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Öhman, Marcus
Publications (10 of 173) Show all publications
Sefidari, H., Wiinikka, H., Lindblom, B., Nordin, L. O., Wu, G., Yazhenskikh, E., . . . Öhman, M. (2019). Comparison of high-rank coals with respect to slagging/deposition tendency at the transfer-chute of iron-ore pelletizing grate-kiln plants: A pilot-scale experimental study accompanied by thermochemical equilibrium modeling and viscosity estimations. Fuel processing technology, 193, 244-262
Open this publication in new window or tab >>Comparison of high-rank coals with respect to slagging/deposition tendency at the transfer-chute of iron-ore pelletizing grate-kiln plants: A pilot-scale experimental study accompanied by thermochemical equilibrium modeling and viscosity estimations
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2019 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 193, p. 244-262Article in journal (Refereed) Published
Abstract [en]

Iron-ore pelletizing plants use high-rank coals to supply the heat necessary to process ores. Ash material from coal, in combination with iron-ore dust originating from the disintegration of the pellets, can cause deposition/slagging which often leads to severe production losses and damage. Deposition/slagging is most prominent in the hot areas of the grate-kiln setup and is more severe at the inlet of the rotary-kiln, i.e., the transfer-chute. Following on from our previous work, high-rank bituminous coals with potential for use in the pelletizing process were combusted in a pilot-scale (0.4 MW) pulverized-coal fired experimental combustion furnace (ECF). The fly-ash particles and short-term deposits were characterized to shed light on the observed difference in slagging/deposition tendencies of the coals. Global thermodynamic equilibrium modeling, in combination with viscosity estimates, was used to interpret the experimental findings and investigate the effect of the coal-ash composition upon deposition/slagging. This approach was carried out with and without the presence of Fe2O3-rich pellet-dust under oxidizing conditions within the temperature range at the transfer-chute of iron-ore pelletizing rotary-kilns. Based on the findings, a Qualitative Slagging Indicator (QSI) was proposed that can help pre-screen new solid fuels for potential slagging issues. The proposed QSI highlights the following: (1) an inverse relationship between viscosity and slagging/deposition tendency of the coals was observed (2) as viscosity decreases (either with increasing temperature or due to the change in the coal-ash composition), stronger deposits will form that will complicate the mechanical removal of the deposited layer. It was therefore inferred that low viscosity molten phases facilitate deposition/slagging, which is exacerbated by the presence of fluxing agents (e.g., CaO, MgO, K2O, Na2O, and Fe2O3) in the deposits. The low viscosity coal-ash-induced molten phases are also more likely to interact with the Fe2O3-rich pellet-dust that results in further decreases in viscosity, thereby intensifying depositions. The results from this work complement the on-going research by our group to elucidate and alleviate ash-related problems in industrial grate kilns.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Iron-ore pelletizing, Coal-ash, Pellet-dust, Deposition (slagging), Thermochemical equilibrium calculations, Viscosity estimations
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-74064 (URN)10.1016/j.fuproc.2019.05.026 (DOI)000473842100026 ()2-s2.0-85066109318 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-10 (oliekm)

Available from: 2019-05-28 Created: 2019-05-28 Last updated: 2019-08-15Bibliographically approved
Wagner, K., Häggström, G., Skoglund, N., Priscak, J., Kuba, M., Öhman, M. & Hofbauer, H. (2019). Layer formation mechanism of K-feldspar in bubbling fluidized bed combustion of phosphorus-lean and phosphorus-rich residual biomass. Applied Energy, 248, 545-554
Open this publication in new window or tab >>Layer formation mechanism of K-feldspar in bubbling fluidized bed combustion of phosphorus-lean and phosphorus-rich residual biomass
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2019 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 248, p. 545-554Article in journal (Refereed) Published
Abstract [en]

The use of phosphorus-rich fuels in fluidized bed combustion is one probable way to support both heat and power production and phosphorus recovery. Ash is accumulated in the bed during combustion and interacts with the bed material to form layers and/or agglomerates, possibly removing phosphorus from the bed ash fraction. To further deepen the knowledge about the difference in the mechanisms behind the ash chemistry of phosphorus-lean and phosphorus-rich fuels, experiments in a 5 kW bench-scale-fluidized bed test-rig with K-feldspar as the bed material were conducted with bark, wheat straw, chicken manure, and chicken manure admixtures to bark and straw. Bed material samples were collected and studied for layer formation and agglomeration phenomena by scanning electron microscopy combined with energy dispersive X-ray spectrometry. The admixture of phosphorus-rich chicken manure to bark changed the layer formation mechanism, shifting the chemistry to the formation of phosphates rather than silicates. The admixture of chicken manure to straw reduced the ash melting and agglomeration risk, making it possible to increase the time until defluidization of the fluidized bed occurred. The results also highlight that an increased ash content does not necessarily lead to more ash melting related problems if the ash melting temperature is high enough.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Phosphorus, Layer formation, Agglomeration, K-feldspar, Fluidized bed
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-73937 (URN)10.1016/j.apenergy.2019.04.112 (DOI)000469891900044 ()2-s2.0-85064643200 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-14 (johcin)

