umu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Backman, Rainer
Alternative names
Publications (10 of 67) Show all publications
Stanicic, I., Hanning, M., Deniz, R., Mattisson, T., Backman, R. & Leion, H. (2020). Interaction of oxygen carriers with common biomass ash components. Fuel processing technology, 200, Article ID 106313.
Open this publication in new window or tab >>Interaction of oxygen carriers with common biomass ash components
Show others...
2020 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 200, article id 106313Article in journal (Refereed) Published
Abstract [en]

Carbon capture and storage (CCS) has been proposed as a bridging technology between the current energy production and a future renewable energy system. One promising carbon capture technology is chemical-looping combustion (CLC). In CLC the reactors are filled with metal oxide bed material called oxygen carriers. The interaction between oxygen carriers and biomass ashes is a poorly explored field. To make CLC a viable process, and thereby creating carbon emission reductions, more knowledge about the interactions between biomass ashes and oxygen carriers is needed. This study investigated solid-state reactions of three promising oxygen carriers, hematite, hausmannite and synthesised ilmenite with different biomass ash components. Oxygen carriers were exposed with the ash components: calcium carbonate, silica and potassium carbonate at 900 degrees C and at different reducing potentials. Crystalline phases of the exposed samples were determined using powder x-ray diffraction (XRD). Results showed that the oxygen carriers hausmannite and hematite interact to a higher extent compared to synthesised ilmenite regarding both physical characteristics and detectable phases. Synthesised ilmenite formed new phases only in systems including potassium. Thermodynamic calculations were performed on the multicomponent system and compared with experimental results. The results suggest that optimisation of systems involving manganese and potassium should be performed.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Oxygen carrier, Biomass ash, Chemical Looping Combustion (CLC), Ilmenite
National Category
Bioenergy
Identifiers
urn:nbn:se:umu:diva-168790 (URN)10.1016/j.fuproc.2019.106313 (DOI)000514024600004 ()
Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Hagman, H., Bostrom, D., Lundberg, M. & Backman, R. (2019). Alloy degradation in a co-firing biomass CFB vortex finder application at 880 degrees C. Corrosion Science, 150, 136-150
Open this publication in new window or tab >>Alloy degradation in a co-firing biomass CFB vortex finder application at 880 degrees C
2019 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 150, p. 136-150Article in journal (Refereed) Published
Abstract [en]

Mechanisms of alloy degradation in a fireside N-S-O-C-H-Cl-Na-K atmosphere at 880 degrees C were elucidated using SEM-EDS, chemical equilibrium calculations, and XRD. Alloys 310S, 800H/HT, and 600 were studied after 0, 8000, and 16,000 h exposure in a boiler co-firing biomass waste. For 310S and 800H/HT it was shown that nitrogen formed internal Cr nitrides lowering the Cr activity and inhibiting internal alloy Cr permeation, and that NaCl and Na2SO4 reacted with Cr oxide to form chromate and to accelerate the S and the Cl pickup. Alloy 600 showed no nitride or major chromate formation.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Na, K, Cl, O-2, CO, CO2, HCl, SO2, NH3, N-2, Nitride, Carbide, Sulfide, Oxide, Chloride, Volatilization, Vortex finder, CFB boiler, High-temperature corrosion, Alloy 310S, Alloy 800H/HT, Alloy 600, Co-combustion
National Category
Corrosion Engineering
Identifiers
urn:nbn:se:umu:diva-157937 (URN)10.1016/j.corsci.2019.01.038 (DOI)000462108000014 ()
Projects
Bio4Energy
Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-08-30Bibliographically approved
Stanicic, I., Andersson, V., Hanning, M., Mattisson, T., Backman, R. & Leion, H. (2019). Combined manganese oxides as oxygen carriers for biomass combustion – Ash interactions. Chemical engineering research & design, 149, 104-120
Open this publication in new window or tab >>Combined manganese oxides as oxygen carriers for biomass combustion – Ash interactions
Show others...
2019 (English)In: Chemical engineering research & design, ISSN 0263-8762, E-ISSN 1744-3563, Vol. 149, p. 104-120Article in journal (Refereed) Published
Abstract [en]

