umu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Pommer, Linda
Publications (10 of 37) Show all publications
Mejtoft, T., Andersson, B. M., Pommer, L., Karolina, J., Kerstin, R., Wåhlin, A., . . . Hallberg, P. (2019). Kan en branschspecifik innovationsmodell öka ”success rate” för medicintekniska innovationer?. In: : . Paper presented at Medicinteknikdagarna 2019, Linköping, Sweden, 2-3 oktober, 2019.
Open this publication in new window or tab >>Kan en branschspecifik innovationsmodell öka ”success rate” för medicintekniska innovationer?
Show others...
2019 (Swedish)Conference paper, Oral presentation only (Other academic)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:umu:diva-166751 (URN)
Conference
Medicinteknikdagarna 2019, Linköping, Sweden, 2-3 oktober, 2019
Available from: 2019-12-26 Created: 2019-12-26 Last updated: 2020-01-02Bibliographically approved
Rudolfsson, M., Borén, E., Pommer, L., Nordin, A. & Lestander, T. A. (2017). Combined effects of torrefaction and pelletization parameters on the quality of pellets produced from torrefied biomass. Applied Energy, 191, 414-424
Open this publication in new window or tab >>Combined effects of torrefaction and pelletization parameters on the quality of pellets produced from torrefied biomass
Show others...
2017 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 191, p. 414-424Article in journal (Refereed) Published
Abstract [en]

A combined torrefaction and pelletization study was performed at industrially relevant settings using a factorial design. First, wood chips of Scots pine were torrefied at high temperatures (291-315 degrees C) and short residence times (6-12 min), facilitating high throughput in a continuous pilot-scale torrefaction process. Then the torrefied materials were pelletized, also in pilot-scale, using varying moisture contents (MCs) (10-14%), sieve sizes (4-6 mm), and press channel lengths (PCLs) (25 and 30 mm), in all 19 batches, each of 400 kg. The resulting so called black pellets exhibited bulk densities of 558-725 kg m(-3), durabilities of 46.3-86.5%, and fines contents of 3.8-85.8%. Through multiple linear regression modelling of all 11 responses, it was found that the parameter with the greatest influence on the responses was the torrefaction temperature, followed by torrefaction time, MC, and PCL. Longer PCL and higher MC resulted in higher pellet quality, with less fines and greater bulk density and durability. Furthermore, a low torrefaction degree decreased the amount of power required for pelletization. The energy required to grind pellets into a powder (<0.5 mm) decreased with increasing torrefaction degree as expected, but also with decreasing MC before pelletizing. Pyrolysis-GC/MS analysis of thermal degradation products from the pellets revealed correlations with the torrefaction temperature and time, but no correlations with the pelletization process. These results are useful for mapping chemical changes in torrefied materials and identifying complementary torrefaction and pelletization settings. Specifically of interest is adjustment of PCLs at low intervals to better match friction properties of torrefied materials.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Pine, Moisture, Press channel lengths, Durability, Fines, Degradation products
National Category
Chemical Process Engineering Bioenergy
Identifiers
urn:nbn:se:umu:diva-134212 (URN)10.1016/j.apenergy.2017.01.035 (DOI)000395963500033 ()
Projects
Bio4Energy
Available from: 2017-06-16 Created: 2017-06-16 Last updated: 2019-09-02Bibliographically approved
Normark, M., Pommer, L., Gräsvik, J., Hedenström, M., Gorzsas, A., Winestrand, S. & Jönsson, L. J. (2016). Biochemical Conversion of Torrefied Norway Spruce After Pretreatment with Acid or Ionic Liquid. Bioenergy Research, 9(1), 355-368
Open this publication in new window or tab >>Biochemical Conversion of Torrefied Norway Spruce After Pretreatment with Acid or Ionic Liquid
Show others...
2016 (English)In: Bioenergy Research, ISSN 1939-1234, E-ISSN 1939-1242, Vol. 9, no 1, p. 355-368Article in journal (Refereed) Published
Abstract [en]

