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Publications (8 of 8) Show all publications
Razmjoo, N., Hermansson, S., Morgalla, M. & Strand, M. (2019). Study of the transient release of water vapor from a fuel bed of wet biomass in a reciprocating-grate furnace. Journal of the Energy Institute, 92(4), 843-854
Open this publication in new window or tab >>Study of the transient release of water vapor from a fuel bed of wet biomass in a reciprocating-grate furnace
2019 (English)In: Journal of the Energy Institute, ISSN 1743-9671, Vol. 92, no 4, p. 843-854Article in journal (Refereed) Published
Abstract [en]

The present study investigates how sudden changes in fuel moisture affected the combustion characteristics of the fuel bed in a 4-MW reciprocating-grate furnace. The moisture content of the fuel fed to the furnace was monitored online using a near-infrared spectroscopy device, and the water vapor concentration in the flue gas was measured continuously. To obtain experimental data on fuel-bed conditions, the temperature and gas composition in the bed were measured using a probe. A simplified drying model was developed using the measured gas composition values as inputs. The model was then used to estimate the drying rate and to simulate the extent of the drying zone along the grate. Measurements indicated that a change in the moisture content of the fuel fed to the furnace was detected as a change in water vapor concentration in the flue gas with a delay of about 2 h. The model predicted that a portion of wet fuel would need about 2 h to become dry, in line with the measured time delay of the water vapor concentration change in the flue gas. Overall, there was good alignment between the measured and simulated results, supporting the validity of the model and the assumed mechanisms.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Bioenergy
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-77594 (URN)10.1016/j.joei.2018.06.014 (DOI)000473381000002 ()2-s2.0-85053155711 (Scopus ID)
Available from: 2018-09-06 Created: 2018-09-06 Last updated: 2019-08-29Bibliographically approved
Morgalla, M., Lin, L. & Strand, M. (2018). Benzene Conversion in a Packed Alumina Bed Continuously Fed with Woody Char Particles. Energy & Fuels, 32(7), 7670-7677
Open this publication in new window or tab >>Benzene Conversion in a Packed Alumina Bed Continuously Fed with Woody Char Particles
2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 7, p. 7670-7677Article in journal (Refereed) Published
Abstract [en]

This Article investigates the decomposition of benzene (as a model tar) over finely dispersed char particles continuously distributed into a packed bed. Fragmented char particles and benzene plus a gasification agent (H2O or CO2) were supplied into a ceramic reactor that was heated electrically. The supplied char particles were retained in the reactor by a bed of alumina grains. Woody char as well as iron-doped and potassium-doped woody char were used. The influence of the gasification agent, char concentration, char weight time (proportional to the instant char mass present in the bed), and bed temperature (600-1050 degrees C) was investigated. Increasing the char concentration and char weight time increased benzene conversions for all tested chars. At similar char weight times, the benzene conversion increased with temperature, whereas the iron- and potassium doped char did not affect the specific conversion. At similar char concentrations, changing the gasification agent from CO2 to steam as well as using doped char led to decreased benzene conversions. This can be explained by accelerated char gasification reactions and thus a diminished char mass in the packed bed. Furthermore, benzene conversion rates were enhanced in the presence of CO2 as compared to steam. As the temperature was increased from 950 to 1050 degrees C, the benzene conversions were slightly reduced. This was interpreted as a combined effect of the enhanced benzene conversion rates and reduced char weight times. The highest benzene conversions achieved in the experiments were approximately 80% at 950-1000 degrees C using CO2 as gasification agent and supplying approximately 20-30 g N m(-3) undoped woody char.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Energy Engineering
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-77403 (URN)10.1021/acs.energyfuels.8b01249 (DOI)000439661300038 ()2-s2.0-85048372503 (Scopus ID)
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2019-08-29Bibliographically approved
Morgalla, M., Lin, L. & Strand, M. (2018). Benzene conversion in a packed bed loaded with biomass char particles. Energy & Fuels, 32(1), 554-560
Open this publication in new window or tab >>Benzene conversion in a packed bed loaded with biomass char particles
2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 1, p. 554-560Article in journal (Refereed) Published
Abstract [en]

This study investigates the conversion of benzene in a packed bed containing fine char particles. Benzene and steam were simultaneously supplied to a tubular ceramic reactor that was heated electrically. Fragmented char particles were suspended and continuously supplied via a separate supply line. A packed bed of crushed alumina balls was positioned in the reactor to retain the char particles. The benzene conversion in the hot char bed was investigated by varying the bed temperature (900–1100 °C), steam concentration (0–27 vol %), and char concentration (5–50 g Nm–3). The highest conversions achieved in the experiments were approximately 75%. At comparable char concentrations, similar benzene conversions occurred at 900 and 1000 °C. Increasing the temperature to 1100 °C or increasing the steam concentration reduced the benzene conversion. The results indicate that the reduced conversion was due to enhanced char gasification reactions at elevated temperatures and steam concentrations and thus to reduced char mass in the packed bed.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
Tar, char, biomass
National Category
Bioenergy
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-69105 (URN)10.1021/acs.energyfuels.7b03236 (DOI)000423253200059 ()2-s2.0-85040791108 (Scopus ID)
Available from: 2017-12-06 Created: 2017-12-06 Last updated: 2019-08-29Bibliographically approved
Morgalla, M., Lin, L. & Strand, M. (2017). Decomposition of benzene using char aerosol particles dispersed in a high-temperature filter. Energy, 118, 1345-1352
Open this publication in new window or tab >>Decomposition of benzene using char aerosol particles dispersed in a high-temperature filter
2017 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 118, p. 1345-1352Article in journal (Refereed) Published
Abstract [en]

