Change search
Refine search result
12 1 - 50 of 55
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Boman, Christoffer
    et al.
    Umeå universitet.
    Mudway, I.S.
    King's College London.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Pettersson, Esbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Nyström, R.
    Umeå universitet.
    Grönberg, C.
    Energy Technology Centre, Piteå.
    Öhrman, Olov
    Pagels, J.
    Ergonomics and Aerosol Technology, Lund University.
    Swietlicki, E.
    Nuclear Physics, Lund University.
    Genberg, J.
    Nuclear Physics, Lund University.
    Westerholm, R.
    Analytical Chemistry, Stockholm University.
    Blomberg, A.
    Department of Public Health and Clinical Medicine, Umeå university.
    Sandström, T.
    Department of Public Health and Clinical Medicine, Umeå university.
    In vitro screening of biomass combustion aerosol toxicity: Part 1: Oxidative potential2011In: Wärme aus Holz – Feinstaubemissionen: Scientific Contributions, 2011Conference paper (Other academic)
  • 2.
    Boman, Christoffer
    et al.
    Umeå universitet.
    Nordin, Anders
    Umeå universitet.
    Pettersson, Esbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    State-of-the-art of small-scale biomass combustion with respect to fine particle emissions: country report from Sweden2008In: Tagungsband: proceedings; Graz (Österreich) 16. - 19. Jänner 2008, Wien: Österreichischer Biomasse-Verband , 2008Conference paper (Other academic)
  • 3.
    Boman, Christoffer
    et al.
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Nyström, Robin
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Sandström, Thomas
    Institutet för Folkhälsa och klinisk medicin, Enheten för medicin/Lungmedicin och allergologi, Umeå universitet.
    Blomberg, Anders
    Institutet för Folkhälsa och klinisk medicin, Enheten för medicin/Lungmedicin och allergologi, Umeå universitet.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Grönberg, Carola
    Energy Technology Centre, Piteå.
    Öhrman, Olov
    Bäfver, Linda
    SP Sveriges Tekniska Forskningsinstitut, SP Energiteknik.
    Rönnbäck, Marie
    SP Sveriges Tekniska Forskningsinstitut, SP Energiteknik.
    Ryde, Daniel
    SP Sveriges Tekniska Forskningsinstitut, SP Energiteknik.
    Johansson, Mathias
    SP Sveriges Tekniska Forskningsinstitut, SP Energiteknik.
    Pagels, Joakim
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Nordin, Erik
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Rissler, Jenny
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Swietlicki, Erik
    Avdelningen för Kärnfysik, Lunds tekniska högskola.
    Eriksson, Axel
    Avdelningen för Kärnfysik, Lunds tekniska högskola.
    Genberg, Johan
    Avdelningen för Kärnfysik, Lunds tekniska högskola.
    Pettersson, Esbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Larsson, Lennart
    Institutet för Laboratoriemedicin, Lunds universitet.
    Strand, Michael
    Avdelningen för Bioenergiteknik, Linnéuniversitet.
    Emissioner från småskalig värmeproduktion med biobränslen: Ett samordnat projekt som berör hälsopåverkande partikel- och tungmetallutsläpp från tradionella och alternativa biobränslen2011Report (Other academic)
  • 4.
    Boman, Christoffer
    et al.
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Nyström, Robin
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Grönberg, Carola
    Energy Technology Centre, Piteå.
    Öhrman, Olov
    Pettersson, Esbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Sandström, Thomas
    Institutet för Folkhälsa och klinisk medicin, Enheten för medicin/Lungmedicin och allergologi, Umeå.
    Blomberg, Anders
    Institutet för Folkhälsa och klinisk medicin, Enheten för medicin/Lungmedicin och allergologi, Umeå.
    Mudway, Ian S.
    King´s College London, MRC-HPA Centre for Environment and Health, School Biomedical & Health Science.
    Westerholm, Roger
    Institutet för Analytisk kemi, Stockholms universitet.
    Pagels, Joakinm
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Swietlicki, Erik
    Avdelningen för Kärnfysik, Lunds tekniska högskola.
    Genberg, Johan
    Avdelningen för Kärnfysik, Lunds tekniska högskola.
    Inverkan av förbränningsteknik och bränsle på hälsofarligheten av partikelemissioner från småskalig biobränsleeldning2011In: Emissioner från småskalig värmeförsörjning med biobränslen: Ett samordnat projekt som berör hälsopåverkande partikel- och tungmetallutsläpp från traditionella och alternativa biob, Umeå: Umeå universitet , 2011Chapter in book (Other academic)
  • 5.
    Carlborg, Markus
    et al.
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umeå University.
    Weiland, Fredrik
    RISE Energy Technology Center.
    Ma, Charlie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Backman, Rainer
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umeå University.
    Landälv, Ingvar
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE Energy Technology Center.
    Exposure of refractory materials during high-temperature gasification of a woody biomass and peat mixture2018In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 38, no 2, p. 777-787Article in journal (Refereed)
    Abstract [en]

    Finding resilient refractory materials for slagging gasification systems have the potential to reduce costs and improve the overall plant availability by extending the service life. In this study, different refractory materials were evaluated under slagging gasification conditions. Refractory probes were continuously exposed for up to 27 h in an atmospheric, oxygen blown, entrained flow gasifier fired with a mixture of bark and peat powder. Slag infiltration depth and microstructure were studied using SEM EDS. Crystalline phases were identified with powder XRD. Increased levels of Al, originating from refractory materials, were seen in all slags. The fused cast materials were least affected, even though dissolution and slag penetration could still be observed. Thermodynamic equilibrium calculations were done for mixtures of refractory and slag, from which phase assemblages were predicted and viscosities for the liquid parts were estimated.

  • 6.
    Carlsson, Per
    et al.
    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.
    Grönberg, Carola
    Energy Technology Centre, Piteå.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Risberg, Mikael
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Öhrman, Olov
    Spatially resolved measurements of gas composition in a pressurised black liquor gasifier2009In: Environmental Progress & Sustainable Energy, ISSN 1944-7442, E-ISSN 1944-7450, Vol. 28, no 3, p. 316-323Article in journal (Refereed)
    Abstract [en]

    Black liquor gasification is a new process for recovery of energy and chemicals in black liquor from the Kraft pulping process. The process can be combined with catalytic conversion of syngas into motor fuels. The potential for motor fuel production from black liquor in Sweden is to replace about 25% of the current consumption of gasoline and diesel. For Finland the figure is even higher while for Canada it is about 14% and for the USA about 2%.

  • 7.
    Carlsson, Per
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lycksam, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Gren, Per
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Gebart, Rikard
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Iisa, Kristiina
    National Renewable Energy Laboratory, Golden, Colorado.
    High-speed imaging of biomass particles heated with a laser2013In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 103, p. 278-286Article in journal (Refereed)
    Abstract [en]

    In this work two types of lignocellulosic biomass particles, European spruce and American hardwood (particle sizes from 100 μm to 500 μm) were pyrolysed with a continuous wave 2 W Nd:YAG laser. Simultaneously a high-speed camera was used to capture the behavior of the biomass particle as it was heated for about 0.1 s. Cover glasses were used as a sample holder which allowed for light microscope studies after the heating. Since the cover glasses are not initially heated by the laser, vapors from the biomass particle are quenched on the glass within about 1 particle diameter from the initial particle. Image processing was used to track the contour of the biomass particle and the enclosed area of the contour was calculated for each frame.The main observations are: There is a significant difference between how much surface energy is needed to pyrolyses the spruce (about 75% more) compared to the hardwood. The oil-like substance which appeared on the glass during the experiment is solid at room temperature and shows different levels of transparency. A fraction of this substance is water soluble. A brownish coat is seen on the unreacted biomass. The biomass showed insignificant swelling as it was heated. The biomass particle appears to melt and boil at the front that is formed between the laser beam and the biomass particle. The part of the particle that is not subjected to the laser beam seems to be unaffected.

