Documents disponibles écrits par cet auteur

Alternative reforming methods of primary tar released from gas treatment of biomass at low temperature for development of pyrolysis/gasification process / Weerawut Chaiwat in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3577–3584 Titre : Alternative reforming methods of primary tar released from gas treatment of biomass at low temperature for development of pyrolysis/gasification process Type de document : texte imprimé Auteurs : Weerawut Chaiwat, Auteur ; Isao Hasegawa, Auteur ; Kazuhiro Mae, Auteur Année de publication : 2010 Article en page(s) : pp. 3577–3584 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Alternative  Reforming  Methods  Primary  Tar  Released  Gas  Treatment  Biomass  Temperature Résumé : Primary tars produced from gas treatment in a low-temperature region were confirmed by thermogravimetric analysis of tar-mixed biomass that they would be easily handled by using simple reforming methods. A two-stage reactor was used to investigate the secondary reaction of light tar decomposition. The effect of air on light tar decomposition showed that gas products increased when the upper temperature was increased from 600 to 900 °C. When biomass char pyrolyzed to 900 °C was loaded in the upper reactor, the decomposition of light tar under inert atmosphere occurred by steam reforming to produce fuel gases even at a low temperature of 600 °C. When the upper temperature was increased to 800−900 °C, the yield of light tar significantly decreased and became almost zero because steam reforming and related reactions could proceed to produce CO and CO2 even in the case without biomass char. However, CO could be selectively obtained at the highest yield of 24.0 wt % because of the effect of catalytic char at a high temperature of 900 °C. Finally, alternative methods of light tar reforming are discussed for the development of a biomass gasification process to obtain tar-free gaseous products and/or valuable chemicals. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901695r?prevSearch=Alternative%2Breforming [...] [article] Alternative reforming methods of primary tar released from gas treatment of biomass at low temperature for development of pyrolysis/gasification process [texte imprimé] / Weerawut Chaiwat, Auteur ; Isao Hasegawa, Auteur ; Kazuhiro Mae, Auteur . - 2010 . - pp. 3577–3584. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3577–3584 Mots-clés : Alternative  Reforming  Methods  Primary  Tar  Released  Gas  Treatment  Biomass  Temperature Résumé : Primary tars produced from gas treatment in a low-temperature region were confirmed by thermogravimetric analysis of tar-mixed biomass that they would be easily handled by using simple reforming methods. A two-stage reactor was used to investigate the secondary reaction of light tar decomposition. The effect of air on light tar decomposition showed that gas products increased when the upper temperature was increased from 600 to 900 °C. When biomass char pyrolyzed to 900 °C was loaded in the upper reactor, the decomposition of light tar under inert atmosphere occurred by steam reforming to produce fuel gases even at a low temperature of 600 °C. When the upper temperature was increased to 800−900 °C, the yield of light tar significantly decreased and became almost zero because steam reforming and related reactions could proceed to produce CO and CO2 even in the case without biomass char. However, CO could be selectively obtained at the highest yield of 24.0 wt % because of the effect of catalytic char at a high temperature of 900 °C. Finally, alternative methods of light tar reforming are discussed for the development of a biomass gasification process to obtain tar-free gaseous products and/or valuable chemicals. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901695r?prevSearch=Alternative%2Breforming [...]

Examination of the low-temperature region in a downdraft gasifier for the pyrolysis product analysis of biomass air gasification / Weerawut Chaiwat in Industrial & engineering chemistry research, Vol. 48 N° 19 (Octobre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 19 (Octobre 2009) . - pp. 8934–8943 Titre : Examination of the low-temperature region in a downdraft gasifier for the pyrolysis product analysis of biomass air gasification Type de document : texte imprimé Auteurs : Weerawut Chaiwat, Auteur ; Isao Hasegawa, Auteur ; Kazuhiro Mae, Auteur Année de publication : 2009 Article en page(s) : pp. 8934–8943 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nitrogen  Low-temperature  region  Gas-treated  precursors Résumé : Treatment of biomass in nitrogen and air at 240−340 °C was conducted in order to examine the low-temperature region in a downdraft gasifier by analyzing the treated precursors and product distribution. Gas-treated precursors were then pyrolyzed in flash mode at 764 °C for further analysis. Overall, the tar yield decreased from approximately 50 wt % to less than 20 wt % upon oxidation of the sample at a very low heating rate to 260−300 °C in air. Moreover, tar evolution was almost completely suppressed during the subsequent flash pyrolysis. This indicates that the structure of the treated precursors was gradually changed to suppress tar release through cross-linking reactions and partial oxidation. From elemental analysis of the precursors treated with air, it was also estimated that dehydration and partial oxidation proceeded simultaneously. The results indicate that the release of tar products such as dimers can be partially suppressed by air treatment at low temperature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900264n [article] Examination of the low-temperature region in a downdraft gasifier for the pyrolysis product analysis of biomass air gasification [texte imprimé] / Weerawut Chaiwat, Auteur ; Isao Hasegawa, Auteur ; Kazuhiro Mae, Auteur . - 2009 . - pp. 8934–8943. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 19 (Octobre 2009) . - pp. 8934–8943 Mots-clés : Nitrogen  Low-temperature  region  Gas-treated  precursors Résumé : Treatment of biomass in nitrogen and air at 240−340 °C was conducted in order to examine the low-temperature region in a downdraft gasifier by analyzing the treated precursors and product distribution. Gas-treated precursors were then pyrolyzed in flash mode at 764 °C for further analysis. Overall, the tar yield decreased from approximately 50 wt % to less than 20 wt % upon oxidation of the sample at a very low heating rate to 260−300 °C in air. Moreover, tar evolution was almost completely suppressed during the subsequent flash pyrolysis. This indicates that the structure of the treated precursors was gradually changed to suppress tar release through cross-linking reactions and partial oxidation. From elemental analysis of the precursors treated with air, it was also estimated that dehydration and partial oxidation proceeded simultaneously. The results indicate that the release of tar products such as dimers can be partially suppressed by air treatment at low temperature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900264n

