[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10977-10982

Titre :	Yield Behavior of Waxy Crude Gel : Effect of Isothermal Structure Development before Prior Applied Stress
Type de document :	texte imprimé
Auteurs :	Banglong Jia, Auteur ; Jinjun Zhang, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10977-10982
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Waxy  crude  oil  Isothermal  structure
Résumé :	The rheological properties of waxy crude oil are dependent upon the shear and thermal histories. It would not be valuable to study the shear effect of waxy crude oil without consideration of the thermal conditions. Currently, researchers study the shear effect of waxy crude oil mainly with different cooling rates or shear temperatures; few studies have been reported about the influence of isothermal structure development on the shear effect. Present studies show that, even at constant temperature below the wax appearance temperature, the characteristics of the waxy crude gels undergo a change with quiescent duration, becoming harder and more stable. In this paper, a specimen of a typical waxy crude oil was held isothermally and quiescently for a time in the range of 0―60 min for structure development at temperatures close to the gelation temperature, followed by the application of constant stress in a wide range of 1―100 Pa at the same temperature. After subsequent cooling to below a temperature of 2 °C, the structure strength of waxy crude gel was examined by measurement of the static yield stress. This showed that the structure strength of waxy crude gel increased with isothermal aging, while the reversibility of the gel structure decreased. In cases of prior application of lower stresses (from 1 to 7 Pa), the situation of shorter aging time was easier to get a strain to overcome the critical strain, which represents the start of structure degradation, and hence induces a lower yield stress value after subsequent cooling. In cases where the specimen was prior loaded with higher stresses (from 10 to 100 Pa), the longer the aging time of structure development before prior stress application, the lower the yield stress tested after subsequent cooling.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie301047g

[article] Yield Behavior of Waxy Crude Gel : Effect of Isothermal Structure Development before Prior Applied Stress [texte imprimé] / Banglong Jia, Auteur ; Jinjun Zhang, Auteur . - 2012 . - pp. 10977-10982.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10977-10982

Mots-clés :	Waxy  crude  oil  Isothermal  structure
Résumé :	The rheological properties of waxy crude oil are dependent upon the shear and thermal histories. It would not be valuable to study the shear effect of waxy crude oil without consideration of the thermal conditions. Currently, researchers study the shear effect of waxy crude oil mainly with different cooling rates or shear temperatures; few studies have been reported about the influence of isothermal structure development on the shear effect. Present studies show that, even at constant temperature below the wax appearance temperature, the characteristics of the waxy crude gels undergo a change with quiescent duration, becoming harder and more stable. In this paper, a specimen of a typical waxy crude oil was held isothermally and quiescently for a time in the range of 0―60 min for structure development at temperatures close to the gelation temperature, followed by the application of constant stress in a wide range of 1―100 Pa at the same temperature. After subsequent cooling to below a temperature of 2 °C, the structure strength of waxy crude gel was examined by measurement of the static yield stress. This showed that the structure strength of waxy crude gel increased with isothermal aging, while the reversibility of the gel structure decreased. In cases of prior application of lower stresses (from 1 to 7 Pa), the situation of shorter aging time was easier to get a strain to overcome the critical strain, which represents the start of structure degradation, and hence induces a lower yield stress value after subsequent cooling. In cases where the specimen was prior loaded with higher stresses (from 10 to 100 Pa), the longer the aging time of structure development before prior stress application, the lower the yield stress tested after subsequent cooling.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie301047g

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10968-10976

Titre :	Electrical capacitance volume tomography imaging of three - dimensional flow structures and solids concentration distributions in a riser and a bend of a gas – solid circulating fluidized bed
Type de document :	texte imprimé
Auteurs :	Wang, Fei, Auteur ; Qussai Marashdeh, Auteur ; Aining Wang, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10968-10976
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Circulating  fluidized  bed  Fluidization  Gas  solid  Riser  Concentration  distribution  Three  dimensional  flow  Imaging  Tomography  Capacitance
Résumé :	Electrical capacitance volume tomography (ECVT) is a newly developed imaging technique that can quantify three-dimensional (3D) multiphase flows in a complex, geometric flow field. In this study, the 3D phase distribution images inside a gas―solid circulating fluidized bed (CFB) are obtained using ECVT. Specifically, measurements are made at a riser section and a 90° bend-shape riser exit section of the CFB. Inside the vertical riser, a symmetric core―annulus structure with a low solids holdup in the riser center along with a high solids holdup near the riser wall is observed. The average volume solids holdup and the thickness of the annulus decrease with the superficial gas velocity. A core―annulus flow structure is formed both in the vertical and horizontal parts of the bend. The annulus structure is noncentro-symmetric in the horizontal part of the bend. The solids holdup in the annulus near the top wall area in the bend is higher than that in other locations of the annulus. At a higher superficial gas velocity in the riser, the centrifugal acceleration increases due to high solids velocity in the bend, and more solids are separated to the outside of the bend from the main stream. A "reversed-S" shape solids holdup distribution along the diagonal line is also observed. The solids holdup increases and then decreases from the outer comer to the center of the bend, which indicates that a relatively dilute region is formed near the outer corner of the bend.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286471

[article] Electrical capacitance volume tomography imaging of three - dimensional flow structures and solids concentration distributions in a riser and a bend of a gas – solid circulating fluidized bed [texte imprimé] / Wang, Fei, Auteur ; Qussai Marashdeh, Auteur ; Aining Wang, Auteur . - 2012 . - pp. 10968-10976.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10968-10976

Mots-clés :	Circulating  fluidized  bed  Fluidization  Gas  solid  Riser  Concentration  distribution  Three  dimensional  flow  Imaging  Tomography  Capacitance
Résumé :	Electrical capacitance volume tomography (ECVT) is a newly developed imaging technique that can quantify three-dimensional (3D) multiphase flows in a complex, geometric flow field. In this study, the 3D phase distribution images inside a gas―solid circulating fluidized bed (CFB) are obtained using ECVT. Specifically, measurements are made at a riser section and a 90° bend-shape riser exit section of the CFB. Inside the vertical riser, a symmetric core―annulus structure with a low solids holdup in the riser center along with a high solids holdup near the riser wall is observed. The average volume solids holdup and the thickness of the annulus decrease with the superficial gas velocity. A core―annulus flow structure is formed both in the vertical and horizontal parts of the bend. The annulus structure is noncentro-symmetric in the horizontal part of the bend. The solids holdup in the annulus near the top wall area in the bend is higher than that in other locations of the annulus. At a higher superficial gas velocity in the riser, the centrifugal acceleration increases due to high solids velocity in the bend, and more solids are separated to the outside of the bend from the main stream. A "reversed-S" shape solids holdup distribution along the diagonal line is also observed. The solids holdup increases and then decreases from the outer comer to the center of the bend, which indicates that a relatively dilute region is formed near the outer corner of the bend.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286471

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10955-10967

Titre :	Lattice boltzmann method for simulation of solutal interfacial convection in gas – liquid system
Type de document :	texte imprimé
Auteurs :	Shuyong Chen, Auteur ; Bo Fu, Auteur ; Xigang Yuan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10955-10967
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Convection
Résumé :	Two approaches based on the lattice Boltzmann method (LBM), the two-BGK (Bhatnagar, Gross, and Krook)-equation LBM and the hybrid LBM―finite-difference method (FDM), were developed for simulations of solutal interfacial convection. Implementations of the gravity/buoyancy and surface tension forces and an interfacial perturbation model, namely, the self-renewal interface model, were proposed for the simulation of interfacial convection, including Rayleigh convection and Marangoni convection, in a gas―liquid mass transfer process. The simulation approaches and model were validated by experimentally measured data via the particle image velocimetry technique for the CO2―ethanol system. The performances of the two simulation methods presented in this paper are discussed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286470

[article] Lattice boltzmann method for simulation of solutal interfacial convection in gas – liquid system [texte imprimé] / Shuyong Chen, Auteur ; Bo Fu, Auteur ; Xigang Yuan, Auteur . - 2012 . - pp. 10955-10967.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10955-10967

Mots-clés :	Convection
Résumé :	Two approaches based on the lattice Boltzmann method (LBM), the two-BGK (Bhatnagar, Gross, and Krook)-equation LBM and the hybrid LBM―finite-difference method (FDM), were developed for simulations of solutal interfacial convection. Implementations of the gravity/buoyancy and surface tension forces and an interfacial perturbation model, namely, the self-renewal interface model, were proposed for the simulation of interfacial convection, including Rayleigh convection and Marangoni convection, in a gas―liquid mass transfer process. The simulation approaches and model were validated by experimentally measured data via the particle image velocimetry technique for the CO2―ethanol system. The performances of the two simulation methods presented in this paper are discussed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286470