  • 8.
    Carlsson, Per
    et al.
    Energy Technology Centre, Piteå.
    Ma, Charlie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Molinder, Roger
    Energy Technology Centre, Piteå.
    Weiland, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Öhrman, Olov
    Energy Technology Centre, Piteå.
    Slag Formation During Oxygen Blown Entrained-Flow Gasification of Stem Wood2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 11, p. 6941−6952-, article id 28Article in journal (Refereed)
    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

  • 9.
    Carlsson, Per
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Furusjö, Erik
    Chemrec.
    Wiinikka, Henrik
    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.
    Black liquor gasification: CFD model predictions compared with measurements2010In: 2010 International Chemical Recovery Conference Proceedings, Norcross, GA: TAPPI Press, 2010, Vol. 2, p. 160-171Conference paper (Refereed)
  • 10.
    Carlsson, Per
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Furusjö, Erik
    Chemrec.
    Wiinikka, Henrik
    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.
    Experiments and mathematical models of black liquor gasification: influence of minor gas components on temperature, gas composition, and fixed carbon conversion2010In: TAPPI Journal, ISSN 0734-1415, Vol. 9, no 9, p. 15-24Article in journal (Refereed)
    Abstract [en]

    In this work, predictions from a reacting Computational Fluid Dynamics (CFD) model of a gasification reactor are compared to experimentally obtained data from an industrial pressurized black liquor gasification plant. The data consists of gas samples taken from the hot part of the gasification reactor using a water cooled sampling probe. During the considered experimental campaign, the oxygen-to-black liquor equivalence ratio (λ) was varied in three increments, which resulted in a change in reactor temperature and gas composition. The presented numerical study consists of CFD and thermodynamic equilibrium calculations in the considered λ-range using boundary conditions obtained from the experimental campaign. Specifically, the influence of methane concentration on the gas composition is evaluated using both CFD and thermodynamic equilibrium. The results show that the main gas components (H2, CO, CO2) can be predicted within a relative error of 5% using CFD if the modeled release of H2S and CH4 are specified a priori. In addition, the calculations also show that the methane concentration has large influence on the reactor outlet temperature and final carbon conversion.

  • 11.
    Carlsson, Per
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Wiinikka, Henrik
    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.
    Comparison and validation of gas phase reaction schemes for black liquor gasification modeling2008In: Conference Proceedings 2008 AiChE annual meeting: Advances in gasification research, 2008Conference paper (Other academic)
    Abstract [en]

    Pressurized Entrained-flow High Temperature Black Liquor Gasification (PEHT-BLG) is a potential substitute or complement to the recovery boiler traditionally used for the recovery of chemicals and energy in black liquor in the Kraft pulping process. Black liquor consists of roughly 30 % moisture, 35 % inorganic pulping chemicals and 35 % combustible material (i.e. lignin). The PEHT-BLG technology can give an increase in total energy efficiency of the mill and provide new products with high added value, such as green motor fuels. The main parts of the recovery unit in the process are; a slagging refractory lined entrained-flow gasification reactor, with a gas assisted burner nozzle producing small black liquor droplets, used for direct gasification of the black liquor at about 1000 °C to produce a ‘raw' syngas and a liquid smelt containing mainly Na2CO3 and Na2S; a quench cooler beneath the reactor where the product gas and smelt are separated and the smelt is dissolved in water forming green liquor; a counter current condenser (CCC) that cools the syngas and condenses water vapor and any volatile and tar species that may be present. The heat recovered from the gas condensation is used to generate low/medium pressure steam that can be used in the pulp and paper process. Furthermore, the chemicals in the green liquor are recovered as cooking chemicals in the downstream processing. Due to lack of demonstration of long term operation of the technology, a development (pilot) plant for PEHT-BLG (named DP-1) with a capacity of 20 tones dry solids/24h is in operation by the technology vendor Chemrec AB at the Energy Technology Centre in Piteå, Sweden. An important tool for reduction of the technical risk associated with scale up of new technology is a comprehensive CFD model for the PEHT-BLG reactor. The current model includes drying, pyrolysis, char gasification and smelt formation of black liquor droplets as well as a simplified gas phase reaction mechanism. The current model has been validated against the outlet gas composition after the Counter Current Condenser (CCC). The model predicted a CO / CO2 ratio that was approximately 50% higher compared to the measurements. However, it is possible that the well known water-gas shift reaction is active in the quench and this could explain that the experimentally determined gas composition after the CCC differs from the computational results at the outlet from the hot zone. Recently, in-situ measurements have been performed in the DP-1 reactor and a further validation of the model has been made possible. The measurements have been performed by sampling gas with a water-cooled suction probe from the lower part of the hot zone, followed by offline gas analyses. The present paper investigates the difference between the current CFD-model and a modified version with an additional CO + O2 reaction added to the simplified gas phase reaction scheme. The simulation results are compared against measurements obtained by the gas sampling probe in the DP-1 reactor. The results suggest that by implementing the additional CO + O2 reaction local flame temperature was increased significantly. However, the effect on volume average and outlet gas temperature was minimal.The results also showed that the CO + O2 reaction had very little effect on outlet gas composition when the reaction was implemented in the PEHT-BLG-CFD model

  • 12. Carlsson, Per
    et al.
    Wiinikka, Henrik
    Energy Technology Centre, Piteå.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Grönberg, Carola
    Energy Technology Centre, Piteå.
    Pettersson, Esbjörn
    Energy Technology Centre, Piteå.
    Lidman, Marcus
    Energy Technology Centre, Piteå.
    Gebart, Rikard
    Energy Technology Centre, Piteå.
    Experimental investigation of an industrial scale black liquor gasifier: 1. Influence of reactor operation parameters on product gas composition2010In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 89, no 12, p. 4025-4034Article in journal (Refereed)
    Abstract [en]

    A novel technology to mitigate the climate changes and improve energy security is Pressurized Entrained flow High Temperature Black Liquor Gasification (PEHT-BLG) in combination with an efficient fuel synthesis using the resulting syngas. In order to optimise the technology for use in a pulp and paper mill based biorefinery, it is of great importance to understand how the operational parameters of the gasifier affect the product gas composition. The present paper is based on experiments where gas samples were withdrawn from the hot part of a 3 MW entrained flow pressurized black liquor gasifier of semi industrial scale using a high temperature gas sampling system. Specifically, the influence of process conditions on product gas composition (CO2, CO, H2, CH4, H2S, and COS) were examined by systematically varying the operational parameters: system pressure, oxygen to black liquor equivalence ratio, black liquor flow rate to pressure ratio and black liquor pre-heat temperature. Due to the harsh environment inside the gasification reactor, gas sampling is a challenging task. However, for the purpose of the current study, a specially designed high temperature gas sampling system was successfully developed and used. The results, obtained from two separate experimental campaigns, show that all of the investigated operational parameters have a significant influence on the product gas composition and present valuable information about to the process characteristics.

  • 13.
    Gebart, Rikard
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Marklund, M.
    Energy Technology Centre, Piteå.
    Carlsson, Per
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Grönberg, C.
    Weiland, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Johansson, A-C
    Öhrman, Olov
    Recent advances in the understanding of pressurized black liquor gasification2011In: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 45, no 7-8, p. 521-526Article in journal (Refereed)
  • 14.
    Holmgren, Per
    et al.
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Wagner, David R.
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Strandberg, Anna
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Molinder, Roger
    RISE Energy Technology Center.
    Wiinikka, Henrik
    RISE Energy Technology Center.
    Umeki, Kentaro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Broström, Markus
    Thermochemical Energy Conversion Laboratory (TEC-Lab), Department of Applied Physics and Electronics, Umeå University.
    Size, shape, and density changes of biomass particles during rapid devolatilization2017In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 206, p. 342-351Article in journal (Refereed)
    Abstract [en]

    Particle properties such as size, shape and density play significant roles on particle flow and flame propagation in pulverized fuel combustion and gasification. A drop tube furnace allows for experiments at high heating rates similar to those found in large-scale appliances, and was used in this study to carry out experiments on pulverized biomass devolatilization, i.e. detailing the first stage of fuel conversion. The objective of this study was to develop a particle conversion model based on optical information on particle size and shape transformation. Pine stem wood and wheat straw were milled and sieved to three narrow size ranges, rapidly heated in a drop tube setup, and solid residues were characterized using optical methods. Different shape descriptors were evaluated and a shape descriptor based on particle perimeter was found to give significant information for accurate estimation of particle volume. The optical conversion model developed was proven useful and showed good agreement with conversion measured using a reference method based on chemical analysis of non-volatilized ash forming elements. The particle conversion model presented can be implemented as a non-intrusive method for in-situ monitoring of particle conversion, provided density data has been calibrated