Gas - liquid - liquid slug flow for improving liquid - liquid extraction in miniaturized channels / Nobuaki Aoki in Industrial & engineering chemistry research, Vol. 50 N° 8 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4672–4677 Titre : Gas - liquid - liquid slug flow for improving liquid - liquid extraction in miniaturized channels Type de document : texte imprimé Auteurs : Nobuaki Aoki, Auteur ; Ryuichi Ando, Auteur ; Kazuhiro Mae, Auteur Année de publication : 2011 Article en page(s) : pp. 4672–4677 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas  Liquid Résumé : To increase the maximum flow rate that enables slug flow formation in miniaturized channels, gas-phase slugs are added in a liquid−liquid slug flow to form a gas−liquid−liquid slug flow. Effects of channel size, void fraction (ratio of volumetric flow rate of gas phase to that of total flow rate), and volume ratio of aqueous phase to organic phase on flow regime are examined. Results indicate that the total liquid-phase flow rate that forms a stable gas−liquid−liquid slug flow increases up to 200 mL/min with air addition (void fraction > 0.1) in a poly(tetrafluoroethylene) (PTFE) tube (inner diameter (i.d.), 3 mm). The mass-transfer rate in the gas−liquid−liquid slug flow was also high because internal circulation flow is enhanced by increased flow rate. The mass-transfer coefficient was then correlated with the channel i.d. and the flow velocity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024326 [article] Gas - liquid - liquid slug flow for improving liquid - liquid extraction in miniaturized channels [texte imprimé] / Nobuaki Aoki, Auteur ; Ryuichi Ando, Auteur ; Kazuhiro Mae, Auteur . - 2011 . - pp. 4672–4677. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4672–4677 Mots-clés : Gas  Liquid Résumé : To increase the maximum flow rate that enables slug flow formation in miniaturized channels, gas-phase slugs are added in a liquid−liquid slug flow to form a gas−liquid−liquid slug flow. Effects of channel size, void fraction (ratio of volumetric flow rate of gas phase to that of total flow rate), and volume ratio of aqueous phase to organic phase on flow regime are examined. Results indicate that the total liquid-phase flow rate that forms a stable gas−liquid−liquid slug flow increases up to 200 mL/min with air addition (void fraction > 0.1) in a poly(tetrafluoroethylene) (PTFE) tube (inner diameter (i.d.), 3 mm). The mass-transfer rate in the gas−liquid−liquid slug flow was also high because internal circulation flow is enhanced by increased flow rate. The mass-transfer coefficient was then correlated with the channel i.d. and the flow velocity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024326

Oxidative dimerization of phenol based on micromixing in single- and two-phase systems / Yoshihito Okubo in Industrial & engineering chemistry research, Vol. 47 N°19 (Octobre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°19 (Octobre 2008) . - p. 7154–7160 Titre : Oxidative dimerization of phenol based on micromixing in single- and two-phase systems Type de document : texte imprimé Auteurs : Yoshihito Okubo, Auteur ; Hideyuki Higashimura, Auteur ; Kazuhiro Mae, Auteur Année de publication : 2008 Article en page(s) : p. 7154–7160 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Phenol  Oxidative  polymerization  Microdroplets  Single-  and  two-phase  systems Résumé : It is an important technique to obtain target products with higher yields by controlling the reaction and mass transfer. In this work, we focused on molecular weight control in the oxidative polymerization of phenol. We attempted selective production of phenol dimers through the formation of microdroplets in both single- and two-phase systems. In a single-phase system, selectivity of dimers to polymers can be improved by rapidly mixing ingredients using a micromixer. Further, we clarified the conditions to utilize such microspace effects by comparing the initial reaction time constant with the mixing time constant by order-of-magnitude estimation. In a two-phase system, it was clarified that controlling of mass transfer by formation of microdroplets using a micromixer was effective in the control of consecutive elementary reactions though the dimer selectivity hardly changes and the effect of micromixing was limited. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800054n [article] Oxidative dimerization of phenol based on micromixing in single- and two-phase systems [texte imprimé] / Yoshihito Okubo, Auteur ; Hideyuki Higashimura, Auteur ; Kazuhiro Mae, Auteur . - 2008 . - p. 7154–7160. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°19 (Octobre 2008) . - p. 7154–7160 Mots-clés : Phenol  Oxidative  polymerization  Microdroplets  Single-  and  two-phase  systems Résumé : It is an important technique to obtain target products with higher yields by controlling the reaction and mass transfer. In this work, we focused on molecular weight control in the oxidative polymerization of phenol. We attempted selective production of phenol dimers through the formation of microdroplets in both single- and two-phase systems. In a single-phase system, selectivity of dimers to polymers can be improved by rapidly mixing ingredients using a micromixer. Further, we clarified the conditions to utilize such microspace effects by comparing the initial reaction time constant with the mixing time constant by order-of-magnitude estimation. In a two-phase system, it was clarified that controlling of mass transfer by formation of microdroplets using a micromixer was effective in the control of consecutive elementary reactions though the dimer selectivity hardly changes and the effect of micromixing was limited. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800054n