Documents disponibles écrits par cet auteur

Hidden semi - markov probability models for monitoring two-dimensional batch operation / Junghui Chen in Industrial & engineering chemistry research, Vol. 50 N° 6 (Mars 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3345–3355 Titre : Hidden semi - markov probability models for monitoring two-dimensional batch operation Type de document : texte imprimé Auteurs : Junghui Chen, Auteur ; Yan-Cheng Jiang, Auteur Année de publication : 2011 Article en page(s) : pp. 3345–3355 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic  Probability Résumé : The repetitive batch operation has a two-dimensional dynamic behavior, including a finite time interval of each batch run in the time domain and infinite repetitions along the batch domain. In this Article, a novel monitoring method that combines dynamic multiway principal component analysis (DMPCA) and hidden segmental semi-Markov models (HSMM) is proposed to resolve the problem caused by the two-dimensional behavior of batch processes. DMPCA utilizes the batch-to-batch dynamic characteristics and eliminates the batch correlation among process variables. HSMM is used to construct the temporal behavior among process variables during each batch run. By constructing a two-dimensional model, the proposed method can generate simple probability monitoring charts and monitor the progress in each batch run. The proposed method has the temporal property of HSMM and the batch-to-batch dynamic characteristics of DMPCA. Its advantages are demonstrated through a simulated fed-batch penicillin cultivation process characterized by fault sources. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101189g [article] Hidden semi - markov probability models for monitoring two-dimensional batch operation [texte imprimé] / Junghui Chen, Auteur ; Yan-Cheng Jiang, Auteur . - 2011 . - pp. 3345–3355. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3345–3355 Mots-clés : Dynamic  Probability Résumé : The repetitive batch operation has a two-dimensional dynamic behavior, including a finite time interval of each batch run in the time domain and infinite repetitions along the batch domain. In this Article, a novel monitoring method that combines dynamic multiway principal component analysis (DMPCA) and hidden segmental semi-Markov models (HSMM) is proposed to resolve the problem caused by the two-dimensional behavior of batch processes. DMPCA utilizes the batch-to-batch dynamic characteristics and eliminates the batch correlation among process variables. HSMM is used to construct the temporal behavior among process variables during each batch run. By constructing a two-dimensional model, the proposed method can generate simple probability monitoring charts and monitor the progress in each batch run. The proposed method has the temporal property of HSMM and the batch-to-batch dynamic characteristics of DMPCA. Its advantages are demonstrated through a simulated fed-batch penicillin cultivation process characterized by fault sources. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101189g

Integrated batch-to-batch control and within-batch online control for batch processes using two-step MPLS-based model structures / Junghui Chen ; Kuen-Chi Lin in Industrial & engineering chemistry research, Vol. 47 n°22 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8693–8703 Titre : Integrated batch-to-batch control and within-batch online control for batch processes using two-step MPLS-based model structures Type de document : texte imprimé Auteurs : Junghui Chen, Auteur ; Kuen-Chi Lin, Auteur Année de publication : 2008 Article en page(s) : p. 8693–8703 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : MPLS-Based  Model Résumé : A feedback profile tracking scheme is proposed for batch-to-batch and within-batch control of the end-point quality in batch processes. This new method is based on two-step multiway partial least squares (MPLS) models. The first-step MPLS model, called the quality MPLS, is used to relate the final qualities with the online measurements; the second one, called the measurement MPLS, can relate the online measurements with both the manipulated variables and the prior measured variables. Because the standard MPLS model embeds all process variables into a single input data block, the input variables can be adjusted only on the basis of target qualities at the end point. With the proposed method, the desired online measured variables along the time axis can be computed using the quality MPLS; then the operating input variables can be appropriately adjusted using the measurement MPLS to match the desired online measured variables at each time point and finally get the target qualities at the end-time point. Under these two-step MPLS model structures, the integrated control strategy is sequentially developed by combining batch-to-batch control with within-batch control. Also, the conventional double exponentially weighted moving average control method can be separately and directly applied to each input−output variable in the reduced space of the latent variables. It can gradually reduce the model errors for the model-plant mismatches between batches. The applications are discussed through a typical batch reactor to demonstrate the advantages of the proposed method in comparison with the conventional methods. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070803w [article] Integrated batch-to-batch control and within-batch online control for batch processes using two-step MPLS-based model structures [texte imprimé] / Junghui Chen, Auteur ; Kuen-Chi Lin, Auteur . - 2008 . - p. 8693–8703. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8693–8703 Mots-clés : MPLS-Based  Model Résumé : A feedback profile tracking scheme is proposed for batch-to-batch and within-batch control of the end-point quality in batch processes. This new method is based on two-step multiway partial least squares (MPLS) models. The first-step MPLS model, called the quality MPLS, is used to relate the final qualities with the online measurements; the second one, called the measurement MPLS, can relate the online measurements with both the manipulated variables and the prior measured variables. Because the standard MPLS model embeds all process variables into a single input data block, the input variables can be adjusted only on the basis of target qualities at the end point. With the proposed method, the desired online measured variables along the time axis can be computed using the quality MPLS; then the operating input variables can be appropriately adjusted using the measurement MPLS to match the desired online measured variables at each time point and finally get the target qualities at the end-time point. Under these two-step MPLS model structures, the integrated control strategy is sequentially developed by combining batch-to-batch control with within-batch control. Also, the conventional double exponentially weighted moving average control method can be separately and directly applied to each input−output variable in the reduced space of the latent variables. It can gradually reduce the model errors for the model-plant mismatches between batches. The applications are discussed through a typical batch reactor to demonstrate the advantages of the proposed method in comparison with the conventional methods. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070803w