  • 15.
    Jokiniemi, Jorma
    et al.
    University of Kuopio.
    Hytönen, Kati
    University of Kuopio.
    Tissari, Jarkko
    University of Kuopio.
    Obernberger, Ingwald
    Graz University of Technology.
    Brunner, Thomas
    Graz University of Technology.
    Bärnthaler, Georg
    Graz University of Technology.
    Friesenbichler, Joachim
    Graz University of Technology.
    Salonen, Raimo
    National Public Health Institute.
    Hirvonen, Maija-Riitta
    National Public Health Institute.
    Jalava, Pasi
    National Public Health Institute.
    Pennanen, Arto
    National Public Health Institute.
    Happo, Mikko
    National Public Health Institute.
    Vallius, Marko
    National Public Health Institute.
    Markkanen, Piia
    National Public Health Institute.
    Hartmann, Hans
    Technology and Support Centre of Renewable Raw Materials.
    Turowski, Peter
    Technology and Support Centre of Renewable Raw Materials.
    Rossmann, Paul
    Technology and Support Centre of Renewable Raw Materials.
    Ellner-Schubert, Frank
    Technology and Support Centre of Renewable Raw Materials.
    Boman, Christoffer
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Pettersson, Esbjörn
    Wiinikka, Henrik
    Energy Technology Centre, Piteå.
    Hillamo, Risto
    Finnish Metrological Institute, Air Quality Research.
    Saarnio, Karri
    Finnish Metrological Institute, Air Quality Research.
    Frey, Anna
    Finnish Metrological Institute, Air Quality Research.
    Saarikoski, Sanna
    Finnish Metrological Institute, Air Quality Research.
    Forsberg, Bertil
    Umeå University, Department of Public Health and Clinical Medicine.
    Biomass combustion in residential heating: particulate measurements, sampling and physiochemical and toxicological characterisation2008Report (Other academic)
  • 16.
    Jonsson, Carrie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Stjernberg, Jesper
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Wiinikka, Henrik
    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.
    Boström, Dan
    Umeå universitet.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Deposit formation in a grate-kiln plant for iron-ore pellet production: Part 1: Characterization of process gas particles2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 10, p. 6159-6170Article in journal (Refereed)
    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.

  • 17.
    Jonsson, Carrie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    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.
    Stjernberg, Jesper
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Comparison of particle and deposit formation between a full-scale grate-kiln plant (40 MW) and a pilot-scale pulverised coal-fired furnace (400 kW)2013Conference paper (Refereed)
    Abstract [en]

    The iron ore pelletizing industry utilizes the grate-kilnprocess to dry and sinter the pellets into finished product.The grate-kiln process has a known deposit formation issuethat needs to be further understood. Combustion ofpulverised coal in the rotary kiln generates fly ash particles;in addition to that, particles generated from disintegratediron ore pellets are also entrained in the process gas stream.The combined effect of both sources of particles cantherefore contribute to the deposit formation in the process.In this work, particle- and deposit formation were studiedboth from a full-scale grate-kiln plant (40 MW) and from apilot-scale pulverised coal fired furnace (400 kW). Particleswere collected with a water-cooled probe with nitrogen gasas dilution medium at the tip of the probe. The particleswere separated simultaneously with a pre-cyclone and a 13stages low-pressure impactor during samplings. Depositswere collected with a refractory plate which was attachedat the tip of a water-cooled probe, exposed to the hightemperature (>1100 °C) process gas stream. Particles anddeposits were characterized with an environmentalscanning electron microscope and a scanning electronmicroscope that equipped with energy dispersivespectroscopy detector. A comparison of particle and depositcharacteristics between the grate-kiln plant and the pilotscale pulverised coal fired furnace is presented in this paper,with focus on the potential influence of disintegrated ironore pellets on the particle- and deposit formation process.

  • 18.
    Ma, Charlie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Carlborg, Markus
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umeå University.
    Hedman, Henry
    SP Energy Technology Center AB.
    Wennebro, Jonas
    SP Energy Technology Center AB.
    Weiland, Fredrik
    SP Energy Technology Center AB.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. SP Energy Technology Center AB.
    Backman, Rainer
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umeå University.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ash Formation in Pilot-Scale Pressurized Entrained-Flow Gasification of Bark and a Bark/Peat Mixture2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 12, p. 10543-10554Article in journal (Refereed)
    Abstract [en]

    Pressurized entrained-flow gasification (PEFG) of bark and a bark/peat mixture (BPM) was carried out in a pilot-scale reactor (600 kWth, 7 bar(a)) with the objective of studying ash transformations and behaviors. The bark fuel produced a sintered but nonflowing reactor slag, while the BPM fuel produced a flowing reactor slag. Si was enriched within these slags compared to their original fuel ash compositions, especially in the bark campaign, which indicated extensive ash matter fractionation. Thermodynamically, the Si contents largely accounted for the differences in the predicted solidus/liquidus temperatures and melt formations of the reactor slags. Suspension flow viscosity estimations were in qualitative agreement with observations and highlighted potential difficulties in controlling slag flow. Quench solids from the bark campaign were mainly composed of heterogeneous particles resembling reactor fly ash particles, while those from the BPM campaign were flowing slags with likely chemical interactions with the wall refractory. Quench effluents and raw syngas particles were dominated by elevated levels of K that, along with other chemical aspects, indicated KOH(g) and/or K(g) were likely formed during PEFG. Overall, the results provide information toward development of woody biomass PEFG and indicate that detailed understanding of the ash matter fractionation behavior is essential.

  • 19.
    Moilanen, Antero
    et al.
    VTT Technical Research Centre of Finland, Espoo.
    Lehtinen, Jere
    VTT Technical Research Centre of Finland, Espoo.
    Kurkela, Minna
    VTT Technical Research Centre of Finland, Espoo.
    Muhola, Mirja
    VTT Technical Research Centre of Finland, Espoo.
    Tuomi, Sanna
    VTT Technical Research Centre of Finland, Espoo.
    Carlsson, Per
    Energy Technology Centre, Piteå.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Güell, Berta Matas
    SINTEF.
    Sandquist, Judit
    SINTEF.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Andersson, Jim
    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.
    Ma, Charlie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Kurkela, Esa
    VTT Technical Research Centre of Finland, Espoo.
    Wiinikka, Henrik
    Wang, Liang
    SINTEF.
    Backman, Rainer
    Umeå university, Åbo Akademi, Energy Technology and Thermal Process Chemistry, Umeå University.
    Biomass gasification fundamentals to support the development of BTL in forest industry2015Report (Other academic)
  • 20.
    Nordgren, Daniel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Berglin, Niklas
    Innventia AB, SE-114 86 Stockholm, Sweden.
    Grönberg, Carola
    Energy Technology Centre, Piteå.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rangmark, Lennart
    AGA AB/Linde Gas.
    Ekman, Tomas
    AGA AB/Linde Gas.
    Studies of heat transfer and furnace temperature uniformity during combustion of oil and wood using oxygen enrichment technology2011In: Swedish-Finnish Flame Days 2011, 2011Conference paper (Other academic)
    Abstract [en]

    In many combustion applications a switch from fossil to renewable fuels, e.g. from fueloil to wood powder, may result in a reduction of production capacity in the boiler,furnace or kiln. Oxygen enrichment of the combustion air can be used to improve thethermal efficiency of practical combustors, i.e. reduce heat losses and promote fuelsavings. In addition, oxygen enrichment can reduce NOx emissions and also facilitateCO2 scrubbing and capture processes in such systems. In this work, flame characteristicsand furnace temperature profiles during oxygen enriched combustion were studied whenoxygen was added to the combustor at different enrichment levels by the use of a lance.The experiments were carried out in a pilot-scale furnace fired with (i) wood powder and(ii) heavy fuel oil (no.5). The results show that for the wood flame, the average furnacetemperature becomes higher and the furnace temperature profile becomes more flat.Thus, compared to conventional air combustion, there are smaller differences betweennear-burner and back-end temperatures as oxygen is added to the process. For the oilflame, as oxygen was added to the process, a higher average furnace temperature wasobserved along with a distinct shift in furnace peak temperature towards the central partsof the furnace, creating a relatively strong temperature gradient towards the back-end ofthe furnace. Comparing the two flames, the furnace temperature profile of the oxygenenriched wood flame becomes more flat compared to the oxygen enriched oil flame. Thisis interpreted as an effect of differences in overall fuel reactivity, in which the oil, being aliquid fuel, ignites and burns faster than the solid fuel wood powder. The results found inthis work shows that the burner that was used, being designed for conventional aircombustion by feeding of air through the primary, secondary and tertiary air vanes, couldhandle the changes in aerodynamics caused by the reduced air flows. The general resultsfrom this work are useful for furnace and kiln applications in which a more controllableflame and process temperature is required, e.g. in a lime kiln where a fuel switch fromfossil fuels to biomass is considered.