The chemical effects of torrefaction and the possibility to combine torrefaction with biochemical conversion were explored in experiments with five preparations of wood of Norway spruce that had been torrefied using different degrees of severity. Compositional analysis and analyses using solid-state CP/MAS C-13 NMR, Fourier-transform infrared (FTIR) spectroscopy, and Py-GC/MS showed small gradual changes, such as decreased hemicellulosic content and increased Klason lignin value, for torrefaction conditions in the range from 260 A degrees C and 8 min up to 310 A degrees C and 8 min. The most severe torrefaction conditions (310 A degrees C, 25 min) resulted in substantial loss of glucan and further increase of the Klason lignin value, which was attributed to conversion of carbohydrate to pseudo-lignin. Even mild torrefaction conditions led to decreased susceptibility to enzymatic hydrolysis of cellulose, a state which was not changed by pretreatment with sulfuric acid. Pretreatment with the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate overcame the additional recalcitrance caused by torrefaction, and the glucose yields after 72 h of enzymatic hydrolysis of wood torrefied at 260 A degrees C for 8 min and at 285 A degrees C for 16.5 min were as high as that of IL-pretreated non-torrefied spruce wood. Compared to IL-pretreated non-torrefied reference wood, the glucose production rates after 2 h of enzymatic hydrolysis of IL-pretreated wood torrefied at 260 A degrees C for 8 min and at 285 A degrees C for 16.5 min were 63 and 40 % higher, respectively. The findings offer increased understanding of the effects of torrefaction and indicate that mild torrefaction is compatible with biochemical conversion after pretreatment with alternative solvents that disrupt pseudo-lignin-containing lignocellulose.

Keywords
Torrefaction, Wood, Acid pretreatment, Ionic liquid, Enzymatic hydrolysis
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:umu:diva-118386 (URN)10.1007/s12155-015-9698-7 (DOI)000370816300032 ()
Projects
Bio4Energy
Available from: 2016-04-22 Created: 2016-03-18 Last updated: 2020-01-30Bibliographically approved
Khwaja, S., Weiland, F., Pettersson, E., Wiinikka, H., Wingren, A., Strandberg, M., . . . Nordin, A. (2016). Entrained Flow Gasification of Torrefied Lignocellulosic Biomass. In: Faaij, APC Baxter, D Grassi, A Helm, P (Ed.), Papers of the 24TH European Biomass Conference: Setting the Course for a Biobased Economy. Paper presented at 24th European Biomass Conference on Setting the Course for a Biobased Economy (EUBCE 2016), Amsterdam, June 6-9, 2016. (pp. 1138-1142). Amsterdam: ETA Florence Renewable Energies
Open this publication in new window or tab >>Entrained Flow Gasification of Torrefied Lignocellulosic Biomass
Show others...
2016 (English)In: Papers of the 24TH European Biomass Conference: Setting the Course for a Biobased Economy / [ed] Faaij, APC Baxter, D Grassi, A Helm, P, Amsterdam: ETA Florence Renewable Energies , 2016, p. 1138-1142Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

An extensive evaluation program was carried out within the European SECTOR project to evaluate the feasibility of torrefied and densified biomass in available entrained flow gasifiers. Different entrained flow reactors (both atmospheric and pressurized) in different scales, from lab scale to a 240 MW industrial gasifier were used for evaluation of torrefied materials as feedstock. Total behaviours of the new fuel throughout the whole supply chains and the EFG systems were evaluated and documented, including process behaviours in terms of operation, gas quality, products of incomplete gasification, etc. Results showed a significant improvement in fuel properties in terms of storage, logistics, milling and feeding behaviour by torrefaction and densification. Entrained flow gasification of the torrefied biomass was also shown to be feasible without any major showstoppers, even improving the gasification processes. Production of tars and other products of incomplete gasification were often found significantly reduced during gasification of torrefied material.

