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Calculation of the optimal macropore size in nanoporous catalysts and its application to DeNOx catalysis / Gang Wang in Industrial & engineering chemistry research, Vol. 47 n°11 (Juin 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3847–3855 Titre : Calculation of the optimal macropore size in nanoporous catalysts and its application to DeNOx catalysis Type de document : texte imprimé Auteurs : Gang Wang, Auteur ; Marc-Olivier Coppens, Auteur Année de publication : 2008 Article en page(s) : p. 3847–3855 Note générale : Bibliogr. p. 3855 Langues : Anglais (eng) Mots-clés : Macropores;  Nanoporous  catalyst;  Molecular  diffusion;  DeNOx  catalysis Résumé : Macropores act as broad highways for molecules to move in and out of a nanoporous catalyst. The macropore “distributor” network in such a hierarchically structured porous catalyst, containing both nanopores and macropores, is optimized with the aim to find the optimal effectiveness factor, ηopt, of a single reaction with general kinetics in the catalyst. Molecular diffusion is assumed to dominate transport in macropores. It is found that the ηopt−Φ0 relation qualitatively recovers the universal η−Φ relation when the generalized distributor Thiele modulus, Φ0, is defined in a way analogous to the generalized Thiele modulus, Φ, but using the molecular diffusivity in the macropores rather than the effective diffusivity in the nanopores. This is because the concentration gradient inside the optimal hierarchically structured, porous catalyst exists only in one principle direction (e.g., the radial direction in a spherical catalyst particle), and molecular diffusion in the macropores dominates the transport process in this principle direction. The universal ηopt−Φ0 relation is used to design a catalyst for power plant NOx emission control. Overall catalytic activity in a mesoporous catalyst with a median pore size of 32.5 nm could be increased by a factor of 1.8−2.8 simply by introducing macropores (occupying 20−40% of the total volume of the catalyst) with a width of 2−22 µm into the mesoporous catalytic material, so that the remaining mesoporous macropore walls are 5−33 µm thick. In practice, this would correspond to a deNOx catalyst consisting of mesoporous particles with a diameter of 5−33 µm and macropores in between them with a size of around 2−22 µm. Information like this is readily applicable to practical catalyst synthesis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071550%2B [article] Calculation of the optimal macropore size in nanoporous catalysts and its application to DeNOx catalysis [texte imprimé] / Gang Wang, Auteur ; Marc-Olivier Coppens, Auteur . - 2008 . - p. 3847–3855. Bibliogr. p. 3855 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3847–3855 Mots-clés : Macropores;  Nanoporous  catalyst;  Molecular  diffusion;  DeNOx  catalysis Résumé : Macropores act as broad highways for molecules to move in and out of a nanoporous catalyst. The macropore “distributor” network in such a hierarchically structured porous catalyst, containing both nanopores and macropores, is optimized with the aim to find the optimal effectiveness factor, ηopt, of a single reaction with general kinetics in the catalyst. Molecular diffusion is assumed to dominate transport in macropores. It is found that the ηopt−Φ0 relation qualitatively recovers the universal η−Φ relation when the generalized distributor Thiele modulus, Φ0, is defined in a way analogous to the generalized Thiele modulus, Φ, but using the molecular diffusivity in the macropores rather than the effective diffusivity in the nanopores. This is because the concentration gradient inside the optimal hierarchically structured, porous catalyst exists only in one principle direction (e.g., the radial direction in a spherical catalyst particle), and molecular diffusion in the macropores dominates the transport process in this principle direction. The universal ηopt−Φ0 relation is used to design a catalyst for power plant NOx emission control. Overall catalytic activity in a mesoporous catalyst with a median pore size of 32.5 nm could be increased by a factor of 1.8−2.8 simply by introducing macropores (occupying 20−40% of the total volume of the catalyst) with a width of 2−22 µm into the mesoporous catalytic material, so that the remaining mesoporous macropore walls are 5−33 µm thick. In practice, this would correspond to a deNOx catalyst consisting of mesoporous particles with a diameter of 5−33 µm and macropores in between them with a size of around 2−22 µm. Information like this is readily applicable to practical catalyst synthesis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071550%2B

