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  • 1.
    Bergström, Dan
    et al.
    Department of Forest Resource Management, Swedish University of Agricultural Sciences.
    Israelsson, Samuel
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahlqvist, Sten-Axel
    Unit of Biomass Technology and Chemistry, SLU.
    Gref, Rolf
    Department of Forest Resource Management, Swedish University of Agricultural Sciences.
    Boman, Christoffer
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Wästerlund, Iwan
    Department of Forest Resource Management, Swedish University of Agricultural Sciences.
    Effects of raw material particle size distribution on the characteristics of Scots pine sawdust fuel pellets2008In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 89, no 12, p. 1324-1329Article in journal (Refereed)
    Abstract [en]

    In order to study the influence of raw material particle size distribution on the pelletizing process and the physical and thermomechanical characteristics of typical fuel pellets, saw dust of Scots pine was used as raw material for producing pellets in a semi industrial scaled mill (∼ 300 kg h- 1). The raw materials were screened to a narrow particle size distribution and mixed into four different batches and then pelletized under controlled conditions. Physical pellet characteristics like compression strength, densities, moisture content, moisture absorption and abrasion resistance were determined. In addition, the thermochemical characteristics, i.e. drying and initial pyrolysis, flaming pyrolysis, char combustion and char yield were determined at different experimental conditions by using a laboratory-scaled furnace. The results indicate that the particle size distribution had some effect on current consumption and compression strength but no evident effect on single pellet and bulk density, moisture content, moisture absorption during storage and abrasion resistance. Differences in average total conversion time determined for pellet batches tested under the same combustion conditions was less than 5% and not significant. The results are of practical importance suggesting that grinding of saw dust particle sizes below 8 mm is probably needless when producing softwood pellets. Thus it seem that less energy could be used if only over sized particles are grinded before pelletizing.

  • 2.
    Biswas, Amit
    et al.
    Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology.
    Umeki, Kentaro
    Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology.
    Yang, Weihong
    Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology.
    Blasiak, Wlodzimierz
    Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology.
    Change of pyrolysis characteristics and structure of woody biomass due to steam explosion pretreatment2011In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 92, no 10, p. 1849-1854Article in journal (Refereed)
    Abstract [en]

    Steam explosion (SE) pretreatment has been implemented for the production of wood pellet. This paper investigated changes in biomass structure due to implication of steam explosion process by its pyrolysis behavior/ characteristics. Salix wood chip was treated by SE at different pretreatment conditions, and then pyrolysis characteristic was examined by thermogravimetric analyzer (TGA) at heating rate of 10 K/min. Both pyrolysis characteristics and structure of biomass were altered due to SE pretreatment. Hemicellulose decomposition region shifted to low temperature range due to the depolymerization caused by SE pretreatment. The peak intensities of cellulose decreased at mild pretreatment condition while they increased at severe conditions. Lignin reactivity also increased due to SE pretreatment. However, severe pretreatment condition resulted in reduction of lignin reactivity due to condensation and re-polymerization reaction. In summary, higher pretreatment temperature provided more active biomass compared with milder pretreatment conditions. © 2011 Elsevier B.V. All rights reserved.

  • 3.
    Biswas, Amit
    et al.
    Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology.
    Yang, Weihong
    Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology.
    Blasiak, Wlodzimierz
    Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology.
    Steam pretreatment of Salix to upgrade biomass fuel for wood pellet production2011In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 92, no 9, p. 1711-1717Article in journal (Refereed)
    Abstract [en]

    Steam explosion (SE) pretreatment is served to separate the main components of woody biomass. In general there is a noticeable gap in literature in terms of application of steam explosion process to upgrade biomass fuel for wood pellet production. In order to study the influence of steam explosion pretreatment on biomass fuel, Salix wood chips was used as raw material. Four different SE experiments were performed by varying two key process factors; time and temperature. Elementary quality and ash properties of the pretreated residue were investigated. Moreover, physical and thermochemical properties of the pellet, produced from the residue, were also investigated. Reduction in ash content especially in alkali metals was observed in steam treated residue. Pretreatment of biomass also enhanced carbon content and reduced oxygen amount in the fuel which enhanced the heating value of the fuel. Moreover, pretreatment enhanced pellet density, impact resistance, and abrasive resistance of pellet. However, small degradation in ash fusion characteristics and char reactivity was also observed as the severity of the process increased. © 2011 Elsevier B.V.

  • 4.
    Budinova, T.
    et al.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Ekinci, E.
    Department of Chemical Engineering, Istanbul Technical University.
    Yardim, F.
    Department of Chemical Engineering, Istanbul Technical University.
    Grimm, Alejandro
    Björnbom, E.
    Department of Chemical Engineering and Technology, Division of Chemical Reaction Engineering, Royal Institute of Technology (KTH).
    Minkova, V.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Goranova, M.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Characterization and application of activated carbon produced by H3PO4 and water vapor activation2006In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 87, p. 899-905Article in journal (Refereed)
  • 5.
    Grimm, Alejandro
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Biomass Technology Centre.
    Elustondo, Diego
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Mäkelä, Mikko
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Biomass Technology Centre.
    Segerström, Markus
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Biomass Technology Centre.
    Kalén, Gunnar
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Biomass Technology Centre.
    Fraikin, Laurent
    University of Liège, Chemical Engineering, PEPs – Products, Environment, and Processes.
    Léonard, Angélique
    University of Liège, Chemical Engineering, PEPs – Products, Environment, and Processes.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Biomass Technology Centre.
    Drying recycled fiber rejects in a bench-scale cyclone: Influence of device geometry and operational parameters on drying mechanisms2017In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 167, p. 631-640Article in journal (Refereed)
    Abstract [en]

