Change search
Link to record
Permanent link

Direct link
Publications (10 of 24) Show all publications
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
Show others...
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
Sepman, A., Malhotra, J. S., Wennebro, J. & Wiinikka, H. (2024). Iron as recyclable electrofuel: Effect on particle morphology from multiple combustion-regeneration cycles. Combustion and Flame, 259, Article ID 113137.
Open this publication in new window or tab >>Iron as recyclable electrofuel: Effect on particle morphology from multiple combustion-regeneration cycles
2024 (English)In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 259, article id 113137Article in journal (Refereed) Published
Abstract [en]

This work describes the morphological and material changes in the iron powder during four regeneration-combustion cycles. The regeneration in H2 and combustion in air experiments were made in a fluidized bed (FB) and an entrained flow reactor (EFR), respectively. The average size of the iron oxide particles more than doubled between the first and fourth combustion cycles, and many of the particles were hollow. The regeneration step did not change the size of the particles but increased their porosity. A mechanism is proposed that describes the formation of large-diameter hollow particles which increases as a function of the regeneration-combustion cycles. The observed increase in particle size and the change in particle morphology complicates the iron fuel concept, as it leads to a degradation of the structural stability of the particle with time.

Place, publisher, year, edition, pages
Elsevier Inc., 2024
Keywords
Fluidized bed combustion; Fluidized beds; Iron oxides; Morphology; Particle size; Air experiments; Average size; Combustion cycle; Entrained Flow Reactor; Iron oxide particles; Material change; Morphological changes; Particle morphologies; Recyclables; Regeneration cycles; Stability
National Category
Energy Engineering Other Environmental Engineering
Identifiers
urn:nbn:se:ri:diva-67706 (URN)10.1016/j.combustflame.2023.113137 (DOI)2-s2.0-85174581752 (Scopus ID)
Available from: 2023-11-06 Created: 2023-11-06 Last updated: 2023-11-16Bibliographically approved
Siddanathi, S. L., Westerberg, L. G., Åkerstedt, H., Wiinikka, H. & Sepman, A. (2023). Computational modeling and temperature measurements using emission spectroscopy on a non-transferred plasma torch. AIP Advances, 13(2), Article ID 025019.
Open this publication in new window or tab >>Computational modeling and temperature measurements using emission spectroscopy on a non-transferred plasma torch
Show others...
2023 (English)In: AIP Advances, E-ISSN 2158-3226, Vol. 13, no 2, article id 025019Article in journal (Refereed) Published
Abstract [en]

A non-transferred plasma torch is a device used to generate a steady thermal plasma jet. Plasma torches have the potential to replace fossil fuel burners used as heat sources in the process industry. Today, however, the available plasma torches are of small scale compared to the power used in the burners in the process industry. In order to understand the effects of large scales on the plasma flow dynamics, it is essential to understand the operation of the plasma torch under different operating conditions and for different geometries. In this study, the analysis of a non-transferred plasma torch has been carried out using both computational and experimental methods. Computationally, the magnetohydrodynamic (MHD) equations are solved using a single-fluid model on a 2D axisymmetric torch geometry. The experiments are performed using emission spectroscopy to measure the plasma jet temperature at the outlet. This paper explains the changes in the arc formation, temperature, and velocity for different working gases and power inputs. Furthermore, the possibilities and disadvantages of the MHD approach, considering a local thermal equilibrium, are discussed. It was found that in general, the computational temperature obtained is supported by the experimental and equilibrium data. The computational temperatures agree by within 10% with the experimental ones at the center of the plasma torch. The paper concludes by explaining the significant impact of input properties like working gas and power input on the output properties like velocity and temperature of plasma jet. © 2023 Author(s).