Integration design of heat exchanger networks into membrane distillation systems to save energy / Yanyue Lu in Industrial & engineering chemistry research, Vol. 51 N° 19 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6798-6810 Titre : Integration design of heat exchanger networks into membrane distillation systems to save energy Type de document : texte imprimé Auteurs : Yanyue Lu, Auteur ; Junghui Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 6798-6810 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Membrane  separation  Membrane  distillation  Heat  exchanger  Meshed  network  Design Résumé : Membrane distillation requires a lower operation temperature than other separation processes. It is also able to use low-grade thermal energy. In this study, an integrated design method that utilizes a membrane distillation (MD) system to produce pure water is presented. This method is the integration of the heat exchanger network (HEN) into the MD system, and it uses the waste heat from HEN as the energy source of the MD process so as to greatly reduce the water cost. In this proposed method, a multistage MD system is designed to generate the optimal system structure and operating conditions. Then the output and input MD streams are merged into the existing HEN so that the energy cost of pure water can be determined by redesigning the HEN with the trans-shipment models. The efficiency of the proposed method is demonstrated through an industrial case. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25900234 [article] Integration design of heat exchanger networks into membrane distillation systems to save energy [texte imprimé] / Yanyue Lu, Auteur ; Junghui Chen, Auteur . - 2012 . - pp. 6798-6810. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6798-6810 Mots-clés : Membrane  separation  Membrane  distillation  Heat  exchanger  Meshed  network  Design Résumé : Membrane distillation requires a lower operation temperature than other separation processes. It is also able to use low-grade thermal energy. In this study, an integrated design method that utilizes a membrane distillation (MD) system to produce pure water is presented. This method is the integration of the heat exchanger network (HEN) into the MD system, and it uses the waste heat from HEN as the energy source of the MD process so as to greatly reduce the water cost. In this proposed method, a multistage MD system is designed to generate the optimal system structure and operating conditions. Then the output and input MD streams are merged into the existing HEN so that the energy cost of pure water can be determined by redesigning the HEN with the trans-shipment models. The efficiency of the proposed method is demonstrated through an industrial case. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25900234

Multibatch model predictive control for repetitive batch operation with input – output linearization / Junghui Chen in Industrial & engineering chemistry research, Vol. 51 N° 28 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 28 (Juillet 2012) . - pp. 9598-9608 Titre : Multibatch model predictive control for repetitive batch operation with input – output linearization Type de document : texte imprimé Auteurs : Junghui Chen, Auteur ; Yu-Hung Lin, Auteur Année de publication : 2012 Article en page(s) : pp. 9598-9608 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Linearization  Batchwise  Predictive  control  Modeling Résumé : Because of the repetitive nature of the batch process, in conventional batch process control, the start of the subsequent batch is often assumed to be the same as that of the prior batch. Nevertheless, in real operation, under the influence of various exterior factors, most batch processes involve gradual changes over batches and, thus, the end-point condition would affect the start of the subsequent process batch. The initial condition at each batch may not be reset to be the desired initial condition. In order to ensure an optimum operation, it is essential to taking into account the effect of the previous batch. In this paper, a multibatch dynamics model is derived. It takes into account this batchwise dynamics. The derived process model can provide the benefits of better prediction and performance. In order to overcome the problem of nonlinearity in the batch process, the nonlinear process is transformed to a linear process through input-output feedback linearization. The identification method of the multibatch model is proposed for such batch processes, and the model will be able to reflect the particular type of batch process, which can be transformed to a linear input-output relation. Based on this model, a model predictive control scheme is derived for the case of unconstrained control as well as constrained control. The applications are discussed through a fed-batch reactor problem for the biosynthesis of penicillin to demonstrate the advantages of the proposed method, in comparison with the conventional methods. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26163297 [article] Multibatch model predictive control for repetitive batch operation with input – output linearization [texte imprimé] / Junghui Chen, Auteur ; Yu-Hung Lin, Auteur . - 2012 . - pp. 9598-9608. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 28 (Juillet 2012) . - pp. 9598-9608 Mots-clés : Linearization  Batchwise  Predictive  control  Modeling Résumé : Because of the repetitive nature of the batch process, in conventional batch process control, the start of the subsequent batch is often assumed to be the same as that of the prior batch. Nevertheless, in real operation, under the influence of various exterior factors, most batch processes involve gradual changes over batches and, thus, the end-point condition would affect the start of the subsequent process batch. The initial condition at each batch may not be reset to be the desired initial condition. In order to ensure an optimum operation, it is essential to taking into account the effect of the previous batch. In this paper, a multibatch dynamics model is derived. It takes into account this batchwise dynamics. The derived process model can provide the benefits of better prediction and performance. In order to overcome the problem of nonlinearity in the batch process, the nonlinear process is transformed to a linear process through input-output feedback linearization. The identification method of the multibatch model is proposed for such batch processes, and the model will be able to reflect the particular type of batch process, which can be transformed to a linear input-output relation. Based on this model, a model predictive control scheme is derived for the case of unconstrained control as well as constrained control. The applications are discussed through a fed-batch reactor problem for the biosynthesis of penicillin to demonstrate the advantages of the proposed method, in comparison with the conventional methods. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26163297