    Significant amounts of waste sludge and rejects are generated by pulp and paper mills, and stricter environmental regulations have made waste handling a global challenge. Thermochemical conversion of mechanically dewatered by-products is expensive and inefficient due to their high moisture content; therefore drying is a vital unit operation in waste management. This paper reports results from drying of light coarse fiber reject in a bench-scale cyclone that allows changes in geometry. For the sake of comparison, convective fixed-bed drying tests were also performed. The results showed that the drying rate in the cyclone was hundreds of times higher than in the fixed-bed. For cyclone drying, the inlet air velocity was the most important factor in both determining the drying rate and residence time of the material. This led to the hypothesis that grinding of the reject particles due to particle-wall and particle-particle collisions play a crucial role in enhancing the efficiency of heat and mass transfer. In addition to inlet air velocity, cyclone geometry was the main factor that determined particle residence time, as drying air temperature mainly determined drying rate.

  • 6.
    Göktepe, Burak
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Umeki, Kentaro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Gebart, Rikard
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Does distance among biomass particles affect soot formation in an entrained flow gasification process?2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 141, no 1, p. 99-105Article in journal (Refereed)
    Abstract [en]

    Soot creates technical challenges in entrained flow biomass gasification processes, e.g. clogging of flow passages, fouling on system components and reduced efficiency of gasification. This paper demonstrates a novel soot reduction method in a laboratory-scale entrained flow reactor by forced dispersion of biomass particles. Gasification of small biomass particles was done in a flat flame burner where a steady stream of biomass was sent. The flat flame burner was operated with a premixed sub-stoichiometric methane–air flame to simulate the conditions in an entrained flow gasifier. The dispersion of biomass particles was enhanced by varying the flow velocity ratio between particle carrier gas and the premixed flame. Primary soot particles evolved with the distance from the burner exit and the soot volume fraction was found to have a peak at a certain location. Enhanced particle separation diminished the peaks in the soot volume fraction by 35–56% depending on the particle feeding rates. The soot volume fraction was found to decrease towards an asymptotic value with increasing inter-particle distance.

  • 7.
    Häggström, Caroline
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Öhrman, Olov
    Rownaghi, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Gebart, Rikard
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Catalytic methanol synthesis via black liquor gasification2012In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 94, no 1, p. 10-15Article in journal (Refereed)
    Abstract [en]

    Biofuel production from gasified black liquor is an interesting route to decrease green house gas emissions. The only pressurised black liquor gasifier currently in pilot operation is located in Sweden. In this work, synthesis gas was taken online directly from this gasifier, purified from hydrocarbons and sulphur compounds and for the first time catalytically converted to methanol in a bench scale equipment. Methanol was successfully synthesised during 45 h in total and the space time yield of methanol produced at 25 bar pressure was 0.16–0.19 g methanol/(g catalyst h). The spent catalyst exposed to gas from the gasifier was slightly enriched in calcium and sodium at the inlet of the reactor and in boron and nickel at the outlet of the reactor. Calcium, sodium and boron likely stem from black liquor whereas nickel probably originates from the stainless steel in the equipment. A slight deactivation, reduced surface area and mesoporosity of the catalyst exposed to gas from the gasifier were observed but it was not possible to reveal the origin of the deactivation. In addition to water, the produced methanol contained traces of hydrocarbons up to C4, ethanol and dimethyl ether.

  • 8.
    Kirtania, Kawnish
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bhattacharya, Sankar
    Department of Chemical Engineering, Monash University.
    Coupling of a distributed activation energy model with particle simulation for entrained flow pyrolysis of biomass2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 137, p. 131-138Article in journal (Refereed)
    Abstract [en]

    This study evaluated the applicability of the distributed activation energy model (DAEM) while incorporated in a particle model designed for entrained flow pyrolysis of biomass. For that purpose, two types of biomass (spruce sawdust and coconut shell) were pyrolyzed in a thermogravimetric analyzer to obtain the intrinsic kinetic parameters. These kinetic parameters were then incorporated in the particle model. For comparison, entrained flow pyrolysis of those samples was also conducted at different temperatures (1073 and 1273 K) by varying particle size (150–250 μm and 500–600 μm). The modeling results were also compared with the literature data. The prediction using DAEM kinetics was improved when pyrolysis heat of reaction was included in the model. Based on the findings, a method was proposed to use the intrinsic kinetic parameters for particle simulation to determine the conversion profile of biomass pyrolysis under laminar entrained flow condition.

  • 9.
    Kirtania, Kawnish
    et al.
    Monash University, Melbourne, VIC.
    Joshua, Janik
    Monash University, Melbourne, VIC.
    Kassim, Mohd Asyraf
    University of Sains.
    Bhattacharya, Sankar
    Monash University, Melbourne, VIC.
    Comparison of CO2 and steam gasification reactivity of algal and woody biomass chars2014In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 117, p. 44-52Article in journal (Refereed)
    Abstract [en]

    This study undertook gasification reactivity measurement of an algal biomass (Chlorella sp.) char prepared in two different reactors with two gasifying agents (CO2 and steam) and compared that with similar measurements on woody biomass (commercial wood mix) char in a thermo-gravimetric analyser at three different temperatures. In general, the woody char from entrained flow reactor showed higher reactivity during gasification. At 800 C and 950 C, similar reactivity was exhibited by algal char from thermo-gravimetric analyser whereas at 1100 C, the woody char became more reactive than the algal char. For algae, the char prepared in entrained flow reactor showed lower reactivity than the char from thermo-gravimetric analyser. The scanning electron microscope images of the char samples showed significant difference in morphology with respect to the char preparation condition and species. For chars of both the species, a temperature of 800 C and time of around 20 min are found to be sufficient to accomplish most conversion; this information is of practical relevance. © 2013 Elsevier B.V.

