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Carmen Branca - One of the best experts on this subject based on the ideXlab platform.
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experimental analysis of reaction heat effects during beech Wood Pyrolysis
Energy & Fuels, 2013Co-Authors: C Di Blasi, Carmen Branca, F Masotta, E De BiaseAbstract:The pyrolytic behavior of a cylindrical packed bed of beech Wood pellets, uniformly heated along the lateral surface, is studied. As the heating conditions are varied, the trends shown by the mass loss rate and the yields of the lumped product classes are in agreement with previous literature. Moreover, detailed measurements of the thermal field permit, for the first time, the observation at the central core of the bed, of sequential (a) exothermic, (b) endothermic, and (c) exothermic effects. The examination of the corresponding temperature ranges indicates that they are linked, in the order, to the (primary and secondary) degradation of (a) hemicellulose, (b) cellulose and lignin, and (c) lignin. The dependence on the heating conditions is also explained of the center temperature overshoot (with respect to the steady value) which attains maximum values around 90 K.
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influences of the chemical state of alkaline compounds and the nature of alkali metal on Wood Pyrolysis
Industrial & Engineering Chemistry Research, 2009Co-Authors: Colomba Di Blasi, A Galgano, Carmen BrancaAbstract:Motivated by the production of compounds of good industrial value, Pyrolysis of fir Wood catalyzed by alkaline compounds (NaOH, KOH, Na2CO3, K2CO3, KC2H3O2, and NaCl) has been investigated. Catalysts have been impregnated in Wood (preliminarily extracted with water) by means of aqueous solutions resulting in concentrations of the K or Na ion in Wood of about 0.37−0.41%. Pyrolysis experiments have been done with a fixed-bed reactor preheated at 800 K.The decomposition process is anticipated at lower temperatures with conversion times from 2.5 (NaOH) to 1.7 (NaCl) times shorter. Formation of char, carbon dioxide, and water is favored with total yields between 70 and 61% versus 48% of extracted Wood (dry sample mass basis). The yields of carbon monoxide are increased approximately from 4% to 6% while the yields of organic compounds are lowered to 19−29% (versus 43%) with the disappearance of sugar compounds and a strong diminution in other typical products of uncatalyzed Wood Pyrolysis but hydroxypropanone. ...
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effects of potassium hydroxide impregnation on Wood Pyrolysis
Energy & Fuels, 2009Co-Authors: Colomba Di Blasi, A Galgano, Carmen BrancaAbstract:The Pyrolysis of a packed bed of fir Wood particles, after impregnation with KOH, is investigated. For a heating temperature of 800 K, maximum variations in the Pyrolysis characteristics are observed for KOH concentrations in Wood below 1%. Decomposition temperatures become lower (35−70 K), and conversion times are rapidly more than halved. Also, the char, water, and gas yields increase (factors of 1.4, 1.6, and 1.7, respectively) at the expense of liquid-phase organic products. Levoglucosan presents a very steep decay, whereas the diminution in hydroxyacetaldehyde and acid acetic is much slower, and a wide zone of approximately constant values appears for hydroxypropanone. However, small quantities of KOH in Wood (about 0.2−0.6%) are apt to increase the yields of furfuryl alcohol up to a factor 15 and some carbohydrates (3-ethyl-2-hydroxy-2-cyclopentenone, 3-methyl-2-cyclopentenone, 1-hydroxy-2-butanone) and phenols (phenol, cresols, hydroquinone, guaiacol, isoeugenol-trans, isoeugenol-cis, 4-acetonguaia...
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products and global weight loss rates of Wood decomposition catalyzed by zinc chloride
Energy & Fuels, 2008Co-Authors: Colomba Di Blasi, Carmen Branca, A GalganoAbstract:Motivated by the production of fine chemicals and the improvement of flame retardance properties, experiments have been performed with a fixed-bed reactor to investigate the catalytic action exerted by zinc chloride on fir Wood Pyrolysis (catalyst concentrations between 0 and 16% on a dry Wood basis and heating temperatures between 650 and 900 K). It has been observed that this Lewis acid acts as a dehydrating and cross-linking agent promoting the formation of char and water with total yields up to about 73%. As a consequence, the majority of organic condensable products generated from uncatalyzed Pyrolysis of Wood (hydroxyacetaldehyde, hydroxypropanone, levoglucosan, and other minor carbohydrates, phenols, and guaiacols) is rapidly reduced to low values. However, zinc chloride is a particularly effective catalyst (concentrations of 1–6% and temperatures of 700–800 K) to maximize the yields of levoglucosenone, acetylfuran, 5-methyl-2-furaldehyde, and, especially, 2-furaldehyde which is augmented by a fact...
