ash to bed material ratio, the ashing temperature, and the bed material particle size had significant effects on the agglomeration temperature, but still the effects were relatively small. The agglomeration temperature of the fuel could be determined to 899 °C (avg) with a reproducibility of ±5 °C (SD). The inaccuracy was determined to be ±30 °C (SD). Based on the results, the method was standardized with respect to ash to bed material ratio, bed material particle size, and ashing temperature. Relative agglomeration temperatures of different fuels, fuel, and additive combinations can thus be determined with a high precision.

  • 36.
    Ohman, M.
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    The role of kaolin in prevention of bed agglomeration during fluidized bed combustion of biomass fuels2000Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 14, nr 3, s. 618-624Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Agglomeration of bed material and fuel ash may cause problems during fluidized bed combustion of biomass fuels. Previous results have shown that a "sticky" coating, which covered the original bed material and consisted of Ca-K-silicates, was directly responsible for the bed agglomeration during biomass combustion. The melting behavior (stickiness) of these coatings was very sensitive to the potassium content. Prior studies have also indicated that bed agglomeration could possibly be prevented by introducing low-cost additives such as kaolinite. The objectives of the present work were, therefore, to illustrate the effect of kaolin addition on the actual agglomeration temperature of two troublesome biomass fuels, and to contribute to the understanding of the role of kaolin in prevention of bed agglomeration. By controlled agglomeration experiments in a 5 kW bench scale fluidized bed reactor, the critical temperatures for agglomeration in a normal quartz bed when firing wheat straw or bark were determined to be 739 and 988°C, respectively. By adding kaolin, 10% w/w of the total amount of the bed, the initial bed agglomeration temperatures increased to 886 and 1000°C, respectively. Samples of bed materials, collected throughout the experimental runs, as well as final agglomerates were analyzed using SEM/EDS and X-ray diffraction. These results showed that kaolin was transformed to meta-kaolinite particles, which adsorbed potassium species. The increased agglomeration temperature was explained by the decreased fraction of melt in the bed particle coatings, i.e., coatings were somewhat depleted in the potassium content by the corresponding potassium-enrichment in the kaolin-derived aggregates.

  • 37.
    Ohman, M.
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Lundholm, K.
    Bostrom, D.
    Hedman, Henry
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Lundberg, M.
    Ash transformations during combustion of meat-, bonemeal, and RDF in a (bench-scale) fluidized bed combustor2003Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 17, nr 5, s. 1153-1159Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Following the recent Bovine spongiform encephalopathy (BSE) experiences, thermal treatment of meat- and bonemeal (MBM) in existing fluidized bed combustion (FBC) plants for refuse-derived fuels (RDFs) has evolved as an interesting disposal and disintegration method. However, only a limited number of studies have previously been performed for combustion of MBM in fluidized beds. The objectives of the present work were, therefore, to determine the bed agglomeration tendencies of these materials during combustion in fluidized beds and to evaluate the effects of dolomite and kaolin addition to the fuel mix, as well as to elucidate the overall ash transformation mechanisms governing the potential bed agglomeration and fouling processes. By controlled agglomeration experiments in a 5 kW bench-scale fluidized bed reactor, the fuel-specific critical agglomeration temperatures in normal quartz bed material were determined for the different fuel/additive mixtures. All collected samples of bed materials, final bed agglomerates, and cyclone ashes were analyzed using SEM/EDS and XRD. The results indicated that the MBM fuels could be expected to be problematic concerning bed agglomeration in normal quartz beds, while kaolin and possibly dolomite addition could be used to reduce this risk to moderate levels. A significant elemental fractionation between the bed material and the cyclone ash was obtained. Apatite (Ca5(PO4)3(OH) or potentially some other calcium phosphates are elutriated from the bed and enriched in the fly ash, while sodium and potassium are enriched in the bed material. The characteristics and the corresponding melting behavior estimations of the necks formed between agglomerated bed particles suggest that silicate melts are responsible for the bed agglomeration. Results from XRD analysis of the fly ash formed from the fuels used in the present study indicated that the risk for melt-related fly ash problems seem relatively small.