Numerical simulation and optimal design of AGMD-based hollow fiber modules for desalination / Li-Hua Cheng in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4948–4959 Titre : Numerical simulation and optimal design of AGMD-based hollow fiber modules for desalination Type de document : texte imprimé Auteurs : Li-Hua Cheng, Auteur ; Ping-Chung Wu, Auteur ; Junghui Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 4948–4959 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Air  gap  membrane  distillation  Desalination  Hollow  fiber Résumé : To improve the permeate flux and to keep the advantage of the high thermal efficiency in air gap membrane distillation (AGMD) for desalination, the optimal design of countercurrent AGMD of the hollow fiber module (AGMD-HF) is proposed. The module is basically composed of hydrophobic porous fiber tubes for feed flow and nonporous tubes for cold flow. The set of mathematical model equations for the entire module is derived from rigorous mass, momentum, and energy balances of both the feed side and the cold side coupled with the simultaneous mass and heat transfer across the membrane. The temperatures across the membrane and along the length of the module are simulated. The sensitivity of the process performance to operating conditions along the fiber length is investigated over a range of temperature and the flow rate. It is found that in the AGMD-HF domain, air/vapor dominates the heat and mass transfer resistances, which are comparable with the available experimental results in the literature. An attempt is then made to adjust the packing density and the surface ratio of the hot porous fibers to the cold nonporous fibers in order to maximize the process performance. Based on the trade-off between productivity and the thermal efficiency under module parameters, optimal design of AGMD-HF using Pareto solutions and the genetic algorithm is finally carried out. The obtained optimal points show that productivity increases considerably at the cost of the higher thermal efficiency with the increase of both packing density of the module and the tube ratio of hot feed fibers to cold fibers, with the latter showing relatively complex effect. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800832z [article] Numerical simulation and optimal design of AGMD-based hollow fiber modules for desalination [texte imprimé] / Li-Hua Cheng, Auteur ; Ping-Chung Wu, Auteur ; Junghui Chen, Auteur . - 2009 . - pp. 4948–4959. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4948–4959 Mots-clés : Air  gap  membrane  distillation  Desalination  Hollow  fiber Résumé : To improve the permeate flux and to keep the advantage of the high thermal efficiency in air gap membrane distillation (AGMD) for desalination, the optimal design of countercurrent AGMD of the hollow fiber module (AGMD-HF) is proposed. The module is basically composed of hydrophobic porous fiber tubes for feed flow and nonporous tubes for cold flow. The set of mathematical model equations for the entire module is derived from rigorous mass, momentum, and energy balances of both the feed side and the cold side coupled with the simultaneous mass and heat transfer across the membrane. The temperatures across the membrane and along the length of the module are simulated. The sensitivity of the process performance to operating conditions along the fiber length is investigated over a range of temperature and the flow rate. It is found that in the AGMD-HF domain, air/vapor dominates the heat and mass transfer resistances, which are comparable with the available experimental results in the literature. An attempt is then made to adjust the packing density and the surface ratio of the hot porous fibers to the cold nonporous fibers in order to maximize the process performance. Based on the trade-off between productivity and the thermal efficiency under module parameters, optimal design of AGMD-HF using Pareto solutions and the genetic algorithm is finally carried out. The obtained optimal points show that productivity increases considerably at the cost of the higher thermal efficiency with the increase of both packing density of the module and the tube ratio of hot feed fibers to cold fibers, with the latter showing relatively complex effect. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800832z

Online monitoring of batch processes using IOHMM based MPLS / Junghui Chen in Industrial & engineering chemistry research, Vol. 49 N° 6 (Mars 2010) 

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Optimal design of multistage membrane distillation systems for water purification / Yanyue Lu in Industrial & engineering chemistry research, Vol. 50 N° 12 (Juin 2011) 

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PCA-ARMA-based control charts for performance monitoring of multivariable feedback control / Junghui Chen in Industrial & engineering chemistry research, Vol. 49 N° 5 (Mars 2010) 

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Using cooling load forecast as the optimal operation scheme for a large multi-chiller system / Yan-Yue Lu in International journal of refrigeration, Vol. 34 N° 8 (Décembre 2011) 

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