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10949-10954

Titre :	Determination of mass - transfer coefficient of CO2 in NH3 and CO2 absorption by materials balance in a rotating packed bed
Type de document :	texte imprimé
Auteurs :	Baochang Sun, Auteur ; Haikui Zou, Auteur ; Guangwen Chu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10949-10954
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Packed  bed  Material  balance  Gas  absorption  Carbon  dioxide  Mass  transfer  Mass  transfer  coefficient
Résumé :	More-accurate overall mass-transfer coefficients in a rotating packed bed (RPB) and local mass-transfer coefficients in different regions of the RPB were deduced by the material balance in order to obtain practical volumetric mass-transfer coefficients in the RPB. Experimental studies on the overall volumetric mass-transfer coefficients (KGa) of CO2 in NH3 and CO2 absorption into water in the RPB was carried out under different conditions. The experimental results indicated that there was a great difference between the value of KGa and KGa* attained by different boundary conditions. And it was concluded that an accurate design equation should be adopted to achieve a practical value of KGa in the RPB. It was also found that the KGa of CO2 increased with the increase of rotation speed, liquid volumetric flow rate, gas volumetric flow rate, NH3/CO2 molar ratio, and the decrease of temperature. The KGa of CO2 in the simultaneous absorption process of NH3 and CO2 was 2―6 times higher than that in the single CO2 absorption process.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286469

[article] Determination of mass - transfer coefficient of CO2 in NH3 and CO2 absorption by materials balance in a rotating packed bed [texte imprimé] / Baochang Sun, Auteur ; Haikui Zou, Auteur ; Guangwen Chu, Auteur . - 2012 . - pp. 10949-10954.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10949-10954

Mots-clés :	Packed  bed  Material  balance  Gas  absorption  Carbon  dioxide  Mass  transfer  Mass  transfer  coefficient
Résumé :	More-accurate overall mass-transfer coefficients in a rotating packed bed (RPB) and local mass-transfer coefficients in different regions of the RPB were deduced by the material balance in order to obtain practical volumetric mass-transfer coefficients in the RPB. Experimental studies on the overall volumetric mass-transfer coefficients (KGa) of CO2 in NH3 and CO2 absorption into water in the RPB was carried out under different conditions. The experimental results indicated that there was a great difference between the value of KGa and KGa* attained by different boundary conditions. And it was concluded that an accurate design equation should be adopted to achieve a practical value of KGa in the RPB. It was also found that the KGa of CO2 increased with the increase of rotation speed, liquid volumetric flow rate, gas volumetric flow rate, NH3/CO2 molar ratio, and the decrease of temperature. The KGa of CO2 in the simultaneous absorption process of NH3 and CO2 was 2―6 times higher than that in the single CO2 absorption process.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286469

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10936-10948

Titre :	Mechanism of particle transport in a fully developed wake flow
Type de document :	texte imprimé
Auteurs :	Jun Yao, Auteur ; Yanlin Zhao, Auteur ; Ning Li, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10936-10948
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Wake  Particle  transport
Résumé :	In this paper, the time-dependent Navier-Stokes equations were integrated in time using a mixed explicit-implicit operator splitting rules. The spatial discretization was processed using the spectral-element method. Nonreflecting conditions were employed at the outflow boundary. Particles were traced by the Lagrangian approach based on one-way coupling between the continuous and the disperse phases. The simulation results of the flow field agree well with experimental data. Particles (St = 4) are found to concentrate in the regions between adjacent vortex structures (RAVS) together with other particles dispersed outside of vortex outlining the boundaries of the large-scale vortex structures, which is independent of the flow Reynolds number. Due to U-velocity component difference, at the entrance of RAVS the flow does "compact" on particles causing particle concentration, and it increases with the flow Reynolds number and particle size. The mechanism of particle transport in the wake flow mostly depends on the strong interactions between two alternative and successive shedding vortex structures with opposite sign. Particle transport in the wake flow could be briefly described as follows: moving around vortices and going ahead with vortices.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286468

[article] Mechanism of particle transport in a fully developed wake flow [texte imprimé] / Jun Yao, Auteur ; Yanlin Zhao, Auteur ; Ning Li, Auteur . - 2012 . - pp. 10936-10948.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10936-10948

Mots-clés :	Wake  Particle  transport
Résumé :	In this paper, the time-dependent Navier-Stokes equations were integrated in time using a mixed explicit-implicit operator splitting rules. The spatial discretization was processed using the spectral-element method. Nonreflecting conditions were employed at the outflow boundary. Particles were traced by the Lagrangian approach based on one-way coupling between the continuous and the disperse phases. The simulation results of the flow field agree well with experimental data. Particles (St = 4) are found to concentrate in the regions between adjacent vortex structures (RAVS) together with other particles dispersed outside of vortex outlining the boundaries of the large-scale vortex structures, which is independent of the flow Reynolds number. Due to U-velocity component difference, at the entrance of RAVS the flow does "compact" on particles causing particle concentration, and it increases with the flow Reynolds number and particle size. The mechanism of particle transport in the wake flow mostly depends on the strong interactions between two alternative and successive shedding vortex structures with opposite sign. Particle transport in the wake flow could be briefly described as follows: moving around vortices and going ahead with vortices.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286468

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10930–10935

Titre :	Salting - Out effect on recovery of 1,3 - propanediol from fermentation broth
Type de document :	texte imprimé
Auteurs :	Ho Shing Wu, Auteur ; Yan Jie Wang, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10930–10935
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Separation  propanediol
Résumé :	This study investigated the separation of 1,3-propanediol from a fermentation broth produced using Klebsiella pneumoniae. Salting-out extraction was used to separate 1,3-propanediol using one-salt and two-salt systems. The highest distribution coefficient and recovery of 1,3-propanediol between pentanol and an aqueous solution of a single-salt system using sodium phosphate (0.4 g/mL) were 3.72% and 72%, respectively; and 2.52% and 65.6%, respectively, when using sodium sulfate (0.4 g/mL). For the two-salt system using sodium phosphate (0.4 g/mL) and sodium sulfate (0.2 g/mL), the results were 47.2% and 92.5%, respectively. The stripping recovery of 1,3-propanediol using pure water was approximately 90%.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300404t

[article] Salting - Out effect on recovery of 1,3 - propanediol from fermentation broth [texte imprimé] / Ho Shing Wu, Auteur ; Yan Jie Wang, Auteur . - 2012 . - pp. 10930–10935.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10930–10935

Mots-clés :	Separation  propanediol
Résumé :	This study investigated the separation of 1,3-propanediol from a fermentation broth produced using Klebsiella pneumoniae. Salting-out extraction was used to separate 1,3-propanediol using one-salt and two-salt systems. The highest distribution coefficient and recovery of 1,3-propanediol between pentanol and an aqueous solution of a single-salt system using sodium phosphate (0.4 g/mL) were 3.72% and 72%, respectively; and 2.52% and 65.6%, respectively, when using sodium sulfate (0.4 g/mL). For the two-salt system using sodium phosphate (0.4 g/mL) and sodium sulfate (0.2 g/mL), the results were 47.2% and 92.5%, respectively. The stripping recovery of 1,3-propanediol using pure water was approximately 90%.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300404t

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10921–10929

Titre :	Adsorption and desorption behavior of lithium ion in spherical PVC – MnO2 ion sieve
Type de document :	texte imprimé
Auteurs :	Guoping Xiao, Auteur ; Kefeng Tong, Auteur ; Longsheng Zhou, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10921–10929
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Adsorption  Lithium  Ion
Résumé :	A spherical PVC–MnO2 ion sieve of 2.0–3.5 mm diameter was prepared by the antisolvent method using synthesized Li4Mn5O12 ultrafine powder as the precursor, poly(vinyl chloride) as the binder, and N-methyl-2-pyrrolidone as solvent. Batch experiments of the adsorption capacity (isotherm) and adsorption rate of Li+ on the spherical PVC–MnO2 ion sieve were studied. Spherical PVC–MnO2 had a high adsorption capacity for Li+, and the isotherm data were well fitted by the Langmuir model; the adsorption kinetics were well described by the Lagergren equation. Furthermore, a mathematical model was set up to calculate the film mass transfer coefficient (kf) and pore diffusivity (Dp) of the adsorbent. Continuous flow experiments for study of Li+ adsorption breakthrough and the subsequent desorption (elution) in a PVC–MnO2 packed column were carried out employing six feed solutions of various pH values and concentrations of Li+, Na+, K+, and Mg2+ for simulating brine samples of various salt lakes and/or seawaters. After the adsorption treatment to concentrate the Li+ on PVC–MnO2, the column was regenerated by 1.0 mol/L HCl which supplied H+ to accomplish elution of the adsorbed Li+ by ion exchange. The experimental results demonstrate that PVC–MnO2 had high selectivity for Li+ and that its adsorption of Li+ from the feed were little affected by Na+, K+, and Mg2+ also present in the feed solution. Spherical PVC–MnO2 is an attractive medium for large scale lithium extraction from brine or seawater.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300087s

