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Comparison of recycle chromatography and simulated moving bed for pseudobinary separations / Ju Weon Lee in Industrial & engineering chemistry research, Vol. 48 N° 16 (Août 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7724–7732 Titre : Comparison of recycle chromatography and simulated moving bed for pseudobinary separations Type de document : texte imprimé Auteurs : Ju Weon Lee, Auteur ; Phillip C. Wankat, Auteur Année de publication : 2009 Article en page(s) : pp. 7724–7732 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Simulated  moving  bed  (SMB)  process  Pseudobinary  separation  Binary  separation Résumé : The simulated moving bed (SMB) process has been extensively used in industrial separations for binary and pseudobinary separations. The SMB has been reported to have higher productivity and requires less desorbent than batch chromatography; however, in pseudobinary separations these advantages are dependent on the difference of adsorption behaviors of the nontarget components. In this research, the performance of batch chromatography with a single recycle stream was compared to SMB processes for pseudobinary separations of ternary nucleosides, a model system with competitive Langmuir isotherms. To compare the performances of SMB and recycle batch chromatography, detailed dynamic simulations of each process were performed with optimized operating conditions. The desorbent to feed ratio, D/F, of recycle chromatography was at least 2 times smaller than that of a four-column SMB process for most retained solute separations. For one case of least retained solute separation (2′-deoxycytidine/2′-deoxythymidine/2′-deoxyadenosine), minimum D/F of the four-column SMB process is approximately 15 times larger than that of recycle chromatography. The maximum productivity of recycle chromatography is 1.5−2 times larger than that of the four-column SMB process. When eight columns are used in the four-zone SMB process (two columns per zone), the performance (productivity, D/F, and pressure drop) is improved compared to the four-column SMB. The eight-column SMB has higher maximum productivity, and at the same productivity, it also has lower D/F and lower pressure drop compared to recycle chromatography. However, the recycle chromatography system is simpler and has fewer columns. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900092y [article] Comparison of recycle chromatography and simulated moving bed for pseudobinary separations [texte imprimé] / Ju Weon Lee, Auteur ; Phillip C. Wankat, Auteur . - 2009 . - pp. 7724–7732. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7724–7732 Mots-clés : Simulated  moving  bed  (SMB)  process  Pseudobinary  separation  Binary  separation Résumé : The simulated moving bed (SMB) process has been extensively used in industrial separations for binary and pseudobinary separations. The SMB has been reported to have higher productivity and requires less desorbent than batch chromatography; however, in pseudobinary separations these advantages are dependent on the difference of adsorption behaviors of the nontarget components. In this research, the performance of batch chromatography with a single recycle stream was compared to SMB processes for pseudobinary separations of ternary nucleosides, a model system with competitive Langmuir isotherms. To compare the performances of SMB and recycle batch chromatography, detailed dynamic simulations of each process were performed with optimized operating conditions. The desorbent to feed ratio, D/F, of recycle chromatography was at least 2 times smaller than that of a four-column SMB process for most retained solute separations. For one case of least retained solute separation (2′-deoxycytidine/2′-deoxythymidine/2′-deoxyadenosine), minimum D/F of the four-column SMB process is approximately 15 times larger than that of recycle chromatography. The maximum productivity of recycle chromatography is 1.5−2 times larger than that of the four-column SMB process. When eight columns are used in the four-zone SMB process (two columns per zone), the performance (productivity, D/F, and pressure drop) is improved compared to the four-column SMB. The eight-column SMB has higher maximum productivity, and at the same productivity, it also has lower D/F and lower pressure drop compared to recycle chromatography. However, the recycle chromatography system is simpler and has fewer columns. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900092y