Influence of nonbasic nitrogen compounds and condensed aromatics on coker gas oil catalytic cracking and their characterization / Ze-kun Li in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 9415–9424 Titre : Influence of nonbasic nitrogen compounds and condensed aromatics on coker gas oil catalytic cracking and their characterization Type de document : texte imprimé Auteurs : Ze-kun Li, Auteur ; Jin-sen Gao, Auteur ; Gang Wang, Auteur Année de publication : 2011 Article en page(s) : pp 9415–9424 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonbasic  nitrogen  compounds  Coker  gas  oil  catalytic Résumé : Contrastive fluid catalytic cracking (FCC) performances of coker gas oil (CGO) narrow-boiling fractions before and after HCl aqueous solution and furfural further treatment were investigated. Nonbasic nitrogen compounds and condensed aromatics in test oil samples were identified by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatography and mass spectrometry (GC–MS), respectively. The results show that basic nitrogen compounds mainly retard the feed conversion and liquid products due to their interaction with Brønsted acid sites or Lewis acid sites during catalytic cracking reactions, while the nonbasic nitrogen compounds and condensed aromatics are hard to convert into smaller molecules, just resulting in obvious effects on yields of gasoline and diesel. Moreover, nonbasic nitrogen compounds with single N species are dominant in CGO, identified as carbazoles, cycloalkyl-carbazoles, benzocarbazoles, and cycloalkyl-benzocarbazoles. Condensed aromatics include three to four rings of large dynamic size, usually presented as chrysene, pyrene, and phenanthrene. These compounds deposit on the surface of catalysts and thus redundant coke is formed; consequently, entrances for other hydrocarbons into acid centers are jammed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003973 [article] Influence of nonbasic nitrogen compounds and condensed aromatics on coker gas oil catalytic cracking and their characterization [texte imprimé] / Ze-kun Li, Auteur ; Jin-sen Gao, Auteur ; Gang Wang, Auteur . - 2011 . - pp 9415–9424. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 9415–9424 Mots-clés : Nonbasic  nitrogen  compounds  Coker  gas  oil  catalytic Résumé : Contrastive fluid catalytic cracking (FCC) performances of coker gas oil (CGO) narrow-boiling fractions before and after HCl aqueous solution and furfural further treatment were investigated. Nonbasic nitrogen compounds and condensed aromatics in test oil samples were identified by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatography and mass spectrometry (GC–MS), respectively. The results show that basic nitrogen compounds mainly retard the feed conversion and liquid products due to their interaction with Brønsted acid sites or Lewis acid sites during catalytic cracking reactions, while the nonbasic nitrogen compounds and condensed aromatics are hard to convert into smaller molecules, just resulting in obvious effects on yields of gasoline and diesel. Moreover, nonbasic nitrogen compounds with single N species are dominant in CGO, identified as carbazoles, cycloalkyl-carbazoles, benzocarbazoles, and cycloalkyl-benzocarbazoles. Condensed aromatics include three to four rings of large dynamic size, usually presented as chrysene, pyrene, and phenanthrene. These compounds deposit on the surface of catalysts and thus redundant coke is formed; consequently, entrances for other hydrocarbons into acid centers are jammed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003973

Reactive characteristics and adsorption heat of Ni/ZnO–SiO2–Al2O3 adsorbent by reactive adsorption desulfurization / Gang Wang in Industrial & engineering chemistry research, Vol. 50 N° 22 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12449-12459 Titre : Reactive characteristics and adsorption heat of Ni/ZnO–SiO2–Al2O3 adsorbent by reactive adsorption desulfurization Type de document : texte imprimé Auteurs : Gang Wang, Auteur ; Yaoshun Wen, Auteur ; Jingxin Fan, Auteur Année de publication : 2012 Article en page(s) : pp. 12449-12459 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Desulfurization  Adsorption Résumé : Reactive adsorption desulfurization (RADS) experiments of fluid catalytic cracking (FCC) gasoline and a model gasoline over an Ni/ZnO–SiO2–Al2O3 adsorbent were carried out in a fixed-fluidized bed reactor at low pressures in an H2 atmosphere. The results show that hydrogenation, hydrogen transfer, and polymerization reactions accompany RADS. Sulfidation and carbon deposits, which can lead to decreases in the regeneration rate and amount of activated Ni, are crucial to the decay of desulfurization and the olefin-hydrogenation capability of the adsorbents. The obvious reduction of C5 and C6 olefins in FCC gasoline mainly contribute to the drop in octane number of the desulfurization product. The desulfurization experiment on model gasoline and the adsorption heats of model compounds show that RADS removes sulfur from sulfur-containing compound through S–M interactions rather than by π-complexation over the Ni/ZnO–SiO2–Al2O3 adsorbent. The adsorption heat of sulfur-containing compound is proportional to the electron density of sulfur atoms. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745718 [article] Reactive characteristics and adsorption heat of Ni/ZnO–SiO2–Al2O3 adsorbent by reactive adsorption desulfurization [texte imprimé] / Gang Wang, Auteur ; Yaoshun Wen, Auteur ; Jingxin Fan, Auteur . - 2012 . - pp. 12449-12459. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12449-12459 Mots-clés : Desulfurization  Adsorption Résumé : Reactive adsorption desulfurization (RADS) experiments of fluid catalytic cracking (FCC) gasoline and a model gasoline over an Ni/ZnO–SiO2–Al2O3 adsorbent were carried out in a fixed-fluidized bed reactor at low pressures in an H2 atmosphere. The results show that hydrogenation, hydrogen transfer, and polymerization reactions accompany RADS. Sulfidation and carbon deposits, which can lead to decreases in the regeneration rate and amount of activated Ni, are crucial to the decay of desulfurization and the olefin-hydrogenation capability of the adsorbents. The obvious reduction of C5 and C6 olefins in FCC gasoline mainly contribute to the drop in octane number of the desulfurization product. The desulfurization experiment on model gasoline and the adsorption heats of model compounds show that RADS removes sulfur from sulfur-containing compound through S–M interactions rather than by π-complexation over the Ni/ZnO–SiO2–Al2O3 adsorbent. The adsorption heat of sulfur-containing compound is proportional to the electron density of sulfur atoms. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745718