[article] Adsorption and desorption behavior of lithium ion in spherical PVC – MnO2 ion sieve [texte imprimé] / Guoping Xiao, Auteur ; Kefeng Tong, Auteur ; Longsheng Zhou, Auteur . - 2012 . - pp. 10921–10929.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10921–10929

Mots-clés :	Adsorption  Lithium  Ion
Résumé :	A spherical PVC–MnO2 ion sieve of 2.0–3.5 mm diameter was prepared by the antisolvent method using synthesized Li4Mn5O12 ultrafine powder as the precursor, poly(vinyl chloride) as the binder, and N-methyl-2-pyrrolidone as solvent. Batch experiments of the adsorption capacity (isotherm) and adsorption rate of Li+ on the spherical PVC–MnO2 ion sieve were studied. Spherical PVC–MnO2 had a high adsorption capacity for Li+, and the isotherm data were well fitted by the Langmuir model; the adsorption kinetics were well described by the Lagergren equation. Furthermore, a mathematical model was set up to calculate the film mass transfer coefficient (kf) and pore diffusivity (Dp) of the adsorbent. Continuous flow experiments for study of Li+ adsorption breakthrough and the subsequent desorption (elution) in a PVC–MnO2 packed column were carried out employing six feed solutions of various pH values and concentrations of Li+, Na+, K+, and Mg2+ for simulating brine samples of various salt lakes and/or seawaters. After the adsorption treatment to concentrate the Li+ on PVC–MnO2, the column was regenerated by 1.0 mol/L HCl which supplied H+ to accomplish elution of the adsorbed Li+ by ion exchange. The experimental results demonstrate that PVC–MnO2 had high selectivity for Li+ and that its adsorption of Li+ from the feed were little affected by Na+, K+, and Mg2+ also present in the feed solution. Spherical PVC–MnO2 is an attractive medium for large scale lithium extraction from brine or seawater.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300087s

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10910-10920

Titre :	Nonlinear and non - gaussian dynamic batch process monitoring using a new multiway kernel independent component analysis and multidimensional mutual information based dissimilarity approach
Type de document :	texte imprimé
Auteurs :	Mudassir M. Rashid, Auteur ; Jie Yu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10910-10920
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Independent  component  analysis  Surveillance  Batchwise
Résumé :	Batch or semibatch process monitoring is a challenging task because of various factors such as strong nonlinearity, inherent time-varying dynamics, batch-to-batch variations, and multiple operating phases. In this article, a novel nonlinear and non-Gaussian dissimilarity method based on multiway kernel independent component analysis (MKICA) and multidimensional mutual information (MMI) is developed and applied to batch process monitoring and abnormal event detection. MKICA models are first built on the normal benchmark and monitored batches to characterize the nonlinear and non-Gaussian variable relationship of batch processes. Then, the kernel independent component (IC) subspaces are extracted from the benchmark and monitored batches. Further, a multidimensional mutual information based dissimilarity index is defined to quantitatively evaluate the statistical dependence between the benchmark and monitored subspaces through the moving-window strategy. With the corresponding control limit estimated from the kernel density function, the integrated MKICA―MMI index can be used to detect the abnormal events in dynamic batch processes. The effectiveness of the proposed batch process monitoring approach is demonstrated using the fed-batch penicillin fermentation process, and its performance is compared to that of the MKICA method. The computational results show that the presented dissimilarity approach is faster and more accurate in detecting different types of process faults.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286465

[article] Nonlinear and non - gaussian dynamic batch process monitoring using a new multiway kernel independent component analysis and multidimensional mutual information based dissimilarity approach [texte imprimé] / Mudassir M. Rashid, Auteur ; Jie Yu, Auteur . - 2012 . - pp. 10910-10920.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10910-10920

Mots-clés :	Independent  component  analysis  Surveillance  Batchwise
Résumé :	Batch or semibatch process monitoring is a challenging task because of various factors such as strong nonlinearity, inherent time-varying dynamics, batch-to-batch variations, and multiple operating phases. In this article, a novel nonlinear and non-Gaussian dissimilarity method based on multiway kernel independent component analysis (MKICA) and multidimensional mutual information (MMI) is developed and applied to batch process monitoring and abnormal event detection. MKICA models are first built on the normal benchmark and monitored batches to characterize the nonlinear and non-Gaussian variable relationship of batch processes. Then, the kernel independent component (IC) subspaces are extracted from the benchmark and monitored batches. Further, a multidimensional mutual information based dissimilarity index is defined to quantitatively evaluate the statistical dependence between the benchmark and monitored subspaces through the moving-window strategy. With the corresponding control limit estimated from the kernel density function, the integrated MKICA―MMI index can be used to detect the abnormal events in dynamic batch processes. The effectiveness of the proposed batch process monitoring approach is demonstrated using the fed-batch penicillin fermentation process, and its performance is compared to that of the MKICA method. The computational results show that the presented dissimilarity approach is faster and more accurate in detecting different types of process faults.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286465

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10895-10909

Titre :	Minimization of attrition and breakage in an airlift crystallizer
Type de document :	texte imprimé
Auteurs :	Anamaria Soare, Auteur ; Richard Lakerveld, Auteur ; Jurjen van Royen, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10895-10909
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Crystallizer  Attrition
Résumé :	Minimization of secondary nucleation by attrition in industrial crystallizers is a major challenge. In this work, a novel airlift crystallizer has been designed, constructed, and experimentally tested aiming at the reduction of attrition by using air for mixing instead of a stirrer or a circulation pump. It is experimentally demonstrated that in this crystallizer ideal growth, i.e., growth of crystals without any nucleation, can be approached up to a seeding load of 0.5% and crystal size of up to 600 μm. Attrition is considerably decreased in an airlift crystallizer compared to conventional impeller-mixed crystallizers. This air-mixed crystallizer enables the production of crystals of high quality and offers a large flexibility of the final crystal size by manipulating the air flow rate and the sparger design. Comparison of different designs showed a large effect of a gas disengagement zone on the performance of the crystallizer, especially when large crystals were desired. The disengagement zone allows high circulation velocities and thus good mixing without entrainment of the gas bubbles in the downcomer, approaching a uniform suspension of the crystals.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286464

[article] Minimization of attrition and breakage in an airlift crystallizer [texte imprimé] / Anamaria Soare, Auteur ; Richard Lakerveld, Auteur ; Jurjen van Royen, Auteur . - 2012 . - pp. 10895-10909.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10895-10909

Mots-clés :	Crystallizer  Attrition
Résumé :	Minimization of secondary nucleation by attrition in industrial crystallizers is a major challenge. In this work, a novel airlift crystallizer has been designed, constructed, and experimentally tested aiming at the reduction of attrition by using air for mixing instead of a stirrer or a circulation pump. It is experimentally demonstrated that in this crystallizer ideal growth, i.e., growth of crystals without any nucleation, can be approached up to a seeding load of 0.5% and crystal size of up to 600 μm. Attrition is considerably decreased in an airlift crystallizer compared to conventional impeller-mixed crystallizers. This air-mixed crystallizer enables the production of crystals of high quality and offers a large flexibility of the final crystal size by manipulating the air flow rate and the sparger design. Comparison of different designs showed a large effect of a gas disengagement zone on the performance of the crystallizer, especially when large crystals were desired. The disengagement zone allows high circulation velocities and thus good mixing without entrainment of the gas bubbles in the downcomer, approaching a uniform suspension of the crystals.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286464

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10887-10894

Titre :	Automatic grading of TFT – LCD glass substrates using optimized support vector machines
Type de document :	texte imprimé
Auteurs :	Ali Yousefian Jazi, Auteur ; Seongkyu Yoon, Auteur ; J. Jay Liu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10887-10894
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Glass
Résumé :	The visual appearance of manufactured products is often one of the major quality attributes for certain types of products, which are used mainly for display purposes or used as the exterior part of other products. TFT―LCD (thin film transistor―liquid crystal display) glass substrates can serve as a representative case. In such cases, visual quality (i.e., visual appearance), as well as the physical or mechanical quality attributes, has to be controlled or maintained. This paper presents an industrial case study of a machine vision methodology for the automatic grading of TFT―LCD glass substrates. In this case study, a classification model was developed using support vector machine (SVM), optimized via the simulated annealing (SA) algorithm. Parallel genetic algorithm (PGA) was also used to reduce the number of features for classification. The results show that utilization of an optimized SVM approach with SA in classification of TFT―LCD glass defects could be a viable alternative to manual classification in the TFT―LCD glass substrate industry.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286463