Hybrid cycles to purify concentrated feeds containing a strongly adsorbed impurity with a nonlinear isotherm / Pradeep K. Sharma in Industrial & engineering chemistry research, Vol. 48 N° 13 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6405–6416 Titre : Hybrid cycles to purify concentrated feeds containing a strongly adsorbed impurity with a nonlinear isotherm : the PSA−TSA supercycle Type de document : texte imprimé Auteurs : Pradeep K. Sharma, Auteur ; Phillip C. Wankat, Auteur Année de publication : 2009 Article en page(s) : pp. 6405–6416 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Adsorption  process  Non-  or  weakly  adsorbing  gas  PSA−TSA  supercycle Résumé : A new adsorption process is developed to remove a strongly adsorbing gaseous impurity that has a very nonlinear isotherm from a non- or weakly adsorbing gas. This process, a number of pressure-swing cycles with low purge ratios followed by thermal regeneration, is called a PSA−TSA supercycle because it consists of thermal cycles on top of PSA cycles. The PSA cycles never reach cyclic steady state by themselves, although the supercycle does reach cyclic steady state. A water/nitrogen mixture with zeolite 13X is taken as model system because water exhibits strongly nonlinear adsorption characteristics. At low feed concentrations (1000 ppm water), PSA works well and is the preferred method. At intermediate feed concentrations (4000 ppm water), TSA is the preferred method. The PSA−TSA supercycle is better than PSA and TSA in handling high solute concentrations in the feed (40 000 ppm water) and producing high-purity product (1 ppm water). PSA fails to meet this purity, and TSA has low productivity. The new hybrid cycle is promising for highly nonlinear systems with high solute concentrations in the feed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801661w [article] Hybrid cycles to purify concentrated feeds containing a strongly adsorbed impurity with a nonlinear isotherm : the PSA−TSA supercycle [texte imprimé] / Pradeep K. Sharma, Auteur ; Phillip C. Wankat, Auteur . - 2009 . - pp. 6405–6416. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6405–6416 Mots-clés : Adsorption  process  Non-  or  weakly  adsorbing  gas  PSA−TSA  supercycle Résumé : A new adsorption process is developed to remove a strongly adsorbing gaseous impurity that has a very nonlinear isotherm from a non- or weakly adsorbing gas. This process, a number of pressure-swing cycles with low purge ratios followed by thermal regeneration, is called a PSA−TSA supercycle because it consists of thermal cycles on top of PSA cycles. The PSA cycles never reach cyclic steady state by themselves, although the supercycle does reach cyclic steady state. A water/nitrogen mixture with zeolite 13X is taken as model system because water exhibits strongly nonlinear adsorption characteristics. At low feed concentrations (1000 ppm water), PSA works well and is the preferred method. At intermediate feed concentrations (4000 ppm water), TSA is the preferred method. The PSA−TSA supercycle is better than PSA and TSA in handling high solute concentrations in the feed (40 000 ppm water) and producing high-purity product (1 ppm water). PSA fails to meet this purity, and TSA has low productivity. The new hybrid cycle is promising for highly nonlinear systems with high solute concentrations in the feed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801661w

Optimized design of recycle chromatography for separation of a single component from a ternary mixture / Ju Weon Lee in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9601–9610 Titre : Optimized design of recycle chromatography for separation of a single component from a ternary mixture Type de document : texte imprimé Auteurs : Ju Weon Lee, Auteur ; Phillip C. Wankat, Auteur Année de publication : 2009 Article en page(s) : p. 9601–9610 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Optimized  design  Chromatography  Ternary  mixture Résumé : Recycle chromatographic systems were designed to isolate one component from a ternary mixture. Since the concentrations of the dilute ternary mixtures studied (phenols, amino acids, and benzenes) were all in the linear range of isotherms, the Lapidus−Amundson equation was used to predict the broadening of elution bands caused by axial dispersion and mass-transfer resistance. Optimum operating conditions were designed to isolate the target solutes with over 99% purity and yield. Compared to complete ternary separation, recycle chromatography for separation of a single component required significantly less solvent and had higher productivity. For the amino acid system the optimum column length and mobile-phase velocity which had maximum productivity were determined with different sizes of adsorbent particle. When large particles were used, longer columns and faster mobile-phase velocities were needed to obtain maximum productivity as compared with small particle sizes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800583p [article] Optimized design of recycle chromatography for separation of a single component from a ternary mixture [texte imprimé] / Ju Weon Lee, Auteur ; Phillip C. Wankat, Auteur . - 2009 . - p. 9601–9610. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9601–9610 Mots-clés : Optimized  design  Chromatography  Ternary  mixture Résumé : Recycle chromatographic systems were designed to isolate one component from a ternary mixture. Since the concentrations of the dilute ternary mixtures studied (phenols, amino acids, and benzenes) were all in the linear range of isotherms, the Lapidus−Amundson equation was used to predict the broadening of elution bands caused by axial dispersion and mass-transfer resistance. Optimum operating conditions were designed to isolate the target solutes with over 99% purity and yield. Compared to complete ternary separation, recycle chromatography for separation of a single component required significantly less solvent and had higher productivity. For the amino acid system the optimum column length and mobile-phase velocity which had maximum productivity were determined with different sizes of adsorbent particle. When large particles were used, longer columns and faster mobile-phase velocities were needed to obtain maximum productivity as compared with small particle sizes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800583p

Separation of concentrated binary gases by hybrid pressure-swing adsorption/simulated-moving bed processes / Kyle P. Kostroski in Industrial & engineering chemistry research, Vol. 48 N° 9 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4445–4465 Titre : Separation of concentrated binary gases by hybrid pressure-swing adsorption/simulated-moving bed processes Type de document : texte imprimé Auteurs : Kyle P. Kostroski, Auteur ; Phillip C. Wankat, Auteur Année de publication : 2009 Article en page(s) : pp. 4445–4465 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Stripping-type  PSA  Rectifying-type  PSA  Gas  separation  Simulated-moving  bed Résumé : Stripping-type PSA (S-PSA) is a commonly used gas separation process for purification of the light component. Rectifying-type PSA (R-PSA), although not commonly used, is a gas separation process for purifying predominately the heavy component. Because S-PSA and R-PSA each tend to favor the production of a single product, these processes are typically not used for complete binary separation. On the other hand, the gas-phase simulated-moving bed (SMB) is capable of achieving complete binary separation; however, its commercial application has been stymied by the need for carrier gas/desorbent recovery and unfavorable economics. In this work, S-PSA and R-PSA are combined with a two-zone SMB to develop S-PSA/SMB and R-PSA/SMB hybrid processes and these processes are integrated into combination-type C-PSA/SMB processes. Combining PSA and SMB eliminates the carrier gas/desorbent by taking advantage of gas expansion and by using both light and heavy purge streams. Separation of H2 and CH4 mixtures with Zeolite 5A was simulated to determine the feasibility of the hybrid processes. The primary products are H2 and CH4 plus an impure offgas may be produced. Complete binary separation can be achieved by recycling the entire offgas stream. The best separation was achieved with an eight-bed combination of the S-PSA/SMB and R-PSA/SMB processes, the SRC-PSA/SMB. This process separated a 70% H2/30% CH4 feed into 99.99% H2 with 99.6% H2 recovery and 99% CH4 with 99.9% CH4 recovery with productivity of 9.37 × 10−5 mol feed/(kg·s) and an energy requirement of 260.9 kJ/mol feed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801371t [article] Separation of concentrated binary gases by hybrid pressure-swing adsorption/simulated-moving bed processes [texte imprimé] / Kyle P. Kostroski, Auteur ; Phillip C. Wankat, Auteur . - 2009 . - pp. 4445–4465. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4445–4465 Mots-clés : Stripping-type  PSA  Rectifying-type  PSA  Gas  separation  Simulated-moving  bed Résumé : Stripping-type PSA (S-PSA) is a commonly used gas separation process for purification of the light component. Rectifying-type PSA (R-PSA), although not commonly used, is a gas separation process for purifying predominately the heavy component. Because S-PSA and R-PSA each tend to favor the production of a single product, these processes are typically not used for complete binary separation. On the other hand, the gas-phase simulated-moving bed (SMB) is capable of achieving complete binary separation; however, its commercial application has been stymied by the need for carrier gas/desorbent recovery and unfavorable economics. In this work, S-PSA and R-PSA are combined with a two-zone SMB to develop S-PSA/SMB and R-PSA/SMB hybrid processes and these processes are integrated into combination-type C-PSA/SMB processes. Combining PSA and SMB eliminates the carrier gas/desorbent by taking advantage of gas expansion and by using both light and heavy purge streams. Separation of H2 and CH4 mixtures with Zeolite 5A was simulated to determine the feasibility of the hybrid processes. The primary products are H2 and CH4 plus an impure offgas may be produced. Complete binary separation can be achieved by recycling the entire offgas stream. The best separation was achieved with an eight-bed combination of the S-PSA/SMB and R-PSA/SMB processes, the SRC-PSA/SMB. This process separated a 70% H2/30% CH4 feed into 99.99% H2 with 99.6% H2 recovery and 99% CH4 with 99.9% CH4 recovery with productivity of 9.37 × 10−5 mol feed/(kg·s) and an energy requirement of 260.9 kJ/mol feed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801371t

Solvent recovery by steamless temperature swing carbon adsorption processes / Pradeep K. Sharma in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11602–11613 Titre : Solvent recovery by steamless temperature swing carbon adsorption processes Type de document : texte imprimé Auteurs : Pradeep K. Sharma, Auteur ; Phillip C. Wankat, Auteur Année de publication : 2011 Article en page(s) : pp. 11602–11613 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solvent  Adsorption  Processes Résumé : Adsorption with activated carbon followed by regeneration with steam is the most common technique for solvent recovery from gas streams. The resulting steam−solvent gaseous mixture when condensed can result in either two separate layers (immiscible) or a single liquid phase (miscible or miscible with an azeotrope). For miscible systems that form azeotropes, the downstream distillation system can easily be more expensive than the adsorbers. An alternative is to use hot nitrogen instead of steam for desorption. By adding a short oxygen/water removal step to the adsorption cycle, the need for distillation is avoided. The model system studied for the azeotropic case was recovery of 0.5 mol % isopropanol (IPA) from air with hot nitrogen for regeneration. Since the nitrogen cost dominates, nitrogen should be recovered and recycled as much as possible. Two- and four-bed adsorption schemes were studied, and the four-bed system, which recovers almost all of the nitrogen, was best. A preliminary total cost comparison showed that solvent recovery of IPA with steam regeneration has total costs that are 14% higher than for IPA recovery with hot nitrogen regeneration if the nitrogen is recovered and recycled. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008019 [article] Solvent recovery by steamless temperature swing carbon adsorption processes [texte imprimé] / Pradeep K. Sharma, Auteur ; Phillip C. Wankat, Auteur . - 2011 . - pp. 11602–11613. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11602–11613 Mots-clés : Solvent  Adsorption  Processes Résumé : Adsorption with activated carbon followed by regeneration with steam is the most common technique for solvent recovery from gas streams. The resulting steam−solvent gaseous mixture when condensed can result in either two separate layers (immiscible) or a single liquid phase (miscible or miscible with an azeotrope). For miscible systems that form azeotropes, the downstream distillation system can easily be more expensive than the adsorbers. An alternative is to use hot nitrogen instead of steam for desorption. By adding a short oxygen/water removal step to the adsorption cycle, the need for distillation is avoided. The model system studied for the azeotropic case was recovery of 0.5 mol % isopropanol (IPA) from air with hot nitrogen for regeneration. Since the nitrogen cost dominates, nitrogen should be recovered and recycled as much as possible. Two- and four-bed adsorption schemes were studied, and the four-bed system, which recovers almost all of the nitrogen, was best. A preliminary total cost comparison showed that solvent recovery of IPA with steam regeneration has total costs that are 14% higher than for IPA recovery with hot nitrogen regeneration if the nitrogen is recovered and recycled. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008019