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Toth, P., Jacobsson, D., Ek, M. & Wiinikka, H. (2019). Real-time, in situ, atomic scale observation of soot oxidation. Carbon, 145, 149-160
Open this publication in new window or tab >>Real-time, in situ, atomic scale observation of soot oxidation
2019 (English)In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 145, p. 149-160Article in journal (Refereed) Published
Abstract [en]

The oxidation of soot is a complex process due to the heterogeneous structure of the material. Several mechanisms have been hypothesized based on ex situ studies, but need confirmation from in situ observation; furthermore, deeper insight is needed to develop and validate structure-dependent reaction mechanisms. In this work, soot oxidation was for the first time observed at atomic scale in situ, in real-time, using a spherical aberration-corrected Environmental Transmission Electron Microscope. The transformation of individual soot particles was followed through from initiation to complete conversion. Observations clearly showed the existence of different burning modes and particle fragmentation previously hypothesized in the literature. Furthermore, transitioning between the modes—affected by temperature and O2 pressure—was unambiguously observed, explaining previous observations regarding structure-dependent and time-varying oxidation rates. A new mode of burning in which oxidation happens rapidly in the bulk phase with the disruption of long-range lamellar order was observed and is suspected to be dominant at practically relevant conditions. The ability to unambiguously relate different burning modes in terms of nanostructure will be of importance for optimizing both soot emission abatement and properties of nanoparticulate carbon products.

Keywords
Aberrations, Oxidation, Soot, Transmission electron microscopy, Environmental transmission electron microscopes, Heterogeneous structures, In-situ observations, Nano particulates, Particle fragmentation, Reaction mechanism, Spherical aberrations, Structure dependent, Dust
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-37328 (URN)10.1016/j.carbon.2019.01.007 (DOI)2-s2.0-85059824929 (Scopus ID)
Note

 Funding details: Vetenskapsrådet, VR, 2017-04902; Funding details: Magyar Tudományos Akadémia, MTA, BO/00333/16; Funding details: Kempestiftelserna, SMK-1641.2; Funding details: Knut och Alice Wallenbergs Stiftelse; Funding text 1: The work has been financed by the Swedish government trough both Bio4Energy, a strategic research platform and via the strategic-competence model for RISE ETC. The high temperature reactor used in this work to produce the GCB has been financed by the Kempe Foundation (grant SMK-1641.2 ) and the foundation Energy Technology Center in Piteå, Sweden . P. Toth is grateful for the kind support of the Hungarian Academy of Sciences through the Bolyai Scholarship (grant no. BO/00333/16 ). Therese Vikström and Yngve Ögren (RISE Energy Technology Center) are gratefully acknowledged for their help in soot sampling. Martin Ek and Daniel Jacobsson are grateful to the Knut and Alice Wallenberg foundation and NanoLund. Martin Ek was supported by the Swedish Research Council (grant 2017-04902 ).

Available from: 2019-01-22 Created: 2019-01-22 Last updated: 2019-01-22Bibliographically approved
Toth, P., ֖gren, Y., Sepman, A., Vikström, T., Gren, P. & Wiinikka, H. (2019). Spray combustion of biomass fast pyrolysis oil: Experiments and modeling. Fuel, 237, 580-591
Open this publication in new window or tab >>Spray combustion of biomass fast pyrolysis oil: Experiments and modeling
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2019 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 237, p. 580-591Article in journal (Refereed) Published
Abstract [en]

In this work, we are the first to report a detailed comparison between the predictions of a current Computational Fluid Dynamics (CFD) model for describing Fast Pyrolysis Oil (FPO) spray combustion and results from a laboratory-scale experiment. The objectives were to assess the predictive power of the CFD model, evaluate its usefulness in a numerical optimization scenario and characterize the spray flame. The spray flame was produced by using an air-assist atomizer piloted by a CH4/air flat-flame. Pyrolysis oil from a cyclone fast pyrolysis plant was combusted. The flame was characterized by using two-color pyrometry, Tunable Diode Laser Absorption Spectroscopy and high-magnification shadowgraphy. Overall, the assessed model correctly predicted flame structure and seemed appropriate for engineering applications, but lacked predictive power in estimating droplet size distributions. Numerical results were the most sensitive to variations in the initial droplet size distribution; however, seemed robust to changes in the multicomponent fuel formulation. Several conclusions were drawn regarding FPO spray combustion itself; e.g., the amount of produced soot in the flames was very low and droplets exhibited microexplosion behavior in a characteristic size-shape regime. 

