| 1. |
- Antti, Lena, et al.
(författare)
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Effects of microwave drying on biomass fatty acid composition and fuel pellet quality
- 2011
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Ingår i: Wood Material Science & Engineering. - : Informa UK Limited. - 1748-0272 .- 1748-0280. ; 6:1-2, s. 34-40
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Tidskriftsartikel (refereegranskat)abstract
- Drying of biomass for fuel pellet production is a time- and energy-consuming process. The objective of this study was to investigate not only whether microwave drying could be an alternative drying method but also whether the microwave treatment brings beneficial chemical properties into the biomass feedstock in terms of, for example, fatty acid composition and, further, whether this could be advantageous in the production of wood pellets. Microwave drying tests were conducted using fresh sawdust from pinewood as a biomass model. In these tests sawdust was dried from weight-based moisture content 0.47 to final moisture contents in the interval 0.08-0.14. The chemical composition, pellet-making and mechanical properties of the pellets were then investigated. It was shown that 0.5 kg sawdust could be dried within 40 min of microwave exposure. The effects of microwave treatment on the fatty and resin acid composition indicated that some changes occurred, but the total amounts were not significantly different from those in oven-dried samples. However, the microwave treatment of sawdust significantly improved pellet density and pellet strength. These results indicate new possibilities to alter fatty and resin acid composition and to improve particle bonding within fuel pellets.
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| 2. |
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| 3. |
- Blomqvist, Johanna, et al.
(författare)
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Temperature-dependent changes in the microbial storage flora of birch and spruce sawdust
- 2014
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Ingår i: Biotechnology and Applied Biochemistry. - : Wiley. - 0885-4513 .- 1470-8744. ; 61, s. 58-64
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Tidskriftsartikel (refereegranskat)abstract
- Sawdust can be used to make pellets (biofuel) and particle boards and as a potential lignocellulose feedstock in bioethanol production. Microbial activity can affect sawdust quality; hence, we monitored the microbial population in birch- and spruce sawdust after 3 months' storage at various temperatures. Species composition was similar on both materials but was strongly influenced by temperature. Bacteria were present on all materials at all conditions: on birch, 2.8x10(8), 1.1x10(8), and 8.8x10(6), and on spruce, 4.1x10(8), 5.6x10(7), and 1.5x10(8)CFU/g DM, at 2, 20, and 37 degrees C, respectively. Dominant bacteria at 2, 20, and 37 degrees C were Pseudomonas spp. (some Enterobacteriaceae spp. present), Luteibacter rhizovicinus, and Fulvimonas sp., respectively. Pseudomonas spp. were absent at 20 degrees C. Among microfungi, yeasts dominated at 2 degrees C but were absent at 37 degrees C, whereas molds dominated at 20 and 37 degrees C. Common yeasts included Cystofilobasidium capitatum, Cystofilobasidium infirmominiatum, Candida saitoana, Candida oregonensis, and Candida railenensis. Ophiostoma quercus was a common mold at 2 and 20 degrees C, whereas the human pathogens Aspergillus fumigatus and Paecilomyces variotii dominated at 37 degrees C. Attempts to influence the microflora by addition of the biocontrol yeasts, Wickerhamomyces anomalus and Scheffersomyces stipitis, were unsuccessful, as their growth in sawdust was poor to absent.
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| 4. |
- Chen, Feng, et al.
(författare)
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Shiitake cultivation as biological preprocessing of lignocellulosic feedstocks – Substrate changes in crystallinity, syringyl/guaiacyl lignin and degradation-derived by-products
- 2022
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 344:Part B
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Tidskriftsartikel (refereegranskat)abstract
- Formulation of substrates based on three hardwood species combined with modulation of nitrogen content by whey addition (0–2%) was investigated in an experiment designed in D-optimal model for their effects on biological preproceesing of lignocellulosic feedstock by shiitake mushroom (Lentinula edodes) cultivation. Nitrogen loading was shown a more significant role than wood species for both mushroom production and lignocellulose degradation. The fastest mycelial colonisation occurred with no nitrogen supplementation, but the highest mushroom yields were achieved when 1% whey was added. Low nitrogen content resulted in increased delignification and minimal glucan consumption. Delignification was correlated with degradation of syringyl lignin unit, as indicated by a significant reduction (41.5%) of the syringyl-to-guaiacyl ratio after cultivation. No significant changes in substrate crystallinity were observed. The formation of furan aldehydes and aliphatic acids was negligible during the pasteurisation and fungal cultivation, while the content of soluble phenolics increased up to seven-fold.
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| 5. |
- Eriksson, D., et al.
(författare)
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Characterization of Scots pine stump-root biomass as feed-stock for gasification
- 2012
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 104, s. 729-736
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Tidskriftsartikel (refereegranskat)abstract
- The main objective was to explore the potential for gasifying Scots pine stump-root biomass (SRB). Washed thin roots, coarse roots, stump heartwood and stump sapwood were characterized (solid wood, milling and powder characteristics) before and during industrial processing. Non-slagging gasification of the SRB fuels and a reference stem wood was successful, and the gasification parameters (synthesis gas and bottom ash characteristics) were similar. However, the heartwood fuel had high levels of extractives (≈19%) compared to the other fuels (2-8%) and thereby ≈16% higher energy contents but caused disturbances during milling, storage, feeding and gasification. SRB fuels could be sorted automatically according to their extractives and moisture contents using near-infrared spectroscopy, and their amounts and quality in forests can be predicted using routinely collected stand data, biomass functions and drill core analyses. Thus, SRB gasification has great potential and the proposed characterizations exploit it. © 2011 Elsevier Ltd.