[article] Automatic grading of TFT – LCD glass substrates using optimized support vector machines [texte imprimé] / Ali Yousefian Jazi, Auteur ; Seongkyu Yoon, Auteur ; J. Jay Liu, Auteur . - 2012 . - pp. 10887-10894.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10887-10894

Mots-clés :	Glass
Résumé :	The visual appearance of manufactured products is often one of the major quality attributes for certain types of products, which are used mainly for display purposes or used as the exterior part of other products. TFT―LCD (thin film transistor―liquid crystal display) glass substrates can serve as a representative case. In such cases, visual quality (i.e., visual appearance), as well as the physical or mechanical quality attributes, has to be controlled or maintained. This paper presents an industrial case study of a machine vision methodology for the automatic grading of TFT―LCD glass substrates. In this case study, a classification model was developed using support vector machine (SVM), optimized via the simulated annealing (SA) algorithm. Parallel genetic algorithm (PGA) was also used to reduce the number of features for classification. The results show that utilization of an optimized SVM approach with SA in classification of TFT―LCD glass defects could be a viable alternative to manual classification in the TFT―LCD glass substrate industry.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286463

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10881–10886

Titre :	Pressure - swing distillation for minimum - and maximum - boiling homogeneous azeotropes
Type de document :	texte imprimé
Auteurs :	William L. Luyben, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10881–10886
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Azeotropic  distillation
Résumé :	Pressure-swing azeotropic distillation uses two columns operating at two different pressures to separate azeotropic mixtures by taking high-purity product streams from one end of the columns and recycling the streams from the other end with compositions near the two azeotropes. This configuration can be economically used when changes in pressure significantly shift the composition of the azeotrope. The larger the shift, the smaller the required recycle flow rates, so the smaller the energy requirements in the two reboilers. Pressure-swing distillation can be applied to both minimum-boiling and maximum-boiling homogeneous azeotropic mixtures. With minimum-boiling systems, the distillate streams are recycled. With maximum-boiling systems, the bottoms streams are recycled. Intuition would lead us to expect that recycling distillate streams would be more energy intensive than recycling bottoms streams. A distillate recycle must be boiled up in the column. A bottoms recycle stream is not boiled up. Therefore, we would expect that less pressure sensitivity of the azeotropic mixture would be required to make the pressure-swing configuration in a maximum-boiling system economical than in a minimum-boiling system. The purpose of this article is to explore this question. The results show that there is very little difference between the two systems in terms of the effect of pressure sensitivity and energy consumption.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3002414

[article] Pressure - swing distillation for minimum - and maximum - boiling homogeneous azeotropes [texte imprimé] / William L. Luyben, Auteur . - 2012 . - pp. 10881–10886.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10881–10886

Mots-clés :	Azeotropic  distillation
Résumé :	Pressure-swing azeotropic distillation uses two columns operating at two different pressures to separate azeotropic mixtures by taking high-purity product streams from one end of the columns and recycling the streams from the other end with compositions near the two azeotropes. This configuration can be economically used when changes in pressure significantly shift the composition of the azeotrope. The larger the shift, the smaller the required recycle flow rates, so the smaller the energy requirements in the two reboilers. Pressure-swing distillation can be applied to both minimum-boiling and maximum-boiling homogeneous azeotropic mixtures. With minimum-boiling systems, the distillate streams are recycled. With maximum-boiling systems, the bottoms streams are recycled. Intuition would lead us to expect that recycling distillate streams would be more energy intensive than recycling bottoms streams. A distillate recycle must be boiled up in the column. A bottoms recycle stream is not boiled up. Therefore, we would expect that less pressure sensitivity of the azeotropic mixture would be required to make the pressure-swing configuration in a maximum-boiling system economical than in a minimum-boiling system. The purpose of this article is to explore this question. The results show that there is very little difference between the two systems in terms of the effect of pressure sensitivity and energy consumption.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3002414

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10869–10880

Titre :	Conventional proportional – integral (PI) control of dividing wall distillation columns : Systematic tuning
Type de document :	texte imprimé
Auteurs :	Alan Martin Zavala-Guzman, Auteur ; Héctor Hernández-Escoto, Auteur ; Salvador Hernandez, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10869–10880
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Wall  distillation  columns
Résumé :	This work addresses the systematic tuning of proportional–integral (PI) controllers for dividing wall distillation columns. By following an approach of stable pole assignment to a linear dynamics that approximately describes the control system convergence, a technique results that forces the gains of controllers to be dependent on well-known parameters for each control loop: a static gain and a time constant that characterize the open-loop response of the output with respect to the control input, and a damping factor and a response velocity that outline the path of the closed-loop response. Then, it becomes possible to tune all the controllers in a simultaneous way, substantially reducing trial-and-error activities on tuning the entire control system. Via simulation, the control system performance is illustrated for disturbance rejection and set-point tracking in a representative dividing wall distillation column, showing that this tuning technique is an effective choice.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300237d

[article] Conventional proportional – integral (PI) control of dividing wall distillation columns : Systematic tuning [texte imprimé] / Alan Martin Zavala-Guzman, Auteur ; Héctor Hernández-Escoto, Auteur ; Salvador Hernandez, Auteur . - 2012 . - pp. 10869–10880.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10869–10880

Mots-clés :	Wall  distillation  columns
Résumé :	This work addresses the systematic tuning of proportional–integral (PI) controllers for dividing wall distillation columns. By following an approach of stable pole assignment to a linear dynamics that approximately describes the control system convergence, a technique results that forces the gains of controllers to be dependent on well-known parameters for each control loop: a static gain and a time constant that characterize the open-loop response of the output with respect to the control input, and a damping factor and a response velocity that outline the path of the closed-loop response. Then, it becomes possible to tune all the controllers in a simultaneous way, substantially reducing trial-and-error activities on tuning the entire control system. Via simulation, the control system performance is illustrated for disturbance rejection and set-point tracking in a representative dividing wall distillation column, showing that this tuning technique is an effective choice.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300237d

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10860-10868

Titre :	Development of an agent - based modeling methodology for an industrial byproduct exchange network design
Type de document :	texte imprimé
Auteurs :	Hyunjoo Kim, Auteur ; Jun-Hyung Ryu, Auteur ; In-Beum Lee, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10860-10868
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Design  Modeling
Résumé :	Byproduct exchange networks are attracting increasing attention to allow the use of byproducts that would have otherwise been discarded. To take full advantage of the benefits, it is necessary to consider the interacting features between the participating byproduct buyers and sellers in terms of both economic and environmental perspectives. This paper proposes an agent-based modeling framework as an alternative. A case of water reuse networks in an iron and steel manufacturing industrial park is presented to illustrate the applicability of the proposed framework.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286460

[article] Development of an agent - based modeling methodology for an industrial byproduct exchange network design [texte imprimé] / Hyunjoo Kim, Auteur ; Jun-Hyung Ryu, Auteur ; In-Beum Lee, Auteur . - 2012 . - pp. 10860-10868.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10860-10868

Mots-clés :	Design  Modeling
Résumé :	Byproduct exchange networks are attracting increasing attention to allow the use of byproducts that would have otherwise been discarded. To take full advantage of the benefits, it is necessary to consider the interacting features between the participating byproduct buyers and sellers in terms of both economic and environmental perspectives. This paper proposes an agent-based modeling framework as an alternative. A case of water reuse networks in an iron and steel manufacturing industrial park is presented to illustrate the applicability of the proposed framework.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286460