Keywords
biomass fast pyrolysis oil, spray combustion, computational fluid dynamics, optical diagnostics
National Category
Industrial Biotechnology
Identifiers
urn:nbn:se:ri:diva-35530 (URN)10.1016/j.fuel.2018.10.031 (DOI)2-s2.0-85054708357 (Scopus ID)
Funder
Swedish Energy Agency, 41985-1Swedish Energy Agency, 44110-1
Available from: 2018-10-30 Created: 2018-10-30 Last updated: 2018-12-17Bibliographically approved
Lestander, T. A., Sandström, L., Wiinikka, H., Öhrman, O. & Thyrel, M. (2018). Characterization of fast pyrolysis bio-oil properties by near-infrared spectroscopic data. Journal of Analytical and Applied Pyrolysis, 133, 9-15
Open this publication in new window or tab >>Characterization of fast pyrolysis bio-oil properties by near-infrared spectroscopic data
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2018 (English)In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 133, p. 9-15Article in journal (Refereed) Published
Abstract [en]

Pyrolysis transforms bulky and heterogeneous lignocellulosic biomass into more easily-handled oils that can be upgraded into bio-based transportation fuels. Existing systems for monitoring pyrolysis processes and characterizing their products rely on slow and time-consuming wet chemical analyses. On-line near-infrared (NIR) spectroscopy could potentially replace such analyses, providing real-time data and reducing costs. To test the usefulness of NIR methods in characterizing pyrolysis oils and processes, biomass from conifers, Salix, and reed canary grass was milled and pyrolyzed at 675, 750, and 775 °C. Two separate pyrolytic fractions (aerosol and condensed) were produced in each experiment, and NIR spectra were collected for each fraction. Multivariate modelling of the resulting data clearly showed that the samples’ NIR spectra could be used to accurately predict important properties of the pyrolysis oils such as their energy values, main organic element (C, H and O) contents, and water content. The spectra also contained predictive information on the samples’ origins, fraction, and temperature treatment, demonstrating the potential of on-line NIR techniques for monitoring pyrolytic production processes and characterizing important properties of pyrolytic oils from lignocellulosic biomass.

Keywords
OPLS-DA, PCA, Prediction, Pyrolysis cyclone, Reed canary grass, Wood-based biomass, Biomass, Chemical analysis, Cracking (chemical), Forecasting, Water content, Fast pyrolysis bio-oil, Lignocellulosic biomass, Predictive information, Temperature treatments, Transportation fuels, Wet chemical analysis, Infrared devices
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34000 (URN)10.1016/j.jaap.2018.05.009 (DOI)2-s2.0-85047194810 (Scopus ID)
Note

 Funding details: 39449-1, Energimyndigheten; Funding details: www.bio4energy.se; A

Available from: 2018-07-03 Created: 2018-07-03 Last updated: 2018-08-17Bibliographically approved
Ögren, Y., Toth, P., Garami, A., Sepman, A. & Wiinikka, H. (2018). Development of a vision-based soft sensor for estimating equivalence ratio and major species concentration in entrained flow biomass gasification reactors. Applied Energy, 226, 450-460
Open this publication in new window or tab >>Development of a vision-based soft sensor for estimating equivalence ratio and major species concentration in entrained flow biomass gasification reactors
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2018 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 226, p. 450-460Article in journal (Refereed) Published
Abstract [en]

A combination of image processing techniques and regression models was evaluated for predicting equivalence ratio and major species concentration (H2, CO, CO2 and CH4) based on real-time image data from the luminous reaction zone in conditions and reactors relevant to biomass gasification. Two simple image pre-processing routines were tested: reduction to statistical moments and pixel binning (subsampling). Image features obtained by using these two pre-processing methods were then used as inputs for two regression algorithms: Gaussian Process Regression and Artificial Neural Networks. The methods were evaluated by using a laboratory-scale flat-flame burner and a pilot-scale entrained flow biomass gasifier. For the flat-flame burner, the root mean square error (RMSE) were on the order of the uncertainty of the experimental measurements. For the gasifier, the RMSE was approximately three times higher than the experimental uncertainty – however, the main source of the error was the quantization of the training dataset. The accuracy of the predictions was found to be sufficient for process monitoring purposes. As a feature extraction step, reduction to statistical moments proved to be superior compared to pixel binning.