Available from: 2019-05-14 Created: 2019-05-14 Last updated: 2019-06-20Bibliographically approved
Faust, R., Hannl, T. K., Berdugo Vilches, T., Kuba, M., Öhman, M., Seemann, M. & Knutsson, P. (2019). Layer Formation on Feldspar Bed Particles during Indirect Gasification of Wood. 1. K-Feldspar. Energy & Fuels, 33(8), 7321-7332
Open this publication in new window or tab >>Layer Formation on Feldspar Bed Particles during Indirect Gasification of Wood. 1. K-Feldspar
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2019 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, no 8, p. 7321-7332Article in journal (Refereed) Published
Abstract [en]

The choice of bed material for biomass gasification plays a crucial role for the overall efficiency of the process. Olivine is the material conventionally used for biomass gasification due to the observed activity of olivine toward cracking of unwanted tars. Despite its catalytic activity, olivine contains high levels of chromium, which complicates the deposition of used bed material. Feldspar has shown the same activity as olivine when used as a bed material in biomass gasification. As opposed to olivine, feldspar does not contain environmentally hazardous compounds, which makes it a preferred alternative for further applications. The interaction of bed material and ash heavily influences the properties of the bed material. In the present study interactions between feldspar and main ash compounds of woody biomass in an indirect gasification system were investigated. Bed material samples were collected at different time intervals and analyzed with SEM-EDS and XRD. The obtained analysis results were then compared to thermodynamic models. The performed study was divided in two parts: in part 1 (the present paper), K-rich feldspar was investigated, whereas Na-rich feldspar is presented in part 2 of the study (DOI: 10.1021/acs.energyfuels.9b01291). From the material analysis performed, it can be seen that, as a result of the bed materials’ interactions with the formed ash compounds, the latter were first deposited on the surface of the K-feldspar particles and later resulted in the formation of Ca- and Mg-rich layers. The Ca enriched in the layers further reacted with the feldspar, which led to its diffusion into the particles and the formation of CaSiO3 and KAlSiO4. Contrary to Ca, Mg did not react with the feldspar and remained on the surface of the particles, where it was found as Mg- or Ca-Mg-silicates. As a result of the described interactions, layer separation was noted after 51 h with an outer Mg-rich layer and an inner Ca-rich layer. Due to the development of the Ca- and Mg-rich layers and the bed material–ash interactions, crack formation was observed on the particles’ surfaces.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
Dual Fluidized Bed, Bed Material, Wood, Feldspar
National Category
Chemical Process Engineering Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-75491 (URN)10.1021/acs.energyfuels.9b01291 (DOI)000481569100046 ()
Funder
Swedish Energy Agency, P46533-1 and P42034-1
Note

Validerad;2019;Nivå 2;2019-09-09 (johcin)

Available from: 2019-08-13 Created: 2019-08-13 Last updated: 2019-09-09Bibliographically approved
Hannl, T. K., Faust, R., Kuba, M., Knutsson, P., Berdugo Vilches, T., Seemann, M. & Öhman, M. (2019). Layer Formation on Feldspar Bed Particles during Indirect Gasification of Wood. 2. Na-Feldspar. Energy & Fuels, 33(8), 7333-7346
Open this publication in new window or tab >>Layer Formation on Feldspar Bed Particles during Indirect Gasification of Wood. 2. Na-Feldspar
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2019 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, no 8, p. 7333-7346Article in journal (Refereed) Published
Abstract [en]