Place, publisher, year, edition, pages
Amsterdam: ETA Florence Renewable Energies, 2016
Series
EUBCE proceedings, ISSN 2282-5819
Keywords
torrefaction, gasification, biomass, entrained flow
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-163258 (URN)000473716900198 ()
Conference
24th European Biomass Conference on Setting the Course for a Biobased Economy (EUBCE 2016), Amsterdam, June 6-9, 2016.
Available from: 2019-09-19 Created: 2019-09-19 Last updated: 2019-09-19
Strandberg, M., Olofsson, I., Pommer, L., Wiklund-Lindström, S., Åberg, K. & Nordin, A. (2015). Effects of temperature and residence time on continuous torrefaction of spruce wood. Fuel processing technology, 134, 387-398
Open this publication in new window or tab >>Effects of temperature and residence time on continuous torrefaction of spruce wood
Show others...
2015 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 134, p. 387-398Article in journal (Refereed) Published
Abstract [en]

As a solid energy carrier, biomass generally has a few disadvantages, which limits its use for coal replacement and as a feedstock for entrained flow gasification. The hydrophilic and fibrous nature, the low calorific value and low bulk energy content imply high accumulated costs in the whole supply chain and severe challenges in more advanced conversion systems. By thermally pretreating the biomass by torrefaction, these properties may be significantly improved. A continuous torrefaction rotary drum reactor was designed, constructed and evaluated to enable an accurate process control and allow a homogeneous well-defined high quality product to be produced. The combined effects of torrefaction temperature (260–310 °C) and residence time (8–25 min) on a large number of product properties (&gt; 25) were determined for Norway spruce. The resulting mass and energy yields were 46–97% and 62–99%, respectively. Exothermic reactions were evident both at low (260 °C) and high temperatures (310 °C) but with no thermal runaway observed. Increased torrefaction severity resulted in decreased milling energy consumption, angle of repose, mass and energy yield, content of volatile matter, hydrogen, cellulose and hemicellulose. Hydrophobicity, heating value, carbon and fixed carbon contents increased. For all responses, the effect of torrefaction temperature was larger than the effect of residence time. Substantial interaction effects were present for mass and energy yields, volatile matter and hydrogen content. Another correlation found was the relationship of hemicellulose degradation and the brittleness of the torrefied product. Data also suggest secondary char forming reactions during the torrefaction process, resulting in higher fixed carbon content in the torrefied material than expected. The results also suggest torrefaction temperature and residence time not to be totally interchangeable.

Keywords
Torrefaction, Hydrophobicity, Grindability, Rotary drum, Continuous reactor
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:umu:diva-103041 (URN)10.1016/j.fuproc.2015.02.021 (DOI)000353739200047 ()
Funder
Bio4EnergySwedish Energy Agency, 31489-1
Available from: 2015-05-18 Created: 2015-05-18 Last updated: 2018-06-07Bibliographically approved
Gao, Q., Haglund, P., Pommer, L. & Jansson, S. (2015). Evaluation of solvent for pressurized liquid extraction of PCDD, PCDF, PCN, PCBz, PCPh and PAH in torrefied woody biomass. Fuel, 154, 52-58
Open this publication in new window or tab >>Evaluation of solvent for pressurized liquid extraction of PCDD, PCDF, PCN, PCBz, PCPh and PAH in torrefied woody biomass
2015 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 154, p. 52-58Article in journal (Refereed) Published
Abstract [en]

Biomass torrefaction for sustainable energy production has gained an increasing interest. However, there is a lack of information on the thermal formation of persistent organic pollutants such as dioxins in the torrefied solid product. In this paper, we investigated the applicability of pressurized liquid extraction (PLE) for simultaneous extraction of a number of polychlorinated planar aromatic compounds from torrefied wood. The targeted compounds included polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), naphthalenes (PCNs), benzenes (PCBz), phenols (PCPhs) and PAHs. PLE tests were conducted on torrefied and non-torrefied (i.e. raw) eucalyptus wood chips using 5 single solvents (n-hexane, toluene, dichloromethane, acetone and methanol) and a mixture of n-hexane/toluene (1:1, v/v). The performance of each solvent was evaluated in terms of recoveries of spiked internal standards and the amount of co-extracted sample matrix. High polarity solvents such as methanol and acetone resulted in poor recoveries from torrefied wood for most of the target compounds, probably due to the high co-extraction of thermally degraded lignocellulosic compounds. Raw wood was less solvent-dependent and comparable results were obtained for polar and non-polar solvents. Toluene showed the best performance of the investigated solvents, with average recoveries of 79 +/- 14% and 66 +/- 9% for raw and torrefied wood, respectively. The method was validated using pentachlorophenol-tainted spruce wood chips. The proposed PLE method was compared to the traditional Soxhlet method. Results show that PLE gave equivalent or better extraction for all target compounds.

