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Ögren, Y., Sepman, A., Fooladgar, E., Weiland, F. & Wiinikka, H. (2024). Development and evaluation of a vision driven sensor for estimating fuel feeding rates in combustion and gasification processes. Energy and AI, 15, Article ID 100316.
Open this publication in new window or tab >>Development and evaluation of a vision driven sensor for estimating fuel feeding rates in combustion and gasification processes
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2024 (English)In: Energy and AI, ISSN 2666-5468, Vol. 15, article id 100316Article in journal (Refereed) Published
Abstract [en]

A machine vision driven sensor for estimating the instantaneous feeding rate of pelletized fuels was developed and tested experimentally in combustion and gasification processes. The feeding rate was determined from images of the pellets sliding on a transfer chute into the reactor. From the images the apparent area and velocity of the pellets were extracted. Area was determined by a segmentation model created using a machine learning framework and velocities by image registration of two subsequent images. The measured weight of the pelletized fuel passed through the feeding system was in good agreement with the weight estimated by the sensor. The observed variations in the fuel feeding correlated with the variations in the gaseous species concentrations measured in the reactor core and in the exhaust. Since the developed sensor measures the ingoing fuel feeding rate prior to the reactor, its signal could therefore help improve process control. 

Place, publisher, year, edition, pages
Elsevier B.V., 2024
Keywords
Combustion, Fuel feeding, Gasification, Image processing, Neural network, Process monitoring, Feeding, Image segmentation, Pelletizing, Process control, Combustion pro-cess, Feeding rate, Gasification process, Images processing, Machine-learning, Machine-vision, Neural-networks, Segmentation models, Transfer chutes
National Category
Environmental Engineering
Identifiers
urn:nbn:se:ri:diva-71916 (URN)10.1016/j.egyai.2023.100316 (DOI)2-s2.0-85181658798 (Scopus ID)
Funder
Swedish Energy Agency, 50470-1Swedish Research Council FormasVinnovaEU, Horizon 2020, 818011
Note

Correspondence Address: Y. Ögren; RISE AB, Piteå, Box 726 SE-941 28, Sweden; . The Bio4Energy, a strategic research environment appointed by the Swedish government and the SwedishCenter for Gasification financed by the Swedish Energy Agency and member companies. The RE:source program finance by the Swedish Energy Agency, Vinnova and Formas. The Pulp&Fuel project financed by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 818011 and the TDLAS-AI project (Swedish energy agency project 50470-1). 

Available from: 2024-02-22 Created: 2024-02-22 Last updated: 2024-02-22Bibliographically approved
Weiland, F., Jacobsson, D., Wahlqvist, D., Ek, M. & Wiinikka, H. (2024). Inorganic Chemistry during Pyrolysis, Gasification, and Oxyfuel Combustion of Kraft Pulping Black Liquor. Energy & Fuels, 38(6), 5279-5287
Open this publication in new window or tab >>Inorganic Chemistry during Pyrolysis, Gasification, and Oxyfuel Combustion of Kraft Pulping Black Liquor
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2024 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 38, no 6, p. 5279-5287Article in journal (Refereed) Published
Abstract [en]

Changed utilization of black liquor in the pulp and paper industry has the potential to offer simplified carbon capture and, thus, negative net emissions from these large point sources. This can be achieved either by adapting existing recovery boilers to oxyfuel combustion or by replacing them with black liquor gasification technology. In this work, the chemistry during black liquor conversion was therefore studied in detail under different atmospheres relevant for pyrolysis, gasification, and oxyfuel combustion. Experiments were performed using environmental scanning transmission electron microscopy (ESTEM) and thermogravimetric analysis (TGA), supported with thermodynamic equilibrium calculations (TECs) to understand and interpret the results. Black liquor conversion was found to be generally similar in air and oxyfuel atmospheres containing approximately 20-25 mol % oxygen. The results however indicated that there was a higher probability of forming carbonates in the melt at higher carbon dioxide (CO2) partial pressures, which in addition was found to be associated with potentially higher sulfur loss during black liquor conversion. Both of these characteristics can negatively affect the chemical recycling at the pulp mill by increasing the need for lime and makeup chemicals.