Carbon capture and storage (CCS) has been acknowledged as an important strategy for mitigation of climate change. Although highly applicable for fossil fuels, CCS with biomass could have the added advantage of resulting in negative emissions of carbon dioxide. One promising carbon capture technology is chemical-looping combustion (CLC). In CLC the reactors are filled with metal oxide bed material called oxygen carriers. Before CLC can be implemented for biomass combustion at a large scale, biomass ash components interaction with oxygen carriers needs to be further understood.

Four combined manganese oxides Mn3O4-SiO2, Mn3O4-SiO2-TiO2, Mn3O4-Fe2O3 and Mn3O4-Fe2O3-Al2O3 were exposed to common biomass ash components K, Ca and P. The ash components can exist in many forms, but here the compounds CaCO3, K2CO3 and CaHPO4 were used. Exposures were performed at 900 °C for six hours in oxidising, reducing and inert conditions. Crystalline phases were analysed by XRD and morphology examined with SEM-EDX.

Results show that oxygen carrier particles containing silicon were more likely to form agglomerates, especially in combination with potassium, whereas the particles including iron were more stable. MnFeAl was the oxygen carrier that showed least agglomerating behaviour while simultaneously showing a propensity to absorb some ash components.

Some inconsistencies between thermodynamic predictions and experimental results is observed. This may be explained by lack of relevant data in the used databases, were only a few of the oxygen carrier-ash systems and subsystems have been optimised. Further optimisation related to manganese rich systems should be performed to obtain reliable results.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Chemical looping combustion (CLC), Combined manganese oxides, Oxygen carrier, Fluidised bed combustion, Ash interactions
National Category
Other Environmental Engineering
Identifiers
urn:nbn:se:umu:diva-164635 (URN)10.1016/j.cherd.2019.07.004 (DOI)000484646500009 ()2-s2.0-85069864735 (Scopus ID)
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-08Bibliographically approved
Hökfors, B. & Backman, R. (2019). Reducing the CO2 footprint of cement production by electrification. In: : . Paper presented at 15th International Congress on the Chemistry of Cement Prague, Czech Republic, September 16–20, 2019.
Open this publication in new window or tab >>Reducing the CO2 footprint of cement production by electrification
2019 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

Transformative actions in CO2 emitting industries are needed to reach the Paris climate agreement.The cement industry, which is responsible for 5-7% of the global CO2 emissions, has the possibility tomake a difference.Cement production is related to two sources of CO2; 1/3 from combustion of fuels and 2/3 fromcalcination of limestone in the cement raw meal. If all the fuels were to be substituted with non-fossilelectricity, the environmental gain would be significant. Cementa and Vattenfall are evaluatingpossibilities on how electricity can be used to substitute fuels in the cement production by 2030.By using electricity for heating, several positive effects are achieved in the production process. Thecleanness of the exhaust gas will be higher due to elimination of volatiles from fuels. The energyconsumption decreases due to lesser volume of gas to be heated. This is related to the exclusion ofnitrogen gas in the process.A feasibility study comprising literature survey and small scale tests have been performed. Electricalheating techniques showing potential are; microwave heating, plasma torches, flash calcination withelectrical heating, hydrogen combustion and a combination of the mentioned techniques.The most relevant finding is that the combustion related CO2 emissions will be eliminated; thecapturing step will be enhanced since the CO2 gas from calcination is clean and accordingly the needof storage or utilization of CO2 is decreased.