Keywords
Persistent organic pollutants, PLE, Dioxin, Solvent effect, Torrefaction
National Category
Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-103714 (URN)10.1016/j.fuel.2015.03.068 (DOI)000353893200007 ()
Funder
Bio4Energy
Available from: 2015-06-11 Created: 2015-05-28 Last updated: 2019-04-09Bibliographically approved
Åberg, K., Pommer, L. & Nordin, A. (2015). Syngas production by combined biomass gasification and in situ biogas reforming. Energy & Fuels, 29(6), 3725-3731
Open this publication in new window or tab >>Syngas production by combined biomass gasification and in situ biogas reforming
2015 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 29, no 6, p. 3725-3731Article in journal (Refereed) Published
Abstract [en]

For small- to medium-sized streams of biogas (methane) produced at a biorefinery site where cost-efficient reforming by traditional methods are unavailable, combined biomass gasification and methane reforming could facilitate co-conversion and increase the H-2/CO ratio in the syngas from the gasification plant. In the present work, co-gasification of biomass with CH4 was evaluated by means of a parametric chemical equilibrium study for both wood/CH4 and black liquor/CH4 feedstocks and bench-scale fluidized-bed gasification experiments for a wood/peat/CH4 fuel mixture. The parametric study indicated that high-temperature, and steam and oxygen addition all facilitate a high conversion rate, i.e., methane reforming. Evaluating the influence of the gasification temperature on CH4 reforming and increasing the H-2/CO ratio experimentally demonstrated that high temperatures are required for efficient co-conversion.

National Category
Bioenergy
Identifiers
urn:nbn:se:umu:diva-106571 (URN)10.1021/acs.energyfuels.5b00405 (DOI)000356755000024 ()
Available from: 2015-07-20 Created: 2015-07-20 Last updated: 2018-06-07Bibliographically approved
Lestander, T. A., Rudolfsson, M., Pommer, L. & Nordin, A. (2014). NIR provides excellent predictions of properties of biocoal from torrefaction and pyrolysis of biomass. Green Chemistry, 16(12), 4906-4913
Open this publication in new window or tab >>NIR provides excellent predictions of properties of biocoal from torrefaction and pyrolysis of biomass
2014 (English)In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 16, no 12, p. 4906-4913Article in journal (Refereed) Published
Abstract [en]

When biomass is exposed to high temperatures in torrefaction, pyrolysis or gasification treatments, the enrichment of carbon in the remaining 'green coal' is correlated with the temperature. Various other properties, currently measured using wet chemical methods, which affect the materials' quality as a fuel, also change. The presented study investigated the possibility of using NIR spectrometry to estimate diverse variables of biomass originating from two sources (above-ground parts of reed canary grass and Norway spruce wood) carbonised at temperatures ranging from 240 to 850 C-circle. The results show that the spectra can provide excellent predictions of its energy, carbon, oxygen, hydrogen, ash, volatile matter and fixed carbon contents. Hence NIR spectrometry combined with multivariate calibration modeling has potential utility as a standardized method for rapidly characterising thermo-treated biomass, thus reducing requirements for more costly, laborious wet chemical analyses and consumables.

National Category
Energy Systems
Identifiers
urn:nbn:se:umu:diva-98460 (URN)10.1039/c3gc42479k (DOI)000345455100009 ()2-s2.0-84911880741 (Scopus ID)
Available from: 2015-02-02 Created: 2015-01-22 Last updated: 2018-06-07Bibliographically approved
Wiklund Lindström, S., Nilsson, D., Nordin, A., Nordwaeger, M., Olofsson, I., Pommer, L. & Geladi, P. (2014). Quality assurance of torrefied biomass using RGB, visual and near infrared (hyper) spectral image data. Journal of Near Infrared Spectroscopy, 22(2), 129-139
Open this publication in new window or tab >>Quality assurance of torrefied biomass using RGB, visual and near infrared (hyper) spectral image data
Show others...
2014 (English)In: Journal of Near Infrared Spectroscopy, ISSN 0967-0335, E-ISSN 1751-6552, Vol. 22, no 2, p. 129-139Article in journal (Refereed) Published
Abstract [en]