Place, publisher, year, edition, pages
American Chemical Society, 2024
Keywords
Combustion; Gasification; Gravimetry; Lime; Pyrolysis; Scanning Electron Microscopy; Sulfur Dioxide; Thermal Analysis; Combustion; Gasification; High resolution transmission electron microscopy; Indicators (chemical); Kraft pulp; Lime; Paper and pulp industry; Pyrolysis; Scanning electron microscopy; Sulfur dioxide; Thermogravimetric analysis; Black liquor; Black liquor gasification; Inorganic chemistry; Oxyfuel combustion; Point-sources; Pulp and paper industry; Pulping black liquor; Pyrolysis combustions; Pyrolysis gasifications; Recovery boilers; Carbon dioxide
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:ri:diva-72825 (URN)10.1021/acs.energyfuels.3c05031 (DOI)2-s2.0-85187342372 (Scopus ID)
Funder
Swedish Energy Agency, P2020-90041
Note

This work was made possible through funding from the Swedish Energy Agency’s initiative “The Industrial Leap”, project P2020-90041.

Available from: 2024-04-29 Created: 2024-04-29 Last updated: 2024-04-29Bibliographically approved
Lestander, T. A., Weiland, F., Grimm, A., Rudolfsson, M. & Wiinikka, H. (2022). Gasification of pure and mixed feedstock components: Effect on syngas composition and gasification efficiency. Journal of Cleaner Production, 369, Article ID 133330.
Open this publication in new window or tab >>Gasification of pure and mixed feedstock components: Effect on syngas composition and gasification efficiency
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2022 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 369, article id 133330Article in journal (Refereed) Published
Abstract [en]

The aim of this work was to investigate whether the use of individual tree components (i.e., stem wood, bark, branches, and needles of spruces) as feedstocks during oxygen blow gasification is more efficient than using mixtures of these components. Experiments were performed at three oxygen levels in an 18-kW oxygen blown fixed bed gasifier with both single and mixed component feedstocks. The composition of the resulting syngas and the cold gas efficiency based on CO and H2 (CGEfuel) were used as response variables to evaluate the influence of different feedstocks on gasification performance. Based on the experimental results and data on the composition of ∼26000 trees drawn from a national Swedish spruce database, multivariate models were developed to simulate gasifier performance under different operating conditions and with different feedstock compositions. The experimental results revealed that the optimal CGEfuel with respect to the oxygen supply differed markedly between the different spruce tree components. Additionally, the models showed that co-gasification of mixed components yielded a lower CGEfuel than separate gasification of pure components. Optimizing the oxygen supply for the average tree composition reduced the GCEfuel by 1.3–6.2% when compared to optimal gasification of single component feedstocks. Therefore, if single-component feedstocks are available, it may be preferable to gasify them separately because doing so provides a higher gasification efficiency than co-gasification of mixed components. © 2022 The Authors

Place, publisher, year, edition, pages
Elsevier Ltd, 2022
Keywords
Bark, Biomass components, Branches, Co-gasification, Cold gas efficiency, Needles, Wood, Efficiency, Forestry, Gasification, Synthesis gas, Trees (mathematics), Tumors, Branch, Gasification efficiency, Gasifiers, Performance, Single components, Tree components, Feedstocks
National Category
Bioprocess Technology
Identifiers
urn:nbn:se:ri:diva-60051 (URN)10.1016/j.jclepro.2022.133330 (DOI)2-s2.0-85135831044 (Scopus ID)
Note

Funding text 1: We thank the Bio4Energy strategic research environment appointed by the Swedish government ( www.bio4energy.se ) for financial support. Gunnar Kalén and Markus Segerström are acknowledged for assistance in the preparation and pelleting of tree components. RISE ETC engineers and technicians are acknowledged for operating the gasification pilot plant.

