| 1. |
- Olsson, Maria, 1976, et al.
(author)
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Oxidative pyrolysis of integral softwood pellets
- 2003
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In: The Journal of Analytical and Applied Pyrolysis. ; 67:1, s. 135-141
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Journal article (peer-reviewed)abstract
- Commercial wood pellets are increasingly used for residential heating. Characterisations were made of smoke components from oxidative pyrolysis of softwood pellets from compressed sawdust and wood shavings. Specific compounds released by flaming and glowing laboratory burning were sampled on Tenax cartridges and assessed by gas chromatography and mass spectrometry. Six lignin-related 2-methoxyphenols with antioxidant properties, together with 1,6-anhydroglucose from cellulose, were the major primary semi-volatile compounds released during flaming burning. Glowing combustion released benzene as the predominant aromatic compound.
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| 2. |
- Olsson, Maria, 1976, et al.
(author)
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Specific chimney emissions and biofuel characteristics of softwood pellets for residential heating in Sweden
- 2003
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In: Biomass and Bioenergy. ; 24:1, s. 51-57
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Journal article (peer-reviewed)abstract
- Softwood pellets are mainly produced from sawdust and to some extent from wood shavings. The moisture content is typically less than half of that in firewood. The present annual residential use in Sweden for pellet burners in boilers and for pellet stoves amounts to more than 100 000 tonnes and is increasing rapidly. The total annual production capacity at the more than 20 units exceeds one million tonnes, and permits continued rapid replacement of firewood and petroleum oil for residential heating.With the purpose of characterising emissions to air, chimney smoke was sampled, and specific compounds were assessed by gas chromatography and mass spectrometry. Benzene was the predominant aromatic compound in emissions from pellet burners. The smoke from stoves contained methoxyphenols with antioxidant properties and lower proportions of aromatic hydrocarbons. Observed differences in emissions from specific burning appliances are of interest with regard to both health hazards and regulation of emissions.Consideration of ecological aspects and pollution hazards indicates that wood pellets should be used primarily for residential heating, whereas controlled large-scale combustion is preferable for most other types of biomass waste.
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| 3. |
- Kjällstrand, Jennica, 1974, et al.
(author)
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Phenolic antioxidants in alder smoke during industrial meat curing
- 2001
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In: Food Chemistry. ; 74, s. 85-89
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Journal article (peer-reviewed)abstract
- Alder wood smoke in a large sausage-curing chamber was analysed with regard to its content of methoxyphenol antioxidants. The use of Tenax adsorbent cartridges permitted simultaneous quantitative sampling of phenols condensed on smoke particles as well as gaseous compounds. The analytical determinations were performed by thermal desorption combined with gas chromatography and mass spectrometry. In addition to methoxyphenols, several other key components were assessed, including 1,6-anhydroglucose, 2-furaldehyde, furans and hydrocarbons. Benzene was the most prominent hydrocarbon. The concentrations of polycyclic aromatic compounds were low, due to a low smoke generation temperature. Predominant smoke components were the 2,6-dimethoxyphenols, which are characteristic thermal degradation products from hardwood. The 2,6-dimethoxyphenols are stronger antioxidants than the 2-methoxyphenols present in lower amounts. The particularly active antioxidants with a 4-alkenyl side-chain constituted 20-30% of total methoxyphenols, which is much more than normally reported for liquid smoke. The phenolic antioxidants may be important not only for the preservation of foods, but also for health as dietary components.
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| 4. |
- Kjällstrand, Jennica, 1974, et al.
(author)
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Phenolic antioxidants in wood smoke
- 2001
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In: The science of the total environment. ; 277, s. 69-75
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Journal article (peer-reviewed)abstract
- Ten prominent dimethoxyphenols were determined in birchwood smoke from choked and open laboratory burning and in chimney smoke from a tiled stove. The structures of the methoxyphenols are similar to those of the well-known tocopherol and ubiquinol antioxidants. The 2,6-dimethoxyphenols characterising hardwood smoke are stronger antioxidants than the corresponding 2-methoxyphenols present mainly in softwood smoke. The antioxidant activity is highest for the 2,6-dimethoxyphenols with 4-alkenyl and 4-alkyl groups, which constitute 60-70% of the total amount of dimethoxyphenols. Phenolic antioxidants are scavengers of oxygen radicals and should be considered when health hazards of small-scale incomplete biomass burning are estimated.
