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Char formation mechanism in supercritical water gasification process / Athika Chuntanapum in Industrial & engineering chemistry research, Vol. 49 N° 9 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4055-4062 Titre : Char formation mechanism in supercritical water gasification process : a study of model compounds Type de document : texte imprimé Auteurs : Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur Année de publication : 2010 Article en page(s) : pp. 4055-4062 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling  Gasification  Supercritical  state  Formation  mechanism Résumé : Char is one of the undesirable products in the supercritical water gasification of biomass, causing a reduction in carbon gasification efficiency. 5-HMF (5-hydroxymethylfurfural) is believed to be an intermediate in the char formation pathway. In this Article, the rate of formation of char particles obtained from experiments using glucose (a biomass model compound) was compared to that from experiments using 5-HMF (Chuntanapum and Matsumura, 2009). The glucose experiments were conducted in a temperature range of 300—400 °C, at 25 MPa, and for a residence time up to 70 s. The initial concentration of glucose was varied from 1.5 to 3 wt % (i.e., 0.083 to 0.167 M). Glucose was found to produce char particles 2 orders of magnitude faster than 5-HMF feedstock. The copresence of the other glucose decomposition products is thought to cause the difference in the char formation mechanism (i.e., the side reaction between 5-HMF and the other decomposition products) from that of 5-HMF alone. FT-IR and Raman spectroscopy of the solid products was carried out. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732894 [article] Char formation mechanism in supercritical water gasification process : a study of model compounds [texte imprimé] / Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur . - 2010 . - pp. 4055-4062. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4055-4062 Mots-clés : Modeling  Gasification  Supercritical  state  Formation  mechanism Résumé : Char is one of the undesirable products in the supercritical water gasification of biomass, causing a reduction in carbon gasification efficiency. 5-HMF (5-hydroxymethylfurfural) is believed to be an intermediate in the char formation pathway. In this Article, the rate of formation of char particles obtained from experiments using glucose (a biomass model compound) was compared to that from experiments using 5-HMF (Chuntanapum and Matsumura, 2009). The glucose experiments were conducted in a temperature range of 300—400 °C, at 25 MPa, and for a residence time up to 70 s. The initial concentration of glucose was varied from 1.5 to 3 wt % (i.e., 0.083 to 0.167 M). Glucose was found to produce char particles 2 orders of magnitude faster than 5-HMF feedstock. The copresence of the other glucose decomposition products is thought to cause the difference in the char formation mechanism (i.e., the side reaction between 5-HMF and the other decomposition products) from that of 5-HMF alone. FT-IR and Raman spectroscopy of the solid products was carried out. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732894

Formation of tarry material from 5-HMF in subcritical and supercritical water / Athika Chuntanapum in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9837–9846 Titre : Formation of tarry material from 5-HMF in subcritical and supercritical water Type de document : texte imprimé Auteurs : Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur Année de publication : 2010 Article en page(s) : pp. 9837–9846 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Compound  5-hydroxymethylfurfural  Biomass  Tarry  material Résumé : The compound 5-hydroxymethylfurfural (5-HMF) is thought to be an intermediate for the formation of tarry material in the supercritical water gasification (SCWG) of biomass. To gain insight on the formation mechanism of tarry material, we examined 5-HMF under both subcritical and supercritical conditions. The experiments of this study were conducted in a continuous reactor designed for an instant heating of 5-HMF solution to the reaction temperature. The reaction temperatures were set at 350 and 450 °C, and the pressure was set at 25 MPa. The initial concentration of 5-HMF and the residence time were adjusted in the range of 0.02−0.15 M (at room temperature) and 80−3000 s, respectively. The formation of char particles was only observed under the subcritical conditions. Char yield increased as the initial concentration of 5-HMF rose, with a reaction order of 4.29, with respect to 5-HMF concentration. The liquid products obtained from the 5-HMF decomposition also contributed to the polymerization to form char, with a reaction order of 1.21, based on their concentration. The sensitivity analysis indicated the high sensitivity of reaction orders on the char yield. The liquid products were identified by liquid chromatography/mass spectroscopy (LC/MS) and high-performance liquid chromatography (HPLC). The char particles were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectrometry. The char characterization results implied that the char particles formed had a polyaromatic structure. Based on our experimental findings, we proposed a mechanism of char particle formation from 5-HMF. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900423g [article] Formation of tarry material from 5-HMF in subcritical and supercritical water [texte imprimé] / Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur . - 2010 . - pp. 9837–9846. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9837–9846 Mots-clés : Compound  5-hydroxymethylfurfural  Biomass  Tarry  material Résumé : The compound 5-hydroxymethylfurfural (5-HMF) is thought to be an intermediate for the formation of tarry material in the supercritical water gasification (SCWG) of biomass. To gain insight on the formation mechanism of tarry material, we examined 5-HMF under both subcritical and supercritical conditions. The experiments of this study were conducted in a continuous reactor designed for an instant heating of 5-HMF solution to the reaction temperature. The reaction temperatures were set at 350 and 450 °C, and the pressure was set at 25 MPa. The initial concentration of 5-HMF and the residence time were adjusted in the range of 0.02−0.15 M (at room temperature) and 80−3000 s, respectively. The formation of char particles was only observed under the subcritical conditions. Char yield increased as the initial concentration of 5-HMF rose, with a reaction order of 4.29, with respect to 5-HMF concentration. The liquid products obtained from the 5-HMF decomposition also contributed to the polymerization to form char, with a reaction order of 1.21, based on their concentration. The sensitivity analysis indicated the high sensitivity of reaction orders on the char yield. The liquid products were identified by liquid chromatography/mass spectroscopy (LC/MS) and high-performance liquid chromatography (HPLC). The char particles were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectrometry. The char characterization results implied that the char particles formed had a polyaromatic structure. Based on our experimental findings, we proposed a mechanism of char particle formation from 5-HMF. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900423g