  • 21.
    Pagels, Joakim
    et al.
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Eriksson, Axel
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Nordin, Erik
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Rissler, Jenny
    Avdelningen för Ergonomi och Aerosolteknologi, Lunds Tekniska Högskola.
    Boman, Christoffer
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Nyström, Robin
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Pettersson, Esbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Applicering av aerosol masspektrometri för tidsupplöst stoftprovtagning från vedeldade lokaleldstäder2010Report (Other academic)
  • 22. Pettersson, Esbjörn
    et al.
    Boman, Christoffer
    Umeå universitet.
    Nyström, Ida-Linn
    Boström, Dan
    Umeå universitet.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Öhrman, Olov
    Burvall, Jan
    Skellefteå Kraft AB.
    Particle emissions from wood powder flames: a field study2008Conference paper (Other academic)
  • 23.
    Salik, Khwaja
    et al.
    Umeå University, Department of Applied Physics and Electronics.
    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, Energy Science.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wingren, Anders
    MEVA Energy, Hisings backa.
    Strandberg, Martin
    Pommer, Linda
    Umeå University, Department of Applied Physics and Electronics.
    Padban, Nader
    Vattenfall Research and Development, Stockholm.
    Hinderson, Anna
    Vattenfall Research and Development, Stockholm.
    Khodayari, Raziyeh
    Vattenfall Research and Development, Stockholm.
    Carbo, Michiel C.
    ECN, Petten.
    Nordin, Anders
    Umeå University, Department of Applied Physics and Electronics.
    Entrained flow gasification of torrefied lignocellulosic biomass2016In: Proceedings of the 24th European Biomass Conference and Exhibition, Amsterdam: ETA Florence Renewable Energies , 2016, p. 1138-1142Conference paper (Refereed)
    Abstract [en]

    An extensive evaluation program was carried out within the European SECTOR project to evaluate the feasibility of torrefied and densified biomass in available entrained flow gasifiers. Different entrained flow reactors (both atmospheric and pressurized) in different scales, from lab scale to a 240 MW industrial gasifier were used for evaluation of torrefied materials as feedstock. Total behaviours of the new fuel throughout the whole supply chains and the EFG systems were evaluated and documented, including process behaviours in terms of operation, gas quality, products of incomplete gasification, etc. Results showed a significant improvement in fuel properties in terms of storage, logistics, milling and feeding behaviour by torrefaction and densification. Entrained flow gasification of the torrefied biomass was also shown to be feasible without any major showstoppers, even improving the gasification processes. Production of tars and other products of incomplete gasification were often found significantly reduced during gasification of torrefied material.

  • 24.
    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.

  • 25.
    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.

  • 26.
    Sepman, A.
    et al.
    SP Energy Technology Center AB.
    Ögren, Yngve
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Gullberg, M.
    SP Energy Technology Center AB.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Development of TDLAS sensor for diagnostics of CO, H2O and soot concentrations in reactor core of pilot-scale gasifier2016In: Applied physics. B, Lasers and optics (Print), ISSN 0946-2171, E-ISSN 1432-0649, Vol. 122, no 2, article id 29Article in journal (Refereed)
    Abstract [en]

    This paper reports on the development of the tunable diode laser absorption spectroscopy sensor near 4350 cm−1 (2298 nm) for measurements of CO and H2O mole fractions and soot volume fraction under gasification conditions. Due to careful selection of the molecular transitions [CO (υ″ = 0 → υ′ = 2) R34–R36 and H2O at 4349.337 cm−1], a very weak (negligible) sensitivity of the measured species mole fractions to the temperature distribution inside the high-temperature zone (1000 K < T < 1900 K) of the gasification process is achieved. The selected transitions are covered by the tuning range of single diode laser. The CO and H2O concentrations measured in flat flames generally agree better than 10 % with the results of 1-D flame simulations. Calibration-free absorption measurements of studied species in the reactor core of atmospheric pilot-scale entrained-flow gasifier operated at 0.1 MW power are reported. Soot concentration is determined from the measured broadband transmittance. The estimated uncertainties in the reactor core CO and H2O measurements are 15 and 20 %, respectively. The reactor core average path CO mole fractions are in quantitative agreement with the µGC CO concentrations sampled at the gasifier output.

  • 27.
    Stjernberg, Jesper
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Jonsson, Carrie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    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.
    Boström, Dan
    Umeå universitet.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Deposit formation in a grate-kiln plant for iron-ore pellet production: Part 2: Characterization of deposits2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 10, p. 6171-6184Article in journal (Refereed)
    Abstract [en]

    Buildup of deposit material in chunks on refractory linings caused by combustion of various fuels is a well-known problem. This study characterizes the short-term deposits on refractory material in a grate–kiln process, carried out through in situ measurements using a water-cooled probe with a part of a refractory brick mounted in its end. Sampling was carried out during combustion of both oil and coal. A significant difference in deposition rates was observed; deposition during oil firing was negligible compared to coal firing. The deposits are mainly hematite particles embedded in bonding phase, mainly comprising Si, Al, Fe, Ca, and O. Moreover, it was found that the prevailing flue-gas direction determines the formation of the deposits on the probe and that inertial impaction controls the deposition rate. However, this rate can also be affected by the amount of air-borne particles present in the kiln.

  • 28.
    Strandberg, Anna
    et al.
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Holmgren, Per
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Wagner, David R.
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Molinder, Roger
    RISE Energy Technology Center.
    Wiinikka, Henrik
    RISE Energy Technology Center.
    Umeki, Kentaro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Broström, Markus
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Effects of pyrolysis conditions and ash formation on gasification rates of biomass char2017In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, no 6, p. 6507-6514Article in journal (Refereed)
    Abstract [en]

    Pyrolysis conditions and the presence of ash-forming elements significantly influence char properties and its oxidation or gasification reactivity. In this study, intrinsic gasification rates of char from high heating rate pyrolysis were analyzed with isothermal thermogravimetry. The char particles were prepared from two biomasses at three size ranges and at two temperatures. Reactivity dependence on original particle size was found only for small wood particles that had higher intrinsic char gasification rates. Pyrolysis temperature had no significant effect on char reactivity within the range tested. Observations of ash formation highlighted that reactivity was influenced by the presence of ash-forming elements, not only at the active char sites but also through prohibition of contact between char and gasification agent by ash layer formation with properties highly depending on ash composition.

