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Trubetskaya, Anna
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Publications (10 of 18) Show all publications
Trubetskaya, A., Brown, A., Tompsett, G. A., Timko, M. T., Kling, J., Broström, M., . . . Umeki, K. (2018). Characterization and reactivity of soot from fast pyrolysis of lignocellulosic compounds and monolignols. Applied Energy, 212, 1489-1500
Open this publication in new window or tab >>Characterization and reactivity of soot from fast pyrolysis of lignocellulosic compounds and monolignols
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2018 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 212, p. 1489-1500Article in journal (Refereed) Published
Abstract [en]

This study presents the effect of lignocellulosic compounds and monolignols on the yield, nanostructure and reactivity of soot generated at 1250 °C in a drop tube furnace. The structure of soot was characterized by electron microscopy techniques, Raman spectroscopy and electron spin resonance spectroscopy. The CO2 reactivity of soot was investigated by thermogravimetric analysis. Soot from cellulose was more reactive than soot produced from extractives, lignin and monolignols. Soot reactivity was correlated with the separation distances between adjacent graphene layers, as measured using transmission electron microscopy. Particle size, free radical concentration, differences in a degree of curvature and multi-core structures influenced the soot reactivity less than the interlayer separation distances. Soot yield was correlated with the lignin content of the feedstock. The selection of the extraction solvent had a strong influence on the soot reactivity. The Soxhlet extraction of softwood and wheat straw lignin soot using methanol decreased the soot reactivity, whereas acetone extraction had only a modest effect.

Place, publisher, year, edition, pages
Oxford: Elsevier, 2018
Keywords
Fast pyrolysis, Lignocellulosic compounds and monolignols, Soot, Reactivity, Nanostructure
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-142747 (URN)10.1016/j.apenergy.2017.12.068 (DOI)000425200700110 ()
Available from: 2017-12-11 Created: 2017-12-11 Last updated: 2018-06-09Bibliographically approved
Trubetskaya, A., Broström, M., Kling, J., Brown, A., Tompsett, G. & Umeki, K. (2017). Effects of Lignocellulosic Compounds on the Yield, Nanostructure and Reactivity of Soot from Fast Pyrolysis at High Temperatures. In: : . Paper presented at Nordic Flame Days, Stockholm, Sweden, October 10-11, 2017.
Open this publication in new window or tab >>Effects of Lignocellulosic Compounds on the Yield, Nanostructure and Reactivity of Soot from Fast Pyrolysis at High Temperatures
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2017 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:umu:diva-141087 (URN)
Conference
Nordic Flame Days, Stockholm, Sweden, October 10-11, 2017
Available from: 2017-10-24 Created: 2017-10-24 Last updated: 2019-06-25Bibliographically approved
Trubetskaya, A., Broström, M., Larsen Andersen, M. & Talbro Barsberg, S. (2017). Modeling of radical structures in biochar using DFT calculations. In: Franco Berruti, Raffaella Ocone and Ondrej Masek (Ed.), ECI Digital Archives: . Paper presented at Biochar: Production, Characterization and Applications. An ECI conference. Alba, Italy, August 20-25, 2017. Digital Commons
Open this publication in new window or tab >>Modeling of radical structures in biochar using DFT calculations
2017 (English)In: ECI Digital Archives / [ed] Franco Berruti, Raffaella Ocone and Ondrej Masek, Digital Commons , 2017Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Carbon is a key ingredient for producing metals used for cellphones, laptop computers, photovoltaic panels, and related solid state silicon devices employed by mankind. Thus, introduction of an alternative reductant based on bioresources into steel manufacturing without significant investments in a new technology is of high importance and wide impact. The production of iron, steel, and many other metals can employ biocarbon as the needed reductant; but because of cost, coals are usually used instead. The anthropogenic CO2 emissions can be decreased by substitution of biochar in the production of silicon and metals due to the lower regeneration time of biomass < 10 years compared to 106-107 years for bituminous coal.

This study aims to develop and to provide knowledge on the biochar structure at the molecular level including the presence of free radicals and oxygen heteroatoms that is essential for the understanding and prediction of biochar valuable properties in metallurgical applications. Both yields and biochar properties are important parameters for the optimization of pyrolysis conditions. Therefore, the pyrolysis conditions for the biochar application as a reducing agent in steel industry were optimized, and the molecular structure of the biochar by the combined use of experimental chemistry (Raman spectroscopy and Fourier transform infrared spectroscopy) and quantum chemistry computations (Density Functional Theory methods) was modified.

The results indicated the formation of stable radicals from biomass pyrolysis at their termination stage which were quantified by the electron spin resonance spectroscopy. Based on the experimental and fitting results, PAH structures were selected as initial compounds for the DFT modeling. The comparison of hydroxylated with methylated PAH structures showed that hydroxylated PAH are excellent candidate to represent the radical structure based on the low bond dissociation energes. The bond dissociation energy of -10 Kcal mol-1 is in the range of the best known antioxidants. The results showed that the present DFT model predicts reasonably the biochar molecular structure, and can capture changes in the biochar molecular structure under different pyrolysis conditions.