  • 10.
    Kuba, Matthias
    et al.
    Bioenergy 2020+ GmbH.
    He, Hanbing
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Kirnbauer, Friedrich
    Bioenergy 2020+ GmbH.
    Boström, Dan
    Umeå universitet, Energy Technology and Thermal Process Chemistry, Umeå University.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hofbauer, Hermann
    Vienna University of Technology, Institute of Chemical Engineering.
    Deposit build-up and ash behavior in dual fluid bed steam gasification of logging residues in an industrial power plant2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 139, p. 33-41Article in journal (Refereed)
    Abstract [en]

    A promising way to substitute fossil fuels for production of electricity, heat, fuels for transportation and synthetic chemicals is biomass steam gasification in a dual fluidized bed (DFB). Using lower-cost feedstock, such as logging residues, instead of stemwood, improves the economic operation. In Senden, near Ulm in Germany, the first plant using logging residues is successfully operated by Stadtwerke Ulm. The major difficulties are slagging and deposit build-up. This paper characterizes inorganic components of ash forming matter and draws conclusions regarding mechanisms of deposit build-up. Olivine is used as bed material. Impurities, e.g., quartz, brought into the fluidized bed with the feedstock play a critical role. Interaction with biomass ash leads to formation of potassium silicates, decreasing the melting temperature. Recirculation of coarse ash back into combustion leads to enrichment of critical fragments. Improving the management of inorganic streams and controlling temperature levels is essential for operation with logging residues.

  • 11.
    Nordgren, Daniel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Padban, Nader
    Vattenfall Research & Development.
    Boström, Dan
    Umeå universitet.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ash transformations in pulverised fuel co-combustion of straw and woody biomass2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 105, p. 52-58Article in journal (Refereed)
    Abstract [en]

    Ash transformation processes have been studied during co-firing of wheat straw and pine stem wood and softwood bark. Pilot-scale trials in a 150 kW pulverised-fuel-fired burner were performed. Thermodynamic equilibrium calculations were made to support the interpretation of the results. The results show that fast reactions involving gaseous ash compounds are favored at the expense of reactions where condensed components participate. Accordingly, the conditions promote gas phase reactions resulting in the formation of chlorides, sulfate and carbonates whereas reactions involving condensed reactants are suppressed. Both the slagging and fouling propensity of all co-firing mixes was reduced compared to that for pure straw. For the wood/straw mixes this was mainly due to a dilution of the ash forming elements of straw whereas for straw/bark, an additional effect from interaction between the fuel ash components was observed to primarily reduce slagging. In general it can be concluded that under powder combustion conditions equilibrium are approached selectively and that the ash matter are strongly fractionated. The general results in this paper are useful for straw-fired power stations looking for alternative co-firing fuels.

  • 12.
    Razmjoo, Narges
    et al.
    Avdelningen för Bioenergiteknik, Linnéuniversitet , Department of Built Environment and Energy Technology, Linnaeus University.
    Sefidari, Hamid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Strand, Michael
    Avdelningen för Bioenergiteknik, Linnéuniversitet , Department of Built Environment and Energy Technology, Linnaeus University.
    Measurements of temperature and gas composition within the burning bed of wet woody residues in a 4 MW moving grate boiler2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 152, p. 438-445Article in journal (Refereed)
    Abstract [en]

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

  • 13. Razmjoo, Nargess
    et al.
    Sefidari, Hamid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Strand, Michael
    Characterization of hot gas in a 4 MW reciprocating grate boiler2014In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 124, p. 21-27Article in journal (Refereed)
  • 14.
    Reichert, G.
    et al.
    BIOENERGY 2020+ GmbH.
    Schmidl, C.
    BIOENERGY 2020+ GmbH.
    Haslinger, Walter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. BIOENERGY 2020+ GmbH.
    Stressler, H.
    BIOENERGY 2020+ GmbH.
    Sturmlechner, R.
    BIOENERGY 2020+ GmbH.
    Schwabl, M.
    BIOENERGY 2020+ GmbH.
    Wöhler, M.
    University of Applied Forest Sciences Rottenburg.
    Hochenauer, C.
    Graz University of Technology, Institute of Thermal Engineering, Thermal Energy Systems and Biomass.
    Impact of oxidizing honeycomb catalysts integrated in firewood stoves on emissions under real-life operating conditions2018In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 177, p. 109-118Article in journal (Refereed)
    Abstract [en]

    Catalytic systems integrated in firewood stoves represent a secondary measure for emission reduction. This study evaluates the impact on emissions of two types of honeycomb catalysts integrated in different firewood stoves. The tests were conducted under real-life related testing conditions. The pressure drop induced by the catalyst's carrier geometry affects primary combustion conditions which can influence the emissions. A negative primary effect reduces the catalytic efficiency and has to be considered for developing catalyst integrated solutions. However, a significant net emission reduction was observed. The ceramic catalyst reduced CO emissions by 83%. The metallic catalyst reduced CO emissions by 93% which was significantly better compared to the ceramic catalyst. The net emission reduction of OGC (~30%) and PM (~20%) was similar for both types of catalysts. In most cases, the “Ecodesign” emission limit values, which will enter into force in 2022 for new stoves, were met although the ignition and preheating batches were respected. PM emission composition showed a lower share of elemental (EC) and organic carbon (OC) with integrated catalyst. However, no selectivity towards more reduction of EC or OC was observed. Further investigations should evaluate the long term stability under real-life operation in the field and the effect of the catalyst on polycyclic aromatic hydrocarbon (PAH) emissions.