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10848–10859

Titre :	Process Goose Queue (PGQ)Approaches toward plantwide process optimization with applications in supervision - driven real - time optimization
Type de document :	texte imprimé
Auteurs :	Hongguang Li, Auteur ; Jingwen Huang, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10848–10859
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Plantwide  process  Optimization
Résumé :	Inspired by the biologic nature of flying geese, process goose queue (PGQ) approaches toward plantwide process optimization are explicitly introduced in this paper along with applications in real-time optimization (RTO). Taking advantage of ad-hoc PGQ metrics, process variables associated with a process unit could be accordingly identical with geese positions of a PGQ. Motivated by the self-organization in flight formation of geese, a process unit can achieve such an optimum formation that every goose in the PGQ benefits from the maximum upwash. In this sense, adjustment rules invoked to track the ideal PGQ formulation are accommodated. Followed by this idea, a plantwide process is first decomposed into several hierarchically connected multilayer PGQs. Subsequently, a plantwide PGQ which includes a PGQ-objective and several multilayer PGQs is constructed, which contributes to solving complex plantwide process optimization problems in a novel way. As applications of PGQ approaches, we initially address a supervision-driven RTO issue concerning economic performance deterioration caused by process supervision. A process unit whose variables are shifted by human operators can be regarded as an ill-PGQ which would trigger the autonomous adjustments of the plantwide PGQ. Enabling algorithms concerning adjustment sequence of the plantwide PGQ with an ill-PGQ are constructed, which are generally characterized by ill-PGQ detection, PGQ follow-up, and PGQ-objective achievement. To demonstrate the feasibility and validity of this contribution, the Tennessee Eastman (TE) benchmark process is employed as an extensive case study, showing that the proposed approaches particularly enjoy considerable computational simplicity in contrast with traditional global optimization strategies.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300374g

[article] Process Goose Queue (PGQ)Approaches toward plantwide process optimization with applications in supervision - driven real - time optimization [texte imprimé] / Hongguang Li, Auteur ; Jingwen Huang, Auteur . - 2012 . - pp. 10848–10859.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10848–10859

Mots-clés :	Plantwide  process  Optimization
Résumé :	Inspired by the biologic nature of flying geese, process goose queue (PGQ) approaches toward plantwide process optimization are explicitly introduced in this paper along with applications in real-time optimization (RTO). Taking advantage of ad-hoc PGQ metrics, process variables associated with a process unit could be accordingly identical with geese positions of a PGQ. Motivated by the self-organization in flight formation of geese, a process unit can achieve such an optimum formation that every goose in the PGQ benefits from the maximum upwash. In this sense, adjustment rules invoked to track the ideal PGQ formulation are accommodated. Followed by this idea, a plantwide process is first decomposed into several hierarchically connected multilayer PGQs. Subsequently, a plantwide PGQ which includes a PGQ-objective and several multilayer PGQs is constructed, which contributes to solving complex plantwide process optimization problems in a novel way. As applications of PGQ approaches, we initially address a supervision-driven RTO issue concerning economic performance deterioration caused by process supervision. A process unit whose variables are shifted by human operators can be regarded as an ill-PGQ which would trigger the autonomous adjustments of the plantwide PGQ. Enabling algorithms concerning adjustment sequence of the plantwide PGQ with an ill-PGQ are constructed, which are generally characterized by ill-PGQ detection, PGQ follow-up, and PGQ-objective achievement. To demonstrate the feasibility and validity of this contribution, the Tennessee Eastman (TE) benchmark process is employed as an extensive case study, showing that the proposed approaches particularly enjoy considerable computational simplicity in contrast with traditional global optimization strategies.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300374g

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10840-10847

Titre :	Process - induced morphology distribution in injection molded syndiotactic polystyrene samples
Type de document :	texte imprimé
Auteurs :	Roberto Pantani, Auteur ; Andrea Sorrentino, Auteur ; Vito Speranza, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10840-10847
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Morphology
Résumé :	In this work, syndiotactic polystyrene was injection molded with different molding conditions. The morphology distribution inside the molded parts was analyzed by several techniques, including optical microscopy, IR spectroscopy, and X-ray diffraction. The final morphology distribution was found to be strongly affected by mold temperature and holding pressures. A peculiar morphology distribution, an alternation of several amorphous and crystalline layers, was found along the samples thickness. The experimental results were analyzed and discussed by means of a software code developed at the University of Salerno. The software implements a model for crystallinity evolution that is able to consider the effects of high cooling rates and high pressures. Furthermore, the software is able to predict the orientation evolution during the injection molding. On commenting on the differences between the experimental data and the model predictions for crystallinity and orientation, it was possible to gain some insights on the causes of the peculiar morphology distributions inside the molded samples.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286458

[article] Process - induced morphology distribution in injection molded syndiotactic polystyrene samples [texte imprimé] / Roberto Pantani, Auteur ; Andrea Sorrentino, Auteur ; Vito Speranza, Auteur . - 2012 . - pp. 10840-10847.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10840-10847

Mots-clés :	Morphology
Résumé :	In this work, syndiotactic polystyrene was injection molded with different molding conditions. The morphology distribution inside the molded parts was analyzed by several techniques, including optical microscopy, IR spectroscopy, and X-ray diffraction. The final morphology distribution was found to be strongly affected by mold temperature and holding pressures. A peculiar morphology distribution, an alternation of several amorphous and crystalline layers, was found along the samples thickness. The experimental results were analyzed and discussed by means of a software code developed at the University of Salerno. The software implements a model for crystallinity evolution that is able to consider the effects of high cooling rates and high pressures. Furthermore, the software is able to predict the orientation evolution during the injection molding. On commenting on the differences between the experimental data and the model predictions for crystallinity and orientation, it was possible to gain some insights on the causes of the peculiar morphology distributions inside the molded samples.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286458

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10833–10839

Titre :	Molecular dynamics simulations of PAA – PMA polyelectrolyte copolymers in dilute aqueous solution : Chain conformations and hydration properties
Type de document :	texte imprimé
Auteurs :	Muralidharan S. Sulatha, Auteur ; Upendra Natarajan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10833–10839
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Dynamics  simulations  Aqueous  solution
Résumé :	Atomistic molecular dynamics simulations of copolymers of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMA) in dilute aqueous solution were performed as a function of charge density, in explicit solvent medium and counterions. The studied polyelectrolytes follow a general behavior of chain expansion with charge density until a point where the repulsion between the electrostatic charges between the anionic residues is effectively neutralized by the counterions. The average persistence length is found to increase and levels off at higher charge densities, and the values imply the chains to be flexible. With increase in PMA content in the chain, counterions show increased correlation with chain backbone and a systematic reduction in the number of water molecules in the first hydration shell. The intermittent hydrogen-bond correlation function for the hydrogen bonds between the chain residues and water decays faster for PAA chain as compared to PMA, indicating a rigid hydration layer for the latter. The shorter H-bond lifetimes coupled with the slower relaxation indicate that MA–water H-bonds break more easily than those of AA–water H-bonds, but the water molecules remain in the vicinity of the chain because of slow diffusivity and can easily reform the bonds.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie301244n

[article] Molecular dynamics simulations of PAA – PMA polyelectrolyte copolymers in dilute aqueous solution : Chain conformations and hydration properties [texte imprimé] / Muralidharan S. Sulatha, Auteur ; Upendra Natarajan, Auteur . - 2012 . - pp. 10833–10839.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10833–10839

Mots-clés :	Dynamics  simulations  Aqueous  solution
Résumé :	Atomistic molecular dynamics simulations of copolymers of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMA) in dilute aqueous solution were performed as a function of charge density, in explicit solvent medium and counterions. The studied polyelectrolytes follow a general behavior of chain expansion with charge density until a point where the repulsion between the electrostatic charges between the anionic residues is effectively neutralized by the counterions. The average persistence length is found to increase and levels off at higher charge densities, and the values imply the chains to be flexible. With increase in PMA content in the chain, counterions show increased correlation with chain backbone and a systematic reduction in the number of water molecules in the first hydration shell. The intermittent hydrogen-bond correlation function for the hydrogen bonds between the chain residues and water decays faster for PAA chain as compared to PMA, indicating a rigid hydration layer for the latter. The shorter H-bond lifetimes coupled with the slower relaxation indicate that MA–water H-bonds break more easily than those of AA–water H-bonds, but the water molecules remain in the vicinity of the chain because of slow diffusivity and can easily reform the bonds.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie301244n

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10824–10832

Titre :	Studies of the thermal and mechanical properties of poly(urethane – siloxane)s cross - linked by hyperbranched polyesters
Type de document :	texte imprimé
Auteurs :	Jasna V. Dzunuzovic, Auteur ; Marija V. Pergal, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10824–10832
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Thermal  mechanical  properties
Résumé :	Polyurethane networks based on Boltorn hyperbranched polyesters (HBPs) of different pseudogenerations as cross-linkers, α,ω-dihydroxy(ethylene oxide–poly(dimethylsiloxane)–ethylene oxide) (EO–PDMS–EO) and 4,4′-methylenediphenyl diisocyanate were synthesized using a two-step polymerization reaction in solution. The influence of the pseudogeneration number of Boltorn HBPs on the thermomechanical and thermal properties and morphologies of polyurethane networks was investigated using FTIR, DMTA, TGA, hardness measurements, SEM, and SAXS. Synthesized polyurethanes showed higher cross-linking density and hardness and lower thermal stability with increasing pseudogeneration number of HBP. Samples with lower EO–PDMS–EO content exhibited slightly better thermal stability and higher hardness. All utilized characterization methods yielded consistent results and confirmed the existence of microphase separated morphology with the appearance of certain microphase mixing between segments as the pseudogeneration number of HBP increased. The obtained results revealed that the synthesized polyurethanes have good thermal and thermomechanical properties, which can be tailored by changing the pseudogeneration number of the HBP or the EO–PDMS–EO content.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300927z