Place, publisher, year, edition, pages
Digital Commons, 2017
Keywords
biochar, radical, density function theory, electron spin resonance spectroscopy, pyrolysis
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:umu:diva-141088 (URN)
Conference
Biochar: Production, Characterization and Applications. An ECI conference. Alba, Italy, August 20-25, 2017
Available from: 2017-10-24 Created: 2017-10-24 Last updated: 2019-06-20Bibliographically approved
Trubetskaya, A., Surup, G., Shapiro, A. & Bates, R. B. (2017). Modeling the influence of potassium content and heating rate on biomass pyrolysis. Applied Energy, 194, 199-211
Open this publication in new window or tab >>Modeling the influence of potassium content and heating rate on biomass pyrolysis
2017 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 194, p. 199-211Article in journal (Refereed) Published
Abstract [en]

This study presents a combined kinetic and particle model that describes the effect of potassium and heating rate during the fast pyrolysis of woody and herbaceous biomass. The model calculates the mass loss rate, over a wide range of operating conditions relevant to suspension firing. The shrinking particle model considers internal and external heat transfer limitations and incorporates catalytic effects of potassium on the product yields. Modeling parameters were tuned with experimentally determined char yields at high heating rates (&gt;200 K s−1) using a wire mesh reactor, a single particle burner, and a drop tube reactor. The experimental data demonstrated that heating rate and potassium content have significant effects on the char yield. The importance of shrinkage on the devolatilization time becomes greater with increasing particle size, but showed little influence on the char yields.

Place, publisher, year, edition, pages
Oxford: Elsevier, 2017
Keywords
Fast pyrolysis, Kinetics, Metaplast, Potassium, Heating rate
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-134518 (URN)10.1016/j.apenergy.2017.03.009 (DOI)000399623600016 ()
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2018-06-09Bibliographically approved
Trubetskaya, A., Poyraz, Y., Weber, R. & Wadembäck, J. (2017). Secondary comminution of wood pellets in power plant and laboratory-scale mills. Fuel processing technology, 160, 216-227
Open this publication in new window or tab >>Secondary comminution of wood pellets in power plant and laboratory-scale mills
2017 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 160, p. 216-227Article in journal (Refereed) Published
Abstract [en]

This study aims to determine the influence of mill type and pellet wood composition on particle size and shape of milled wood. The size and shape characteristics of pellets comminuted using power plant roller mills were compared with those obtained by using laboratory-scale roller- and hammer mills. A 2D dynamic imaging device was used for particle characterization. It was shown that mill type has a significant impact on particle size but an almost negligible effect on the shape of milled wood. Comminution in the pilot plant using a Loesche roller mill requires less energy than using a hammer mill, but generates a larger fraction of coarse particles. The laboratory-scale roller mill provides comparable results with the power plant roller mill with respect to particle size and shape.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Pellets, Hammer mill, Roller mill, Particle size, Shape
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-134515 (URN)10.1016/j.fuproc.2017.02.023 (DOI)
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2018-06-09Bibliographically approved
Trubetskaya, A., Jensen, A. D., Andersen, M. L. & Talbro Barsberg, S. (2016). Characterization of Free Radicals By Electron Spin Resonance Spectroscopy in Biochars from Pyrolysis at High Heating Rates and at High Temperatures.
Open this publication in new window or tab >>Characterization of Free Radicals By Electron Spin Resonance Spectroscopy in Biochars from Pyrolysis at High Heating Rates and at High Temperatures
2016 (English)Other (Other academic)
Keywords
Energy Engineering, Energiteknik
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-134509 (URN)
Note

2017-04-20T13:42:27.163+02:00

Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2018-06-09
Trubetskaya, A., Jensen, P. A., Jensen, A. D., Stiebel, M., Spliethoff, H., Glarborg, P. & Larsen, F. H. (2016). Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity. Biomass and Bioenergy, 86, 76-87
Open this publication in new window or tab >>Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity
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2016 (English)In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 86, p. 76-87Article in journal (Refereed) Published
Abstract [en]

Fast pyrolysis of wheat straw and rice husk was carried out in an entrained flow reactor at high-temperatures (1000–1500) °C. The collected char was analyzed using X-ray diffractometry, N2-adsorption, scanning electron microscopy, particle size analysis with CAMSIZER XT, 29Si and 13C solid-state nuclear magnetic resonance spectroscopy and thermogravimetric analysis to investigate the effect of inorganic matter on the char morphology and oxygen reactivity. The silicon compounds were dispersed throughout the turbostratic structure of rice husk char in an amorphous phase with a low melting temperature (≈730 °C), which led to the formation of a glassy char shell, resulting in a preserved particle size and shape of chars. The high alkali content in the wheat straw resulted in higher char reactivity, whereas the lower silicon content caused variations in the char shape from cylindrical to near-spherical char particles. The reactivities of pinewood and rice husk chars were similar with respect to oxidation, indicating less influence of silicon oxides on the char reactivity.