  • 15.
    Samuelsson, Lina N.
    et al.
    Department of Chemical Engineering and Technology, KTH Royal Institute of Technology.
    Umeki, Kentaro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Babler, Matthaus U.
    Department of Chemical Engineering and Technology, KTH Royal Institute of Technology.
    Mass loss rates for wood chips at isothermal pyrolysis conditions: A comparison with low heating rate powder data2017In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 158, p. 26-34Article in journal (Refereed)
    Abstract [en]

    Spruce chips of three different thicknesses were pyrolyzed isothermally in a vertical furnace macro-TGA at 574 to 676K, which is the temperature range relevant for char production. The measured mass loss data was analyzed in terms of mass loss rate, thermal lag and char yield as a function of chip size and pyrolysis temperature. The char yield decreased with increasing temperature and there was no significant difference in char yield as a function of sample thickness, ranging from 1mm to 7mm. Thermal lag was present for all chip sizes above 600K. At 574K the data suggests that chips below 1mm in thickness are decomposing at rates governed by reaction kinetics. An isoconversional kinetic model based on low heating rate data of spruce powder was adopted to analyze the data. The model predicted lower mass loss rates than those measured for the chips, suggesting that the pyrolysis process of wood proceeds through a network of parallel reactions. Despite this, the model could predict the final char yield of the wood chips with an accuracy above 80%. The predictive capability of the isoconversional reaction rate expression is promising since the procedure to derive such a rate expression is straight-forward, compared to the conventional model-fitting methods. The data and modeling approach presented in this work is important to the field of biomass pyrolysis as it covers the temperature range and chip sizes relevant for pyrolysis in multi-staged gasification plants which has been given little attention.

  • 16.
    Sefidari, Hamid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lindblom, Bo
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. Luossavaara-Kiirunavaara Aktiebolag (LKAB).
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE ETC (Energy Technology Centre) AB.
    Nordin, Lars Olof
    Loussavaara-Kiirunavaara Limited, Luleå.
    Lennartsson, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bhuiyan, Iftekhar Uddin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace: Part II: Thermochemical equilibrium calculations and viscosity estimations2018In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 180, p. 189-206Article in journal (Refereed)
    Abstract [en]

    Fly ash particles from the combustion of solid-fuels together with disintegrated particles arising from iron-ore pellets result in accumulation of deposits on the refractory linings of the grate-kiln induration machine during the iron-ore pelletizing process. The deposits amass in the high-temperature regions of the induration furnace thus disturbing the flow of gas and pellets. Therefore, to tackle the above-mentioned issues, an understanding of deposit formation mechanism is of crucial importance. This study was conducted with the objective of addressing the effect of disintegrated iron-ore pellet dust on deposit formation and the mechanisms behind deposition (slagging) in the grate-kiln process. A comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal- fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale setup. Fly ash particles and short-term deposits were characterized and deposition was addressed in Part I of this study. In light of the experimental observations (Part I) and the thermochemical equilibrium calculations (Part II), a scheme of ash transformation during the iron-ore pelletizing process was proposed. The dissolution of hematite particles into the Ca-rich-aluminosilicate melt (from the coal-ash constituents) decreased the viscosity and resulted in the formation of stronger (heavily sintered) deposits. Overall, this pilot-scale work forms part of a wider study which aims at deepening the understanding of ash transformation phenomena during the large-scale pelletizing process.

  • 17.
    Sefidari, Hamid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lindholm, Bo
    Luossavaara-Kiirunavaara Aktiebolag (LKAB).
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE ETC (Energy Technology Centre) AB.
    Nordin, Lars Olof
    Loussavaara-Kiirunavaara Limited, Luleå.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bhuiyan, Iftekhar Uddin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace: Part I: Characterization of process gas particles and deposits2018In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 177, p. 283-298Article in journal (Refereed)
    Abstract [en]

    o initiate the elucidation of deposit formation during the iron-ore pelletization process, a comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal-fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale grate-kiln setup. Particles and deposits were sampled from 3 positions of different temperature via a water-cooled sampling probe. Three distinct fragmentation modes were identified based on the aerodynamic particle diameter (Dp). The fine mode: Particles with 0.03 < Dp < 0.06 μm. The first fragmentation mode: Particles with 1 < Dp < 10 μm. The second fragmentation mode: Coarse particles (cyclone particles, Dp > 10 μm). A transition from a bimodal PSD (particle size distribution) to a trimodal PSD was observed when pellet dust was added (Case 3) and consequently the elemental bulk composition of the abovementioned modes was changed. The most extensive interaction between pellet dust and coal-ash particles was observed in the coarse mode where a significant number of coal ash globules were found attached to the surface of the hematite particles. The morphology of the sharp-edged hematite particles was changed to smooth-edged round particles which proved that hematite particles must have interacted with the surrounding aluminosilicate glassy phase originating from the coal ash. The short-term deposits collected during coal combustion (Case 1) were highly porous in contrast to the high degree of sintering observed in the experiments with pellet dust addition (Case 3) which is attributed to the dissolution of hematite particles in the aluminosilicate glassy phase. The results suggest that pellet dust itself (Case 2) has low slagging tendency, independent of temperature. However, when coal-ash is present (Case 3), auxiliary phases are added such that tenacious particles are formed and slagging occurs.