National Category
Chemical Engineering
Identifiers
urn:nbn:se:umu:diva-162787 (URN)
Conference
15th International Congress on the Chemistry of Cement Prague, Czech Republic, September 16–20, 2019
Available from: 2019-08-28 Created: 2019-08-28 Last updated: 2019-10-30Bibliographically approved
Strandberg, A., Skoglund, N., Thyrel, M., Lestander, T. A., Broström, M. & Backman, R. (2019). Time-Resolved Study of Silicate Slag Formation During Combustion of Wheat Straw Pellets. Energy & Fuels, 33(3), 2308-2318
Open this publication in new window or tab >>Time-Resolved Study of Silicate Slag Formation During Combustion of Wheat Straw Pellets
Show others...
2019 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, no 3, p. 2308-2318Article in journal (Refereed) Published
Abstract [en]

Ash formation during single-fuel pellet combustion of wheat straw at 700 and 1000 °C was studied throughout fuel conversion by quench cooling and analysis at different char conversion degrees. The combination of X-ray microtomography analysis and scanning electronic microscopy with energy-dispersive X-ray spectroscopy showed that ash accumulated in rigid net structures at 700 °C with streaks or small beads surrounding the char, and the pellet mostly maintained its size during the entire fuel conversion. At 1000 °C, the ash formed high-density melts that developed into bubbles on the surface. As the conversion proceeded, these bubbles grew in size and covered parts of the active char surface area, but without entirely blocking the gas transport. The successive char conversion dissolved increasing amounts of calcium in the potassium silicate melts, probably causing differences in the release of potassium to the gas phase. Similarities were found with slag from a combustion experiment in a domestic boiler, with regard to relative composition and estimated and apparent viscosity of the slag. Complete char encapsulation by ash layers limiting char burnout was not found at the single pellet level, nor to any greater extent from the experiment performed in a small domestic boiler.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Inorganic Chemistry Other Environmental Engineering
Identifiers
urn:nbn:se:umu:diva-157725 (URN)10.1021/acs.energyfuels.8b04294 (DOI)000462260600064 ()
Projects
Bio4Energy
Funder
Swedish Research Council, 2014-5041Bio4Energy
Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2019-08-30Bibliographically approved
Strandberg, A., Skoglund, N., Thyrel, M., Lestander, T. A., Broström, M. & Backman, R. (2019). Wheat straw pellet combustion – characterization with X-ray micro-tomography and SEM-EDS analysis. In: : . Paper presented at World Sustainable Energy Days, Wels, Austri, Febrary 28, 2019.
Open this publication in new window or tab >>Wheat straw pellet combustion – characterization with X-ray micro-tomography and SEM-EDS analysis
Show others...
2019 (English)Conference paper, Oral presentation only (Other academic)
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-157286 (URN)
Conference
World Sustainable Energy Days, Wels, Austri, Febrary 28, 2019
Funder
Swedish Research Council, 2014-5041Swedish Research Council Formas, 2017-01613
Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2020-02-05Bibliographically approved
Broström, M., Holmgren, P. & Backman, R. (2018). Ash fractionation and slag formation during entrained flow biomass gasification. In: : . Paper presented at The 27th International Conference on the Impacts of Fuel Quality on Power Production and the Environment, Lake Louise, Alberta, Canada, September 24-28 2018..
Open this publication in new window or tab >>Ash fractionation and slag formation during entrained flow biomass gasification
2018 (English)Conference paper, Oral presentation only (Other academic)
National Category
Chemical Engineering Bioenergy
Identifiers
urn:nbn:se:umu:diva-152042 (URN)
Conference
The 27th International Conference on the Impacts of Fuel Quality on Power Production and the Environment, Lake Louise, Alberta, Canada, September 24-28 2018.
Available from: 2018-09-25 Created: 2018-09-25 Last updated: 2018-11-22Bibliographically approved
Strandberg, A., Thyrel, M., Skoglund, N., Lestander, T. A., Broström, M. & Backman, R. (2018). Biomass pellet combustion: cavities and ash formation characterized by synchrotron X-ray micro-tomography. Fuel processing technology, 176, 211-220
Open this publication in new window or tab >>Biomass pellet combustion: cavities and ash formation characterized by synchrotron X-ray micro-tomography
Show others...
2018 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 176, p. 211-220Article in journal (Refereed) Published
Abstract [en]