Visible and near infrared imaging techniques for analysing characteristics of torrefied biomass were evaluated for possible use in future online process control. The goal of such a control system is to identify products with the desired properties and reject products outside the specification. Two pushbroom hyperspectral cameras with different wavelength regions and a commercial digital colour camera were evaluated. The hyperspectrat cameras, short wave infrared (SWIR) and visible-near infrared (VNIR), covered the ranges of 1000-2500 nm and 400-1000 nm, respectively. The biomass was produced according to an experimental design in a torrefaction pilot plant at different temperatures, residence times, and nitrogen and steam flow rates to obtain a wide range of different characteristics and qualities of torrefied material. Chemical characteristics, heating values and milling energy of the different torrefied materials were analysed or calculated using standardized procedures and were used for calibration. For the hyperspectral images, a principal-component analysis was performed on the absorbance spectra. The score plots and score images were used interactively to separate background, outlier pixels and shading effects from sample signal. Averaged spectra of individual torrefied woodchips were used. Partial least-squares regression was used to relate average spectra to heating values and chemical characteristics of the torrefied biomass. Owing to the small size of the data sets, cross-validation using leave-one-out validation was used for testing the models. The ratio of standard error of prediction to sample standard deviation (RPD) values were used for comparing the imaging techniques. For ROB images, all RPD values were 4 or lower. The RPD values for the VNIR technique were all below 5, while the SWIR images produced RPD values above 5 for eight of the 13 properties. The promising results of the SWIR technique strongly suggested that the torrefied biomass undergoes changes to chemical structures, which are not necessarily manifested as changes to the colour of the material.

Keywords
PLS, hyperspectral imaging (HSI), SWIR, NIRS, VNIR, PAT, torrefaction, pushbroom imaging technique
National Category
Bio Materials
Identifiers
urn:nbn:se:umu:diva-91291 (URN)10.1255/jnirs.1100 (DOI)000337932200007 ()
Available from: 2014-07-28 Created: 2014-07-28 Last updated: 2018-06-07Bibliographically approved
Werner, K., Pommer, L. & Broström, M. (2014). Thermal decomposition of hemicelluloses. Journal of Analytical and Applied Pyrolysis, 110, 130-137
Open this publication in new window or tab >>Thermal decomposition of hemicelluloses
2014 (English)In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 110, p. 130-137Article in journal (Refereed) Published
Abstract [en]

Decomposition modeling of biomass often uses commercially available xylan as model compound representing hemicelluloses, not taking in account the heterogeneous nature of that group of carbohydrates. In this study, the thermal decomposition behavior of seven different hemicelluloses (beta-glucan, arabinogalactan, arabinoxylan, galactomannan, glucomannan, xyloglucan, and xylan) were investigated in inert atmosphere using (i) thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, (ii) differential scanning calorimetry, and (iii) pyrolysis-gas chromatography/mass spectroscopy. Results on decomposition characteristics (mass loss rate, reaction heat and evolving gas composition) were compared and summarized for the different hemicelluloses and for comparison also crystalline cellulose was included in the study. The mass loss rate characteristics differed between the polysaccharides, with cellulose and glucan-based hemicelluloses as the thermally most stable and xylan as the least stable sample. The heat flow during slow heating in nitrogen flow showed a much more exothermal decomposition of xylan compared with the other hemicelluloses. The composition of off-gases during heating showed large differences between the samples. During decomposition of xylan high levels of CO2 and lower levels of other components were formed, whereas also CO, methanol, methane, furfural, 5-hydroxymethylfurfural and anhydrosugars were formed in substantial amounts from the other polysaccharides. The formation of anhydrosugar was correlated to the monosaccharide composition of the polysaccharide chain. The results from the current study contribute to new knowledge concerning thermochemical behavior of different hemicelluloses.

Keywords
Pyrolysis, Thermal decomposition, Hemicellulose, Xylan
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:umu:diva-100161 (URN)10.1016/j.jaap.2014.08.013 (DOI)000347496800015 ()
Available from: 2015-02-25 Created: 2015-02-24 Last updated: 2018-06-07Bibliographically approved
Organisations

Search in DiVA

Show all publications