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devolatilization and heterogeneous combustion of Wood fast Pyrolysis oils
Industrial & Engineering Chemistry Research, 2005Co-Authors: Carmen Branca, Colomba Di Blasi, Rosario ElefanteAbstract:Weight loss curves of Wood fast Pyrolysis oils in air have been measured, under controlled thermal conditions, carrying out two separate sets of experiments. The first, which has a final temperature of 600 K, concerns evaporation/cracking of the oil and secondary char formation, processes associated with sample swelling and solidification. After collection and milling, in the second set of experiments, heterogeneous combustion of the secondary char is carried out to temperatures of 873 K. Although the details of the rate curves appear to be dependent on the commercial process (BTG, Dynamotive, Ensyn, Pyrovac) applied to produce the oil, the same qualitative features are observed in all cases. Secondary char formation and sample modification begin for temperatures of about 460−490 K. Moreover, a conceptual reaction mechanism, consisting of six main zones, can always explain the low-temperature (≤600 K) devolatilization characteristics. Similar to primary char produced from Wood Pyrolysis, secondary char ex...
Colomba Di Blasi - One of the best experts on this subject based on the ideXlab platform.
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influences of the chemical state of alkaline compounds and the nature of alkali metal on Wood Pyrolysis
Industrial & Engineering Chemistry Research, 2009Co-Authors: Colomba Di Blasi, A Galgano, Carmen BrancaAbstract:Motivated by the production of compounds of good industrial value, Pyrolysis of fir Wood catalyzed by alkaline compounds (NaOH, KOH, Na2CO3, K2CO3, KC2H3O2, and NaCl) has been investigated. Catalysts have been impregnated in Wood (preliminarily extracted with water) by means of aqueous solutions resulting in concentrations of the K or Na ion in Wood of about 0.37−0.41%. Pyrolysis experiments have been done with a fixed-bed reactor preheated at 800 K.The decomposition process is anticipated at lower temperatures with conversion times from 2.5 (NaOH) to 1.7 (NaCl) times shorter. Formation of char, carbon dioxide, and water is favored with total yields between 70 and 61% versus 48% of extracted Wood (dry sample mass basis). The yields of carbon monoxide are increased approximately from 4% to 6% while the yields of organic compounds are lowered to 19−29% (versus 43%) with the disappearance of sugar compounds and a strong diminution in other typical products of uncatalyzed Wood Pyrolysis but hydroxypropanone. ...
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effects of potassium hydroxide impregnation on Wood Pyrolysis
Energy & Fuels, 2009Co-Authors: Colomba Di Blasi, A Galgano, Carmen BrancaAbstract:The Pyrolysis of a packed bed of fir Wood particles, after impregnation with KOH, is investigated. For a heating temperature of 800 K, maximum variations in the Pyrolysis characteristics are observed for KOH concentrations in Wood below 1%. Decomposition temperatures become lower (35−70 K), and conversion times are rapidly more than halved. Also, the char, water, and gas yields increase (factors of 1.4, 1.6, and 1.7, respectively) at the expense of liquid-phase organic products. Levoglucosan presents a very steep decay, whereas the diminution in hydroxyacetaldehyde and acid acetic is much slower, and a wide zone of approximately constant values appears for hydroxypropanone. However, small quantities of KOH in Wood (about 0.2−0.6%) are apt to increase the yields of furfuryl alcohol up to a factor 15 and some carbohydrates (3-ethyl-2-hydroxy-2-cyclopentenone, 3-methyl-2-cyclopentenone, 1-hydroxy-2-butanone) and phenols (phenol, cresols, hydroquinone, guaiacol, isoeugenol-trans, isoeugenol-cis, 4-acetonguaia...
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products and global weight loss rates of Wood decomposition catalyzed by zinc chloride
Energy & Fuels, 2008Co-Authors: Colomba Di Blasi, Carmen Branca, A GalganoAbstract:Motivated by the production of fine chemicals and the improvement of flame retardance properties, experiments have been performed with a fixed-bed reactor to investigate the catalytic action exerted by zinc chloride on fir Wood Pyrolysis (catalyst concentrations between 0 and 16% on a dry Wood basis and heating temperatures between 650 and 900 K). It has been observed that this Lewis acid acts as a dehydrating and cross-linking agent promoting the formation of char and water with total yields up to about 73%. As a consequence, the majority of organic condensable products generated from uncatalyzed Pyrolysis of Wood (hydroxyacetaldehyde, hydroxypropanone, levoglucosan, and other minor carbohydrates, phenols, and guaiacols) is rapidly reduced to low values. However, zinc chloride is a particularly effective catalyst (concentrations of 1–6% and temperatures of 700–800 K) to maximize the yields of levoglucosenone, acetylfuran, 5-methyl-2-furaldehyde, and, especially, 2-furaldehyde which is augmented by a fact...