  • 29.
    Weiland, Fredrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Öhrman, Olov
    Gebart, Rikard
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Pressurized oxygen blown entrained-flow gasification of wood powder2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 2, p. 932-941Article in journal (Refereed)
    Abstract [en]

    In the present study, an oxygen blown pilot scale pressurized entrained-flow biomass gasification plant (PEBG, 1 MWth) was designed, constructed, and operated. This Article provides a detailed description of the pilot plant and results from gasification experiments with stem wood biomass made from pine and spruce. The focus was to evaluate the performance of the gasifier with respect to syngas quality and mass and energy balance. The gasifier was operated at an elevated pressure of 2 bar(a) and at an oxygen equivalence ratio (λ) between 0.43 and 0.50. The resulting process temperatures in the hot part of the gasifier were in the range of 1100-1300 °C during the experiments. As expected, a higher λ results in a higher process temperature. The syngas concentrations (dry and N 2 free) during the experiments were 25-28 mol % for H2, 47-49 mol % for CO, 20-24 mol % for CO2, and 1-2 mol % for CH 4. The dry syngas N2 content was varied between 18 and 25 mol % depending on the operating conditions of the gasifier. The syngas H 2/CO ratio was 0.54-0.57. The gasifier cold gas efficiency (CGE) was approximately 70% for the experimental campaigns performed in this study. The synthesis gas produced by the PEBG has potential for further upgrading to renewable products, for example, chemicals or biofuels, because the performance of the gasifier is close to that of other relevant gasifiers

  • 30.
    Weiland, Fredrik
    et al.
    SP Energy Technological Center.
    Hedman, Henry
    SP Energy Technological Center.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. SP Energy Technology Center.
    Marklund, Magnus
    SP Energy Technological Center.
    Pressurized Entrained Flow Gasification of Pulverized Biomass: Experiences from Pilot Scale Operation2016In: Chemical Engineering Transactions, ISSN 1974-9791, E-ISSN 2283-9216, Vol. 50, p. 325-330Article in journal (Refereed)
    Abstract [en]

    One of the goals in the national energy strategy of Sweden is that the vehicle fleet should be independent of fossil fuels by 2030. To reach that goal and to domestically secure for supply of alternative fuels, one of the suggested routes is methanol production from forest residues via pressurized and oxygen blown entrained flow gasification. In this context, ongoing industrial research in a 1 MWth gasification pilot plant is carried out at SP Energy Technology Center (SP ETC) in Pitea, Sweden. The plant is operated with pulverized or liquid fuels at process pressures up to 10 bar and this work summarizes the experiences from over 600 hours of operation with forest based biomass fuels. This paper covers results from thorough process characterization as well as results from extractive samplings of both permanent gases and particulate matter (soot) from inside the hot gasifier. Furthermore, the challenges with pressurized entrained flow gasification of pulverized biomass are discussed. During the characterization work, four of the most important process parameters (i.e. oxygen stoichiometric ratio (lambda), fuel load, process pressure and fuel particle size distribution) were varied with the purpose of studying the effect on the process performance and the resulting syngas quality. The experimental results showed that the maximum cold gas efficiency (CGE) based on all combustible species in the syngas was 75% (at lambda=0.30), whereas the corresponding value based only on CO and H-2 (with respect to further MeOH synthesis from the syngas) was 70% (at lambda=0.35). As expected, the pilot experiments showed that both the soot yield and soot particle size was reduced by increasing lambda. One of the additional conclusions from this work was that; minimizing heat losses from the gasifier is of utmost importance to optimize the process performance regarding energy efficiency (i.e. CGE). Therefore, a well-insulated refractory lined gasifier is the primary alternative in regards to reactor design to maximize the CGE. Future development of the PEBG process should focus on identifying suitable hot-phase refractory, that exhibit long life-time and can sustain the alkali-rich biomass ash under gasification conditions. In addition to this, the remaining issue around how to improve the slag flow from the reactor, by additives or fuel mixing, should be investigated.

  • 31.
    Weiland, Fredrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Nilsson, Patrik T.
    Ergonomics and Aerosol Technology, Lund University.
    Gebart, Rikard
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    Gudmundsson, Anders
    Ergonomics and Aerosol Technology, Lund University.
    Sanati, Mehri
    Ergonomics and Aerosol Technology, Lund University.
    Online Characterization of Syngas Particulates Using Aerosol Mass Spectrometry in Entrained-Flow Biomass Gasification2014In: Aerosol Science and Technology, ISSN 0278-6826, E-ISSN 1521-7388, Vol. 48, no 11, p. 1145-1155Article in journal (Refereed)
    Abstract [en]

    Entrained flow gasification is a promising technique where biomass is converted to a synthesis gas (syngas) under fuel rich conditions. In contrast to combustion, where the fuel is converted to heat, CO2 and H2O, the syngas from gasification is rich in energetic gases such as CO and H2. These compounds (CO and H2) represent the building blocks for further catalytic synthesis to chemicals or biofuels. Impurities in the syngas, such as particulates, need to be reduced to different levels depending on the syngas application. The objective of this work was to evaluate the amount of particulates; the particle size distribution and the particle composition from entrained flow gasification of pine stem wood at different operating conditions of the gasifier. For this purpose online time resolved measurements were performed with a Soot Particle Aerosol Mass Spectrometer (SP-AMS) and a Scanning Mobility Particle Sizer (SMPS). The main advantage of SP-AMS compared to other techniques is that the particle composition (soot, PAH, organics and ash forming elements) can be obtained with high time resolution and thus studied as a direct effect of the gasifier operating conditions. The results suggest that syngas particulates were essentially composed of soot at these tested process temperatures in the reactor (1200–1400 °C). Furthermore, the AMS analysis showed a clear correlation between the amounts of polycyclic aromatic hydrocarbons (PAH) and soot in the raw syngas. Minimization of soot and PAH yields from entrained flow gasification of wood proved to be possible by further increasing the O2 addition.

  • 32.
    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.

  • 33.
    Weiland, Fredrik
    et al.
    SP Energy Technology Center AB.
    Sweeney, Daniel J.
    SP Energy Technology Center AB.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Extractive Sampling of Gas and Particulates from the Reactor Core of an Entrained Flow Biomass Gasifier2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 8, p. 6405-6412Article in journal (Refereed)
    Abstract [en]

    With the purpose of demonstrating a process for pressurized entrained flow gasification for pulverized biomass, the aim with this work was to characterize the conditions inside the gasifier. To gain a broader understanding, it was important to extract both gases. and particulate matter from the hot reaction zone. The objectives were, therefore, to (1) develop a sampling system capable of extracting both gas and particulates from the gasifier, (2) study the production of particulate matter as well as its composition and size distribution as a function of different operating conditions, and (3) extract time-resolved data for the syngas species (CO, CO2, and CH4) in order to study the compositional variance. The results indicated that the syngas heating value was lower at the sampling position in the gasifier compared to the heating value measured downstream of the quench cooler. The difference was most probably an effect of ongoing gasification of carboneous Solids downstream of the sampling position in the gasifier. Furthermore, it was concluded that the fuel feedrate was fluctuating, most likely because of heterogeneity in the fuel powder and/or the challenges, in the fuel feeding system itself. With regards to particulate matter, in the syngas, it was shown to mostly consist of soot. The soot yield was significantly reduced by increasing lambda. The reactor cote sampling system proved superior to the traditional sampling system downstream of the quench with regard to measuring soot yield at different operating conditions of the gasifier. Finally, it was concluded that the submicron fly ash particles from oxygen blown biomass gasification contain high propotions of refractory elements (e.g., Ca, Mg, and Si) in addition to the more volatile elements (e.g., K, Na, S, and Cl). This is probably due to extremely high temperature in the flame and substoichiometric condition in the gasifier, which may promote vaporization of refractory elements during, char gasification

  • 34.
    Weiland, Fredrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wiinikka, Henrik
    Hedman, Henry
    Energy Technology Centre, Piteå, SP Energy Technology Center AB.
    Wennebro, Jonas
    SP Energy Technology Center AB.
    Pettersson, Esbjörn
    LTU/ETC, Energy Technology Centre, Piteå, SP Energy Technology Center AB.
    Gebart, Rikard
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Influence of process parameters on the performance of an oxygen blown entrained flow biomass gasifier2015In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 153, p. 510-519Article in journal (Refereed)
    Abstract [en]

    Pressurized, O2 blown, entrained flow gasification of pulverized forest residues followed by methanol production is an interesting option for synthetic fuels that has been particularly investigated in the Nordic countries. In order to optimize gasification plant efficiency, it is important to understand the influence of different operating conditions. In this work, a pressurized O2 blown and entrained flow biomass gasification pilot plant was used to study the effect of four important process variables; (i) the O2 stoichiometric ratio (λ), (ii) the load of the gasifier, (iii) the gasifier pressure, and (iv) the fuel particle size. Commercially available stem wood fuels were used and the process was characterized with respect to the resulting process temperature, the syngas yield, the fuel conversion and the gasification process efficiency. It was found that CH4 constituted a significant fraction of the syngas heating value at process temperatures below 1400 °C. If the syngas is intended for catalytic upgrading to a synthetic motor fuel where CO and H2 are the only important syngas species, the process should be optimized aiming for a process temperature slightly above 1400 °C in order to reduce the energetic losses to CH4 and C6H6. This resulted in a cold gas efficiency (based only on CO and H2) of 70%. The H2/CO ratio was experimentally determined within the range 0.45–0.61. Thus, the syngas requires shifting in order to increase the syngas composition of H2 prior to fuel synthesis.