  • 18.
    Sefidari, Hamid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. Luossavaara-Kiirunavaara Aktiebolag (LKAB), Luleå, Sweden.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE ETC (Energy Technology Centre) AB, Piteå, Sweden.
    Lindblom, Bo
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. Luossavaara-Kiirunavaara Aktiebolag (LKAB), Luleå, Sweden.
    Nordin, Lars Olof
    Luossavaara-Kiirunavaara Aktiebolag (LKAB), Luleå, Sweden.
    Wu, G
    GTT Technologies, Herzogenrath, Germany.
    Yazhenskikh, E
    Institute of Energy and Climate Research, Microstructure and Properties of Materials (IEK-2), Forschungszentrum Jülich GmbH, Jülich, Germany.
    Müller, M
    Institute of Energy and Climate Research, Microstructure and Properties of Materials (IEK-2), Forschungszentrum Jülich GmbH, Jülich, Germany.
    Ma, C
    Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory, Umeå University, Umeå, Sweden.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Comparison of high-rank coals with respect to slagging/deposition tendency at the transfer-chute of iron-ore pelletizing grate-kiln plants: A pilot-scale experimental study accompanied by thermochemical equilibrium modeling and viscosity estimations2019In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 193, p. 244-262Article in journal (Refereed)
    Abstract [en]

    Iron-ore pelletizing plants use high-rank coals to supply the heat necessary to process ores. Ash material from coal, in combination with iron-ore dust originating from the disintegration of the pellets, can cause deposition/slagging which often leads to severe production losses and damage. Deposition/slagging is most prominent in the hot areas of the grate-kiln setup and is more severe at the inlet of the rotary-kiln, i.e., the transfer-chute. Following on from our previous work, high-rank bituminous coals with potential for use in the pelletizing process were combusted in a pilot-scale (0.4 MW) pulverized-coal fired experimental combustion furnace (ECF). The fly-ash particles and short-term deposits were characterized to shed light on the observed difference in slagging/deposition tendencies of the coals. Global thermodynamic equilibrium modeling, in combination with viscosity estimates, was used to interpret the experimental findings and investigate the effect of the coal-ash composition upon deposition/slagging. This approach was carried out with and without the presence of Fe2O3-rich pellet-dust under oxidizing conditions within the temperature range at the transfer-chute of iron-ore pelletizing rotary-kilns. Based on the findings, a Qualitative Slagging Indicator (QSI) was proposed that can help pre-screen new solid fuels for potential slagging issues. The proposed QSI highlights the following: (1) an inverse relationship between viscosity and slagging/deposition tendency of the coals was observed (2) as viscosity decreases (either with increasing temperature or due to the change in the coal-ash composition), stronger deposits will form that will complicate the mechanical removal of the deposited layer. It was therefore inferred that low viscosity molten phases facilitate deposition/slagging, which is exacerbated by the presence of fluxing agents (e.g., CaO, MgO, K2O, Na2O, and Fe2O3) in the deposits. The low viscosity coal-ash-induced molten phases are also more likely to interact with the Fe2O3-rich pellet-dust that results in further decreases in viscosity, thereby intensifying depositions. The results from this work complement the on-going research by our group to elucidate and alleviate ash-related problems in industrial grate kilns.

  • 19.
    Skoglund, Nils
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bäfver, Linda
    SP Sveriges Tekniska Forskningsinstitut, SP Energiteknik, Pöyry SwedPower AB.
    Fahlström, Johan
    Rang-Sells Miljökonsult AB.
    Holmén, Erik
    ENA Energy AB.
    Renström, Caroline
    Pöyry SwedPower AB.
    Fuel design in co-combustion of demolition wood chips and municipal sewage sludge2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 141, no 2, p. 196-201Article in journal (Refereed)
    Abstract [en]

    Municipal sewage sludge (MSS) is a waste stream resource which contains both energy and elements such as phosphorus which could be recycled. If these two aspects of this waste stream resource are to be used to their full potential the sludge should not be used in landfills or road construction. There is some use of sludge in agriculture today but not all MSS produced is suitable for direct use on arable land due to its content of potentially harmful elements, pathogens or anthropogenic chemicals. By combusting sludge that is not used directly in agriculture the problematic organic content could be destroyed. The combustion process also produces an ash that possibly could be used either directly in agriculture or as a raw material for recovering phosphorus and energy could be recovered. Building mono-combustion plants for sewage sludge is not economically feasible in all parts of the world so it is of interest to investigate how MSS can be introduced together with other fuels in existing infrastructure which already have extensive cleaning systems for potentially harmful elements.To investigate this possible path, demolition wood chips (DWC) were co-combusted with municipal sewage sludge (MSS) in a grate-fired combined heat and power plant running at 50% capacity producing 25 MWth and 9 MWel. The amount of MSS that was suitable to introduce in blends was determined using a “fuel fingerprint” based on the composition of the raw materials. Thermodynamic equilibrium calculations were made to evaluate potential problems with slagging based on the ash content prior to the combustion experiments. The fuels were introduced as a reference case with only demolition wood and pre-blended fuel mixtures in two ratios; 65 w/w-% DWC/35 w/w-% MSS and 55 w/w-% DWC/45 w/w-% MSS and were fired for 12 h. The high water content of the MSS affected how much MSS that could be introduced without compromising the heat and power production.The fuel blends worked nicely for 12 h of continuous combustion with small adjustments where the primarily the air inlet configuration was changed. The main problems encountered related to cleaning of the flue gases and to some extent ash removal. The bed ash and fly ash produced was analysed both using ICP-AES (elemental) and XRD (speciation) and the bottom ash was subjected to ash melting tests. The major nutrient phosphorus was mainly found in bottom ash (80 w/w-%) as whitlockites with some hydroxyapatite whereas fly ash (20 w/w-%) contained larger amounts of hydroxyapatite, especially for the reference fuel. The amount of alkali chloride in the fly ash was reduced in favour of alkali sulphate formation.