Place, publisher, year, edition, pages
American Institute of Physics Inc., 2023
Keywords
Emission spectroscopy, Fossil fuels, Magnetohydrodynamics, Plasma diagnostics, Plasma jets, Temperature measurement, Computational modelling, Gas input, Heat sources, Large-scales, Power, Power input, Process industries, Small scale, Thermal plasma jets, Working gas, Plasma torches
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-64103 (URN)10.1063/5.0129653 (DOI)2-s2.0-85147798595 (Scopus ID)
Note

Funding details: Energimyndigheten, 49609-1; Funding text 1: This work was funded by the Swedish Energy Agency, Grant No. 49609-1.

Available from: 2023-02-28 Created: 2023-02-28 Last updated: 2023-05-19Bibliographically approved
Mousavi, S. M., Thorin, E., Schmidt, F. M., Sepman, A., Bai, X. S. & Fatehi, H. (2023). Numerical Study and Experimental Verification of Biomass Conversion and Potassium Release in a 140 kW Entrained Flow Gasifier. Energy & Fuels, 37(2), 1116-1130
Open this publication in new window or tab >>Numerical Study and Experimental Verification of Biomass Conversion and Potassium Release in a 140 kW Entrained Flow Gasifier
Show others...
2023 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 37, no 2, p. 1116-1130Article in journal (Refereed) Published
Abstract [en]

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

Place, publisher, year, edition, pages
American Chemical Society, 2023
Keywords
Chlorine compounds, Combustion, Dissociation, Forestry, Gases, Gasification, Potassium hydroxide, Salts, Biomass conversion, Combustion zones, Entrained flow gasifiers, Eulerian Lagrangian models, Experimental verification, Gas-phases, Gasifiers, Inorganic salts, Potassium release, Residence time, Biomass
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-62973 (URN)10.1021/acs.energyfuels.2c03107 (DOI)2-s2.0-85146130812 (Scopus ID)
Note

Funding details: 22538-4; Funding details: 36160-1, 50470-1; Funding details: College of Science, Technology, Engineering, and Mathematics, Youngstown State University, STEM; Funding details: Knut och Alice Wallenbergs Stiftelse; Funding details: Energimyndigheten; Funding details: Kempestiftelserna, JCK-1316; Funding details: Horizon 2020, 637020; Funding text 1: This work was supported by the Swedish Energy Agency (STEM) through KC-CECOST, project No. 22538-4, the Swedish Gasification center, project No. 50470-1, project No. 36160-1, and the Knut & Alice Wallenberg foundation (KAW COCALD project). The authors also acknowledge the financial support from the Swedish strategic research program Bio4Energy and the Kempe Foundations (project JCK-1316). The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at PDC (Dardel). The fuels were received from a project which received funding from the European Unions Horizon 2020 research and innovation program under grant agreement no. 637020 Mobile Flip.

Available from: 2023-01-25 Created: 2023-01-25 Last updated: 2023-07-06Bibliographically approved
Thorin, E., Sepman, A., Ögren, Y., Ma, C., Carlborg, M., Wennebro, J., . . . Schmidt, F. M. (2023). Quantitative real-time in situ measurement of gaseous K, KOH and KCl in a 140 kW entrained-flow biomass gasifier. Proceedings of the Combustion Institute, 39(1), 1337-1345
Open this publication in new window or tab >>Quantitative real-time in situ measurement of gaseous K, KOH and KCl in a 140 kW entrained-flow biomass gasifier
Show others...
2023 (English)In: Proceedings of the Combustion Institute, ISSN 1540-7489, E-ISSN 1873-2704, Vol. 39, no 1, p. 1337-1345Article in journal (Refereed) Published
Abstract [en]