  • 35.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    High temperature aerosol formation and emission minimisation during combustion of wood pellets2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Combustion of solid biomass under fixed bed conditions is a common technique to generate heat and power in both small and large scale grate furnaces (domestic boilers, stoves, district heating plants). From both an environmental and economical perspective, one of the most interesting alternatives to replace oil and electricity for heating of family houses and apartments in Sweden is wood pellets made of stem wood sawdust from pine and spruce. Unfortunately, combustion of biomass (also wood pellets) will produce particle emissions that may have a negative implication on the human health. The smallest (< 1.0 microns) particles are very hard to separate in ordinary cleaning devices. However, for large plants, advanced gas cleaning devices are an acceptable option and therefore a relative high amount of particles in the flue gas before cleaning may be tolerated. For small appliances such as wood pellets burners and stoves advanced gas cleaning devices is not an option due to its relative high costs. Hence, the only way to reduce emissions of small particles small scale equipments is therefore to reduce the formation of particles already in the combustion process. The aim with this work was to study the formation mechanisms and the influence from different operating and fuel parameters on particle emission during combustion of wood pellets. The results from this work may then be used as a basis for design with aim to minimise the particle emissions already in the combustion process. To address these issues, experiments were carried out in an 8-11 kW updraft fired wood pellets reactor that has been custom designed for systematic investigation of particle emissions. To investigate the formation mechanisms, particle samples were withdrawn from the centre line of reactor through 10 sampling ports by a rapid dilution sampling probe. The corresponding temperatures at the sampling positions were in the range of 200-1450 ¢ªC. The particle sample was size segregated in a low pressure impactor, allowing physical and chemical resolution of the fine particles. The chemical composition of the particles was investigated by SEM/EDS and XRD analysis. Furthermore, the experimental results were compared to theoretical models of particle formation and growth. When the influence from fuel and operating parameters was investigated, particle samples were withdrawn isokinetically in the flue gas stack after the reactor. The particle mass were analysed with traditional filtering technique. The particle mass and number size distribution were analysed by low pressure impactor and a scanning mobility particle sizer. The chemical composition of the particles was furthermore analysed with SEM/EDS. The results in this work show that combustion generated particles during wood pellets combustion is produced from several mechanisms resulting in a bimodal or a trimodal size distribution. The largest particles (> 10 microns) are produced from residual fly ash particles (refractory metals) that have left the fuel bed and been carried by the gas upwards. The finest particles (< 1 microns) are produced from two mechanisms, vaporisation and condensation of easily volatile ash elements (K, Na, S, Cl, Zn and in some case also P) and from incomplete combustion (i.e. soot particles). The middle mode between the coarse and the fine mode (~1 microns), is produced from a combination of refractory oxides, unburned carbon and condensable inorganic species. In general the fine mode (< 1 microns) dominates the mass and number concentration of the total particle emissions in the flue gases after the combustion chamber followed by the coarse mode (> 10 microns). The mass concentration of the middle mode (~1 microns) are significantly lower then both the fine and the coarse mode. The particle concentration in the flue gas channel is affected by both operating and fuel parameters. The results showed that both the temperature and the flow pattern in the combustion zone affect the particle emissions. Increasing combustion temperature yields decreasing emissions of coarse fly ash (> 10 microns) and soot particles, however, the emissions of submicron fly ash particles increases simultaneously. Increased mixing rate in the combustion chamber will also decrease the emissions of soot particles. In addition to the operating conditions, significant differences in particle emissions were found between different biomass fuels. For the particles that were dominated by ash elements the particle emissions were correlated to the ash concentration in the unburned fuel. However, if the combustion condition allowed for organic particles, the sooting tendency of each fuel becomes important. Furthermore, the results showed that in general the fuel type affects the particle emissions stronger than the influence from different operating and construction parameters.

  • 36.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Particle emissions from wood pellet combustion2003Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Combustion of solid biomass under fixed bed conditions is a common technique to generate heat and power in both small and large scale grate furnaces (domestic boilers, stoves, district heating plants). Unfortunately, combustion of biomass will generate particle emissions containing both large fly ash particles and fine particles that consist of fly ash and soot. The large fly ash particles have been produced from fusion of non-volatile ash-forming species in burning char particle. The inorganic fine particles have been produced from nucleation of volatilised ash elements (K, Na, S, Cl and Zn). If the combustion is incomplete, soot particles are also produced from secondary reaction of tar. The particles in the fine fraction grows by coagulation and coalescence to a particle diameter around 0.1 microns. Since the smallest particles are very hard to collect in ordinary cleaning devices they contribute to the ambient air pollution. Furthermore, fine airborne particles have been correlated to adverse effects on the human health. It is therefore essential to minimize particle formation from the combustion process and thereby reduce the emissions of particulates to the ambient air. The aim with this thesis is to study particle emissions from small scale combustion of wood pellets and to investigate the impact of different operating, construction and fuel parameters on the amount and characteristic of the combustion generated particles. To address these issues, experiments were carried out in a 10 kW updraft fired wood pellets reactor that has been custom designed for systematic investigations of particle emissions. In the flue gas stack, particle emissions were sampled on a filter. The particle mass and number size distributions were analysed by a low pressure cascade impactor and a SMPS (Scanning Electron Mobility Particle Sizer). The results showed that the temperature and the flow pattern in the combustion zone affect the particle emissions. Increasing combustion temperature yields decreasing emissions of coarse fly ash and soot particles, however, the emissions of submicron fly ash particles increases simultaneously. Increased mixing rate in the combustion chamber will also decrease the emissions of soot particles. In addition to the operating conditions, significant differences in particle emissions were found between different biomass fuels. For the particles that were dominated by ash elements the particle emissions were correlated to the ash concentration in the unburned fuel. However, if the combustion condition allowed for organic particles, the sooting tendency of each fuel becomes important. Furthermore, the results showed that the fuel type affects the particle emissions more than the influence from different operating and construction parameters.

  • 37.
    Wiinikka, Henrik
    et al.
    Energy Technology Centre, Piteå.
    Carlsson, Per
    Granberg, Fredrik
    Chemrec.
    Löfström, Johan
    Chemrec.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Tegman, Ragnar
    Chemrec.
    Lindblom, Mats
    Chemrec.
    Gebart, Rikard
    Swerea SICOMP AB, Box 271, 941 26, Piteå.
    Design and methodology of a high temperature gas sampling system for pressurized black liquor gasification2010In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 89, no 9, p. 2583-2591Article in journal (Refereed)
    Abstract [en]

    This paper describes the system design and methodology for high temperature gas sampling during pressurized black liquor gasification. The motivation for developing a system that can withstand the harsh conditions in the reactor part of the gasifier (30 bar, 1000 °C, reducing conditions and corrosive environment) comes from an ambition to better understand the various stages in the conversion of the fuel (black liquor) and provide spatially resolved data of the gas composition inside the gasification reactor. Important components in the high temperature sampling system which are all described in detail in the paper, are the syngas sampling line, nitrogen purging system, water cooling line and an aerodynamic quench probe with an anti-clogging shield. Several measurement campaigns have been conducted in the gasifier where the concentration of CO2, CO, H2, CH4, H2S, and COS close to the outlet of the hot reactor have been measured with the high temperature gas sampling system. The results showed that the repeatability of the measured gas composition was excellent and that significant effects on the gas composition from different operating parameters of the gasifier could be found.