Available from: 2022-10-04 Created: 2022-10-04 Last updated: 2023-05-19Bibliographically approved
Weiland, F., Lundin, L., Celebi, M., van der Vlist, K. & Moradian, F. (2021). Aspects of chemical recycling of complex plastic waste via the gasification route. Waste Management, 126, 65-77
Open this publication in new window or tab >>Aspects of chemical recycling of complex plastic waste via the gasification route
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2021 (English)In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 126, p. 65-77Article in journal (Refereed) Published
Abstract [en]

Oxygen blown high-temperature gasification constitutes an opportunity for chemical recycling of plastic wastes. This article summarizes the results from comparative tests of combustion and gasification of two complex plastic wastes: a plastic reject (PR) from processing recycled paper and an automotive shredder residue (ASR). Calculated gasification efficiencies corresponded to about 80% and 60%, respectively. Gasification resulted in lower yields of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) compared to direct combustion. A two-stage process, including gasification followed by syngas combustion, reduced the emissions of HCl and PCDD/F in the flue gas to <1.4% and <0.2%, respectively, compared to the levels from direct combustion of the PR feedstock. Most of the PCDD/F (>99%) was captured along with particulate matter (soot) during gasification. The contribution to the toxic concentration of PCDD/F was mainly from the PCDF congeners. Fly ash particulate matter from ASR combustion contained a significant proportion of zinc, which thus constitutes a great potential for use in zinc recycling. © 2021 Elsevier Ltd

Place, publisher, year, edition, pages
Elsevier Ltd, 2021
Keywords
Chemical recycling, Chlorine, Dioxins, Gasification, Plastic waste, Syngas, Chlorine compounds, Fly ash, Gas emissions, Municipal solid waste, Plastic recycling, Synthesis gas, Waste incineration, Zinc, Automotive shredder residues, Comparative tests, Direct combustion, High-temperature gasification, Oxygen-blown, Particulate Matter, Plastics waste, Polychlorinated dibenzo-p-dioxin and dibenzofuran, Syn gas, Organic pollutants
National Category
Environmental Sciences
Identifiers
urn:nbn:se:ri:diva-52624 (URN)10.1016/j.wasman.2021.02.054 (DOI)2-s2.0-85102630812 (Scopus ID)
Available from: 2021-03-25 Created: 2021-03-25 Last updated: 2023-05-16Bibliographically approved
Weiland, F., Qureshi, M., Wennebro, J., Lindfors, C., Ohra-Aho, T., Shafaghat, H. & Johansson, A.-C. (2021). Entrained flow gasification of polypropylene pyrolysis oil. Molecules, 26(23), Article ID 7317.
Open this publication in new window or tab >>Entrained flow gasification of polypropylene pyrolysis oil
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2021 (English)In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 23, article id 7317Article in journal (Refereed) Published
Abstract [en]

Petrochemical products could be produced from circular feedstock, such as waste plastics. Most plants that utilize syngas in their production are today equipped with entrained flow gasifiers, as this type of gasifier generates the highest syngas quality. However, feeding of circular feedstocks to an entrained flow gasifier can be problematic. Therefore, in this work, a two-step process was studied, in which polypropylene was pre-treated by pyrolysis to produce a liquid intermediate that was easily fed to the gasifier. The products from both pyrolysis and gasification were thoroughly characterized. Moreover, the product yields from the individual steps, as well as from the entire process chain, are reported. It was estimated that the yields of CO and H2 from the two-step process were at least 0.95 and 0.06 kg per kg of polypropylene, respectively, assuming that the pyrolysis liquid and wax can be combined as feedstock to an entrained flow gasifier. On an energy basis, the energy content of CO and H2 in the produced syngas corresponded to approximately 40% of the energy content of the polypropylene raw material. This is, however, expected to be significantly improved on a larger scale where losses are proportionally smaller. © 2021 by the authors. 