  • 38.
    Ohman, M.
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Skrifvars, B.-J.
    Backman, Rainier
    Hupa, M.
    Bed agglomeration characteristics during fluidized bed combustion of biomass fuels2000Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 14, nr 1, s. 169-178Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The in-bed behavior of ash-forming elements in fluidized bed combustion (FBC) of different biomass fuels was examined by SEM/EDS analysis of samples collected during controlled agglomeration test runs. Eight fuels were chosen for the test. To cover the variations in biomass characteristics and to represent as many combinations of ash-forming elements in biomass fuels as possible, the selection was based on a principal-component analysis of some 300 biomass fuels, with respect to ash-forming elements. The fuels were then combusted in a bench-scale fluidized bed reactor (5 kW), and their specific agglomeration temperatures were determined. Bed samples were collected throughout the tests, and coatings and necks formed were characterized by SEM/EDS analyses. On the basis of their compositions, the corresponding melting behaviors were determined, using data extracted from phase diagrams. The bench-scale reactor bed samples were finally compared with bed samples collected from biomass-fired full-scale fluidized bed boilers. In all the analyzed samples, the bed particles were coated with a relatively homogeneous ash layer. The compositions of these coatings were most commonly constricted to the ternary system K2O-CaO-SiO2. Sulfur and chlorine were further found not to `participate' in the agglomeration mechanism. The estimated melting behavior of the bed coating generally correlated well with the measured agglomeration temperature, determined in the 5 kW bench-scale fluidized bed reactor. Thus, the results indicate that partial melting of the coating of the bed particles would be directly responsible for the agglomeration.

  • 39.
    Olwa, Joseph
    et al.
    Luleå University of Technology, Sweden; Makerere University, Uganda.
    Öhman, Marcus
    Luleå University of Technology, Sweden.
    Pettersson, Esbjörn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Boström, Dan
    Umeå University, Sweden.
    Okure, Mackay
    Makerere University, Uganda.
    Kjellström, Björn
    Exergetics AB, Sweden.
    Potassium retention in updraft gasification of wood2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 11, s. 6718-6724Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The release of compounds of K with producer gas during biomass gasification is known to play significant roles in fouling and high-temperature corrosion in boilers and high-temperature heat exchangers as well as blades in gas turbines that use producer gas as fuel. These phenomena are a major setback in the application of biomass fuel in combination with advanced process conditions. Updraft gasification provides gas filtering by the fuel bed with a gas cooling effect, conditions anticipated to create an avenue for K retention in the gasifier. The objective of this study was to determine the K retention potential of such gasifiers during wood gasification. Samples for the determination of the fate of K compounds included in the feedstock were collected from the generated producer gas using Teflon filters and gas wash bottles and also from wall deposits and ash residues. Analyses of samples were carried out using inductively coupled plasma-atomic emission spectrometry/mass spectrometry and X-ray diffraction methods. The finding was that about 99% of K was retained in the gasifier. K was found in the ash samples as a crystalline phase of K 2Ca(CO3)2(s) (fairchildite). A possible reaction mechanism leading to the formation of K2Ca(CO 3)2 is discussed in the paper. The 1% K understood as released, equivalent to 1200 ppbw content of K entrained in the producer gas stream, exceeds a known limit for application of the gas in conventional gas turbines. This would suggest application of the gas in an externally fired gas turbine system, where some limited K and other depositions in the heat exchanger can be relatively easy to handle.

