Documents disponibles écrits par cet auteur

Evolution of char structure during the steam gasification of biochars produced from the pyrolysis of various mallee biomass components / Hongwei Wu in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10431–10438 Titre : Evolution of char structure during the steam gasification of biochars produced from the pyrolysis of various mallee biomass components Type de document : texte imprimé Auteurs : Hongwei Wu, Auteur ; Kongvui Yip, Auteur ; Fujun Tian, Auteur Année de publication : 2010 Article en page(s) : pp. 10431–10438 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Evolution--Structure--during--Steam--Gasification--Biochars--Produced--Pyrolysis--Various--Mallee--Biomass--Components Résumé : This study reports the evolution of char structure during the steam gasification of biochars under chemical-reaction-controlled conditions. Partially gasified samples were collected at various conversion levels during the steam gasification of both the raw biochars and the acid-treated biochars that had been prepared via acid-washing of the raw biochars. Results from FT-Raman spectroscopy show that the biochars have highly heterogeneous and disordered structures, which are selectively consumed with progress of steam gasification, leading to enrichment of larger aromatic ring systems, hence the so-called “selective gasification”. Selective gasification of biochar can be significantly influenced by the inherent alkali and alkaline earth metallic (AAEM) species in the biochars. The abundant catalysts present in the raw biochars can alter the gasification reaction pathway, but such an alteration appears to have little effect on the evolution of pore surface area, which increases significantly with conversion. While the wood biochar has too low a content of AAEM species to have an apparent effect on selective gasification, for the raw leaf and bark biochars with high contents of AAEM species, selective gasification is considerably less significant in comparison with the respective acid-treated biochars. For acid-treated biochars, gasification seems to take place slowly throughout the biochar on carbon active sites to consume the smaller rings selectively; the reactivity is controlled by the biochar carbon structure. However, for the raw leaf and bark biochars, gasification would be more focused or localized on the catalytic sites so that the activity of carbon active sites becomes less important. The catalytic effect of the inherent AAEM species seems to in turn depend on the carbon structure that probably affects the catalyst dispersion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901025d [article] Evolution of char structure during the steam gasification of biochars produced from the pyrolysis of various mallee biomass components [texte imprimé] / Hongwei Wu, Auteur ; Kongvui Yip, Auteur ; Fujun Tian, Auteur . - 2010 . - pp. 10431–10438. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10431–10438 Mots-clés : Evolution--Structure--during--Steam--Gasification--Biochars--Produced--Pyrolysis--Various--Mallee--Biomass--Components Résumé : This study reports the evolution of char structure during the steam gasification of biochars under chemical-reaction-controlled conditions. Partially gasified samples were collected at various conversion levels during the steam gasification of both the raw biochars and the acid-treated biochars that had been prepared via acid-washing of the raw biochars. Results from FT-Raman spectroscopy show that the biochars have highly heterogeneous and disordered structures, which are selectively consumed with progress of steam gasification, leading to enrichment of larger aromatic ring systems, hence the so-called “selective gasification”. Selective gasification of biochar can be significantly influenced by the inherent alkali and alkaline earth metallic (AAEM) species in the biochars. The abundant catalysts present in the raw biochars can alter the gasification reaction pathway, but such an alteration appears to have little effect on the evolution of pore surface area, which increases significantly with conversion. While the wood biochar has too low a content of AAEM species to have an apparent effect on selective gasification, for the raw leaf and bark biochars with high contents of AAEM species, selective gasification is considerably less significant in comparison with the respective acid-treated biochars. For acid-treated biochars, gasification seems to take place slowly throughout the biochar on carbon active sites to consume the smaller rings selectively; the reactivity is controlled by the biochar carbon structure. However, for the raw leaf and bark biochars, gasification would be more focused or localized on the catalytic sites so that the activity of carbon active sites becomes less important. The catalytic effect of the inherent AAEM species seems to in turn depend on the carbon structure that probably affects the catalyst dispersion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901025d