Selecting a suitable bed material for the thermochemical conversion of a specific feedstock in a fluidized bed system requires identification of the characteristics of potential bed materials. An essential part of these characteristics is the interaction of the bed material with feedstock ash in a fluidized bed, which leads to layer formation and morphology changes. For this purpose, the interaction of feldspar bed material with the main ash-forming elements in wood ash (Ca, K, Mg, Si) in an indirect gasification system was analyzed using SEM-EDS, XRD, and thermodynamic modeling. In part 1 of this work (DOI: 10.1021/acs.energyfuels.9b01291), the layer formation on K-feldspar dominated by Ca reaction and ash deposition was investigated. The aim of this second part of the work was to determine the time-dependent layer formation on Na-feldspar and compare the results with the findings for K-feldspar. Interaction of Na-feldspar with ash-derived elements resulted in different layers on Na-feldspar: K reaction layers, where K replaced Na and Si shares decreased; Ca reaction layers, where Ca enriched and reacted with the Na-feldspar; and ash deposition layers, where wood ash elements accumulated on the surface. Ca reaction layers were formed first and became continuous on the surface before K reaction layers and ash deposition layers were detected. Cracks and crack layer formation in the Na-feldspar particles were found after several days of operation. The layer compositions and growth rates indicate that the diffusion of Ca and K plays an essential role in the formation of Ca reaction and K reaction layers. The reaction with Ca and the crack formation coincide with the interaction previously found for quartz and K-feldspar. In contrast to K-feldspar, Na-feldspar showed high potential for reaction with K. The findings indicate that the reaction of Na-feldspar with ash-derived K makes Na-feldspar a less stable bed material than K-feldspar during the thermochemical conversion of K-rich feedstocks in a fluidized bed system.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
Dual Fluidized Bed, Bed Material, Wood, Feldspar
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-75473 (URN)10.1021/acs.energyfuels.9b01292 (DOI)000481569100047 ()
Funder
Swedish Energy Agency, P46533-1 and P42034-1
Note

Validerad;2019;Nivå 2;2019-09-09 (johcin)

Available from: 2019-08-13 Created: 2019-08-13 Last updated: 2019-09-09Bibliographically approved
Wagner, K., Häggström, G., Mauerhofer, A. M., Kuba, M., Skoglund, N., Öhman, M. & Hofbauer, H. (2019). Layer formation on K-feldspar in fluidized bed combustion and gasification of bark and chicken manure. Biomass and Bioenergy, 127, Article ID 105251.
Open this publication in new window or tab >>Layer formation on K-feldspar in fluidized bed combustion and gasification of bark and chicken manure
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2019 (English)In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 127, article id 105251Article in journal (Refereed) Published
Abstract [en]

Understanding layer formation on bed materials used in fluidized beds is a key step for advances in the application of alternative fuels. Layers can be responsible for agglomeration-caused shut-downs but they can also improve the gas composition in fluidized bed gasification. Layers were observed on K-feldspar (KAlSi3O8) impurities originating from the combined heat and power plant Senden which applies the dual fluidized bed (DFB) steam gasification technology. Pure K-feldspar was therefore considered as alternative bed material in DFB steam gasification. Focusing on the interactions between fuel ash and bed material, K-feldspar was tested in combustion and DFB steam gasification atmospheres using different fuels, namely Ca-rich bark, Ca- and P-rich chicken manure, and an admixture of chicken manure to bark. The bed particle layers formed on the bed material surface were characterized using combined scanning electron microscopy and energy-dispersive X-ray spectroscopy; area mappings and line scans were carried out for all samples. The obtained data show no essential influence of operational mode on the layer-formation process. During the combustion and DFB steam gasification of Ca-rich bark, a layer rich in Ca formed while K was diffusing out of the layer. The use of Ca- and P-rich chicken manure inhibited the diffusion of K, and a layer rich in Ca and P formed. The addition of P to bark via chicken manure also changed the underlying layer-formation processes to reflect the same processes as observed for pure chicken manure.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Fluidized bed, Layer formation, K-feldspar, Phosphorous, Combustion, DFB steam gasification
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-75063 (URN)10.1016/j.biombioe.2019.05.020 (DOI)000478564300032 ()2-s2.0-85066481346 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-27 (johcin)

Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-08-20Bibliographically approved
Wagner, K., Kuba, M., Häggström, G., Skoglund, N., Öhman, M. & Hofbauer, H. (2018). Influence of phosphorus on the layer formation on k-feldspar during fluidized bed combustion and gasification. Paper presented at 26th EU Biomass Conference & Exhibition, Copenhagen, 14-17 May 2018. European biomass conference and exhibition proceedings, 26thEUBCE, 486-492
Open this publication in new window or tab >>Influence of phosphorus on the layer formation on k-feldspar during fluidized bed combustion and gasification
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2018 (English)In: European biomass conference and exhibition proceedings, E-ISSN 2282-5819, Vol. 26thEUBCE, p. 486-492Article in journal (Refereed) Published
Abstract [en]