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devolatilization and heterogeneous combustion of Wood fast Pyrolysis oils
Industrial & Engineering Chemistry Research, 2005Co-Authors: Carmen Branca, Colomba Di Blasi, Rosario ElefanteAbstract:Weight loss curves of Wood fast Pyrolysis oils in air have been measured, under controlled thermal conditions, carrying out two separate sets of experiments. The first, which has a final temperature of 600 K, concerns evaporation/cracking of the oil and secondary char formation, processes associated with sample swelling and solidification. After collection and milling, in the second set of experiments, heterogeneous combustion of the secondary char is carried out to temperatures of 873 K. Although the details of the rate curves appear to be dependent on the commercial process (BTG, Dynamotive, Ensyn, Pyrovac) applied to produce the oil, the same qualitative features are observed in all cases. Secondary char formation and sample modification begin for temperatures of about 460−490 K. Moreover, a conceptual reaction mechanism, consisting of six main zones, can always explain the low-temperature (≤600 K) devolatilization characteristics. Similar to primary char produced from Wood Pyrolysis, secondary char ex...
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devolatilization in the temperature range 300 600 k of liquids derived from Wood Pyrolysis and gasification
Fuel, 2005Co-Authors: Carmen Branca, Colomba Di Blasi, Carmine RussoAbstract:Abstract A thermogravimetric system, previously developed for solid fuel degradation, has been modified to examine liquids obtained from conventional Pyrolysis and updraft gasification of beech Wood. Thermogravimetric curves in air show two main reaction stages. The first (temperatures ≤600 K) concerns evaporation, formation and release of gases and formation of secondary char (coke). Then, at higher temperatures, heterogeneous combustion of secondary char takes place. A reliable procedure has been developed to carry out the first stage under assigned temperature using a PID controller and the applied heat flux as the manipulated variable. It has been found that the Pyrolysis temperature does not affect significantly weight loss dynamics and amount of secondary char (approximately equal to 20% of the liquid on a dry basis). The thermogravimetric curves are well predicted by a global mechanism consisting of three parallel first-order reactions (activation energies of 66, 32 and 36 kJ/mol, respectively). Due to strong physico-chemical transformations (sample swelling and solidification) associated with secondary char formation, it is not possible to avoid ignition during heterogeneous combustion. Therefore, this reaction stage should be investigated separately after collection and adequate re-preparation of the charred sample.
J Ramirezrico - One of the best experts on this subject based on the ideXlab platform.
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permeability and mechanical integrity of porous biomorphic sic ceramics for application as hot gas filters
Materials & Design, 2016Co-Authors: A Gomezmartin, M P Orihuela, J A Becerra, J Martinezfernandez, J RamirezricoAbstract:Abstract Biomorphic SiC is a biotemplated material fabricated by Si melt-infiltration of carbon preforms from Wood Pyrolysis. In this work, porous bioSiC ceramics from five different Wood precursors, with porosities between 45 and 72% were studied for their feasibility in filtering applications. Gas permeability and mechanical stability were investigated as a function of the microstructure of the starting Wood precursor. Air-permeation performance at room temperature was measured for a range of flow rates, and the permeability constants were assessed by fitting of Forchheimer's equation to the experimental data. Darcian permeabilities were achieved in the range 10− 11–10− 12 m2, while inertial terms were in the range 10− 7–10− 8 m, showing a correlation with the average pore size and orientation of the larger channels. Regarding the mechanical stability, maximum compressive strength values were reached in the range of 3–115 MPa. These results improve our understanding of the ways in which the microstructure influences permeability and mechanical robustness, enabling the device requirements to be tailored by selecting the Wood precursor. It was also shown that these materials are promising for hot-gas filtering applications.
Shiro Saka - One of the best experts on this subject based on the ideXlab platform.