[article] Studies of the thermal and mechanical properties of poly(urethane – siloxane)s cross - linked by hyperbranched polyesters [texte imprimé] / Jasna V. Dzunuzovic, Auteur ; Marija V. Pergal, Auteur . - 2012 . - pp. 10824–10832.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10824–10832

Mots-clés :	Thermal  mechanical  properties
Résumé :	Polyurethane networks based on Boltorn hyperbranched polyesters (HBPs) of different pseudogenerations as cross-linkers, α,ω-dihydroxy(ethylene oxide–poly(dimethylsiloxane)–ethylene oxide) (EO–PDMS–EO) and 4,4′-methylenediphenyl diisocyanate were synthesized using a two-step polymerization reaction in solution. The influence of the pseudogeneration number of Boltorn HBPs on the thermomechanical and thermal properties and morphologies of polyurethane networks was investigated using FTIR, DMTA, TGA, hardness measurements, SEM, and SAXS. Synthesized polyurethanes showed higher cross-linking density and hardness and lower thermal stability with increasing pseudogeneration number of HBP. Samples with lower EO–PDMS–EO content exhibited slightly better thermal stability and higher hardness. All utilized characterization methods yielded consistent results and confirmed the existence of microphase separated morphology with the appearance of certain microphase mixing between segments as the pseudogeneration number of HBP increased. The obtained results revealed that the synthesized polyurethanes have good thermal and thermomechanical properties, which can be tailored by changing the pseudogeneration number of the HBP or the EO–PDMS–EO content.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300927z

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10800–10823

Titre :	Investigation of different drug deposition techniques on drug releasing properties of cardiovascular drug coated balloons
Type de document :	texte imprimé
Auteurs :	Pankaj J. Gandhi, Auteur ; Zagabathuni Venkata Panchakshari Murthy, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10800–10823
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Techniques  Drug  Releasing  Properties
Résumé :	The advent of the drug eluting stent (DES) has changed the management of coronary vessel revascularization very effectively. However, a DES imposes risk of long-term adverse clinical events such as inadequate vascular endothelization, inflammatory response, and stent thrombosis. A drug coated balloon offers advantages of deploying antiproliferative drugs at blocked lesions while eliminating the long-term risk associated with drug eluting stents. The major mechanism of drug delivery from this coated balloon involves adsorption of drug particles on inner lumen of coronary artery upon balloon expansion after which drug diffuses to the inner layers due to the concentration gradient. The major challenges in engineering such drug delivery devices are (1) to retain majority amount of drug on balloon during tracking and (2) program faster drug delivery within shorter exposure time. In the current research work, we have adopted different drug coating methods such as dip coating, brush coating, coating with ultrasonic atomization, and coating with air brush spray method to coat nanoparticles of Sirolimus drug encapsulated in phospholipids. For each of the methods, samples were studied for drug loading, coating integrity, and release characteristics of the Sirolimus coated balloon. An arterial path was simulated to measure the amount of drug loss during navigation and tracking. Drug release was measured for each of the coated system in phosphated buffer saline (PBS) solution of pH 7.4 and in Hank’s solution of 7.4 pH at 37 °C at different time intervals. Also, the sample surface was analyzed for coating integrity after coating, after tracking, and after drug release. The resultant surface characteristics were correlated to the stages of balloon coating, tracking, and drug release, respectively. Among the different coating techniques employed, the method that was best in terms of coating durability and release effectiveness was further investigated for the drug release mechanism using available mathematical models. The analyses of drug loading on balloon surfaces and drug release from balloon surfaces were evaluated with the help of different statistical techniques. It is found that release of drug was not purely under influence of diffusion but mechanical abrasion during balloon expansion also played vital role.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3006676

[article] Investigation of different drug deposition techniques on drug releasing properties of cardiovascular drug coated balloons [texte imprimé] / Pankaj J. Gandhi, Auteur ; Zagabathuni Venkata Panchakshari Murthy, Auteur . - 2012 . - pp. 10800–10823.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10800–10823

Mots-clés :	Techniques  Drug  Releasing  Properties
Résumé :	The advent of the drug eluting stent (DES) has changed the management of coronary vessel revascularization very effectively. However, a DES imposes risk of long-term adverse clinical events such as inadequate vascular endothelization, inflammatory response, and stent thrombosis. A drug coated balloon offers advantages of deploying antiproliferative drugs at blocked lesions while eliminating the long-term risk associated with drug eluting stents. The major mechanism of drug delivery from this coated balloon involves adsorption of drug particles on inner lumen of coronary artery upon balloon expansion after which drug diffuses to the inner layers due to the concentration gradient. The major challenges in engineering such drug delivery devices are (1) to retain majority amount of drug on balloon during tracking and (2) program faster drug delivery within shorter exposure time. In the current research work, we have adopted different drug coating methods such as dip coating, brush coating, coating with ultrasonic atomization, and coating with air brush spray method to coat nanoparticles of Sirolimus drug encapsulated in phospholipids. For each of the methods, samples were studied for drug loading, coating integrity, and release characteristics of the Sirolimus coated balloon. An arterial path was simulated to measure the amount of drug loss during navigation and tracking. Drug release was measured for each of the coated system in phosphated buffer saline (PBS) solution of pH 7.4 and in Hank’s solution of 7.4 pH at 37 °C at different time intervals. Also, the sample surface was analyzed for coating integrity after coating, after tracking, and after drug release. The resultant surface characteristics were correlated to the stages of balloon coating, tracking, and drug release, respectively. Among the different coating techniques employed, the method that was best in terms of coating durability and release effectiveness was further investigated for the drug release mechanism using available mathematical models. The analyses of drug loading on balloon surfaces and drug release from balloon surfaces were evaluated with the help of different statistical techniques. It is found that release of drug was not purely under influence of diffusion but mechanical abrasion during balloon expansion also played vital role.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3006676

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10793-10799

Titre :	Physical and chemical mechanism for increased surface area and pore volume of CaO in water hydration
Type de document :	texte imprimé
Auteurs :	Zhenchao Sun, Auteur ; Hao Chi, Auteur ; Liang-Shih Fan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10793-10799
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydration  Surface  area
Résumé :	The present work explores the fundamental mechanism behind the increased surface area and pore volume of CaO after hydration. First, a widely believed mechanism, the "physical attrition theory", is experimentally examined and is found to have limitations in explaining this phenomenon. Next, to explain the improvement of morphological properties by hydration, a typical water hydration process is examined by dividing the process into four independent chemical and physical substeps. The morphological changes of Ca(OH)2 and its derived CaO by each substep are measured by Brunauer―Emmett―Teller (BET) analysis. During the first step, the intrinsic chemical conversion from CaO to Ca(OH)2, the formed Ca(OH)2 product layer disintegrates because of its low tensile strength and weak crack resistance, which explains the increases in surface area and pore volume by steam/moisture hydration as well as the rapid heat release during hydration. The physical interaction with water (the second step) slightly decreases the surface area and pore volume, possibly by lodging microparticles into the porous structure of bigger particles and inducing stronger particle agglomeration. The Ca(OH)2 solid can further chemically bond water molecules (the third step), which significantly enlarges the solid volume during water-bonding and consequently generates a more porous structure during dehydration. The final precipitation of the dissolved Ca(OH)2 (the fourth step) decreases the solid's surface area and pore volume. This decrease is attributed to the formed microparticles from solution, which can plug some surface pores on the larger particles during the drying process.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286454

[article] Physical and chemical mechanism for increased surface area and pore volume of CaO in water hydration [texte imprimé] / Zhenchao Sun, Auteur ; Hao Chi, Auteur ; Liang-Shih Fan, Auteur . - 2012 . - pp. 10793-10799.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10793-10799