  • 20.
    Skoglund, Nils
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Werner, Kajsa
    Thermochemical Energy Conversion Laboratory (TEC-Lab), Department of Applied Physics and Electronics, Umeå University.
    Nylund, Göran M.
    Department of Marine Sciences - Tjärnö, University of Gothenburg.
    Pavia, Henrik
    Department of Marine Sciences - Tjärnö, University of Gothenburg.
    Albers, Eva
    Division Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology.
    Broström, Markus
    Thermochemical Energy Conversion Laboratory (TEC-Lab), Department of Applied Physics and Electronics, Umeå University.
    Combustion of seaweed: A fuel design strategy2017In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 165, p. 155-161Article in journal (Refereed)
    Abstract [en]

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

  • 21.
    Trubetskaya, Anna
    et al.
    Department of Chemical and Biochemical Engineering, Technical University of Denmark.
    Jensen, Peter Arendt
    Department of Chemical and Biochemical Engineering, Technical University of Denmark.
    Jensen, Anker Degn
    Department of Chemical and Biochemical Engineering, Technical University of Denmark.
    Llamas, Angel David Garcia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Umeki, Kentaro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Glarborg, Peter
    Department of Chemical and Biochemical Engineering, Technical University of Denmark.
    Effect of fast pyrolysis conditions on biomass solid residues at high temperatures2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 143, p. 118-129Article in journal (Refereed)
    Abstract [en]

    Fast pyrolysis of wood and straw was conducted in a drop tube furnace (DTF) and compared with corresponding data from a wire mesh reactor (WMR) to study the influence of temperature (1000-1400)°C, biomass origin (pinewood, beechwood, wheat straw, alfalfa straw), and heating rate (103 °C/s, 104 °C/s) on the char yield and morphology. Scanning electron microscopy (SEM), elemental analysis, and ash compositional analysis were applied to characterize the effect of operational conditions on the solid residues (char, soot) and gaseous products. The char yield from fast pyrolysis in the DTF setup was 3 to 7% (daf) points lower than in the WMR. During fast pyrolysis pinewood underwent drastic morphological transformations, whereas beechwood and straw samples retained the original porous structure of the parental fuel with slight melting on the surface. The particle size of Danish wheat straw char decreased in its half-width with respect to the parental fuel, whereas the alfalfa straw char particle size remained unaltered at higher temperatures. Soot particles in a range from 60 to 300 nm were obtained during fast pyrolysis. The soot yield from herbaceous fuels was lower than from wood samples, possibly due to differences in the content of lignin and resin acids

  • 22.
    Trubetskaya, Anna
    et al.
    Department of Chemical and Biochemical Engineering, Denmark Technical University.
    Jensen, Peter Arendt
    Department of Chemical and Biochemical Engineering, Denmark Technical University.
    Jensen, Anker Degn
    Department of Chemical and Biochemical Engineering, Denmark Technical University.
    Steibel, Markus
    Department of Mechanical Engineering, Institute for Energy Systems, Technical University of Munich.
    Spliethoff, Hartmut
    Department of Mechanical Engineering, Institute for Energy Systems, Technical University of Munich.
    Glarborg, Peter
    Department of Chemical and Biochemical Engineering, Denmark Technical University.
    Influence of fast pyrolysis conditions on yield and structural transformation of biomass chars2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 140, p. 205-214Article in journal (Refereed)
    Abstract [en]

    Fast pyrolysis of biomass (wood, straw, rice husk) and its major components (cellulose, hemicellulose, lignin) was conducted in a wire mesh reactor. The aim of this study was to understand the influence of temperature (350-1400 ∗ C), heating rate (10-3000 ∗ C/s), particle size (0.05-2 mm) and holding time (1-4 s) on the char morphology and char yield. Scanning electron microscopy (SEM) and elemental analysis were conducted to determine the effect of operating conditions on char softening and melting during pyrolysis. The char yield decreased with heating rate for rates ≤ 600 ∗ C/s; above this value a similar biomass char yield was obtained. The potassium content affected the char yield stronger than other minerals, while the distribution of the three major biomass constituents (cellulose, hemicellulose, lignin) affected the char yield only to a minor degree. Moreover, it was found that the heat treatment temperature had a larger influence on the char yield than the heating rate. Scanning electron microscopy indicated different types of biomass char plasticization influenced by the applied temperatures, heating rates, particle sizes and holding times, except for the rice husk char that formed chars with a structure similar to the parental fuel at all conditions. The less severe morphological changes of rice husk char were attributed to a high silica content.