Keywords
Fast pyrolysis, Si-29 solid-state NMR, Entrained flow reactor, Oxygen reactivity, Si bearing compounds
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-134514 (URN)10.1016/j.biombioe.2016.01.017 (DOI)000371331800009 ()
Note

article; 2017-04-20T13:45:19.690+02:00

Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2018-06-09Bibliographically approved
Trubetskaya, A., Jensen, P. A., Jensen, A. D., Llamas, A. D., Umeki, K. & Glarborg, P. (2016). Effect of fast pyrolysis conditions on biomass solid residues at high temperatures. Fuel processing technology, 143, 118-129
Open this publication in new window or tab >>Effect of fast pyrolysis conditions on biomass solid residues at high temperatures
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2016 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 143, p. 118-129Article in journal (Refereed) Published
Abstract [en]

Fast pyrolysis of wood and straw was conducted in a drop tube furnace (DTF) and compared with corresponding data from a wire mesh reactor (WMR) to study the influence of temperature (1000-1400)°C, biomass origin (pinewood, beechwood, wheat straw, alfalfa straw), and heating rate (103 °C/s, 104 °C/s) on the char yield and morphology. Scanning electron microscopy (SEM), elemental analysis, and ash compositional analysis were applied to characterize the effect of operational conditions on the solid residues (char, soot) and gaseous products. The char yield from fast pyrolysis in the DTF setup was 3 to 7% (daf) points lower than in the WMR. During fast pyrolysis pinewood underwent drastic morphological transformations, whereas beechwood and straw samples retained the original porous structure of the parental fuel with slight melting on the surface. The particle size of Danish wheat straw char decreased in its half-width with respect to the parental fuel, whereas the alfalfa straw char particle size remained unaltered at higher temperatures. Soot particles in a range from 60 to 300 nm were obtained during fast pyrolysis. The soot yield from herbaceous fuels was lower than from wood samples, possibly due to differences in the content of lignin and resin acids.

Place, publisher, year, edition, pages
Amsterdam: Elsevier, 2016
Keywords
Fast pyrolysis, Drop tube furnace, Wire mesh reactor, Soot, CAMSIZER XT
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-134512 (URN)10.1016/j.fuproc.2015.11.002 (DOI)000369455300014 ()
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2018-06-09Bibliographically approved
Trubetskaya, A., Jensen, P. A., Glarborg, P., Garcia Llamas, A. D., Umeki, K., Kling, J., . . . Jensen, A. D. (2016). Effects of Biomass Feedstock on the Yield and Reactivity of Soot from Fast Pyrolysis at High Temperatures.
Open this publication in new window or tab >>Effects of Biomass Feedstock on the Yield and Reactivity of Soot from Fast Pyrolysis at High Temperatures
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2016 (English)Other (Other academic)
Keywords
Energy Engineering, Energiteknik
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-134510 (URN)
Note

2017-04-20T13:43:13.100+02:00

Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2018-06-09
Trubetskaya, A., Jensen, P. A., Jensen, A. D., Llamas, A. D., Umeki, K., Gardini, D., . . . Glarborg, P. (2016). Effects of several types of biomass fuels on the yield, nanostructure and reactivity of soot from fast pyrolysis at high temperatures. Applied Energy, 171, 468-482
Open this publication in new window or tab >>Effects of several types of biomass fuels on the yield, nanostructure and reactivity of soot from fast pyrolysis at high temperatures
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2016 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 171, p. 468-482Article in journal (Refereed) Published
Abstract [en]

This study presents the effect of biomass origin on the yield, nanostructure and reactivity of soot. Soot was produced from wood and herbaceous biomass pyrolysis at high heating rates and at temperatures of 1250 and 1400 °C in a drop tube furnace. The structure of solid residues was characterized by electron microscopy techniques, X-ray diffraction and N2 adsorption. The reactivity of soot was investigated by thermogravimetric analysis. Results showed that soot generated at 1400 °C was more reactive than soot generated at 1250 °C for all biomass types. Pinewood, beechwood and wheat straw soot demonstrated differences in alkali content, particle size and nanostructure. Potassium was incorporated in the soot matrix and significantly influenced soot reactivity. Pinewood soot particles produced at 1250 °C had a broader particle size range (27.2–263 nm) compared to beechwood soot (33.2–102 nm) and wheat straw soot (11.5–165.3 nm), and contained mainly multi-core structures.

Place, publisher, year, edition, pages
Oxford: Elsevier, 2016
Keywords
Fast pyrolysis, Drop tube reactor, Soot, Potassium, Reactivity
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-134511 (URN)10.1016/j.apenergy.2016.02.127 (DOI)000375515500040 ()
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2018-06-09Bibliographically approved
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