Keywords
AI, Gasification diagnostics, Gaussian process regression, Image processing, Machine learning, Neural network, Process monitoring
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33999 (URN)10.1016/j.apenergy.2018.06.007 (DOI)2-s2.0-85048807165 (Scopus ID)
Available from: 2018-07-03 Created: 2018-07-03 Last updated: 2018-07-11Bibliographically approved
Carlborg, M., Weiland, F., Ma, C., Backman, R., Landälv, I. & Winikka, H. (2018). Exposure of refractory materials during high-temperature gasification of a woody biomass and peat mixture. Journal of the European Ceramic Society, 38(2), 777-787
Open this publication in new window or tab >>Exposure of refractory materials during high-temperature gasification of a woody biomass and peat mixture
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2018 (English)In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 38, no 2, p. 777-787Article in journal (Refereed) Published
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. © 2017 Elsevier Ltd

Keywords
Biomass, Entrained flow, Gasification, Oxygen blown, Refractory, Slag, Mixtures, Peat, Slags, Crystalline phasis, Entrained flow gasifiers, High-temperature gasification, Oxygen-blown, Phase assemblages, Plant availability, Thermodynamic equilibrium calculation, Refractory materials
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33235 (URN)10.1016/j.jeurceramsoc.2017.09.016 (DOI)2-s2.0-85029532285 (Scopus ID)
Note

 Funding details: Bio4Gasification, Energimyndigheten; Funding text: This work has been founded by the Swedish Energy Agency through Bio4Gasification.

Available from: 2018-02-13 Created: 2018-02-13 Last updated: 2018-03-16Bibliographically approved
Ögren, Y., Gullberg, M., Wennebro, J., Sepman, A., Toth, P. & Wiinikka, H. (2018). Influence of oxidizer injection angle on the entrained flow gasification of torrefied wood powder. Fuel processing technology, 181, 8-17
Open this publication in new window or tab >>Influence of oxidizer injection angle on the entrained flow gasification of torrefied wood powder
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2018 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 181, p. 8-17Article in journal (Refereed) Published
Abstract [en]

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

Keywords
Biomass, Burner design, Entrained flow gasification, Process optimization, Syngas, TDLAS, Absorption spectroscopy, Carbon, Efficiency, Gas chromatography, Gasification, Optimization, Thermocouples, Conventional methods, Hydrocarbon production, Measurement uncertainty, Syn-gas, Tunable diode laser absorption spectroscopy, Uncertainty analysis
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35577 (URN)10.1016/j.fuproc.2018.09.005 (DOI)2-s2.0-85053436599 (Scopus ID)
Note

Funding details: Energimyndigheten; Funding text: This work was performed within the platform for entrained-flow gasification (Bio4Gasification) at the Swedish Gasification Centre financed by the Swedish Energy Agency and the member companies.

Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2018-11-12Bibliographically approved
Winikka, H., Toth, P., Jansson, K., Molinder, R., Broström, M., Sandström, L., . . . Weiland, F. (2018). Particle formation during pressurized entrained flow gasification of wood powder: Effects of process conditions on chemical composition, nanostructure, and reactivity. Combustion and Flame, 189, 1339-1351
Open this publication in new window or tab >>Particle formation during pressurized entrained flow gasification of wood powder: Effects of process conditions on chemical composition, nanostructure, and reactivity
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2018 (English)In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 189, p. 1339-1351Article in journal (Refereed) Published
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.

Keywords
Biomass, Gasification, HRTEM, Nanostructure, Soot, Dust, Electron microscopy, High resolution transmission electron microscopy, Internal oxidation, Meteorological instruments, Nanostructures, Oxidation, Oxidation resistance, Scanning electron microscopy, Temperature, Thermogravimetric analysis, Transmission electron microscopy, Elemental compositions, Mass size distribution, Ordered nanostructures, Particle concentrations, Particle formation process, Pressurized entrained flow gasification, Reactive particle shells, Particle size analysis, fuel, inorganic compound, nanomaterial, oxygen, Article, ash, chemical composition, chemical structure, combustion, crystallization, gas flow, heat loss, high temperature, image analysis, partial pressure, particle size, particulate matter, powder, priority journal, solid, thermal analysis, thermodynamics, thermostability, wood
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33230 (URN)10.1016/j.combustflame.2017.10.025 (DOI)2-s2.0-85034087389 (Scopus ID)
Note

 Funding details: LTU, Luleå Tekniska Universitet; Funding details: Bio4Energy, Energimyndigheten; Funding details: NSF, National Science Foundation; Funding details: MTA, Magyar Tudományos Akadémia; Funding details: SU, Stockholms Universitet; Funding details: Knut och Alice Wallenbergs Stiftelse; Funding text: The authors wish to acknowledge the PEBG project financed by the Swedish Energy Agency , IVAB , Sveaskog and Smurfit Kappa Kraftliner . The Bio4Energy, a strategic research environment appointed by the Swedish goverment. The Swedish Center for Gasification financed by the Swedish Energy Agency and the member companies. Pal Toth is thankful for the support of the Bolyai Scholarship of the Hungarian Academy of Sciences, and Kjell Jansson to the Knut and Alice Wallenberg foundation for support to the electron microscope facility at MMK, Stockholm University. Prof. Marcus Öhman, Luleå University of Technology is also acknowledged for discussions regarding the inorganic phase of the particles and Esbjörn Pettersson, RISE ETC AB is acknowledged for sampling of the particles during the experiments. This material is based upon work while Dr. Lighty served at the National Science Foundation. Any opinions, findings, and conclusions expressed in this publication are those of the authors and do not necessarily reflect the views of the National Science Foundation.