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role of methoxyl group in char formation from lignin related compounds
Journal of Analytical and Applied Pyrolysis, 2009Co-Authors: Takashi Hosoya, Haruo Kawamoto, Shiro SakaAbstract:Abstract Although char formation from lignin is an important process in Wood Pyrolysis, the molecular mechanism has not been clarified yet. In this study, the vapor-phase char formation of various lignin-related compounds was studied under the Pyrolysis conditions of N 2 /600 °C/80 s. The methoxyl groups were found necessary for char formation. Interestingly, ethoxyl group was not effective in such char formation. Guaiacol and 2-ethoxyphenol gave pyrocatechol (formed through thermal homolysis of the O–R bonds) and the ether-rearranged products ( o -cresol, 2-ethylphenol, xanthenes and 2,3-benzofuran). The latter products are likely formed via an o -quinone methide intermediate, initiated from the H-abstraction of the phenolic hydroxyl groups. 2-Ethoxyphenol gave larger amounts of 2,3-benzofuran and less xanthenes and char than guaiacol, with yields of other products similar. Such reactivity difference is explainable with the different reactivities of the o -quinone methide intermediates. Based on the results, o -quinone methide is proposed as an important intermediate for lignin char formation during Pyrolysis.
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Influence of inorganic matter on Wood Pyrolysis at gasification temperature
Journal of Wood Science, 2007Co-Authors: Takashi Hosoya, Haruo Kawamoto, Shiro SakaAbstract:The influence of inorganic matter on the Pyrolysis of Japanese cedar (Cryptomeria japonica) Wood was studied at a gasification temperature of 800°C with demineralization through acid washing. Some influences on the formation of char, tar, and low molecular weight products coincided with results reported at temperatures lower than the gasification temperature. However, the carbonization behavior of the volatile products and the yield of polysaccharide fraction were not able to be explained as a sum of the Pyrolysis of cellulose, hemicellulose, and lignin even after demineralization. These results suggest some interactions between Wood constituent polymers other than the influence of inorganic matter.
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cellulose hemicellulose and cellulose lignin interactions in Wood Pyrolysis at gasification temperature
Journal of Analytical and Applied Pyrolysis, 2007Co-Authors: Takashi Hosoya, Haruo Kawamoto, Shiro SakaAbstract:Abstract Cellulose–hemicellulose and cellulose–lignin interactions during Pyrolysis at gasification temperature (800 °C) were investigated with various cellulose samples mixed with hemicellulose (glucomannan or xylan) or milled Wood lignin. Significant interactions were observed in cellulose–lignin Pyrolysis; lignin inhibited the thermal polymerization of levoglucosan formed from cellulose and enhanced the formation of the low molecular weight products from cellulose with reduced yield of char fraction; cellulose reduced the secondary char formation from lignin and enhanced the formation of some lignin-derived products including guaiacol, 4-methyl-guaiacol and 4-vinyl-guaiacol. Comparatively weak interactions were also observed in cellulose–hemicellulose Pyrolysis. Finally, factors influencing the Wood Pyrolysis at gasification temperature are discussed.
Anja Oasmaa - One of the best experts on this subject based on the ideXlab platform.
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Fast Pyrolysis of Forestry Residue. 2. Physicochemical Composition of Product Liquid
Energy & Fuels, 2003Co-Authors: Anja Oasmaa, Eeva Kuoppala, Yrjo SolantaustaAbstract:In this second article on fuel oil, use of forestry residue Pyrolysis liquids, their physicochemical properties, and the behavior of these liquids are described. Understanding of the chemical composition of forestry residue liquids enables the selection of correct handling and storage conditions. Forestry residue is one of the most viable biomass feedstocks for liquid production in Northern softWood forest zone. A 10−25 wt % top phase with a high heating value is produced from forestry residue due to the high content of extractives and low water content. However, it has high solid and ash contents. The main product, bottom phase, is similar to bark-free Wood Pyrolysis liquid: volatile acids 8−10 wt %; aldehydes and ketones 10−15 wt %; water 25−30 wt %; “sugar constituents” 30−35 wt %; water-insoluble, mainly lignin-based constituents 15−20 wt %; and extractives (2−6 wt %). Its physical properties (water 28 wt %, pH 3.0, viscosity at 40 °C 15 cSt, LHV 14 MJ/kg, solids < 0.05 wt %), making it suitable for ...
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Wood-Pyrolysis oil as fuel in a diesel-power plant
Bioresource Technology, 1993Co-Authors: Yrjo Solantausta, Mårten Westerholm, Tiina Koljonen, Nils Olof Nylund, Anja OasmaaAbstract:Flash-Pyrolysis oil is projected as the most competitive liquid fuel from biomass. The use of Pyrolysis oil as a diesel-power-plant fuel is studied. Pyrolysis-oil fuel characteristics are analysed, the oil is employed as fuel in a test diesel engine, and the economics of the system are analysed. The diesel-power-plant concept has several advantages, especially in small-scale production. The concept has several technical uncertainties, which are addressed in a research project. © 1993.