Photofragmentation tunable diode laser absorption spectroscopy (PF-TDLAS) was used to simultaneously measure the concentrations of gas phase atomic potassium (K), potassium hydroxide (KOH) and potassium chloride (KCl) in the reactor core of a 140 kWth atmospheric entrained-flow gasifier (EFG). In two gasification experiments at air-to-fuel equivalence ratio of 0.5, the EFG was first run on forest residues (FR) and then on an 80/20 mixture of FR and wheat straw (FR/WS). Combustion at air-to-fuel equivalence ratio of 1.3 was investigated for comparison. A high K(g) absorbance was observed in gasification, requiring the photofragmentation signals from KOH(g) and KCl(g) to be recorded at a fixed detuning of 7.3 cm-1 from the center of the K(g) absorption profile. In combustion, the fragments recombined instantly after the UV pulse within around 10 μs, whereas in gasification, the K(g) fragment concentration first increased further for 30 μs after the UV pulse, before slowly decaying for up to hundreds of μs. According to 0D reaction kinetics simulations, this could be explained by a difference in recombination kinetics, which is dominated by oxygen reactions in combustion and by hydrogen reactions in gasification. The K species concentrations in the EFG were stable on average, but periodic short-term variations due to fuel feeding were observed, as well as a gradual increase in KOH(g) over the day as the reactor approached global equilibrium. A comparison of the average K species concentrations towards the end of each experiment showed a higher total K in the gas phase for FR/WS, with higher K(g) and KCl(g), but lower KOH(g), compared to the FR fuel. The measured values were in reasonable agreement with predictions by thermodynamic equilibrium calculations. © 2022 The Author(s). 

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Biomass, Entrained-flow gasification, Photofragmentation, Potassium (K), Tunable diode laser absorption spectroscopy (TDLAS), Absorption spectroscopy, Combustion, Fuels, Gases, Gasification, Potassium hydroxide, Reaction kinetics, Semiconductor lasers, Entrained flow gasification, Entrained flow gasifiers, Equivalence ratios, Forest residue, Gas-phases, Potassium chloride, Tunable diode laser absorption spectroscopy, Chlorine compounds
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-61456 (URN)10.1016/j.proci.2022.07.180 (DOI)2-s2.0-85139508080 (Scopus ID)
Note

 Funding details: 36160-1, 50470-1; Funding details: Energimyndigheten; Funding details: Kempestiftelserna, JCK-1316; Funding details: Horizon 2020, 637020; Funding text 1: The authors acknowledge financial support from the Swedish strategic research program Bio4Energy, the Kempe Foundations ( JCK-1316 ), and the Swedish Energy Agency through both the Swedish Gasification Centre and projects no. 50470-1 and 36160-1 . The fuels were received from a project which received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 637020 - Mobile Flip.

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2023-07-06Bibliographically approved
Sepman, A., Thorin, E., Ögren, Y., Ma, C., Carlborg, M., Wennebro, J., . . . Schmidt, F. (2022). Laser-based detection of methane and soot during entrained-flow biomass gasification. Combustion and Flame, 237, Article ID 111886.
Open this publication in new window or tab >>Laser-based detection of methane and soot during entrained-flow biomass gasification
Show others...
2022 (English)In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 237, article id 111886Article in journal (Refereed) Published
Abstract [en]

Methane is one of the main gas species produced during biomass gasification and may be a desired or undesired product. Syngas CH4 concentrations are typically >5 vol-% (when desired) and 1–3 vol-% even when efforts are made to minimize it, while thermochemical equilibrium calculations (TEC) predict complete CH4 decomposition. How CH4 is generated and sustained in the reactor core is not well understood. To investigate this, accurate quantification of the CH4 concentration during the process is a necessary first step. We present results from rapid in situ measurements of CH4, soot volume fraction, H2O and gas temperature in the reactor core of an atmospheric entrained-flow biomass gasifier, obtained using tunable diode laser absorption spectroscopy (TDLAS) in the near-infrared (1.4 µm) and mid-infrared (3.1 µm) region. An 80/20 wt% mixture of forest residues and wheat straw was converted using oxygen-enriched air (O2>21 vol%) as oxidizer, while the global air-fuel equivalence ratio (AFR) was set to values between 0.3 and 0.7. Combustion at AFR 1.3 was performed as a reference. The results show that the CH4 concentration increased from 1 to 3 vol-% with decreasing AFR, and strongly correlated with soot production. In general, the TDLAS measurements are in good agreement with extractive diagnostics at the reactor outlet and TEC under fuel-lean conditions, but deviate significantly for lower AFR. Detailed 0D chemical reaction kinetics simulations suggest that the CH4 produced in the upper part of the reactor at temperatures >1700 K was fully decomposed, while the CH4 in the final syngas originated from the pyrolysis of fuel particles at temperatures below 1400 K in the lower section of the reactor core. It is shown that the process efficiency was significantly reduced due to the C and H atoms bound in methane and soot. © 2021 The Authors