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| 6. |
- Finell, Michael, et al.
(författare)
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Laboratory-scale production of biofuel pellets from electron beam treated Scots pine (Pinus silvestris L.) sawdust
- 2009
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Ingår i: Radiation Physics and Chemistry. - : Elsevier BV. - 0969-806X. ; 78, s. 281-287
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Tidskriftsartikel (refereegranskat)abstract
- The effect of electron beam (EB) treatment on pine sawdust used as raw material for fuel pellets was studied. Dry sawdust was EB treated at different dosage levels up to 100 kGy. The effect of EB treatment on fatty and resin acid composition was studied for different dosage levels and compared to untreated sawdust. Pellets were pressed in a laboratory single pellet press unit according to a D-optimal, response surface modeling (RSM) experimental design, where sawdust moisture content and die temperature were varied independently for EB treatment dosages of 0, 18.2 and 48.9 kGy. The responses of the designed experiment were density and strength for the produced pellets. The results showed that the free fatty and resin acid content in the sawdust initially decreased with increasing EB doses but at the highest EB doses it increased. The total content of extractives however initially increased and then decreased with increasing EB dose. Pellets made of EB treated sawdust had a significantly (at 95% confidence level) higher density and compressive strength than pellets made from untreated sawdust. EB treated sawdust behaved similarly to stored (mature) sawdust as a pellet raw material. Thus, EB treatment opens the possibility for controlled ageing (maturation) of pellet raw materials.
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| 7. |
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| 8. |
- Geladi, Paul, et al.
(författare)
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Biomass properties in association with plant species and assortments. II: A synthesis based on literature data for ash elements
- 2012
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Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1364-0321. ; 16, s. 3507-3522
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Tidskriftsartikel (refereegranskat)abstract
- A study was carried out based on ash composition data (relative proportion of SiO2, K2O, CaO, MgO, Na2O, P2O5, Al2O3, Fe2O3 and SO2 in ash) in a large number of biomass species and assortments. The data were collected from 109 peer-reviewed publications and consisted of 367 objects for ash composition analysis. Principal component analysis (PCA) was used to analyze the data. The analyses were performed at five levels of plant classifications respectively: level 1-3 for lifeforms/species groups, level 4 for assortments and level 5 for species. Woody species data points tended to differ from herbaceous ones in terms of PCA for level 1 analysis. The loading plot of the two first components (PC1 and PC2) indicated that the woody species tended to be associated with Ca-Mg-P-K-S, while the herbaceous ones were closer to Si. Ca and Si had the largest contributions in forming the pattern. The woody group had a larger variation than the herbaceous group in terms of ash composition but this could be explained only by differentiation in assortments as illustrated with the level 4 analysis. The PCA analyses at levels 2 and 3 did not generate significant patterns, as the variations within the groups were larger than between the groups. The variation of the herbaceous data, however, could be explained by all level 2-5 analyses and attributed to differences between herbaceous dicots and graminoids, between C3 and C4 plants, and between assortments such as husk, fruit residues and bagasse. The robust analysis had in general the same results. These results could be further interpreted by the trend that Si decreased but Ca increased gradually in the following order: C3 graminoids -> C4 graminoids -> herbaceous dicots -> woody groups. It was also found that K, P, Mg and S were higher in herbaceous dicots than in graminoids
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| 9. |
- Geladi, Paul, et al.
(författare)
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Chemometrics in spectroscopy : Part 2. Examples
- 2004
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Ingår i: SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY. - : Elsevier BV. - 0584-8547. ; 59:9, s. 1347-57
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Tidskriftsartikel (refereegranskat)abstract
- Some of the principles and main methods of chemometrics are illustrated by examples. The examples are from electrochemistry, process analytical chemistry and multivariate imaging. Principal component analysis, partial least squares regression and multivariate image analysis are used to illustrate the power of chemometrical thinking. The emphasis is on plotting and visualization for showing the salient features of a model or data set.
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| 10. |
- Hedayati, Ali, 1984-, et al.
(författare)
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Fate of phosphorus and potassium in single-pellet thermal conversion of forest residues with a focus on the char composition
- 2021
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 150
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Tidskriftsartikel (refereegranskat)abstract
- The phosphorus and potassium contents of the char obtained from thermal conversion of forest residues can limit its utilization as an alternative fuel and reducing agent to substitute coal/coke in the steelmaking industry. In this study, ash transformation and release of K and P during single-pellet thermal conversion of different types of forest residues (i.e., bark, twigs, and bark+twigs) were investigated with the aid of a vertical tube furnace (Macro-TGA) at different temperatures (i.e., 600, 800, and 950 °C) and within and after different fuel conversion stages, i.e., devolatilization and char gasification. The residual char before and after full devolatilization, and ash after char gasification were characterized by SEM-EDS, XRD, and ICP-OES with the support of thermochemical equilibrium calculations. The concentrations of K (7970–19500 mg/kg) and P (1440–4925 mg/kg) in the char produced after devolatilization were more than four times higher than in coke and pulverized coal frequently used in metallurgical processes. A low amount of P and K (≤15%) were released from all fuels. K and P were evenly distributed within the char residues, and no crystalline compounds containing K and P were found. In ash residues of bark, K was found in K2Ca2(CO3)3, and K2Ca(CO3)2. K in ash residues from twigs and bark+twigs was mainly found in the amorphous part of ash, most likely in the form of K-Ca rich silicates. Apatite was found as the main P crystalline compound in all ashes at all temperatures. Estimations show that a release of more than 80% is needed for the studied forest residual assortments to reach K and P concentrations typical of blast furnace coals and cokes.
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