  • 23.
    Trubetskaya, Anna
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Poyraz, Yunus
    Institute of Energy Processes Engineering and Fuel Technology, Clausthal University of Technology.
    Weber, Roman
    Institute of Energy Processes Engineering and Fuel Technology, Clausthal University of Technology.
    Wadenbäck, Johan
    Amager power plant, HOFOR A/S.
    Secondary comminution of wood pellets in power plant and laboratory-scale mills2017In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 160, p. 216-227Article in journal (Refereed)
    Abstract [en]

    This study aims to determine the influence of mill type and pellet wood composition on particle size and shape of milled wood. The size and shape characteristics of pellets comminuted using power plant roller mills were compared with those obtained by using laboratory-scale roller- and hammer mills. A 2D dynamic imaging device was used for particle characterization. It was shown that mill type has a significant impact on particle size but an almost negligible effect on the shape of milled wood. Comminution in the pilot plant using a Loesche roller mill requires less energy than using a hammer mill, but generates a larger fraction of coarse particles. The laboratory-scale roller mill provides comparable results with the power plant roller mill with respect to particle size and shape.

  • 24.
    Umeki, Kentaro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Namioka, Tomoaki
    Tokyo Institute of Technology.
    Yoshikawa, Kunio
    Tokyo Institute of Technology.
    The effect of steam on pyrolysis and char reactions behavior during rice straw gasification2012In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 94, no 1, p. 53-60Article in journal (Refereed)
    Abstract [en]

    Steam gasification of biomass can generate hydrogen-rich, medium heating value gas. We investigated pyrolysis and char reaction behavior during biomass gasification in detail to clarify the effect of steam presence. Rice straw was gasified in a laboratory scale, batch-type gasification reactor. Time-series data for the yields and compositions of gas, tar and char were examined under inert and steam atmosphere at the temperature range of 873–1173 K. Obtained experimental results were categorized into those of pyrolysis stage and char reaction stage. At the pyrolysis stage, low H2, CO and aromatic tar yields were observed under steam atmosphere while total tar yield increased by steam. This result can be interpreted as the dominant, but incomplete steam reforming reactions of primary tar under steam atmosphere. During the char reaction stage, only H2 and CO2 were detected, which were originated from carbonization of char and char gasification with steam (C + H2O→CO + H2). It implies the catalytic effect of char on the water–gas shift reaction. Acceleration of char carbonization by steam was implied by faster hydrogen loss from solid residue.

  • 25.
    Weiland, Fredrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Nordwaeger, Martin
    Umeå University. Department of Applied Physics and Electronics.
    Olofsson, Ingemar
    Umeå University. Department of Applied Physics and Electronics.
    Nordin, Anders
    Umeå University. Department of Applied Physics and Electronics.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Entrained flow gasification of torrefied wood residues2014In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 125, p. 51-58Article in journal (Refereed)
    Abstract [en]

    In this work, four different fuels were gasified in a pressurized entrained flow pilot plant gasifier at approximately 270 kWth. The different fuels were; two torrefied wood residues, one raw wood residue and one torrefied stem wood. The system pressure and oxygen equivalence ratio (λ) were held constant for all four gasification experiments. It was found that the torrefaction pretreatment significantly reduced the milling energy consumption for fuel size reduction, which in turn contributed to increased gasification plant efficiency. Furthermore, the results indicate that the carbon conversion efficiency may be enhanced by an intermediate torrefaction pretreatment, whereas both less severe torrefaction and more severe torrefaction resulted in reduced carbon conversions. The results also indicate that the CH4 yield was significantly reduced for the most severely torrefied fuel.

  • 26.
    Wiinikka, Henrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Johansson, Ann-Christine
    Energy Technology Centre, Piteå.
    Wennebro, Jonas
    SP Energy Technology Center AB.
    Carlsson, Per
    Energy Technology Centre, Piteå.
    Öhrman, Olov
    Energy Technology Centre, Piteå.
    Evaluation of black liquor gasification intended for synthetic fuel or power production2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 139, p. 216-225Article in journal (Refereed)
    Abstract [en]

    The performance of a high-temperature pressurized black liquor gasifier intended for fuel or power production was evaluated both by thermochemical equilibrium calculations and with experiments performed in a development plant with a maximum capacity corresponding to 3 MWth. The aim of this paper was to investigate how the energy efficiency and the performance of the gasifier change with desired use of the syngas and to provide an accurate process analysis which can be used in future work for process optimization and understanding. Experiments in the plant were performed for an oxygen equivalence ratio (lambda) between 0.414-0.462 at two system pressures, 24.6 and 28.7 bar, respectively. The thermal load on the gasifier was 2.7 MWth during the experiments. The experimentally verified cold gas efficiency taking into account all gaseous species varied between 59.0-62.4%. However, if only CO and H-2 (which are the effective molecules for synthetic fuel production) were taken into account; the cold gas efficiency decreased considerably to 53.7-55.4% due to the presence of CH4 in the gas. The results indicate that optimal performance for synthetic fuel production occurs at a higher lambda compared to power production. There is also a potential to further improve the performance for an optimal operated commercial plant in the future since the theoretical results indicate that the cold gas efficiency could be as high as 68.8% (lambda = 035) for fuel production and 81.7% (lambda = 0.27) for power production. (C) 2015 Elsevier B.V. All rights reserved.