Place, publisher, year, edition, pages
Elsevier Inc., 2022
Keywords
Biomass, Entrained-flow reactor, Gasification, Methane, Soot, Tunable diode laser absorption spectroscopy (TDLAS), Absorption spectroscopy, Atmospheric movements, Atmospheric temperature, Dust, Infrared devices, Reaction kinetics, Semiconductor lasers, Surface reactions, Synthesis gas, Air/fuel equivalence ratio, Biomass Gasification, CH 4, Entrained flow, Entrained Flow Reactor, Equilibrium calculation, Syn gas, Thermochemical equilibrium, Tunable diode laser absorption spectroscopy
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-57326 (URN)10.1016/j.combustflame.2021.111886 (DOI)2-s2.0-85120458898 (Scopus ID)
Note

 Funding details: 50470-1; Funding details: Energimyndigheten; Funding details: Horizon 2020, 637020; Funding text 1: The authors acknowledge financial support from the Swedish strategic research program Bio4Energy and the Swedish Energy Agency through both the Swedish Gasification Centre and project no. 50470-1. The fuels were received from a project, which received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 637020 - Mobile Flip.

Available from: 2021-12-16 Created: 2021-12-16 Last updated: 2023-05-19Bibliographically approved
Sepman, A., Ögren, Y., Wennebro, J. & Wiinikka, H. (2022). Simultaneous diagnostics of fuel moisture content and equivalence ratio during combustion of liquid and solid fuels. Applied Energy, 324, Article ID 119731.
Open this publication in new window or tab >>Simultaneous diagnostics of fuel moisture content and equivalence ratio during combustion of liquid and solid fuels
2022 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 324, article id 119731Article in journal (Refereed) Published
Abstract [en]

The precise control of bio-based combustion is challenging due to the varying composition and moisture content of the fuels, difficulties in achieving stable fuel feeding, and complex underlying thermochemical processes. We present simultaneous online diagnostics of two combustion parameters, the equivalence ratio and fuel moisture content, in a pilot-scale environment. The parameters were evaluated by analysing the H2O and CO2 concentrations. These were measured using a Fourier transform infrared (FTIR) spectrometer (exhaust) and tuneable diode laser (TDL) absorption spectroscopy (combustion chamber) in pilot-scale diesel and pulverized biomass combustion. Liquid H2O was added into the combustion chamber to represent fuel moisture. The equivalence ratio of diesel and wood combustion was varied by adjusting the flows of combustion air in a staged manner or by using rapid periodic variations (on the order of seconds). The moisture fuel levels calculated using the measured fuel and water flow rates (flow method) and the FTIR and TDL H2O and CO2 concentrations agree within 3% (absolute) for both fuels. The TDL and FTIR equivalence ratios agreed quantitatively for both diesel and biomass combustion. However, close to stoichiometry, the TDL values for biomass are up to 15% lower than the FTIR values, indicating ongoing combustion at the location of the TDL measurements. © 2022 The Authors

Place, publisher, year, edition, pages
Elsevier Ltd, 2022
Keywords
Biomass, Entrained flow reactor, Equivalence ratio, Fuel moisture content, tuneable diode laser absorption spectroscopy (TDLAS), Absorption spectroscopy, Carbon dioxide, Combustion, Combustion chambers, Diesel engines, Flow of water, Fourier transform infrared spectroscopy, Fuels, Moisture determination, Semiconductor lasers, Spectrometers, Biomass combustion, CO 2 concentration, Diode-laser, Equivalence ratios, Fourier transform infrared, Pilot scale, Tuneable diode laser absorption spectroscopies, Tuneable diode laser absorption spectroscopy
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:ri:diva-59893 (URN)10.1016/j.apenergy.2022.119731 (DOI)2-s2.0-85134966967 (Scopus ID)
Note

Correspondence Address: Sepman, A.; RISE AB, Box 726, Sweden; email: alexey.sepman@ri.se; Funding details: Energimyndigheten; Funding text 1: We gratefully acknowledge financial support from the Swedish Energy Agency through the 50470-1 project.