In this study the tar-removal suitability of char particles finely dispersed in a high-temperature filter was investigated. Benzene was selected as the model tar. An aerosol-based method was designed and used to investigate the benzene decomposition behaviour. Two types of char were used: commercially available activated charcoal and pine char prepared in the laboratory. The conversion behaviour of both chars was investigated in the temperature range between 750 and 900 °C using steam as the gasification medium. During the experiments, different benzene concentrations, amounts of deposited char and gas residence times were tested. The results indicate that both activated carbon and pine char reduced the benzene concentration. Activated carbon generally produced higher and more stable benzene conversions compared to the pine char particles. Decreasing the benzene concentration or increasing the gas residence time or char mass improved the benzene conversion. It was concluded that the char gasification rate became slower while benzene was simultaneously converted. The aerosol-based method was also used to investigate benzene decomposition behaviour while continuously supplying fresh char particles together with steam at 1000 °C. In that way, the deactivated and gasified char particles were steadily replaced, preventing the benzene conversion from decreasing over time.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Biomass, Gasification, Char, Tar, Particles
National Category
Bioenergy
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-58100 (URN)10.1016/j.energy.2016.11.016 (DOI)000395048900116 ()2-s2.0-85006356091 (Scopus ID)
Funder
Swedish Energy Agency
Available from: 2016-11-11 Created: 2016-11-11 Last updated: 2019-08-29Bibliographically approved
Morgalla, M., Lin, L., Seemann, M. & Strand, M. (2015). Characterization of particulate matter formed during wood pellet gasification in an indirect bubbling fluidized bed gasifier using aerosol measurement techniques. Fuel processing technology, 138, 578-587
Open this publication in new window or tab >>Characterization of particulate matter formed during wood pellet gasification in an indirect bubbling fluidized bed gasifier using aerosol measurement techniques
2015 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 138, p. 578-587Article in journal (Refereed) Published
Abstract [en]

This study characterizes particulate matter, organic compounds, and inorganic compounds formed in an atmospheric indirect bubbling fluidized bed gasifier at two different steam-to-fuel ratios using wood pellets as fuel. The sampling and conditioning system consisted of a high-temperature dilution probe to quench aerosol dynamics and condense inorganic vapors, a primary thermodenuder to adsorb tar components, and a secondary thermodenuder to investigate the volatility/thermal stability of the remaining aerosol. Both online and offline instruments were used to characterize the aerosol in terms of number size distribution, mass size distribution, particle mass concentration, particle number concentration, morphology, and elemental analysis. Size distributions with three distinct modes were established. The fine and intermediate modes were mainly formed by tar and alkali vapors that had condensed in the sampling and conditioning systems. The coarse mode mainly consisted of the original particles, which are char, fly ash, and fragmented bed material. At the higher steam-to-fuel ratio, tar components seem to be reduced and more coarse-mode particles emitted compared to the low steam case. Furthermore, a possibility for online monitoring of heavy tar is suggested. (C) 2015 Elsevier B.V. All rights reserved.

Keywords
Gasification, Biofuels, Particle sampling, Tar
National Category
Bioenergy
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-47074 (URN)10.1016/j.fuproc.2015.06.041 (DOI)000362920200066 ()2-s2.0-84954196789 (Scopus ID)
Available from: 2015-11-06 Created: 2015-11-06 Last updated: 2019-06-25Bibliographically approved
Morgalla, M., Lin, L. & Strand, M. (2015). Characterization Of Particulate Matter In Biomass Gasification. In: I. Obernberger, D. Baxter, A.Grassi, P.Helm (Ed.), Proceedings for the 23rd European Biomass Conference and Exhibition: . Paper presented at 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria (pp. 664-667). ETA-Florence Renewable Energies
Open this publication in new window or tab >>Characterization Of Particulate Matter In Biomass Gasification
2015 (English)In: Proceedings for the 23rd European Biomass Conference and Exhibition / [ed] I. Obernberger, D. Baxter, A.Grassi, P.Helm, ETA-Florence Renewable Energies , 2015, p. 664-667Conference paper, Published paper (Refereed)
Abstract [en]

The purpose of this work is to examine the potential of monitoring heavy tar compounds contained in the product gas of a biomass gasifier. The hot product gas from atmospheric indirect bubbling fluidized bed gasification of wood pellets was extracted. The sampling and conditioning system consisted of a high-temperature dilution probe, a primary thermodenuder and a secondary thermodenuder. Online and semi-online instruments were used to characterize the aerosol in terms of number size distribution and particle mass concentration. The fine mode (mobility equivalent diameter db < 150 nm) was found to mainly consist of heavy tar compounds. An Electrical low­pressure impactor (ELPI) was used to measure this mode with a time resolution of 1 second and thus showed the potential for online measurements of heavy tar.