  • 27.
    Zhang, Qinglin
    et al.
    Royal Institute of Technology (KTH), School of Industrial Engineering and Management, Department of Material Science and Engineering, Division of Energy and Furnace Technology.
    Dor, Liran
    Environmental Energy Resources Ltd..
    Biswas, Amit
    Royal Institute of Technology (KTH), School of Industrial Engineering and Management, Department of Material Science and Engineering, Division of Energy and Furnace Technology.
    Yang, Weihong
    Royal Institute of Technology (KTH), School of Industrial Engineering and Management, Department of Material Science and Engineering, Division of Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    Royal Institute of Technology (KTH), School of Industrial Engineering and Management, Department of Material Science and Engineering, Division of Energy and Furnace Technology.
    Modeling of steam plasma gasification for municipal solid waste2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 106, p. 546-554Article in journal (Refereed)
    Abstract [en]

    Plasma gasification melting (PGM) is a promising gasification technology aiming at providing sustainable disposal for various wastes. In this work, an Euler-Euler multiphase model was developed to study the characteristics of air and steam gasification of municipal solid waste in a PGM reactor. The model is validated by measurement data from a demonstration PGM reactor. With this model, three groups of simulations were performed to study the influences of operating conditions. It is confirmed that injection of high temperature steam is important for increasing the cold gas efficiency and syngas lower-heating-value. The effect of steam injection is affected by steam feeding rate, air feeding rate and plasma power. Based on the simulated results, an optimal condition is suggested for air and steam gasification in the PGM reactor. © 2012 Elsevier B.V.

  • 28.
    Ögren, Yngve
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE-Energy Technology Center AB, Piteå, Sweden.
    Gullberg, Marcus
    RISE-Energy Technology Center AB, Piteå, Sweden.
    Wennebro, Jonas
    RISE-Energy Technology Center AB, Piteå, Sweden.
    Sepman, Alexey
    RISE-Energy Technology Center AB, Piteå, Sweden.
    Tóth, Pál
    RISE-Energy Technology Center AB, Piteå, Sweden. University of Miskolc, Department of Combustion and Thermal Energy, Miskolc-Egyetemváros, Miskolc, Hungary.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE-Energy Technology Center AB, Piteå, Sweden.
    Influence of oxidizer injection angle on the entrained flow gasification of torrefied wood powder2018In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 181, p. 8-17Article in journal (Refereed)
    Abstract [en]

    In the present work, 5 different axisymmetric burners with different directions of the oxidizer inlets were experimentally tested during oxygen blown gasification of torrefied wood powder. The burners were evaluated under two different O2/fuel ratios at a thermal power of 135 kWth, based on the heating value of torrefied wood powder. The evaluation was based on both conventional methods such as gas chromatography measurements and thermocouples and in-situ measurements using Tunable Diode Laser Absorption Spectroscopy. It was shown that changes in the near burner region influence the process efficiency significantly. Changing the injection angle of the oxidizer stream to form a converging oxidizer jet increased process efficiency by 20%. Besides increased process efficiency, it was shown that improvements in burner design also influence carbon conversion and hydrocarbon production. The burner with the best performance also produced less CH4 and achieved the highest carbon conversion. The effect of generating swirl via rotating the oxidizer jet axes was also investigated. Swirl broadened or removed the impingement area between the fuel and oxidizer jets, however resulting in differences in performance within the measurement uncertainty. 

  • 29. Öhrman, Olov
    et al.
    Weiland, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Pettersson, Esbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Johansson, Ann-Christine
    Energy Technology Centre, Piteå.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Pedersen, Mads
    Biogasol, Lautrupvang 2A, 2750 Ballerup.
    Pressurized oxygen blown entrained flow gasification of a biorefinery lignin residue2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 115, p. 130-138Article in journal (Refereed)
    Abstract [en]

    Renewable fuels could in the future be produced in a biorefinery which involves highly integrated technologies. It has been reported that thermochemical conversion (gasification) of lignocellulosic biomass has a high potential for end production of renewable biofuels. In this work, lignin residue from biochemical conversion of wheat straw was gasified in an oxygen blown pressurized entrained flow gasifier (PEBG) at 0.25–0.30 MWth, 0.45 < λ < 0.5 and 1 bar (g). A video camera mounted inside the PEBG was used to observe the flame during start up and during operation. Hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2) were the main gas components with H2/CO ratios varying during the gasification test (0.54–0.63). The methane (CH4) concentration also varied slightly and was generally below 1.7% (dry and N2 free). C2-hydrocarbons (< 1810 ppm) and benzene (< 680 ppm) were also observed together with low concentrations of hydrogen sulfide (H2S, < 352 ppm) and carbonyl sulfide (COS, < 131 ppm). The process temperature in the reactor was around 1200 °C. The slag seemed to consist of Cristobalite (SiO2) and Berlinite (AlPO4) and Na, Ca, Mg, K and Fe in lower concentrations. Cooling of the burner will be necessary for longer tests to avoid safety shut downs due to high burner temperature. The cold gas efficiency and carbon conversion was estimated but more accurate measurements, especially the syngas flow, needs to be determined during a longer test in order to obtain data on the efficiency at optimized operating conditions. The syngas has potential for further upgrading into biofuels, but will need traditional gas cleaning such as acid gas removal and water gas shifting. Also, higher pressures and reducing the amount of N2 is important in further work.

1 - 29 of 29
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