  • 40.
    Pettersson, Esbjörn
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Boman, Christoffer
    Westerholm, R.
    Bostrom, D.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Stove performance and emission characteristics in residential wood log and pellet combustion: Part 2: Wood stove2011Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, nr 1, s. 315-323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The characteristics and quantities of a large number of gaseous and particulate emission components during combustion in a residential wood log stove with variations in fuel, appliance and operational conditions were determined experimentally. The measurement campaign included CO, NOx, organic gaseous carbon (OGC), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions, and inorganic composition. CO varied in the range of 1100 to 7200 mg/MJ fuel, while OGC varied from 210 to 3300 mg/MJfuel. Dominating VOCs were methane, followed by ethene, acetylene, and benzene. Methane varied from 9 to 1600 mg/MJfuel. The nonmethane volatile organic compound (NMVOC) emissions were in the range of 20-2300 mg/MJ fuel. The PAHtot emissions varied from 1.3 to 220 mg/MJfuel, in most cases dominated by phenantrene, fluoranthene, and pyrene. PMtot were in all cases dominated by fine particles and varied in the range 38-350 mg/MJfuel. The mass median particle diameters and the peak mobility diameters of the fine particles varied in the range 200-320 and 220-330 nm, respectively, and number concentrations in the range of 1-4 × 1013 particles/MJfuel. Air starved conditions, at high firing intensity, gave the highest emissions, especially for hydrocarbons. This type of condition is seldom considered, though it may occur occasionally. The emissions from Swedish wood stoves, comparing a Swedish field study, are covered fairly well with the applied methodology, but other field studies report considerably higher emissions especially for diluted particle sampling. © 2011 American Chemical Society.

  • 41.
    Pettersson, Esbjörn
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, ETC Energy Technology Center.
    Lindmark, F.
    Ohman, M.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Nordin, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Westerholm, R.
    Boman, Christoffer
    Design changes in a fixed-bed pellet combustion device: Effects of temperature and residence time on emission performance2010Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 24, nr 2, s. 1333-1340Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of wood fuel pellets has proven to be well-suited for the small-scale market, enabling controlled and efficient combustion with low emission of products of incomplete combustion (PIC). Still, a potential for further emission reduction exists, and a thorough understanding of the influence of combustion conditions on the emission characteristics of air pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and particulatematter (PM), is important. The objective of the present work was to determine the effect of design changes, i.e., increasing the temperature and/or residence time, on the emission performance and characteristics for a pellet combustion device using a laboratory fixed-bed reactor (850 °C) in the bed zone with intensive, air-rich, and well-mixed conditions was illustrated forwood pellets combustion with almost a total depletion of all studied PIC. The importance of the residence time was shown to be limited, and the results emphasize the need for further verification studies and technology development work. Copyrigh © 2010 American Chemical Society.

  • 42.
    Pettersson, Jens
    et al.
    Linnaeus University, Sweden.
    Andersson, Sven
    Babcock & Wilcox Vølund AB, Sweden; Chalmers University of Technology, Sweden.
    Bäfver, Linda
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Strand, Michael
    Linnaeus University, Sweden.
    Investigation of the Collection Efficiency of a Wet Electrostatic Precipitator at a Municipal Solid Waste-Fueled Combined Heat and Power Plant Using Various Measuring Methods2019Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, nr 6, s. 5282-5292Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article reports results from measurements of mainly submicrometer particles at the inlet and outlet of a newly designed industrial wet electrostatic precipitator (WESP) in a combined heat and power plant fueled with municipal solid waste. The measurements were carried out with dual electric low-pressure impactors in parallel at the precipitator inlet and outlet. In addition, measurements were carried out with traditional total dust filters, low-pressure impactors, a scanning mobility particle sizer, and an aerodynamic particle sizer. The measurements aimed to characterize the aerosol particles and measure the efficiency of the WESP with special attention to fine and ultrafine particles. In general, the WESP performance and response to varying conditions was found to be in line with predictions made for the design. The WESP featured a cooled collector surface, but based on the limited results, no conclusion could be drawn regarding any possible improvement from collector cooling. The characterization of the aerosol particulate matter was challenging because of fast fluctuations in particle concentration. Methodological considerations are pointed out, mainly regarding the SMPS and ELPI measuring systems.