Available from: 2022-08-11 Created: 2022-08-11 Last updated: 2023-05-19Bibliographically approved
Sepman, A., Fredriksson, C., Ögren, Y. & Wiinikka, H. (2021). Laser-Based, Optical, and Traditional Diagnostics of NO and Temperature in 400 kW Pilot-Scale Furnace. Applied Sciences, 11(15), Article ID 7048.
Open this publication in new window or tab >>Laser-Based, Optical, and Traditional Diagnostics of NO and Temperature in 400 kW Pilot-Scale Furnace
2021 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 11, no 15, article id 7048Article in journal (Refereed) Published
Abstract [en]

A fast sensor for simultaneous high temperature (above 800 K) diagnostics of nitrogen oxide (NO) concentration and gas temperature (T) based on the spectral fitting of low-resolution NO UV absorption near 226 nm was applied in pilot-scale LKAB’s Experimental Combustion Furnace (ECF). The experiments were performed in plasma and/or fuel preheated air at temperatures up to 1550 K, which is about 200 K higher than the maximal temperature used for the validation of the developed UV NO sensor previously. The UV absorption NO and T measurements are compared with NO probe and temperature measurements via suction pyrometry and tuneable diode laser absorption (TDL) using H2O transitions at 1398 nm, respectively. The agreement between the NO UV and NO probe measurements was better than 15%. There is also a good agreement between the temperatures obtained using laser-based, optical, and suction pyrometer measurements. Comparison of the TDL H2O measurements with the calculated H2O concentrations demonstrated an excellent agreement and confirms the accuracy of TDL H2O measurements (better than 10%). The ability of the optical and laser techniques to resolve various variations in the process parameters is demonstrated.

Keywords
NO UV absorption, temperature, TDLAS, pilot-scale furnace
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:ri:diva-55657 (URN)10.3390/app11157048 (DOI)
Available from: 2021-08-05 Created: 2021-08-05 Last updated: 2023-05-19Bibliographically approved
Likitha, S. S., Westerberg, L. G., Akerstedt, H. O., Wiinikka, H. & Sepman, A. (2021). Modelling of heat flow and electromagnetic phenomena in a non transferred plasma torch. In: 47th EPS Conference on Plasma Physics, EPS 2021: . Paper presented at 47th EPS Conference on Plasma Physics, EPS 2021, 21 June 2021 through 25 June 2021 (pp. 1088-1091). European Physical Society (EPS)
Open this publication in new window or tab >>Modelling of heat flow and electromagnetic phenomena in a non transferred plasma torch
Show others...
2021 (English)In: 47th EPS Conference on Plasma Physics, EPS 2021, European Physical Society (EPS) , 2021, p. 1088-1091Conference paper, Published paper (Refereed)
Abstract [en]

Over the decades, computational methods have been used to model and describe the flow and ionization dynamics in plasma torches. However, the impact of the operational parameters such as gas flow rate, swirl number and input current density on flow is still inexplicit. In this study, the flow in a non-transferred plasma torch is modelled using COMSOL Multiphysics, and the influence of these parameters is studied. The analysis is carried out on an axisymmetric geometry with the conical-shaped cathode, nozzle-shaped anode, and Argon is used as the plasma gas. A thermal plasma (equilibrium discharges) is considered, i.e., the plasma is under partial to complete local thermodynamic equilibrium in which the magnetohydrodynamic (MHD) equations are solved. This is treated in the Equilibrium Discharge Interface in COMSOL’s plasma module that has been used in the present study. The laminar flow analysis is performed for low-velocity cases and turbulent flow analysis for higher velocities. It was found that the velocity increase across the plasma arc due to ionization and gas expansion, could be observed only for sufficiently high plasma inflow velocities. The position of the plasma arc is determined for different operating conditions. It was further found that the velocity has a negligible effect on the length of the plasma arc, whereas the dependency of the arc length and attachment point on the anode wall, to the input current density and cathode tip temperature is well explained. The paper concludes by presenting the variations in temperature and velocity of plasma arc due to swirling inflow