Ash formation during thermochemical conversion of biomass-based pellets influences both char conversion rates and ash-related operational problems. The objective of the present study was to provide detailed insights into changes in fuel and ash properties during fuel conversion. Pellets of poplar wood and wheat straw were used as model biofuels, representing vastly different compositions of ash-forming elements. Pellet samples at different char conversion phases were analyzed by synchrotron-based 3D X-ray micro-tomography, to map and visualize the development of cracks, internal cavities, and ash layers during conversion. The analysis of ash layers was complemented by scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. The results provide new insights into how large cracks and internal cavities are developed already during devolatilization, for example, the poplar wood pellets had a 64% void fraction after the devolatilization stage. As expected, there were large variations between the ash layer properties for the two fuels. A porous, low density, and calcium-rich ash was formed from the poplar fuel, whereas the wheat straw ash was a high-density silicate melt that developed into bubbles on the surface. As the conversion proceeded, the wheat straw ash covered parts of the active char surface area, but without blocking the gas transport.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
ash composition, pellet, thermochemical conversion, wheat straw, poplar, SEM-EDS
National Category
Chemical Process Engineering Bioenergy
Identifiers
urn:nbn:se:umu:diva-146673 (URN)10.1016/j.fuproc.2018.03.023 (DOI)000435062600027 ()2-s2.0-85044919238 (Scopus ID)
Projects
Bio4Energy
Available from: 2018-04-17 Created: 2018-04-17 Last updated: 2020-01-14Bibliographically approved
Carlborg, M., Weiland, F., Ma, C., Backman, R., Landälv, I. & Wiinikka, 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
Show others...
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.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Gasification, Oxygen blown, Biomass, Entrained flow, Slag, Refractory
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:umu:diva-143620 (URN)10.1016/j.jeurceramsoc.2017.09.016 (DOI)000418211000047 ()2-s2.0-85029532285 (Scopus ID)
Projects
Bio4Energy
Available from: 2018-01-30 Created: 2018-01-30 Last updated: 2020-01-08Bibliographically approved
Holmgren, P., Broström, M. & Backman, R. (2018). Slag Formation during Entrained Flow Gasification: Silicon Rich Grass Fuel with KHCO3 Additive. Energy & Fuels, 32(10), 10720-10726
Open this publication in new window or tab >>Slag Formation during Entrained Flow Gasification: Silicon Rich Grass Fuel with KHCO3 Additive
2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 10, p. 10720-10726Article in journal (Refereed) Published
Abstract [en]

Prediction of ash particle adherence to walls, melting, and flow properties are important for successful operation of slagging entrained flow gasifiers. In the present study, silicon-rich reed canary grass was gasified at 1000 and 1200 °C with solid KHCO3 added at 0, 1, or 5 wt % to evaluate the impact and efficiency of the dry mixed additive on slag properties. The fuel particles collided with an angled flat impact probe inside the hot reactor, constructed to allow for particle image velocimetry close to the surface of the probe. Ash deposit layer buildup was studied in situ as well as ash particle shape, size, and velocity as they impacted on the probe surface. The ash deposits were analyzed using scanning electron microscopy–energy-dispersive X-ray spectroscopy, giving detailed information on morphology and elemental composition. Results were compared to thermodynamic equilibrium calculations for phase composition and viscosity. The experimental observations (slag melting, flow properties, and composition) were in good qualitative agreement with the theoretical predictions. Accordingly, at 1000 °C, no or partial melts were observed depending upon the potassium/silicon ratio; instead, high amounts of additive and a temperature of at least 1200 °C were needed to create a flowing melt.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Energy Engineering Other Chemical Engineering
Identifiers
urn:nbn:se:umu:diva-151688 (URN)10.1021/acs.energyfuels.8b02545 (DOI)000448087000068 ()2-s2.0-85053900505 (Scopus ID)
Projects
Bio4Energy
Available from: 2018-09-10 Created: 2018-09-10 Last updated: 2019-08-30Bibliographically approved
Projects
Optimization of processes for production of cement and lime [2014-04073_Vinnova]; Umeå University
Organisations

Search in DiVA

Show all publications