Today, mainly wood-based feedstocks are used in thermo-chemical biomass conversion since they have a comparably high heating value and contain a small amount of ash. Fluidized beds allow a greater variety of fuels to be used, since they are rather flexible regarding their fuel input. The use of biogenic waste streams (chicken manure, horse manure, etc.) and sewage sludge would not only increase the fuel diversity in fluidized beds but might also enhance the usability of side products. The contained essential nutrients like phosphorus, potassium, calcium, etc. in these fuels are enriched in the ash after thermochemical conversion. Thus, in the near future it may be possible to apply this ash as secondary resource for fertilizer. Especially the recovery of phosphorus is of importance due to the imminent phosphorus scarcity. Due to its tendency to react with ash forming elements in fuels, phosphorus influences the ash chemistry severely. Especially the agglomeration and layer formation on bed materials during biomass combustion and gasification is highly dependent on the predominant ash forming elements. Phosphorus therefore has a significant impact on those mechanisms. Until now, the behavior of phosphorus-rich fuels in fluidized beds has not been studied in much detail. To develop a basic understanding of the behavior, phosphorus-rich feedstock was combusted in a bench-scale fluidized bed reactor. Ash layers on bed particles, which were formed during these experiments, were studied and compared to results with phosphorus-lean fuels. Furthermore, layer formation of phosphorus-rich and phosphorus-lean fuels from dual fluid bed gasification were compared to those from fluidized bed combustion. The studied layers on bed materials showed significant amounts of phosphorus. The data also indicates a change in layer formation as soon as phosphorus is present. An increased catalytic activity due ash-layer formation was observed for both phosphorus-rich and phosphorus-lean feedstock, independent from the presence of phosphorus in the ash layer

Place, publisher, year, edition, pages
ETA-Florence Renewable Energies, 2018
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-70379 (URN)2-s2.0-85051038323 (Scopus ID)
Conference
26th EU Biomass Conference & Exhibition, Copenhagen, 14-17 May 2018
Available from: 2018-08-14 Created: 2018-08-14 Last updated: 2018-08-14Bibliographically approved
Sefidari, H., Lindholm, 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]

o initiate the elucidation of deposit formation during the iron-ore pelletization process, a comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal-fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale grate-kiln setup. Particles and deposits were sampled from 3 positions of different temperature via a water-cooled sampling probe. Three distinct fragmentation modes were identified based on the aerodynamic particle diameter (Dp). The fine mode: Particles with 0.03 < Dp < 0.06 μm. The first fragmentation mode: Particles with 1 < Dp < 10 μm. The second fragmentation mode: Coarse particles (cyclone particles, Dp > 10 μm). A transition from a bimodal PSD (particle size distribution) to a trimodal PSD was observed when pellet dust was added (Case 3) and consequently the elemental bulk composition of the abovementioned modes was changed. The most extensive interaction between pellet dust and coal-ash particles was observed in the coarse mode where a significant number of coal ash globules were found attached to the surface of the hematite particles. The morphology of the sharp-edged hematite particles was changed to smooth-edged round particles which proved that hematite particles must have interacted with the surrounding aluminosilicate glassy phase originating from the coal ash. The short-term deposits collected during coal combustion (Case 1) were highly porous in contrast to the high degree of sintering observed in the experiments with pellet dust addition (Case 3) which is attributed to the dissolution of hematite particles in the aluminosilicate glassy phase. The results suggest that pellet dust itself (Case 2) has low slagging tendency, independent of temperature. However, when coal-ash is present (Case 3), auxiliary phases are added such that tenacious particles are formed and slagging occurs.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Energy Engineering Chemical Engineering Chemical Process Engineering
Research subject
Energy Engineering; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-68712 (URN)10.1016/j.fuproc.2018.05.004 (DOI)000437819600030 ()2-s2.0-85046802389 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-05-14 (andbra)

Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2019-01-18Bibliographically approved
Sefidari, H., Lindblom, B., Wiinikka, H., Nordin, L. O., Lennartsson, A., Mouzon, J., . . . Öhman, M. (2018). The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace: Part II: Thermochemical equilibrium calculations and viscosity estimations. Fuel processing technology, 180, 189-206
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 II: Thermochemical equilibrium calculations and viscosity estimations
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2018 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 180, p. 189-206Article in journal (Refereed) Published
Abstract [en]