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
Chemical recycling, Gasification, Plastic waste, Pyrolysis, Syngas
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-57332 (URN)10.3390/molecules26237317 (DOI)2-s2.0-85120819446 (Scopus ID)
Note

Export Date: 16 December 2021; Article; CODEN: MOLEF; Correspondence Address: Weiland, F.; RISE Energy Technology Center AB, Box 726, Sweden; email: fredrik.weiland@ri.se; Funding details: Teknologian Tutkimuskeskus VTT; Funding text 1: Funding: This research was funded by RISE Research Institutes of Sweden and VTT Technical Research Centre of Finland, respectively. Additionally, the gasification part of the work received funding from the B4G node of Swedish Gasification Centre (SFC).

Available from: 2021-12-22 Created: 2021-12-22 Last updated: 2024-05-17Bibliographically approved
Weiland, F., Lundström, S. & Ögren, Y. (2021). Oxygen-blown gasification of pulp mill bark residues for synthetic fuel production. Processes, 9(1), Article ID 163.
Open this publication in new window or tab >>Oxygen-blown gasification of pulp mill bark residues for synthetic fuel production
2021 (English)In: Processes, ISSN 2227-9717, Vol. 9, no 1, article id 163Article in journal (Refereed) Published
Abstract [en]

Synthetic fuel production via gasification of residual biomass streams from the pulp and paper industry can be an opportunity for the mills to enable improved resource utilization and at the same time reduce the production of excess heat. This paper summarizes initial oxygen-blown gasification experiments with two bark residues from a European pulp and paper mill, i.e., a softwood bark and a hardwood bark. The gasification process was characterized by measuring syngas yields and process efficiency to find optimum operating conditions. In addition, impurities in the syngas and ash behavior were characterized. Maximum yields of CO and H2 were obtained from softwood bark and amounted to approximately 29 and 15 mol/kg fuel, respectively. Optimum cold gas efficiency was achieved at an oxygen stoichiometric ratio of λ = 0.40 and was approximately 76% and 70% for softwood bark and hardwood bark, respectively. Increased λ had a reducing effect on pollutants in the syngas, e.g., higher hydrocarbons, NH3, HCl, and soot. The situation for sulfur species was more complex. Evaluation of the bark ashes indicated that slag formation could start already from 800◦C. Furthermore, a non-intrusive laser diagnostics technique gave rapid feedback on the millisecond scale. Measured syngas temperature and water content were in good agreement with the applied reference methods. © 2021 by the authors. 

Place, publisher, year, edition, pages
MDPI AG, 2021
Keywords
Bark residues, Gasification, Online TDLAS process measurement, Oxygen blown, Pulp mill, Syngas
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-52222 (URN)10.3390/pr9010163 (DOI)2-s2.0-85099947248 (Scopus ID)
Note

Funding details: Horizon 2020; Funding details: Energimyndigheten; Funding details: 818011; Funding text 1: This is exactly the combination of processes that are being studied in the European Pulp & Fuel project within which this work has been performed, i.e., oxygen-blown gasification of bark residues in combination with SCWG of black liquor aiming for synthetic fuel production. The Pulp & Fuel project received funding from the European Union’s Horizon 2020 research and innovation program and consists of ten partners from four European countries. The project addresses the thermochemical conversion of industrial wastes produced at a pulp and paper mill into biofuel.; Funding text 2: Funding: The Pulp&Fuel project, within which this work was mainly carried out, received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 818011. The TDLAS method, for temperature and water concentration measurements, was developed within the Bio4Gasification (B4G) and Swedish Gasification Center (SFC), financed by the Swedish Energy Agency together with academia and industry partners.