  • 43.
    Purnomo, Victor
    et al.
    Chalmers University of Technology, Sweden.
    Mei, Daofeng
    Chalmers University of Technology, Sweden.
    Soleimanisalim, Amir H
    Chalmers University of Technology, Sweden.
    Mattisson, Tobias
    Chalmers University of Technology, Sweden.
    Leion, Henrik
    Chalmers University of Technology, Sweden.
    Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification2022Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 36, nr 17, s. 9768-9779Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemical looping gasification (CLG) is an emerging process that aims to produce valuable chemical feedstocks. The key operational requirement of CLG is to limit the oxygen transfer from the air reactor (AR) to the fuel reactor (FR). This can be accomplished by partially oxidizing the oxygen carrier in the AR, which may lead to a higher reduction degree of the oxygen carrier under the fuel conversion. A highly reduced oxygen carrier may experience multiple issues, such as agglomeration and defluidization. Given such an interest, this study examined how the variation of the mass conversion degree of ilmenite may affect the conversion of pine forest residue char in a fluidized bed batch reactor. Ilmenite was pre-reduced using diluted CO and then underwent the char conversion at 850, 900, 950, and 975 °C. Our investigations showed that the activation energy of the char conversion was between 194 and 256 kJ/mol, depending upon the mass conversion degree of ilmenite. Furthermore, the hydrogen partial pressure in the particle bed increased as the oxygen carrier mass conversion degree decreased, which was accompanied by a lower reaction rate and a higher reduction potential. Such a hydrogen inhibition effect was confirmed in the experiments; therefore, the change in the mass conversion degree indirectly affected the char conversion. Langmuir-Hinshelwood mechanism models used to evaluate the char conversion were validated. On the basis of the physical observation and characterizations, the use of ilmenite in CLG with biomass char as fuel will likely not suffer from major agglomeration or fluidization issues.

  • 44.
    Pushp, Mohit
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Safety.
    Gall, Dan
    University of Gothenburg, Sweden.
    Davidsson, Kent
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Energi och cirkulär ekonomi.
    Seemann, Martin
    Chalmers University of Technology, Sweden.
    Pettersson, Jan B C
    University of Gothenburg, Sweden.
    Influence of Bed Material, Additives, and Operational Conditions on Alkali Metal and Tar Concentrations in Fluidized Bed Gasification of Biomass2018Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, nr 6, s. 6797-6806Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gasification of biomass results in release of tar and alkali metal compounds that constitute a significant challenge to the optimization of the gasification process. Here we describe on-line measurements of alkali, condensable tar, and particle concentrations in product gas from a 2-4 MWth dual fluidized bed gasifier, with the aims to characterize typical concentrations and contribute to the understanding of alkali-tar interactions. The influence of bed material, additives, and operational parameters on the concentrations is investigated. Alkali concentrations are measured with a surface ionization detector, and particle and tar concentrations are determined using aerosol measurement techniques. The gasification of wood chips using quartz or olivine as bed material results in an alkali concentration of 30-250 mg m-3, and the observed alkali levels are consistent with a significant release of the fuel alkali content. Addition of ilmenite to a quartz bed and additions of K2SO4 and K2CO3 to an olivine bed influence both alkali and heavy tar concentrations. The additions result in changes in alkali concentration that relaxes to a new steady state in tens of minutes. The concentration of condensable tar is lower for the olivine bed than for the quartz bed, and tends to decrease when potassium or sulfur is added. The concentration of condensable tar compounds is anticorrelated with the alkali concentration when a quartz bed is used, while no clear trend is observed with an olivine bed. An increase in steam flow rate results in a substantial decrease in heavy tar concentration from a quartz sand bed, while the alkali concentration increases slightly with increasing flow rate. This is in contrast to the alkali concentrations observed when using an activated olivine bed, where concentrations are higher and tend to decrease with increasing steam flow rate. The study confirms that several primary methods are available to optimize the alkali and tar behavior in the gasifier, and suggests that on-line monitoring is needed to systematically change the operational conditions and to study the underlying processes.