Fly ash particles from the combustion of solid-fuels together with disintegrated particles arising from iron-ore pellets result in accumulation of deposits on the refractory linings of the grate-kiln induration machine during the iron-ore pelletizing process. The deposits amass in the high-temperature regions of the induration furnace thus disturbing the flow of gas and pellets. Therefore, to tackle the above-mentioned issues, an understanding of deposit formation mechanism is of crucial importance. This study was conducted with the objective of addressing the effect of disintegrated iron-ore pellet dust on deposit formation and the mechanisms behind deposition (slagging) in the grate-kiln process. A comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal- fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale setup. Fly ash particles and short-term deposits were characterized and deposition was addressed in Part I of this study. In light of the experimental observations (Part I) and the thermochemical equilibrium calculations (Part II), a scheme of ash transformation during the iron-ore pelletizing process was proposed. The dissolution of hematite particles into the Ca-rich-aluminosilicate melt (from the coal-ash constituents) decreased the viscosity and resulted in the formation of stronger (heavily sintered) deposits. Overall, this pilot-scale work forms part of a wider study which aims at deepening the understanding of ash transformation phenomena during the large-scale pelletizing process.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Energy Engineering Chemical Engineering Metallurgy and Metallic Materials Chemical Process Engineering
Research subject
Energy Engineering; Chemical Technology; Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-69019 (URN)10.1016/j.fuproc.2018.05.005 (DOI)000447580600020 ()2-s2.0-85047214684 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-11-05 (johcin) 

Available from: 2018-05-31 Created: 2018-05-31 Last updated: 2019-01-18Bibliographically approved
Sundberg, P., Hermansson, S., Tullin, C. & Öhman, M. (2018). Traceability of bulk biomass: Application of radio frequency identification technology on a bulk pellet flow. Biomass and Bioenergy, 118, 149-153
Open this publication in new window or tab >>Traceability of bulk biomass: Application of radio frequency identification technology on a bulk pellet flow
2018 (English)In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 118, p. 149-153Article in journal (Refereed) Published
Abstract [en]

Radio frequency identification (RFID) technology has been used since the 1950s in a wide range of applications. In the energy sector, there is a potential to use the technology to follow biomass fuels throughout a supply chain. In addition to logistic information, the RFID tags can be used to convey vital information of the fuel properties directly to the energy plant to be used at the moment of combustion. A detailed knowledge of the fuel composition at the moment it reaches the furnace can be used to improve energy efficiency, reduce emissions and limit problems with fouling and slagging. In this work, RFID technology was used in three separate trials to trace wood pellets, from the production site to the furnace. In the trials, RFID tags were added to batches of pellets containing 5% or 100% peat. In this way it was possible to follow the shift in pellet quality from standard pellets (100% wood) to the pellets containing the RFID tags by monitoring the change in flue gas composition. From the results it can be concluded that RFID tags indeed can be used to convey logistic information and thus information of fuel quality parameters throughout a supply chain for wood pellets. However, work on optimization is needed to design the RFID carrier properly to mix well with the pellets as illustrated in a separate trial. Finally, an economic estimate indicates that the marginal cost to implement a RFID system would be less than 1% of the total production cost of wood pellets.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-70829 (URN)10.1016/j.biombioe.2018.08.018 (DOI)000445897300018 ()2-s2.0-85052882718 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-09-17 (svasva)

Available from: 2018-09-11 Created: 2018-09-11 Last updated: 2019-03-27Bibliographically approved
Xiong, S., Bozaghian, M., Lestander, T. A., Samuelsson, R., Hellqvist, S. & Öhman, M. (2017). Calcium oxide as an additive for both conservation and improvement of the combustion properties of energy grass: A preliminary study. Biomass and Bioenergy, 99, 1-10
Open this publication in new window or tab >>Calcium oxide as an additive for both conservation and improvement of the combustion properties of energy grass: A preliminary study
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2017 (English)In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 99, p. 1-10Article in journal (Refereed) Published
Abstract [en]

Degradation of biomass is one of the major reasons for high costs of feedstock collection, transport, and storage, which is largely associated with biomass moisture and microbial activities. Our concept is to add calcium oxide (CaO) to the biomass already when it is collected and in its natural (wet) condition. When a suitable quantity of CaO is added to moistened biomass, an alkali microenvironment will be formed with a pH exceeding 9, based on the reaction CaO + H2O ↔ Ca(OH)2. As a consequence, microbial activities are largely inhibited. The Ca(OH)2 will then successively react with CO2, following the reaction Ca(OH)2 + CO2 ↔ CaCO3 + H2O. The CaCO3 will reside in the feedstock throughout the entire production chain and end up as an additive/sorbent to improve combustion by decreasing slagging. Two experiments were conducted and proved the concept works for at least reed canary grass, but, as expected, the strength of the effect was dependent on the CaO dosage and initial biomass moisture.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-62178 (URN)10.1016/j.biombioe.2017.02.010 (DOI)000399515400001 ()2-s2.0-85013452746 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-02-27 (andbra)

Available from: 2017-02-27 Created: 2017-02-27 Last updated: 2018-09-13Bibliographically approved
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