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| 5. |
- Kjällstrand, Jennica, 1974, et al.
(author)
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Phenols and aromatic hydrocarbons in chimney emissions from traditional and modern residential wood burning
- 2001
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In: Environmental Technology. ; 22, s. 391-395
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Journal article (peer-reviewed)abstract
- The emissions from a traditional tiled stove consisted mainly of lignin-related methoxyphenols with antioxidant properties, and 1,6-anhydroglucose from cellulose degradation. A wood stove of presently introduced energy-efficient design for residential heating and hot-water supply was shown to emit small amounts of methoxyphenols and anhydrosugars from primary wood pyrolysis. Secondary harmful components like benzene and polycyclic aromatic hydrocarbons constituted a major portion of the organic emissions. It is concluded that differences in smoke composition are essential to consider in recommendations and rules for proper choices of wood burning devices.
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| 6. |
- Kjällstrand, Jennica, 1974, et al.
(author)
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Coniferyl alcohol from newsprint burning
- 2000
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In: Nordic pulp and paper journal. ; 15, s. 98-100
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Journal article (peer-reviewed)abstract
- Coniferyl alcohol constitutes almost half of the amount of methoxyphenols in smoke from choked burning of newsprint produced from thermomechanical pulp. The results indicate that coniferyl alcohol is a key component not only in biosynthesis but also in thermal decomposition of lignin. The trans isomer was formed in 5-10 times larger amounts than the cis isomer. Coniferyl alcohol and the oxidised analogue coniferaldehyde were also shown to be the most prominent methoxyphenols in chimney smoke from stove burning of newsprint.
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| 7. |
- Kjällstrand, Jennica, 1974, et al.
(author)
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Methoxyphenols from burning of Scandinavian forest plant materials
- 2000
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In: Chemosphere. ; 41, s. 735-741
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Journal article (peer-reviewed)abstract
- Semivolatile compounds in smoke from gram-scale incomplete burning of plant materials were assessed by gas chromatography and mass spectrometry. Gas syringe sampling was shown to be adequate by comparison with adsorbent sampling. Methoxyphenols as well as 1,6-anhydroglucose were released in amounts as large as 10 mg kg(-1) of dry biomass at 90% combustion efficiency. Wood, twigs, bark and needles from the conifers Norway spruce and Scots pine emitted 12 reported 2-methoxyphenols in similar proportions. Grass, heather and birchwood released the same 2-methoxyphenols but also the corresponding 2,6-dimethoxyphenols which are characteristic of angiosperms. The methoxyphenols are formed from lignin and differ in structure by the group in para position relative to the phenolic OH group. Prominent phenols were those with trans-1-propenyl and ethenyl groups in that position. Vanillin, 4-hydroxy-3-methoxybenzaldehyde, was a prominent carbonyl compound from the conifer materials.
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| 8. |
- Kjällstrand, Jennica, 1974, et al.
(author)
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Gas chromatographic and mass spectrometric analyses of 36 lignin-related methoxyphenols from uncontrolled combustion of wood
- 1998
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In: Journal of Chromatography A. ; 824, s. 205-210
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Journal article (peer-reviewed)abstract
- Eighteen 4-hydroxy-3-methoxyphenyl (guaiacyl) compounds in wood smoke from spruce, and 18 4-hydroxy-3,5-dimethoxyphenyl (syringyl) analogues in birchwood smoke were analysed. Smoke samples were taken by a gas syringe from wood burning under varying but more or less choked conditions in laboratory pot experiments. Retention index data for a methylsilicone column and basic mass spectral data are given for all compounds. Retention index in combination with molecular mass and structure-specific fragment ions greatly facilitates qualitative analysis. The syringyl and guaiacyl analogues differ by 240 units in retention index and the matching structure-specific ions in their mass spectra by 30 mass units. The identified methoxyphenols differ in the structure of the sidechain, which may be lacking, an alkyl group, an alkenyl group, a carbonyl-containing group or an alcoholic moiety. The proportions between these groups of compounds varied strongly with combustion conditions whereas the proportions of phenols within them were quite specific for each group. The phenols with reactive olefinic linkages in the sidechain were present in larger proportions than reported in other studies of methoxyphenols.
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