  • 38.
    Wiinikka, Henrik
    et al.
    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.
    Critical parameters for particle emissions in small-scale fixed-bed combustion of wood pellets2004In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 18, no 4, p. 897-907Article in journal (Refereed)
    Abstract [en]

    In this study, laboratory experiments in a small-scale (10 kW) reactor have been performed to investigate the particle formation mechanisms and the influence of different operating parameters on the particle emissions from combustion of wood pellets under fixed-bed conditions. The results presented herein show that the particles from fixed-bed combustion are formed from three different mechanisms: coarse fly ash particles (>10 μm) are released by mechanical ejection from the fuel bed, submicrometer-sized fly ash particles are produced from the vaporization and nucleation of ash minerals, and, finally, submicrometer-sized soot particles are produced from incomplete combustion. Significant effects on the particle emissions have been observed for the combustor wall temperature and the flow pattern in the combustion zone. Increasing the combustor wall temperature yields a decrease in the emissions of coarse fly ash and soot particles; however, the emissions of submicrometer-sized fly ash particles increase simultaneously. For example, the emissions of soot are reduced by a factor of ~5 and the emissions of fly ash are increased by a factor of ~2 when the wall temperature increases from 400° C to 950°C. Increasing the mixing rate in the combustion chamber will also decrease the emissions of soot particles. An important conclusion from this study is that the total emissions of particles can be minimized in fixed-bed combustion of a solid biomass by minimizing the combustion temperature in the burning char particle and maximizing the temperature in the secondary combustion zone.

  • 39.
    Wiinikka, Henrik
    et al.
    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.
    Detailed experimental investigation of the formation of submicron aerosols in wood pellets flames2004In: NOSA Aerosol Symposium Stockholm: Conference Proceedings, Nordic Society for Aerosol Research , 2004Conference paper (Other academic)
  • 40.
    Wiinikka, Henrik
    et al.
    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.
    Experimental investigations of the influence from different operating conditions on the particle emissions from a small-scale pellets combustor2004In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 27, no 6, p. 645-652Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to determine how different design parameters in an idealised small-scale combustor affect the emission of particulates in the flue gas and to provide insight that can be used for design optimisation. The design parameters are the primary air factor, the total air factor and the magnitude of swirling flow in the combustion chamber. Particles from the reactor were collected from two different sampling lines, one located in the combustion zone, just above the fuel bed, and the other in the flue stack after the reactor. The measurements show that this burner gives very low emissions of particulates and CO in the flue gas. Furthermore, the concentration of particles in the flue gas is uncoupled to the concentration of particles immediately above the fuel bed, probably as a result of a well-designed secondary air supply. The variable that had the strongest effect on the total particulate emission from the combustor was the total air factor. In order to understand the qualitative differences in the flow nature between different operating conditions, CFD simulations of the flow field were also performed.

  • 41.
    Wiinikka, Henrik
    et al.
    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.
    Formation of soot and submicron fly ash in a wood pellets flame2004Conference paper (Refereed)
  • 42.
    Wiinikka, Henrik
    et al.
    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.
    The influence of air distribution rate on particle emissions in fixed bed combustion of biomass2005In: Combustion Science and Technology, ISSN 0010-2202, E-ISSN 1563-521X, Vol. 177, no 9, p. 1747-1766Article in journal (Refereed)
    Abstract [en]

    Combustion of biomass under fixed-bed conditions will generate both coarse and fine particles that have a negative effect on technical performance or pose health hazards. It is therefore important to reduce the emissions of these particles that are already in the combustion process. The aim of this study was to experimentally investigate how different air supply strategies affect the particle emission in fixed-bed combustion of biomass. The air was supplied either through the grate, through a secondary air register, or equally divided between the two. The results showed that the air supply affects the emissions of both coarse and especially fine fly ash particles. The emissions of fine particles decrease when the air supply through the grate decreases, probably due to lower oxygen concentration in the fuel bed and thereby lower temperature in the burning char particles, which results in less vaporisation of ash elements. Hence, changing or optimizing the air supply strategy appears to be an attractive way to reduce the particle emissions already in the combustion process. Copyright

  • 43.
    Wiinikka, Henrik
    et al.
    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.
    The influence of fuel type on particle emissions in combustion of biomass pellets2005In: Combustion Science and Technology, ISSN 0010-2202, E-ISSN 1563-521X, Vol. 177, no 4, p. 741-763Article in journal (Refereed)
    Abstract [en]

    Three different biomass fuels (bark pellets, wood pellets and granulates made from hydrolysis residues) were burned under identical conditions to determine the effect of biomass type on the amount and composition of the combustion-generated particles under fixed-bed conditions. Significant differences in emissions of dust, submicron particles, and the shape of the particle number and mass size distributions were found between the different biomass fuels. For the particles that were dominated by ash elements, the particle emissions were correlated to the ash concentration in the unburned fuel. However, if the combustion condition allowed for organic particles, the "sooting" tendency of the fuel was found to become more important than the amount of ash in the fuel. Furthermore, the fuel type affects the particle emissions more than changes in reactor operating parameters.

  • 44.
    Wiinikka, Henrik
    et al.
    Energy Technology Centre, Piteå.
    Gebart, Rikard
    Energy Technology Centre, Piteå.
    Boman, Christoffer
    Umeå universitet.
    Boström, Dan
    Umeå universitet.
    Öhman, Marcus
    Influence of fuel ash composition on high temperature aerosol formation in fixed bed combustion of woody biomass pellets2007In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 86, no 1, p. 181-193Article in journal (Refereed)
    Abstract [en]

    In this work, the influence of fuel ash composition on high temperature aerosol formation during fixed bed combustion of woody biomass (two wood pellets and one bark pellets) were investigated experimentally in a laboratory reactor and theoretically through chemical equilibrium model calculations. For all fuels, the particle mass size distribution in the PM2.5 region was bimodal, with one fine mode and one coarse mode. Early in the flame, the fine mode was dominated by particles from incomplete combustion and these particles were rapidly oxidised in the post flame zone. After the hot flame, the fine mode concentration and the particle diameter increases gradually when the temperature decreases due to condensation of vaporised inorganic matter, K, Na, S, Cl, and Zn. For two of the fuels also P could be found in the fine particles. The coarse mode consisted of carbon, refractory metals and considerable amount of alkali. Further, the initial fuel alkali concentration and the alkali to silicon ratio (K + Na)/Si influenced the amount of vaporised aerosol forming alkali matter. Finally, the present study shows that, combustion temperature and fuel ash composition is of major importance for the formation of high temperature aerosols in fixed bed combustion of woody biomass pellets.

  • 45.
    Wiinikka, Henrik
    et al.
    Energy Technology Centre, Piteå.
    Gebart, Rikard
    Energy Technology Centre, Piteå.
    Boman, Christoffer
    Umeå university.
    Boström, Dan
    Umeå university.
    Öhman, Marcus
    Nordin, Anders
    Umeå university.
    High-temperature aerosol formation in wood pellets flames: spatially resolved measurements2006In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 147, no 4, p. 278-293Article in journal (Refereed)
    Abstract [en]

    The formation and evolution of high-temperature aerosols during fixed bed combustion of wood pellets in a realistic combustion environment were investigated through spatially resolved experiments. The purpose of this work was to investigate the various stages of aerosol formation from the hot flame zone to the flue gas channel. The investigation is important both for elucidation of the formation mechanisms and as a basis for development and validation of particle formation models that can be used for design optimization. Experiments were conducted in an 8-kW-updraft fired-wood-pellets combustor. Particle samples were withdrawn from the centerline of the combustor through 10 sampling ports by a rapid dilution sampling probe. The corresponding temperatures at the sampling positions were in the range 200-1450 °C. The particle sample was size-segregated in a low-pressure impactor, allowing physical and chemical resolution of the fine particles. The chemical composition of the particles was investigated by SEM/EDS and XRD analysis. Furthermore, the experimental results were compared to theoretical models for aerosol formation processes. The experimental data show that the particle size distribution has two peaks, both of which are below an aerodynamic diameter of 2.5 μm (PM2.5). The mode diameters of the fine and coarse modes in the PM2.5 region were [similar to] 0.1 and [similar to] 0.8 μm, respectively. The shape of the particle size distribution function continuously changes with position in the reactor due to several mechanisms. Early, in the flame zone, both the fine mode and the coarse mode in the PM2.5 region were dominated by particles from incomplete combustion, indicated by a significant amount of carbon in the particles. The particle concentrations of both the fine and the coarse mode decrease rapidly in the hot oxygen-rich flame due to oxidation of the carbon-rich particles. After the hot flame, the fine mode concentration and particle diameter increase gradually when the temperature of the flue gas drops. The main contribution to this comes from condensation on preexisting particles in the gas of alkali sulfates, alkali chlorides, and Zn species formed from constituents vaporized in the fuel bed. The alkali sulfates were found to condense at a temperature of [similar to] 950 ° C and alkali chlorides condensed later at [similar to] 600 ° C. This agrees well with results of chemical equilibrium calculation of the gas-to-particle conversion temperature. After the hot flame the coarse mode concentration decreased very little when the flue gas was cooled. In addition to carbon, the coarse mode consists of refractory metals and also considerable amounts of alkali.