  • 45.
    Rissler, Jenny
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign. Lund University, Sweden.
    Klementiev, Konstantin
    Lund University, Sweden.
    Dahl, Jonas
    RISE Research Institutes of Sweden, Samhällsbyggnad, Energi och resurser.
    Steenari, Britt-Marie
    Chalmers University of Technology, Sweden.
    Edo, Mar
    RISE Research Institutes of Sweden, Samhällsbyggnad, Systemomställning och tjänsteinnovation.
    Identification and Quantification of Chemical Forms of Cu and Zn in MSWI Ashes Using XANES2020Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 11, s. 14505-14514Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Incineration is in many countries a common treatment method for municipal solid waste, and utilization of the ash residues has attracted significant interest. The bottom ash is best suited as a secondary construction material, whereas the fly ash is being investigated as a secondary raw material for recovery of, for example, Zn, Cu, and salts. For both types of application, knowledge about the chemical speciation of Zn and Cu in the ashes is valuable. The present work focuses on identifying and quantifying the chemical species of Zn and Cu in 12 samples of fly ash and bottom ash from three waste-to-energy plants using X-ray absorption near edge structure (XANES). The XANES spectra of the ash samples showed similar distinctive features, and both in the bottom and fly ash samples, the same chemical forms were identified but in various ratios. Cu and Zn occurred in several chemical forms, with typically 5-7 forms present in the same sample. For Cu, the XANES spectra of the fly ash samples were nearly identical, indicating very similar chemical speciation (same chemical forms and similar ratios). Cu was found to exist in various oxide, hydroxide, chloride, silicate, and metallic forms. The most commonly occurring Zn compounds were the aluminate, ferrite, silicate, and oxide along with chloride, basic carbonate (hydrozincite), and occasionally metallic forms, probably alloyed with Cu in brass. Cu occurred in different oxidation states from zero to +II, with a higher prevalence of the lower oxidation states in bottom ash than in fly ash. Zn occurred mainly in oxidation state +II in all ashes analyzed. Finally, we showed that during outdoor storage of bottom ash, levels of Cu and Zn hydroxycarbonates were increased compared to fresh bottom ash. This carbonate formation aims to make Cu and Zn less leachable.

  • 46.
    Sepman, Alexey
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, ETC Energy Technology Center.
    Ögren, Yngve
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, ETC Energy Technology Center.
    Qu, Zhechau
    Umeå University, Sweden; PTB Physikalisch-Technische Bundesanstalt, Germany.
    Wiinikka, Henrik
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, ETC Energy Technology Center.
    Schmidt, Florian
    Umeå University, Sweden.
    Tunable diode laser absorption spectroscopy diagnostics of potassium, carbon monoxide, and soot in oxygen-enriched biomass combustion close to stoichiometry2019Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, nr 11, s. 11795-11803Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Combustion facilities run on pulverized biomass often exhibit fluctuations in fuel feeding and, thus, equivalence ratio and would benefit from fast process control based on optical λ sensors installed in the reactor core. The conversion of softwood powder is investigated in an atmospheric entrained-flow reactor (EFR) operated close to stoichiometry using two different burners (swirl and jet) and three oxygen concentrations (21, 30, and 40%). Tunable diode laser absorption spectroscopy (TDLAS) is used to conduct time-resolved (0.1-1 s) in situ measurements of the gas temperature, carbon monoxide (CO), water vapor (H2O), gaseous atomic potassium [K(g)], and soot volume fraction in the lower part of the reactor core and in the exhaust of the EFR. At both locations, the measurement parameters show significant, correlating fluctuations. The local equivalence ratio is derived from a comparison of measured CO and H2O concentrations (for fuel-rich and fuel-lean conditions, respectively) to thermodynamic equilibrium calculations (TEC) and found to vary in a wide range (0.8-1.3). Soot production decreases with an increasing local equivalence ratio and oxygen enrichment and is lower for the swirl compared to the jet burner. The measured K(g) concentrations follow the general behavior predicted by TEC around stoichiometry. In the relevant temperature range (1100-1700 K), K(g) is 2-4 orders of magnitude higher under fuel-rich than fuel-lean conditions, with a sharp transition at stoichiometry. While K(g) concentrations are lower than TEC in the reactor core and under fuel-rich conditions, excellent agreement is found at the exhaust after complete fuel conversion. Precise, wide dynamic range detection of K(g) using TDLAS enables discrimination between fuel-rich and fuel-lean conditions and has the potential for lambda sensing close to the hot reaction zone of combustion plants.