Place, publisher, year, edition, pages
ETA-Florence Renewable Energies, 2015
Keywords
aerosol, biomass, gasification, particles emission, tar
National Category
Energy Systems
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-45651 (URN)10.5071/23rdEUBCE2015-2DO.8.1 (DOI)978-88-89407-516 (ISBN)
Conference
23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria
Available from: 2015-08-10 Created: 2015-08-10 Last updated: 2019-02-22Bibliographically approved
Yang, J., Lin, L., Morgalla, M., Gebremedhin, A. & Strand, M. (2015). High-Temperature Characterization of Inorganic Particles and Vapors in a Circulating Fluidized Bed Boiler Cofiring Wood and Rubber Waste. Energy & Fuels, 29(2), 863-871
Open this publication in new window or tab >>High-Temperature Characterization of Inorganic Particles and Vapors in a Circulating Fluidized Bed Boiler Cofiring Wood and Rubber Waste
Show others...
2015 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 29, no 2, p. 863-871Article in journal (Refereed) Published
Abstract [en]

The effects of varying fuel mixtures and using a lime additive were studied in a 125-MWth circulating fluidized bed boiler. A high-temperature aerosol measurement method using a hot-dilution probe was used to characterize the particles and condensing inorganic vapors upstream from the superheater. The particle size distributions of the extracted samples indicate that when high-sulfur rubber waste, waste wood, and forest fuel were cocombusted, the hot flue gas contained no substantial amount of particulate matter in the fine (<0.3 mu m) particle size range, although the SO2 concentration exceeded 70 ppm. Only a nucleation mode was observed, which was presumably formed from inorganic vapors that condensed in the sampling probe. The size-segregated elemental analysis of the extracted samples indicated that when lime was added, the nucleation mode mainly comprised condensed alkali chlorides, while the sulfates dominated the mode when no lime was added. The presumed explanation for the sulfates in the nucleation mode was the sulfation of the alkali chlorides inside the sampling system. When only the wood fuels and no rubber fuel were cocombusted, the SO2 concentration in the gas was approximately 5 ppm. In this case, an alkali sulfate particle mode formed at approximately 70 nm in the hot flue gas. In addition, vapors of alkali chlorides and lead formed particulate matter inside the sampling probe when using low dilution ratios.

National Category
Chemical Process Engineering
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-41910 (URN)10.1021/ef502455u (DOI)000349943300047 ()2-s2.0-84923309346 (Scopus ID)
Available from: 2015-04-09 Created: 2015-04-09 Last updated: 2019-02-22Bibliographically approved
Lin, L., Morgalla, M. & Strand, M. (2015). Study on char fragmentation during biomass gasification in bubbling fluidized bed. In: 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria: . Paper presented at 23rd European Biomass Conference and Exhibition (pp. 652-655). ETA-Florence Renewable Energies
Open this publication in new window or tab >>Study on char fragmentation during biomass gasification in bubbling fluidized bed
2015 (English)In: 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, ETA-Florence Renewable Energies , 2015, p. 652-655Conference paper, Published paper (Refereed)
Abstract [en]

In this work a bench scale bubbling fluidized bed gasifier was built to work with an aerosol sampling and measuring system in order to study char fragmentation phenomenon during biomass gasification process. Both barbeque char and wood pellets were gasified in CO2 (20 vol.%) -N2 mixture and steam (30 vol.%)-N2 mixture, respectively. An aerodynamic particle sizer (APS) was used to measure fragmented char particles during the whole gasification process. For the wood pellet gasification case, major fragmentation was observed during the devolatilization stage, which should be attributed to the combined effect of primary fragmentation and attrition. The aerodynamic diameter of those elutriable particles which can be measured by the current system was in the range of 0.5-8 µm. During the char gasification stage, a distinct mode of char fragments was produced in the size range of 1-7 µm in either case. The total mass concentration of elutriable particles gradually increased when gasification of char started, and then decreased while the reaction approached completion.

Place, publisher, year, edition, pages
ETA-Florence Renewable Energies, 2015
Keywords
biomass, gasification, char, fluidized bed, aerosol, fragmentation
National Category
Energy Systems
Research subject
Technology (byts ev till Engineering), Bioenergy Technology
Identifiers
urn:nbn:se:lnu:diva-45714 (URN)10.5071/23rdEUBCE2015-2DO.5.2 (DOI)978-88-89407-516 (ISBN)
Conference
23rd European Biomass Conference and Exhibition
Funder
Swedish Energy Agency
Available from: 2015-08-17 Created: 2015-08-17 Last updated: 2019-02-22Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8086-1518

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