Place, publisher, year, edition, pages
European Physical Society (EPS), 2021
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:ri:diva-57369 (URN)2-s2.0-85119657278 (Scopus ID)9781713837046 (ISBN)
Conference
47th EPS Conference on Plasma Physics, EPS 2021, 21 June 2021 through 25 June 2021
Note

Funding details: Energimyndigheten, 49609-1; Funding text 1: This project is funded by the Swedish Energy Agency, project grant no. 49609-1.

Available from: 2021-12-29 Created: 2021-12-29 Last updated: 2023-05-19Bibliographically approved
Toth-Pal, Z., Ögren, Y., Sepman, A., Gren, P. O. & Wiinikka, H. (2020). Combustion behavior of pulverized sponge iron as a recyclable electrofuel. Powder Technology, 373, 210-219
Open this publication in new window or tab >>Combustion behavior of pulverized sponge iron as a recyclable electrofuel
Show others...
2020 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 373, p. 210-219Article in journal (Refereed) Published
Abstract [en]

In this work, the combustion behavior of pulverized sponge iron (PSI), a practical-grade iron product that was proposed as a potential candidate in the metal fuel cycle, was observed directly using high-magnification shadowgraphy and other optical diagnostics techniques. The PSI was combusted in a laboratory-scale, McKenna flat-flame burner. Results suggest that, in agreement with theoretical models, PSI combusted heterogeneously, with most of the particle mass converting to an intact, solid oxide. However, in contrast with previous hypotheses, the formation of a microflame of combusting aerosol that was attached to the particle surface was observed. Results from quantitative shadowgraphy indicated near-instantaneous melting and complex behavior—we attempted to explain these based on the Fe–O phase diagram. The analysis of micron- and nano-sized combustion products confirmed that the PSI combusted heterogeneously and a gaseous sub-oxide was formed. Combustion under high excess oxygen was hypothesized to reduce the formation of these oxides.

Place, publisher, year, edition, pages
Elsevier B.V., 2020
Keywords
Energy carrier, Energy vector, Iron combustion, Metal combustion, Metal fuels, Zero‑carbon, Combustion, Sponge iron, Combustion behavior, Combustion products, Excess oxygen, Flat flame burner, High magnifications, Optical diagnostics technique, Particle mass, Particle surface, Pulverized fuel, fuel, iron, oxygen, pulverized sponge iron, unclassified drug, Article, calibration, controlled study, digital imaging, measurement accuracy, particle size, pyrometry, scanning electron microscopy, shadowgraphy, surface property, theoretical model, velocity
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-45373 (URN)10.1016/j.powtec.2020.05.078 (DOI)2-s2.0-85087108013 (Scopus ID)
Note

Funding details: Energimyndigheten, EFOP-3.6.1-16-00011, 45374-1; Funding details: European Social Fund, ESF; Funding details: European Commission, EC; Funding text 1: The authors thank Jonas Persson for his assistance in carrying out the experiments. This work has been financed by the Swedish Energy Agency , project number 45374-1 . Pal Toth was partly financed by the project EFOP-3.6.1-16-00011 that was implemented in the framework of the Szechenyi 2020 program of Hungary . Financial support was provided by the European Union , co-financed by the European Social Fund .

Available from: 2020-07-22 Created: 2020-07-22 Last updated: 2023-05-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2253-6845

Search in DiVA

Show all publications