  • 47.
    Shafaghat, Hoda
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Johansson, Ann-Christine
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Wikberg, Elena
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Narvesjö, Jimmy
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Wagner, Jakob Birkedal
    DTU Technical University of Denmark, Denmark.
    Öhrman, Olov
    Preem AB, Sweden.
    Customized Atmospheric Catalytic Hydropyrolysis of Biomass to High-Quality Bio-Oil Suitable for Coprocessing in Refining Units2024Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 38, nr 6, s. 5288-5302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study aimed to investigate the critical elements of the biomass ex situ catalytic hydropyrolysis (CHP) concept to improve the quality of fast pyrolysis bio-oil (FPBO) for further coprocessing in a fluid catalytic cracking (FCC) refining unit. Generally, the high oxygen and low hydrogen contents of biomass result in a bio-oil with low quality, necessitating its upgrading, which can be performed as integrated in the pyrolysis process via in situ or ex situ configuration. In this work, the quality of stem wood-derived pyrolyzates (520 °C) was improved via ex situ CHP (400 °C) using a continuous bench-scale drop tube pyrolyzer (60 g h-1), and then the produced FPBO was coprocessed with vacuum gas oil (VGO) fossil oil using a lab-scale FCC unit (525 °C). CHP of stem wood was carried out using different metal-acid catalysts such as Ni/HZSM-5, Ni/HBeta, Mo/TiO2, and Pt/TiO2 at atmospheric pressure. FCC runs were performed using an equilibrium FCC catalyst and conventional fossil FCC feedstock cofed with 20 wt % stem wood-derived bio-oil in a fluidized bed reactor. Cofeeding the nonupgraded FPBO with fossil oil into the FCC unit decreased the generation of hydrocarbons in the range of gasoline and naphtha, indicating that bio-oil needs to be upgraded for further coprocessing in the FCC unit. Experimental results showed that different catalysts significantly affected the product composition and yield; Ni-based catalysts were strongly active tending to generate a high yield of gas, while Mo- and Pt-based catalysts seemed better for production of liquid with improved quality. The quality of FPBO was improved by reducing the formation of reactive oxygenates through the atmospheric CHP process. The composition of oil obtained from hydropyrolysis also showed that the yields of phenols and aromatic hydrocarbons were enhanced. © 2024 The Authors. 

    Fulltekst (pdf)
    fulltext
  • 48.
    Shafaghat, Hoda
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Linderberg, Mats
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemiska processer och läkemedel.
    Janosik, Tomasz
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemiska processer och läkemedel.
    Hedberg, Martin
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Kemiska processer och läkemedel.
    Wiinikka, Henrik
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Sandström, Linda
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Johansson, Ann-Christine
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Enhanced Biofuel Production via Catalytic Hydropyrolysis and Hydro-Coprocessing2022Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 36, nr 1, s. 450-462Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to successfully integrate biomass pyrolysis oils as starting materials for conventional oil refineries, upgrading of the pyrolysis oils is needed to achieve desired properties, something which can be performed either as part of the pyrolysis process and/or by separate catalytic treatment of the pyrolysis intermediate oil products. In this study, the quality of stem wood-derived pyrolysis oil was improved via ex situ catalytic hydropyrolysis in a bench-scale pyrolyzer (stage 1), followed by catalytic hydro-coprocessing with fossil co-feed in a laboratory-scale high pressure autoclave (stage 2). The effect of pyrolysis upgrading conditions was investigated based on the quality of intermediate products and their suitability for hydro-coprocessing. HZSM-5 and Pt/TiO2 catalysts (400 °C, atmospheric pressure) were employed for ex situ pyrolysis, and the NiMoS/Al2O3 catalyst (330 °C, 100 bar H2 initial pressure) was used for hydro-coprocessing of the pyrolysis oil. The application of HZSM-5 in the pyrolysis of stem wood under a N2 atmosphere decreased the formation of acids, ketones, aldehydes, and furans and increased the production of aromatic hydrocarbons and phenolics (guaiacols and phenols). Replacing HZSM-5 with Pt/TiO2 and N2 with H2 resulted in complete conversion of guaiacols and significant production of phenols, with further indications of increased stability and reduced coking tendencies.