  • 46.
    Wiinikka, Henrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Grönberg, Carola
    Boman, Christoffer
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Emissions of heavy metals during fixed-bed combustion of six biomass fuels2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 2, p. 1073-1080Article in journal (Refereed)
    Abstract [en]

    Few studies examine heavy metal emissions during the small-scale combustion of various solid biofuels. This issue may become more important, as one can expect new regulations governing such emissions from biomass combustion similar to those governing waste incineration. This paper investigates the emissions of particulate-associated heavy metals (i.e., Sb, As, Cd, Co, Cr, Cu, Pb, Mn, Ni, Tl, V, Hg, and Zn) during the fixed-bed combustion of six solid biofuels (i.e., stemwood from birch and pine/spruce, bark from birch and pine, salix, and oat grains) and of peat and bituminous coal for comparison. The results indicate that the flue gas concentration (normalized to 11% O2) of the sum of all measured metals (Zn excluded) during the biomass combustion tests ranged from 57 μg Nm-3 for birch stemwood to 198 μg Nm-3 for birch bark. The concentration of Zn in the flue gas was generally considerably higher than those of the other metals, ranging from 646 μg Nm-3 for spruce/pine stemwood to 7948 μg Nm-3 for birch bark. Compared with coal and peat, the biomass fuels produced higher Zn emissions, but lower or similar emissions of the sum of the other metals. The volatile behavior and concentration of the metal in the flue gases as a function of the heavy metal in the fuel are also presented for selected heavy metals

  • 47.
    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.

  • 48.
    Wiinikka, Henrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE Energy Technology Center AB.
    Tóth, Pál
    RISE Energy Technology Center AB.
    Jansson, Kjell
    Department of Materials and Environmental Chemistry, Stockholm University, Stockholm.
    Molinder, Roger
    RISE Energy Technology Center.
    Broström, Markus
    Thermochemical Energy Conversion Laboratory (TEC-Lab), Department of Applied Physics and Electronics, Umeå University.
    Sandström, Linda
    RISE Energy Technology Center AB.
    Lighty, Jo Ann S.
    Department of Chemical Engineering, University of Utah, Salt Lake City, UT.
    Weiland, Fredrik
    RISE Energy Technology Center.
    Particle formation during pressurized entrained flow gasification of wood powder: Effects of process conditions on chemical composition, nanostructure, and reactivity2018In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 189, p. 240-256Article in journal (Refereed)
    Abstract [en]

    The influence of operating condition on particle formation during pressurized, oxygen blown gasification of wood powder with an ash content of 0.4 wt% was investigated. The investigation was performed with a pilot scale gasifier operated at 7 bar(a). Two loads, 400 and 600 kW were tested, with the oxygen equivalence ratio (λ) varied between 0.25 and 0.50. Particle concentration and mass size distribution was analyzed with a low pressure cascade impactor and the collected particles were characterized for morphology, elemental composition, nanostructure, and reactivity using scanning electron microscopy/high resolution transmission electron microscopy/energy dispersive spectroscopy, and thermogravimetric analysis. In order to quantify the nanostructure of the particles and identify prevalent sub-structures, a novel image analysis framework was used. It was found that the process temperature, affected both by λ and the load of the gasifier, had a significant influence on the particle formation processes. At low temperature (1060 °C), the formed soot particles seemed to be resistant to the oxidation process; however, when the oxidation process started at 1119 °C, the internal burning of the more reactive particle core began. A further increase in temperature (> 1313 °C) lead to the oxidation of the less reactive particle shell. When the shell finally collapsed due to severe oxidation, the original soot particle shape and nanostructure also disappeared and the resulting particle could not be considered as a soot anymore. Instead, the particle shape and nanostructure at the highest temperatures (> 1430 °C) were a function of the inorganic content and of the inorganic elements the individual particle consisted of. All of these effects together lead to the soot particles in the real gasifier environment having less and less ordered nanostructure and higher and higher reactivity as the temperature increased; i.e., they followed the opposite trend of what is observed during laboratory-scale studies with fuels not containing any ash-forming elements and where the temperature was not controlled by λ

  • 49.
    Wiinikka, Henrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE Energy Technology Center AB, Division of Bioeconomy, RISE Research Institutes of Sweden.
    Vikström, Therese
    RISE Energy Technology Center AB, Division of Bioeconomy, RISE Research Institutes of Sweden.
    Wennebro, Jonas
    RISE Energy Technology Center AB, Division of Bioeconomy, RISE Research Institutes of Sweden.
    Toth, Pal
    RISE Energy Technology Center AB, Division of Bioeconomy, RISE Research Institutes of Sweden.
    Sepman, Alexey
    RISE Energy Technology Center AB, Division of Bioeconomy, RISE Research Institutes of Sweden.
    Pulverized Sponge Iron, a Zero-Carbon and Clean Substitute for Fossil Coal in Energy Applications2018In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 9, p. 9982-9989Article in journal (Refereed)
    Abstract [en]

    The direct combustion of recyclable metals has the potential to become a zero-carbon energy production alternative, much needed to alleviate the effects of global climate change caused by the increased emissions of the greenhouse gas CO2. In this work, we show that the emission of CO2 is insignificant during the combustion of pulverized sponge iron, compared to that of pulverized coal combustion. The emissions of the other harmful pollutants NOx and SO2 were 25 and over 30 times lower, respectively, than in the case of pulverized coal combustion. Furthermore, 96 %wt. of the solid combustion products consisted of micron-sized, solid or hollow hematite (α-Fe2O3) spheres. The remaining 4 %wt. of products was maghemite (γ-Fe2O3) nanoparticles. According to thermodynamic calculations, this product composition implies near-complete combustion, with a conversion above 98%. The results presented in this work strongly suggest that sponge iron is a clean energy carrier and may become a substitute to pulverized coal as fuel in existing or newly designed industrial systems.

  • 50.
    Wiinikka, Henrik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    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.
    Öhrman, Olov
    Carlsson, Per
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Stjernberg, Jesper
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Characterisation of submicron particles produced during oxygen blown entrained flow gasification of biomass2014In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 161, no 7, p. 1923-1934Article in journal (Refereed)
    Abstract [en]

    In this paper submicron particles sampled after the quench during 200 kW, 2 bar(a) pressurised, oxygen blown gasification of three biomass fuels, pure stem wood of pine and spruce, bark from spruce and a bark mixture, have been characterised with respect to particle size distribution with a low pressure cascade impactor. The particles were also characterised for morphology and elemental composition by a combination of scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and high resolution transmission electron microscopy/energy dispersive spectroscopy/selected area electron diffraction pattern (HRTEM/EDS/SAED) techniques. The resulting particle concentration in the syngas after the quench varied between 46 and 289 mg/Nm3 consisting of both carbon and easily volatile ash forming element significantly depending on the fuel ash content. Several different types of particles could be identified from classic soot particles to pure metallic zinc particles depending on the individual particle relation of carbon and ash forming elements. The results also indicate that ash forming elements and especially zinc interacts in the soot formation process creating a particle with shape and microstructure significantly different from a classical soot particle.

12 1 - 50 of 55
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf