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Kinetics study of 3-methylthiophene alkylation with isobutylene catalyzed by NKC-9 ion exchange resin / Yu Liu in Industrial & engineering chemistry research, Vol. 50 N° 16 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9609-9616 Titre : Kinetics study of 3-methylthiophene alkylation with isobutylene catalyzed by NKC-9 ion exchange resin Type de document : texte imprimé Auteurs : Yu Liu, Auteur ; Bolun Yang, Auteur ; Chunhai Yi, Auteur Année de publication : 2011 Article en page(s) : pp. 9609-9616 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ion  exchange  resin  Catalytic  reaction  Alkylation  Kinetics Résumé : A series of experiments were carried out in a stirred batch reactor at the temperature range of 333-363 K and the pressure of 1.5—2.5 MPa by using NKC-9 ion-exchange resin to investigate the alkylation kinetics of 3-methylthiophene (3MT) with isobutylene (IB). The effect of various operation parameters such as stirring speed, catalyst particle size, temperature, pressure, and sulfur content on the conversion and selectivity of alkylation reaction were studied. Experimental results indicated that the alkylation of 3MT with IB was followed by a parallel reaction of IB oligomerization; higher temperature could improve the alkylation activity while lower temperature was profitable to the reaction selectivity over the NKC-9 catalyst; however, the operating pressure has little effect on the alkylation and oligomerization; much sulfur content could inhibit IB dimerization. The Eley-Rideal (ER) law can be used to explain the reaction mechanism, and the kinetics models that considered the alkylation and oligomerization at the same time were established. Kinetics parameters were solved, and the calculation results agreed well with the experimental results. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425204 [article] Kinetics study of 3-methylthiophene alkylation with isobutylene catalyzed by NKC-9 ion exchange resin [texte imprimé] / Yu Liu, Auteur ; Bolun Yang, Auteur ; Chunhai Yi, Auteur . - 2011 . - pp. 9609-9616. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9609-9616 Mots-clés : Ion  exchange  resin  Catalytic  reaction  Alkylation  Kinetics Résumé : A series of experiments were carried out in a stirred batch reactor at the temperature range of 333-363 K and the pressure of 1.5—2.5 MPa by using NKC-9 ion-exchange resin to investigate the alkylation kinetics of 3-methylthiophene (3MT) with isobutylene (IB). The effect of various operation parameters such as stirring speed, catalyst particle size, temperature, pressure, and sulfur content on the conversion and selectivity of alkylation reaction were studied. Experimental results indicated that the alkylation of 3MT with IB was followed by a parallel reaction of IB oligomerization; higher temperature could improve the alkylation activity while lower temperature was profitable to the reaction selectivity over the NKC-9 catalyst; however, the operating pressure has little effect on the alkylation and oligomerization; much sulfur content could inhibit IB dimerization. The Eley-Rideal (ER) law can be used to explain the reaction mechanism, and the kinetics models that considered the alkylation and oligomerization at the same time were established. Kinetics parameters were solved, and the calculation results agreed well with the experimental results. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425204