Removal and recycling of inherent inorganic nutrient species in mallee biomass and derived biochars by water leaching / Hongwei Wu in Industrial & engineering chemistry research, Vol. 50 N° 21 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12143-12151 Titre : Removal and recycling of inherent inorganic nutrient species in mallee biomass and derived biochars by water leaching Type de document : texte imprimé Auteurs : Hongwei Wu, Auteur ; Kongvui Yip, Auteur ; Zhaoying Kong, Auteur Année de publication : 2011 Article en page(s) : pp. 12143-12151 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Lixiviation  Biomass  Recycling Résumé : Biomass growth extracts inorganic nutrients from soil as inherent nutrient species in the biomass. Unless at least some of these inherent inorganic nutrients are eventually recycled to the soil, biomass utilization during its full life cycle may not be sustainable. This study reports the removal and recycling of inherent inorganic species in mallee biomass and its derived biochars by water leaching. A series of biochars were produced from the pyrolysis of various mallee components including wood, leaf, and bark under various conditions. An increasing pyrolysis temperature leads to increases in biochar C content and aromaticity and decreases in biochar H and O contents as well as oxygen functional groups. Most of the alkali and alkaline earth metallic species (Na, K, Mg, and Ca) and P are retained in the biochars, while substantial amounts of S, N, and Cl are released during pyrolysis. For biomass samples, almost all of K, Na, and Cl and large proportions of S, P, and Mg can be recycled by water leaching, but limited Ca and little N can be recycled. However, nutrients recycling via water leaching of biochars results in substantial reductions in the overall recycling of most nutrient species orignally present in biomass, due to either substantial release of nutrients (Cl, S, and N) during pyrolysis or the forms of nutrient species (Na, K, Mg, P) in biochars becoming increasingly water insoluble. The results also suggest that heat treatment may be employed to tune the biochars to facilitate the recycling of Ca which is the dominant inherent inorganic nutrient species of the samples investigated. It is noted that water leaching can also remove small amounts of organic matter, generally <2% (quantified as total organic carbon) of the total carbon in these biochars. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697531 [article] Removal and recycling of inherent inorganic nutrient species in mallee biomass and derived biochars by water leaching [texte imprimé] / Hongwei Wu, Auteur ; Kongvui Yip, Auteur ; Zhaoying Kong, Auteur . - 2011 . - pp. 12143-12151. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12143-12151 Mots-clés : Lixiviation  Biomass  Recycling Résumé : Biomass growth extracts inorganic nutrients from soil as inherent nutrient species in the biomass. Unless at least some of these inherent inorganic nutrients are eventually recycled to the soil, biomass utilization during its full life cycle may not be sustainable. This study reports the removal and recycling of inherent inorganic species in mallee biomass and its derived biochars by water leaching. A series of biochars were produced from the pyrolysis of various mallee components including wood, leaf, and bark under various conditions. An increasing pyrolysis temperature leads to increases in biochar C content and aromaticity and decreases in biochar H and O contents as well as oxygen functional groups. Most of the alkali and alkaline earth metallic species (Na, K, Mg, and Ca) and P are retained in the biochars, while substantial amounts of S, N, and Cl are released during pyrolysis. For biomass samples, almost all of K, Na, and Cl and large proportions of S, P, and Mg can be recycled by water leaching, but limited Ca and little N can be recycled. However, nutrients recycling via water leaching of biochars results in substantial reductions in the overall recycling of most nutrient species orignally present in biomass, due to either substantial release of nutrients (Cl, S, and N) during pyrolysis or the forms of nutrient species (Na, K, Mg, P) in biochars becoming increasingly water insoluble. The results also suggest that heat treatment may be employed to tune the biochars to facilitate the recycling of Ca which is the dominant inherent inorganic nutrient species of the samples investigated. It is noted that water leaching can also remove small amounts of organic matter, generally <2% (quantified as total organic carbon) of the total carbon in these biochars. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697531