Regeneration characteristics and kinetics of Ni / ZnO – SiO2 – A l2O3 adsorbent for reactive adsorption desulfurization / Yaoshun Wen in Industrial & engineering chemistry research, Vol. 51 N° 10 (Mars 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 10 (Mars 2012) . - pp. 3939–3950 Titre : Regeneration characteristics and kinetics of Ni / ZnO – SiO2 – A l2O3 adsorbent for reactive adsorption desulfurization Type de document : texte imprimé Auteurs : Yaoshun Wen, Auteur ; Gang Wang, Auteur ; Qian Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 3939–3950 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics  Adsorbent  Desulfurization Résumé : Regeneration experiments on Ni/ZnO–SiO2–Al2O3 adsorbents for gasoline reactive adsorption desulfurization (RADS) were carried out in a fixed-bed microreactor at atmosphere pressure. X-ray diffraction, scanning electron microscopy/energy-dispersive spectroscopy, X-ray photoelectron spectrometry, and N2 isotherms were used to identify changes in the physical and chemical properties of the adsorbent before and after regeneration. The results showed that high O2 concentrations significantly increase the regeneration rate of the adsorbent but yield zinc sulfate. A regeneration condition that decreases the formation of zinc sulfate, including low O2 concentration with high temperature, was then investigated. Finally, a shrinking core model (SCM) was applied to account for the regeneration kinetics of the Ni/ZnO–SiO2–Al2O3 adsorbent, and the relevant kinetic parameters were determined. The regeneration is controlled first by a chemical reaction and then by layer diffusion. The desulfurization activity of the regenerated adsorbent over three desulfurization and regeneration cycles is almost identical to that of fresh adsorbent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202730w [article] Regeneration characteristics and kinetics of Ni / ZnO – SiO2 – A l2O3 adsorbent for reactive adsorption desulfurization [texte imprimé] / Yaoshun Wen, Auteur ; Gang Wang, Auteur ; Qian Wang, Auteur . - 2012 . - pp. 3939–3950. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 10 (Mars 2012) . - pp. 3939–3950 Mots-clés : Kinetics  Adsorbent  Desulfurization Résumé : Regeneration experiments on Ni/ZnO–SiO2–Al2O3 adsorbents for gasoline reactive adsorption desulfurization (RADS) were carried out in a fixed-bed microreactor at atmosphere pressure. X-ray diffraction, scanning electron microscopy/energy-dispersive spectroscopy, X-ray photoelectron spectrometry, and N2 isotherms were used to identify changes in the physical and chemical properties of the adsorbent before and after regeneration. The results showed that high O2 concentrations significantly increase the regeneration rate of the adsorbent but yield zinc sulfate. A regeneration condition that decreases the formation of zinc sulfate, including low O2 concentration with high temperature, was then investigated. Finally, a shrinking core model (SCM) was applied to account for the regeneration kinetics of the Ni/ZnO–SiO2–Al2O3 adsorbent, and the relevant kinetic parameters were determined. The regeneration is controlled first by a chemical reaction and then by layer diffusion. The desulfurization activity of the regenerated adsorbent over three desulfurization and regeneration cycles is almost identical to that of fresh adsorbent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202730w