Process simulation based on experimental investigations for 3 - methylthiophene alkylation with isobutylene in a reactive distillation column / Yu Liu in Industrial & engineering chemistry research, Vol. 51 N° 29 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 29 (Juillet 2012) . - pp. 9803-9811 Titre : Process simulation based on experimental investigations for 3 - methylthiophene alkylation with isobutylene in a reactive distillation column Type de document : texte imprimé Auteurs : Yu Liu, Auteur ; Bolun Yang, Auteur ; Shasha Li, Auteur Année de publication : 2012 Article en page(s) : pp. 9803-9811 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Distillation  column  Distillation  with  reaction  Alkylation Résumé : A new approach that substitutes the original two-step olefinic alkylation of thiophenic sulfur (OATS) technology with a reactive distillation (RD) column was proposed to remove sulfur compounds from fluid catalytic cracking (FCC) gasoline. 3-Methylthiophene (3MT) and isobutylene (IB) were designated as the model compounds for sulfide and olefin, respectively; NKC-9 cation exchange resin mixed with the 2 mm × 2 mm θ ring packing was used as the catalyst bed. The process parameters such as feed composition, molar ratio of 3MT to IB, and reflux ratio were investigated experimentally in the RD column. Simulation for this process was carried out by using the equilibrium stage model—the RADFRAC module of Aspen Plus. The multicomponent vapor―liquid equilibria were predicted by an UNIQUAC method, and the kinetics model that is essential in the RD process was obtained from our previous work. The key design factors (e.g., number of reactive and nonreactive stages, location of feed stage, column pressure, mass ratio of distillate to feed, and catalyst weight) were optimized. The theoretical calculations from the equilibrium stage model matched well with the experimental results. Optimization of the process revealed that applying RD technology into OATS process offers higher alkylation selectivity and better catalytic stability, and the sulfur content in FCC gasoline declined by more than 99%. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26184959 [article] Process simulation based on experimental investigations for 3 - methylthiophene alkylation with isobutylene in a reactive distillation column [texte imprimé] / Yu Liu, Auteur ; Bolun Yang, Auteur ; Shasha Li, Auteur . - 2012 . - pp. 9803-9811. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 29 (Juillet 2012) . - pp. 9803-9811 Mots-clés : Distillation  column  Distillation  with  reaction  Alkylation Résumé : A new approach that substitutes the original two-step olefinic alkylation of thiophenic sulfur (OATS) technology with a reactive distillation (RD) column was proposed to remove sulfur compounds from fluid catalytic cracking (FCC) gasoline. 3-Methylthiophene (3MT) and isobutylene (IB) were designated as the model compounds for sulfide and olefin, respectively; NKC-9 cation exchange resin mixed with the 2 mm × 2 mm θ ring packing was used as the catalyst bed. The process parameters such as feed composition, molar ratio of 3MT to IB, and reflux ratio were investigated experimentally in the RD column. Simulation for this process was carried out by using the equilibrium stage model—the RADFRAC module of Aspen Plus. The multicomponent vapor―liquid equilibria were predicted by an UNIQUAC method, and the kinetics model that is essential in the RD process was obtained from our previous work. The key design factors (e.g., number of reactive and nonreactive stages, location of feed stage, column pressure, mass ratio of distillate to feed, and catalyst weight) were optimized. The theoretical calculations from the equilibrium stage model matched well with the experimental results. Optimization of the process revealed that applying RD technology into OATS process offers higher alkylation selectivity and better catalytic stability, and the sulfur content in FCC gasoline declined by more than 99%. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26184959

Three-dimensional damage model for concrete. I / Yu Liu in Journal of engineering mechanics, Vol. 134 N°1 (Janvier 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 N°1 (Janvier 2008) Titre : Three-dimensional damage model for concrete. I : Theory Type de document : texte imprimé Auteurs : Yu Liu, Auteur ; Susanto Teng, Auteur ; Chee-Kiong Soh, Auteur Année de publication : 2008 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Concrete  Constitutive  models  Cracking  Damage  Three-dimensional  models Résumé : A damage model for concrete is proposed based on the existing displacement equivalence-based model for brittle materials. The model is established in a randomly selected coordinate system so as to consider the cases where the principal directions of damage do not coincide with those of stress and strain. The effect of shear stress is also considered. The slipping cracks of concrete under triaxial compression and the stiffness reduction under hydrostatic compression are also taken into account. The friction at crack tips has been introduced to account for the permanent deformation and a blend of elastic and secant unloading/reloading routine is obtained. The evolution rule of damage is combined with the predefined basic damage evolution patterns. ISSN : 0733-9399 En ligne : http://cedb.asce.org/cgi/WWWdisplay.cgi?161981 [article] Three-dimensional damage model for concrete. I : Theory [texte imprimé] / Yu Liu, Auteur ; Susanto Teng, Auteur ; Chee-Kiong Soh, Auteur . - 2008. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 N°1 (Janvier 2008) Mots-clés : Concrete  Constitutive  models  Cracking  Damage  Three-dimensional  models Résumé : A damage model for concrete is proposed based on the existing displacement equivalence-based model for brittle materials. The model is established in a randomly selected coordinate system so as to consider the cases where the principal directions of damage do not coincide with those of stress and strain. The effect of shear stress is also considered. The slipping cracks of concrete under triaxial compression and the stiffness reduction under hydrostatic compression are also taken into account. The friction at crack tips has been introduced to account for the permanent deformation and a blend of elastic and secant unloading/reloading routine is obtained. The evolution rule of damage is combined with the predefined basic damage evolution patterns. ISSN : 0733-9399 En ligne : http://cedb.asce.org/cgi/WWWdisplay.cgi?161981