Mots-clés :	Hydration  Surface  area
Résumé :	The present work explores the fundamental mechanism behind the increased surface area and pore volume of CaO after hydration. First, a widely believed mechanism, the "physical attrition theory", is experimentally examined and is found to have limitations in explaining this phenomenon. Next, to explain the improvement of morphological properties by hydration, a typical water hydration process is examined by dividing the process into four independent chemical and physical substeps. The morphological changes of Ca(OH)2 and its derived CaO by each substep are measured by Brunauer―Emmett―Teller (BET) analysis. During the first step, the intrinsic chemical conversion from CaO to Ca(OH)2, the formed Ca(OH)2 product layer disintegrates because of its low tensile strength and weak crack resistance, which explains the increases in surface area and pore volume by steam/moisture hydration as well as the rapid heat release during hydration. The physical interaction with water (the second step) slightly decreases the surface area and pore volume, possibly by lodging microparticles into the porous structure of bigger particles and inducing stronger particle agglomeration. The Ca(OH)2 solid can further chemically bond water molecules (the third step), which significantly enlarges the solid volume during water-bonding and consequently generates a more porous structure during dehydration. The final precipitation of the dissolved Ca(OH)2 (the fourth step) decreases the solid's surface area and pore volume. This decrease is attributed to the formed microparticles from solution, which can plug some surface pores on the larger particles during the drying process.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286454

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10785-10792

Titre :	Synthesis and properties of biodegradable poly(ester - co - carbonate) multiblock copolymers comprising of poly(butylene succinate) and poly(butylene carbonate) by chain extension
Type de document :	texte imprimé
Auteurs :	Jin Wang, Auteur ; Liuchun Zheng, Auteur ; Chuncheng Li, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10785-10792
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Properties  biodegradable  Copolymers
Résumé :	A series of biodegradable poly(ester-co-carbonate) multiblock copolymers consisting of poly(butylene succinate) and poly(butylene carbonate) (PBS-b-PBC) were synthesized successfully by chain-extension reaction of dihydroxyl terminated PBS-diol prepolymer and dihydroxyl terminated PBC-diol prepolymer using hexamethylene diisocyanate (HDI) as a chain extender. The chemical structures and molecular weights of copolymers were characterized by proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The thermal properties, crystallization behavior, morphology and mechanical properties of PBS-b-PBC were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), phase-contrast optical microscopy (PCOM), and mechanical testing. It was found that the PBC soft segment is effective in enhancing the impact strength, while hardly decreases the melting point (Tm) of the copolymers. The resulting novel copolymers are expected to find a potential application in the area of biodegradable polymer materials.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300547g

[article] Synthesis and properties of biodegradable poly(ester - co - carbonate) multiblock copolymers comprising of poly(butylene succinate) and poly(butylene carbonate) by chain extension [texte imprimé] / Jin Wang, Auteur ; Liuchun Zheng, Auteur ; Chuncheng Li, Auteur . - 2012 . - pp. 10785-10792.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10785-10792

Mots-clés :	Properties  biodegradable  Copolymers
Résumé :	A series of biodegradable poly(ester-co-carbonate) multiblock copolymers consisting of poly(butylene succinate) and poly(butylene carbonate) (PBS-b-PBC) were synthesized successfully by chain-extension reaction of dihydroxyl terminated PBS-diol prepolymer and dihydroxyl terminated PBC-diol prepolymer using hexamethylene diisocyanate (HDI) as a chain extender. The chemical structures and molecular weights of copolymers were characterized by proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The thermal properties, crystallization behavior, morphology and mechanical properties of PBS-b-PBC were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), phase-contrast optical microscopy (PCOM), and mechanical testing. It was found that the PBC soft segment is effective in enhancing the impact strength, while hardly decreases the melting point (Tm) of the copolymers. The resulting novel copolymers are expected to find a potential application in the area of biodegradable polymer materials.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300547g

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10778-10784

Titre :	Real - time thermal imaging of fast exothermic reactions involving the hazardous combination of methyl ethyl ketone peroxide and inorganic acids
Type de document :	texte imprimé
Auteurs :	Yan-Fu Lin, Auteur ; Yi-Huan Wu, Auteur ; Syu-Ming Lai, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10778-10784
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Exothermic  reaction  Imaging  Real  time  system  Real  time
Résumé :	The vigorous, exothermic decomposition of methyl ethyl ketone peroxide (MEKPO) can be stimulated by acids, metals, or heat, and the initial stage is critical to runaway reactions. Real-time thermal data are important in the evaluation of the hazards of fast reactions during the initial stage. We report the first real-time observation of the reaction of MEKPO with inorganic acids using a thermal imaging camera (TIC), which we used to determine the rate of heat evolution and to recognize the degree of the hazard present during accidents. In addition, ab initio computational methods were used to estimate the thermokinetic parameters for the proposed reaction mechanisms. The results indicated that the temperature of the solution, the concentration of the acid, and the dehydration ability were the primary factors that affected the thermal reaction. This work provides a new method to study thermal chemistry and to evaluate thermal hazards.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286452

[article] Real - time thermal imaging of fast exothermic reactions involving the hazardous combination of methyl ethyl ketone peroxide and inorganic acids [texte imprimé] / Yan-Fu Lin, Auteur ; Yi-Huan Wu, Auteur ; Syu-Ming Lai, Auteur . - 2012 . - pp. 10778-10784.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10778-10784

Mots-clés :	Exothermic  reaction  Imaging  Real  time  system  Real  time
Résumé :	The vigorous, exothermic decomposition of methyl ethyl ketone peroxide (MEKPO) can be stimulated by acids, metals, or heat, and the initial stage is critical to runaway reactions. Real-time thermal data are important in the evaluation of the hazards of fast reactions during the initial stage. We report the first real-time observation of the reaction of MEKPO with inorganic acids using a thermal imaging camera (TIC), which we used to determine the rate of heat evolution and to recognize the degree of the hazard present during accidents. In addition, ab initio computational methods were used to estimate the thermokinetic parameters for the proposed reaction mechanisms. The results indicated that the temperature of the solution, the concentration of the acid, and the dehydration ability were the primary factors that affected the thermal reaction. This work provides a new method to study thermal chemistry and to evaluate thermal hazards.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286452

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10768-10777

Titre :	Chemical processing in high - pressure aqueous environments. 9. process development for catalytic gasification of algae feedstocks
Type de document :	texte imprimé
Auteurs :	Douglas C. Elliott, Auteur ; Todd R. Hart, Auteur ; Gary G. Neuenschwander, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10768-10777
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Algae  Gasification  Catalytic  reaction
Résumé :	Through the use of a metal catalyst, gasification of wet algae slurries can be accomplished with high levels of carbon conversion to gas at relatively low temperature (350 °C). In a pressurized-water environment (20 MPa), near-total conversion of the organic structure of the algae to gases has been achieved in the presence of a supported ruthenium metal catalyst. The process is essentially steam reforming, as there is no added oxidizer or reagent other than water. In addition, the gas produced is a medium-heating value gas due to the synthesis of high levels of methane, as dictated by thermodynamic equilibrium. As opposed to earlier work, biomass trace components were removed by processing steps so that they did not cause processing difficulties in the fixed catalyst bed tubular reactor system. As a result, the algae feedstocks, even those with high ash contents, were much more reliably processed without plugging the feeding systems or the fixed catalyst bed. High conversions were obtained even with high slurry concentrations. Consistent catalyst operation in these short-term tests suggested good stability and minimal poisoning effects. High methane content in the product gas was noted with significant carbon dioxide captured in the aqueous byproduct in combination with alkali constituents and the ammonia byproduct derived from proteins in the algae. High conversion of algae to gas products was found with low levels of byproduct water contamination and low to moderate loss of carbon in the mineral separation step. Further development is required to demonstrate protection of the catalyst bed from sulfur poisoning.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286451

[article] Chemical processing in high - pressure aqueous environments. 9. process development for catalytic gasification of algae feedstocks [texte imprimé] / Douglas C. Elliott, Auteur ; Todd R. Hart, Auteur ; Gary G. Neuenschwander, Auteur . - 2012 . - pp. 10768-10777.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10768-10777

Mots-clés :	Algae  Gasification  Catalytic  reaction
Résumé :	Through the use of a metal catalyst, gasification of wet algae slurries can be accomplished with high levels of carbon conversion to gas at relatively low temperature (350 °C). In a pressurized-water environment (20 MPa), near-total conversion of the organic structure of the algae to gases has been achieved in the presence of a supported ruthenium metal catalyst. The process is essentially steam reforming, as there is no added oxidizer or reagent other than water. In addition, the gas produced is a medium-heating value gas due to the synthesis of high levels of methane, as dictated by thermodynamic equilibrium. As opposed to earlier work, biomass trace components were removed by processing steps so that they did not cause processing difficulties in the fixed catalyst bed tubular reactor system. As a result, the algae feedstocks, even those with high ash contents, were much more reliably processed without plugging the feeding systems or the fixed catalyst bed. High conversions were obtained even with high slurry concentrations. Consistent catalyst operation in these short-term tests suggested good stability and minimal poisoning effects. High methane content in the product gas was noted with significant carbon dioxide captured in the aqueous byproduct in combination with alkali constituents and the ammonia byproduct derived from proteins in the algae. High conversion of algae to gas products was found with low levels of byproduct water contamination and low to moderate loss of carbon in the mineral separation step. Further development is required to demonstrate protection of the catalyst bed from sulfur poisoning.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286451