Research on reactive adsorption desulfurization over Ni/ZnO−SiO2−Al2O3 adsorbent in a fixed-fluidized bed reactor / Jingxin Fan in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8450–8460 Titre : Research on reactive adsorption desulfurization over Ni/ZnO−SiO2−Al2O3 adsorbent in a fixed-fluidized bed reactor Type de document : texte imprimé Auteurs : Jingxin Fan, Auteur ; Gang Wang, Auteur ; Yu Sun, Auteur Année de publication : 2010 Article en page(s) : pp. 8450–8460 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Desulfurization  Adsorption Résumé : Reactive adsorption desulfurization of FCC gasoline over a Ni/ZnO−SiO2−Al2O3 adsorbent was carried out in a fixed-fluidized bed reactor at low pressures in the presence of hydrogen. The results show that high temperature, high pressure, high molar ratios of hydrogen-to-oil, and low weight hourly space velocity are favorable to improve the desulfurization ability of adsorbent but not conducive to maintaining the octane number of FCC gasoline throughout the condition range examined. Under optimal operating conditions, ultralow sulfur gasoline can be produced, and the RON loss is only 1 unit. Furthermore, the effect of prereduction and adsorbent characterization data (SEM/EDX, N2 adsorption) reveal that reduction increases the interaction between Ni and S compounds and improves the pore structure of adsorbent, leading to a significant improvement in the desulfurization capability of adsorbent. Take 3-methylthiophene for example, after adsorbing on an active Ni atom via the S−Ni bond, the sulfur of 3-methylthiophene is removed by direct hydrogenolysis of the C−S bond, resulting in the formation of NiSx and 2-methyl-1,3-butadiene in hydrogen atmosphere. The latter is mainly hydrogenated to 2-methyl-2-butene and 2-methylbutane. ZnO acts as a sulfur-acceptor, which can regenerate the active Ni in situ in hydrogen atmosphere. The complete sulfidation of adsorbent particles takes place by ion diffusion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100923v [article] Research on reactive adsorption desulfurization over Ni/ZnO−SiO2−Al2O3 adsorbent in a fixed-fluidized bed reactor [texte imprimé] / Jingxin Fan, Auteur ; Gang Wang, Auteur ; Yu Sun, Auteur . - 2010 . - pp. 8450–8460. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8450–8460 Mots-clés : Desulfurization  Adsorption Résumé : Reactive adsorption desulfurization of FCC gasoline over a Ni/ZnO−SiO2−Al2O3 adsorbent was carried out in a fixed-fluidized bed reactor at low pressures in the presence of hydrogen. The results show that high temperature, high pressure, high molar ratios of hydrogen-to-oil, and low weight hourly space velocity are favorable to improve the desulfurization ability of adsorbent but not conducive to maintaining the octane number of FCC gasoline throughout the condition range examined. Under optimal operating conditions, ultralow sulfur gasoline can be produced, and the RON loss is only 1 unit. Furthermore, the effect of prereduction and adsorbent characterization data (SEM/EDX, N2 adsorption) reveal that reduction increases the interaction between Ni and S compounds and improves the pore structure of adsorbent, leading to a significant improvement in the desulfurization capability of adsorbent. Take 3-methylthiophene for example, after adsorbing on an active Ni atom via the S−Ni bond, the sulfur of 3-methylthiophene is removed by direct hydrogenolysis of the C−S bond, resulting in the formation of NiSx and 2-methyl-1,3-butadiene in hydrogen atmosphere. The latter is mainly hydrogenated to 2-methyl-2-butene and 2-methylbutane. ZnO acts as a sulfur-acceptor, which can regenerate the active Ni in situ in hydrogen atmosphere. The complete sulfidation of adsorbent particles takes place by ion diffusion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100923v

Retardation effect of basic nitrogen compounds on hydrocarbons catalytic cracking in coker gas oil and their structural identification / Ze-kun Li in Industrial & engineering chemistry research, Vol. 50 N° 7 (Avril 2011) 

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Static and dynamic axial response of drilled piers / Gang Wang in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 12 (Décembre 2011) 

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Static and dynamic axial response of drilled piers / Gang Wang in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 12 (Décembre 2011) 

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Study of optimal reaction conditions and a modified residue catalytic cracking process for maximizing liquid products / Gang Wang in Industrial & engineering chemistry research, Vol. 48 N° 7 (Avril 2009) 

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Synergistic process for coker gas oil and heavy cycle oil conversion for maximum light production / Gang Wang in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

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Upgrading residue by carbon rejection in a fluidized - bed reactor and its multiple lump kinetic model / Hong-liang Wang in Industrial & engineering chemistry research, Vol. 50 N° 22 (Novembre 2011) 

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