Three-dimensional damage model for concrete. II / Yu Liu in Journal of engineering mechanics, Vol. 134 N°1 (Janvier 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 N°1 (Janvier 2008) . - pp.82-89 Titre : Three-dimensional damage model for concrete. II : Verification Type de document : texte imprimé Auteurs : Yu Liu, Auteur ; Susanto Teng, Auteur ; Chee-Kiong Soh, Auteur Année de publication : 2008 Article en page(s) : pp.82-89 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Concrete  Constitutive  models  Cracking  Three-dimensional  models  Damage Résumé : A three-dimensional damage model for concrete has been proposed in the preceding paper, Part I: Theory. This paper focuses on the application of the damage model for quasi-brittle materials such as concrete. The determination of model parameters for the evolution rule of damage is discussed. The model parameters to consider the frictional stress and the stiffness reduction under hydrostatic compression are also studied. For verification, the proposed model is applied to concrete subjected to confined compression, triaxial, loading, and cyclic loading. Consistent results, as compared with other researchers’ experimental data, were obtained, and the proposed model is considered worthy of further research work. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A1%2882 [...] [article] Three-dimensional damage model for concrete. II : Verification [texte imprimé] / Yu Liu, Auteur ; Susanto Teng, Auteur ; Chee-Kiong Soh, Auteur . - 2008 . - pp.82-89. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 N°1 (Janvier 2008) . - pp.82-89 Mots-clés : Concrete  Constitutive  models  Cracking  Three-dimensional  models  Damage Résumé : A three-dimensional damage model for concrete has been proposed in the preceding paper, Part I: Theory. This paper focuses on the application of the damage model for quasi-brittle materials such as concrete. The determination of model parameters for the evolution rule of damage is discussed. The model parameters to consider the frictional stress and the stiffness reduction under hydrostatic compression are also studied. For verification, the proposed model is applied to concrete subjected to confined compression, triaxial, loading, and cyclic loading. Consistent results, as compared with other researchers’ experimental data, were obtained, and the proposed model is considered worthy of further research work. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A1%2882 [...]

Viscoelastic model for discrete element simulation of asphalt mixtures / Yu Liu in Journal of engineering mechanics, Vol. 135 N° 4 (Avril 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 4 (Avril 2009) . - pp. 324-333 Titre : Viscoelastic model for discrete element simulation of asphalt mixtures Type de document : texte imprimé Auteurs : Yu Liu, Auteur ; Qingli Dai, Auteur ; Zhanping You, Auteur Article en page(s) : pp. 324-333 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Asphalts  Mixtures  Discrete  elements  Viscoelasticity  Simulation. Résumé : This paper presents a viscoelastic model of asphalt mixtures with the discrete element method, where the viscoelastic behaviors of asphalt mastics (fine aggregates, fines, and asphalt binder) are represented by a Burger's model. Aggregates are simulated with irregular shape particles consisting of balls bonded together by elastic contact models, and the interplaces between aggregates are filled with balls bonded with viscoelastic Burger's model to represent asphalt mastic. Digital samples were prepared with the image analysis technique. The micromechanical model was developed with four constitutive laws to represent the interactions at contacts of discrete elements (balls) within an aggregate, within mastic, between an aggregate and mastic, and between two adjacent aggregates. Each of these constitutive laws consists of three parts: a stiffness model, a slip model, and a bonding model in order to provide a relationship between the contact force and relative displacement and also in order to describe slipping and tensile strength at a particular contact. The relationship between the microscale model input and macroscale material properties was derived, and an iterative procedure was developed to fit the dynamic modulus test data of asphalt mastic with Burger's model. The favorable agreement between the discrete element prediction and the lab results on dynamic moduli and phase angles indicates that the viscoelastic discrete element model developed in this study is very capable of simulating constitutive behavior of asphalt mixtures DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Viscoelastic model for discrete element simulation of asphalt mixtures [texte imprimé] / Yu Liu, Auteur ; Qingli Dai, Auteur ; Zhanping You, Auteur . - pp. 324-333. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 4 (Avril 2009) . - pp. 324-333 Mots-clés : Asphalts  Mixtures  Discrete  elements  Viscoelasticity  Simulation. Résumé : This paper presents a viscoelastic model of asphalt mixtures with the discrete element method, where the viscoelastic behaviors of asphalt mastics (fine aggregates, fines, and asphalt binder) are represented by a Burger's model. Aggregates are simulated with irregular shape particles consisting of balls bonded together by elastic contact models, and the interplaces between aggregates are filled with balls bonded with viscoelastic Burger's model to represent asphalt mastic. Digital samples were prepared with the image analysis technique. The micromechanical model was developed with four constitutive laws to represent the interactions at contacts of discrete elements (balls) within an aggregate, within mastic, between an aggregate and mastic, and between two adjacent aggregates. Each of these constitutive laws consists of three parts: a stiffness model, a slip model, and a bonding model in order to provide a relationship between the contact force and relative displacement and also in order to describe slipping and tensile strength at a particular contact. The relationship between the microscale model input and macroscale material properties was derived, and an iterative procedure was developed to fit the dynamic modulus test data of asphalt mastic with Burger's model. The favorable agreement between the discrete element prediction and the lab results on dynamic moduli and phase angles indicates that the viscoelastic discrete element model developed in this study is very capable of simulating constitutive behavior of asphalt mixtures DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]

Visualization and measurement of CO2 flooding in porous media using MRI / Yuechao Zhao in Industrial & engineering chemistry research, Vol. 50 N° 8 (Avril 2011) 

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