  • 49.
    Simonsson, Johan
    et al.
    Lund University, Sweden.
    Bladh, Henrik
    Lund University, Sweden.
    Gullberg, Marcus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Pettersson, Esbjörn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Sepman, Alexey
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Ögren, Yngve
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Bengtsson, Per-Erik
    Lund University, Sweden.
    Soot Concentrations in an Atmospheric Entrained Flow Gasifier with Variations in Fuel and Burner Configuration Studied Using Diode-Laser Extinction Measurements2016Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, nr 3, s. 2174-2186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soot concentration measurements were performed using diode-laser extinction in an atmospheric air-blown entrained flow gasifier at two vertical levels. The gasifier was operated at different air-fuel equivalence ratios and with variations in fuel and burner configurations. Two fuels were investigated: wood powder and peat powder. These were burned using two burner configurations, one giving a rotating flow inside the gasifier (swirl), and one where the fuel and air were injected parallel with the gasifier axis (jet). The diode-laser measurements were performed at the wavelength 808 nm from which the soot concentrations were estimated, and additionally at 450 nm in order to gain insight into the spectral dependence of the extinction to estimate measurement quality. Additional diagnostic techniques were used, such as an electrical low-pressure impactor (ELPI) for soot size distributions and gas chromatography for species concentration measurements. The results show that wood powder produces higher soot concentrations than peat powder, especially at lower air-fuel equivalence ratios. Furthermore, the burner configuration had in general much less impact than the choice of fuel on the soot concentration.

  • 50.
    Sjövall, Peter
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Metodik för produktframtagning.
    Zhang, Yunlong
    ExxonMobil Research and Engineering Company, USA.
    Ruiz-Morales, Yosadara
    Instituto Mexicano del Petroleo, Mexico.
    Mullins, Oliver
    Schlumberger-Doll Research, USA.
    Evaluation of Molecular Fragmentation in Polycyclic Aromatic Hydrocarbons by Time-of-Flight Secondary Ion Mass Spectrometry2023Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 37, s. 7071-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In time-of-flight secondary ion mass spectrometry (TOF-SIMS), ionized molecules and molecular fragments (secondary ions) are generated in collisions of high-energy ions (primary ions) with a solid sample surface. Mass spectra of the emitted secondary ions are typically used to identify molecular species and to determine their spatial distribution on the sample surface. Here, we extend this application in a TOF-SIMS study of a series of polycyclic aromatic hydrocarbons (PAHs) where we focus on the fragmentation of these molecules, with the purpose of better understanding the fragmentation patterns of heavy aromatic molecules in petroleum. For all PAHs, the collision process generated (i) a series of smaller cation fragments and (ii) cations close in size to the original PAH (molecular cations). Stark differences are measured for various PAHs regarding the abundance of smaller fragments versus molecular cations. Observation of hydrogen-deficient (H-deficient) cation fragments indicates the formation of polyynes and allenes. For PAHs producing higher fractions of small cation fragments, these ions are surprisingly hydrogen rich (H-rich). The H/C ratio of fragments does not scale with the fraction of Clar sextet carbon, nor with energies of low-lying electronic transitions. Free radical cation fragments tend to be suppressed. For sufficiently large fragments, aromatic cations appear to be formed and include some free radical aromatics. There is ample production of molecular ions with loss of a single carbon atom or a methine group, which corresponds to the reduction of a 6-membered aromatic ring to a 5-membered ring. There is some enhancement of free radical molecular cations due to the corresponding formation of neutral polyynes. Fragment anions are also produced with a strong preference for very H-deficient carbon clusters, in some cases being the same as carbon cluster anions observed in space. Comparisons of PAH TOF-SIMS spectra with those of asphaltenes are discussed in detail.

12 1 - 50 of 67
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
v. 2.43.0