Available from: 2021-02-09 Created: 2021-02-09 Last updated: 2023-05-16Bibliographically approved
Bergvall, N., Sandström, L., Weiland, F. & Öhrman, O. G. W. (2020). Corefining of Fast Pyrolysis Bio-Oil with Vacuum Residue and Vacuum Gas Oil in a Continuous Slurry Hydrocracking Process. Energy & Fuels, 34(7), 8452-8465
Open this publication in new window or tab >>Corefining of Fast Pyrolysis Bio-Oil with Vacuum Residue and Vacuum Gas Oil in a Continuous Slurry Hydrocracking Process
2020 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, no 7, p. 8452-8465Article in journal (Refereed) Published
Abstract [en]

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

Place, publisher, year, edition, pages
American Chemical Society, 2020
Keywords
fast pyrolysis biofuel vacuum residue gas oil hydrocracking process
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-46566 (URN)10.1021/acs.energyfuels.0c01322 (DOI)
Available from: 2020-08-21 Created: 2020-08-21 Last updated: 2023-05-26Bibliographically approved
Ma, C., Wang, N., Chen, Y., Khokarale, S., Bui, T., Weiland, F., . . . Ji, X. (2020). Towards negative carbon emissions: Carbon capture in bio-syngas from gasification by aqueous pentaethylenehexamine. Applied Energy, 279, Article ID 115877.
Open this publication in new window or tab >>Towards negative carbon emissions: Carbon capture in bio-syngas from gasification by aqueous pentaethylenehexamine
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2020 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 279, article id 115877Article in journal (Refereed) Published
Abstract [en]

In this work, an aqueous pentaethylenehexamine (PEHA) solution was studied for CO2 removal from bio-syngas for the first time. Firstly, pure CO2 absorption in aqueous PEHA solution under different conditions was conducted, and 20 wt% PEHA solution was identified as the best option. Secondly, the capture of CO2 was tested with synthetic syngas from a gas cylinder, and the species other than CO2 showed a negligible impact on CO2 removal. Finally, to evaluate the practical feasibility of using aqueous PEHA solution on the downstream CO2 capture, the pilot experiments of gasification with boreal forest-based biomasses were designed to provide real syngas with a realistic distribution in composition for further testing. The results showed that the operating conditions and the type of feedstocks affected the distribution in the bio-syngas composition. Among these feedstocks, at the optimal oxygen supply, using spruce needles generated the highest yields of CO and H2 and, meanwhile, gave rise to similar yields of other gases such as CO2, CH4, etc. The influence of the species other than CO2 for CO2 removal was negligible. Additionally, aqueous PEHA solution was tested as a biomass pretreatment agent, showing that no significant changes could be identified by the ultimate analysis (except for increased nitrogen content), but the yields of CO were affected negatively. On the other hand, when using the pretreated biomass by the aqueous PEHA solution, the NH3 concentration in bio-syngas reached to the highest (4000 parts per million), which slightly affected the CO2 absorption capacity and initial absorption rate of 20 wt% PEHA solution in a positive way.

Place, publisher, year, edition, pages
Elsevier Ltd, 2020
Keywords
Bio-syngas, Biomass pre-treatment, CO2 removal, Gasification, Negative carbon emission, Pentaethylenehexamine
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-48925 (URN)10.1016/j.apenergy.2020.115877 (DOI)2-s2.0-85091345059 (Scopus ID)
Note

Funding details: Energimyndigheten; Funding details: Energimyndigheten, P40548-1; Funding text 1: The Bio4Energy program and Kempe Foundations are acknowledged. This work is also a part of the activities of the Åbo Akademi University Johan Gadolin Process Chemistry Centre . This work is also supported by the Swedish Energy Agency (Energimyndigheten) ( P40548-1 ).

Available from: 2020-10-13 Created: 2020-10-13 Last updated: 2023-05-16Bibliographically 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: 2023-05-19Bibliographically 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: 2023-05-25Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-2890-3546

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