Available from: 2018-02-12 Created: 2018-02-12 Last updated: 2018-08-17Bibliographically approved
Wiinikka, H., Vikström, T., Wennebro, J., Toth, P. & Sepman, A. (2018). Pulverized Sponge Iron, a Zero-Carbon and Clean Substitute for Fossil Coal in Energy Applications. Energy & Fuels, 32(9), 9982-9989
Open this publication in new window or tab >>Pulverized Sponge Iron, a Zero-Carbon and Clean Substitute for Fossil Coal in Energy Applications
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2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 9, p. 9982-9989Article in journal (Refereed) Published
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 micrometer-sized, solid or hollow hematite (α-Fe2O3) spheres. The remaining 4 wt % of products was maghemite (Î-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 a fuel in existing or newly designed industrial systems.

Keywords
Carbon, Carbon dioxide, Climate change, Coal, Emission control, Gas emissions, Greenhouse gases, Hematite, Pulverized fuel, Sponge iron, Direct combustion, Energy applications, Global climate changes, Industrial systems, Product composition, Pulverized coal combustion, Pulverized coals, Thermodynamic calculations, Coal combustion
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35286 (URN)10.1021/acs.energyfuels.8b02270 (DOI)2-s2.0-85052297503 (Scopus ID)
Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2019-02-04Bibliographically approved
Toth, P., Ögren, Y., Sepman, A., Vikström, T., Gren, P. & Wiinikka, H. (2018). Spray combustion of biomass fast pyrolysis oil: experiments and modeling. Fuel, 7, 580-591
Open this publication in new window or tab >>Spray combustion of biomass fast pyrolysis oil: experiments and modeling
Show others...
2018 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 7, p. 580-591Article in journal (Refereed) Published
Abstract [en]

In this work, we are the first to report a detailed comparison between the predictions of a current Computational Fluid Dynamics (CFD) model for describing Fast Pyrolysis Oil (FPO) spray combustion and results from a laboratory- scale experiment. The objectives were to assess the predictive power of the CFD model, evaluate its usefulness in a numerical optimization scenario and characterize the spray flame. The spray flame was produced by using an air-assist atomizer piloted by a CH4/air flat-flame. Pyrolysis oil from a cyclone fast pyrolysis plant was combusted. The flame was characterized by using two-color pyrometry, Tunable Diode Laser Absorption Spectroscopy and high-magnification shadowgraphy. Overall, the assessed model correctly predicted flame structure and seemed appropriate for engineering applications, but lacked predictive power in estimating droplet size distributions. Numerical results were the most sensitive to variations in the initial droplet size distribution; however, seemed robust to changes in the multicomponent fuel formulation. Several conclusions were drawn regarding FPO spray combustion itself; e.g., the amount of produced soot in the flames was very low and droplets exhibited microexplosion behavior in a characteristic size-shape regime.

Keywords
biomass, fast pyrolysis oil, spray combustion, computational fluid dynamics, optical diagnostics, biofuel
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-37680 (URN)10.1016/j.fuel.2018.10.031 (DOI)
Available from: 2019-01-29 Created: 2019-01-29 Last updated: 2019-01-29Bibliographically approved
Sefidari, H., Lindblom, B., Wiinikka, H., Nordin, L.-O., Mouzon, J., Bhuiyan, I. U. & Öhman, M. (2018). 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 deposits. Fuel processing technology, 177, 283-298
Open this publication in new window or tab >>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 deposits
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2018 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 177, p. 283-298Article in journal (Refereed) Published
Abstract [en]

To 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.

Keywords
Coal combustion, Coal-ash, Deposition (slagging), Iron-ore pellet dust, Iron-ore pelletizing
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34424 (URN)10.1016/j.fuproc.2018.05.004 (DOI)2-s2.0-85046802389 (Scopus ID)
Note

 Funding text: LKAB (Luossavaara-Kiirunavaara Aktiebolag) and Luleå University of Technology are acknowledged for their financial support of this study ( Dnr 93_2014 ). Many thanks to the supportive personnel at RISE-ETC (Piteå, Sweden) and Swerea MEFOS (Luleå, Sweden) for their efforts and dedication to the project.

Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2019-02-04Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9395-9928

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