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10755–10767

Titre :	Continuous synthesis and in situ monitoring of biodiesel production in different microfluidic devices
Type de document :	texte imprimé
Auteurs :	Edgar L. Martinez Arias, Auteur ; Patricia Fazzio Martins, Auteur ; André L. Jardini Munhoz, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10755–10767
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Biodiesel  Microfluidic
Résumé :	Currently, there is great interest in developing new processes for continuous biodiesel synthesis in order to overcome problems imposed by biphasic reaction and thermodynamic equilibrium, as well as to reduce production costs related to the conventional batch reaction processes. The use of microreactors can significantly improve the mixing between reactants and phases, enhancing the transfer rates, and, consequently, increasing biodiesel yields. Therefore, in this work, microreactors with different internal geometries have been fabricated and used for continuous production of biodiesel from castor oil and ethanol. The influences of the microchannel geometry (Tesla-, omega-, and T-shaped) on the performance of the biodiesel synthesis were experimentally studied. Higher biodiesel yields were reached using the Tesla- and omega-shaped microchannels than during the T-shaped microchannels due to better mixture mechanism efficiency. Using a catalyst loading of 1.0 wt % NaOH and a reaction temperature of 50 °C, ethyl ester conversions of 96.7, 95.3, and 93.5% were achieved using Tesla-, omega-, and T-shaped microreactors, respectively. In addition, transesterification reaction in situ monitoring by near-infrared spectroscopy using a fiber-optic probe was evaluated, showing that more studies must be performed in order to allow its use in online monitoring of continuous processes.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300486v

[article] Continuous synthesis and in situ monitoring of biodiesel production in different microfluidic devices [texte imprimé] / Edgar L. Martinez Arias, Auteur ; Patricia Fazzio Martins, Auteur ; André L. Jardini Munhoz, Auteur . - 2012 . - pp. 10755–10767.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10755–10767

Mots-clés :	Biodiesel  Microfluidic
Résumé :	Currently, there is great interest in developing new processes for continuous biodiesel synthesis in order to overcome problems imposed by biphasic reaction and thermodynamic equilibrium, as well as to reduce production costs related to the conventional batch reaction processes. The use of microreactors can significantly improve the mixing between reactants and phases, enhancing the transfer rates, and, consequently, increasing biodiesel yields. Therefore, in this work, microreactors with different internal geometries have been fabricated and used for continuous production of biodiesel from castor oil and ethanol. The influences of the microchannel geometry (Tesla-, omega-, and T-shaped) on the performance of the biodiesel synthesis were experimentally studied. Higher biodiesel yields were reached using the Tesla- and omega-shaped microchannels than during the T-shaped microchannels due to better mixture mechanism efficiency. Using a catalyst loading of 1.0 wt % NaOH and a reaction temperature of 50 °C, ethyl ester conversions of 96.7, 95.3, and 93.5% were achieved using Tesla-, omega-, and T-shaped microreactors, respectively. In addition, transesterification reaction in situ monitoring by near-infrared spectroscopy using a fiber-optic probe was evaluated, showing that more studies must be performed in order to allow its use in online monitoring of continuous processes.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300486v

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10742-10747

Titre :	CaC2 production from pulverized coke and CaO at low temperatures — reaction mechanisms
Type de document :	texte imprimé
Auteurs :	Guodong Li, Auteur ; Qingya Liu, Auteur ; Zhenyu Liu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10742-10747
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Reaction  mechanism  Low  temperature  Production
Résumé :	CaC2 production with pulverized feeds was proven viable at temperatures about 400 °C lower than that required by the current electric arc technology (2100―2200 °C), which led to development of an autothemal process. For the purpose of reactor design, the reaction mechanism of coke (C) with CaO at temperatures up to 1750 °C is studied in a thermogravimetric analyzer (TGA) coupled with a mass spectrometer (MS). Results indicate that the reaction of C with CaO generally proceeds in three stages, starting at 1460 °C for CaC2 formation, followed by reaction of CaC2 with CaO and by decomposition of CaC2. The second stage is observable only at the complete consumption of C while the third is controlled by surface evaporation of Ca. Reaction behavior at the surface of coke and CaO particles is proposed, including the three-stage reactions and the role of CaC2―CaO eutectics, that promotes CaO diffusion and CaC2 production.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286448

[article] CaC2 production from pulverized coke and CaO at low temperatures — reaction mechanisms [texte imprimé] / Guodong Li, Auteur ; Qingya Liu, Auteur ; Zhenyu Liu, Auteur . - 2012 . - pp. 10742-10747.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10742-10747

Mots-clés :	Reaction  mechanism  Low  temperature  Production
Résumé :	CaC2 production with pulverized feeds was proven viable at temperatures about 400 °C lower than that required by the current electric arc technology (2100―2200 °C), which led to development of an autothemal process. For the purpose of reactor design, the reaction mechanism of coke (C) with CaO at temperatures up to 1750 °C is studied in a thermogravimetric analyzer (TGA) coupled with a mass spectrometer (MS). Results indicate that the reaction of C with CaO generally proceeds in three stages, starting at 1460 °C for CaC2 formation, followed by reaction of CaC2 with CaO and by decomposition of CaC2. The second stage is observable only at the complete consumption of C while the third is controlled by surface evaporation of Ca. Reaction behavior at the surface of coke and CaO particles is proposed, including the three-stage reactions and the role of CaC2―CaO eutectics, that promotes CaO diffusion and CaC2 production.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286448

[article] 
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10731-10741

Titre :	Rheology and crystallization of long - chain branched poly (l - lactide)s with controlled branch length
Type de document :	texte imprimé
Auteurs :	Liangyan Wang, Auteur ; Xiabin Jing, Auteur ; Haibo Cheng, Auteur
Année de publication :	2012
Article en page(s) :	pp. 10731-10741
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Crystallization
Résumé :	A series of long-chain branched poly(L-lactide)s (LCB-PLAs) with controlled branch length were prepared by a simple and efficient method through a combination of ring-opening polymerization (ROP) of L-lactide and a coupling reaction between the terminal OH groups of the PLA prepolymers and the NCO groups of HDI. The influences of reaction conditions on the synthesis of the LCB-PLAs were investigated, and the structures of the resultant LCB-PLAs were characterized by 1H NMR spectroscopy and SEC-MALLS. By adjusting the degree of polymerization and the composition of the prepolymers, LCB-PLAs with different branch densities and molecular weights between branch points were obtained. The effect of macromolecular chain branching on the rheology and crystallization of PLA was also investigated. The LCB structure contributed to the enhancement of the zero-shear viscosity, complex viscosity, storage modulus, melt strength, and strain hardening under elongational flow. Thermal behavior indicated that the branch structure resulted in a short nucleation induction period and more rapid crystallization, which can be a guarantee of high-strength foams.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286447

[article] Rheology and crystallization of long - chain branched poly (l - lactide)s with controlled branch length [texte imprimé] / Liangyan Wang, Auteur ; Xiabin Jing, Auteur ; Haibo Cheng, Auteur . - 2012 . - pp. 10731-10741.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 33 (Août 2012) . - pp. 10731-10741

Mots-clés :	Crystallization
Résumé :	A series of long-chain branched poly(L-lactide)s (LCB-PLAs) with controlled branch length were prepared by a simple and efficient method through a combination of ring-opening polymerization (ROP) of L-lactide and a coupling reaction between the terminal OH groups of the PLA prepolymers and the NCO groups of HDI. The influences of reaction conditions on the synthesis of the LCB-PLAs were investigated, and the structures of the resultant LCB-PLAs were characterized by 1H NMR spectroscopy and SEC-MALLS. By adjusting the degree of polymerization and the composition of the prepolymers, LCB-PLAs with different branch densities and molecular weights between branch points were obtained. The effect of macromolecular chain branching on the rheology and crystallization of PLA was also investigated. The LCB structure contributed to the enhancement of the zero-shear viscosity, complex viscosity, storage modulus, melt strength, and strain hardening under elongational flow. Thermal behavior indicated that the branch structure resulted in a short nucleation induction period and more rapid crystallization, which can be a guarantee of high-strength foams.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26286447