Documents disponibles écrits par cet auteur

Constrained nonlinear estimation for industrial process fouling / Benjamin J. Spivey in Industrial & engineering chemistry research, Vol. 49 N° 17 (Septembre 1, 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7824–7831 Titre : Constrained nonlinear estimation for industrial process fouling Type de document : texte imprimé Auteurs : Benjamin J. Spivey, Auteur ; John D. Hedengren, Auteur ; Thomas F. Edgar, Auteur Année de publication : 2010 Article en page(s) : pp 7824–7831 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonlinear  estimation  Industrial  process. Résumé : Industrial process monitoring tools require robust and efficient estimation techniques that maintain a high service factor by remaining online during abnormal operating conditions, such as during loss of measurements, changes in control status, or maintenance. Constraints incorporate additional process knowledge into estimation by bounding estimated disturbances within feasibility limits thereby providing robustness to faulty measurements or conditions that violate process models. Moving horizon estimation (MHE) and unscented Kalman filtering (UKF) are two estimation techniques that permit incorporation of constraints prior to evaluating the a priori estimate. This paper evaluates both constrained nonlinear estimators versus the extended Kalman filter (EKF) using industrial process data provided by ExxonMobil Chemical Company. Results provide short-term insight into the fouling process, and parameter estimates produced by UKF and MHE are shown to be more accurate than EKF. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018116 [article] Constrained nonlinear estimation for industrial process fouling [texte imprimé] / Benjamin J. Spivey, Auteur ; John D. Hedengren, Auteur ; Thomas F. Edgar, Auteur . - 2010 . - pp 7824–7831. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7824–7831 Mots-clés : Nonlinear  estimation  Industrial  process. Résumé : Industrial process monitoring tools require robust and efficient estimation techniques that maintain a high service factor by remaining online during abnormal operating conditions, such as during loss of measurements, changes in control status, or maintenance. Constraints incorporate additional process knowledge into estimation by bounding estimated disturbances within feasibility limits thereby providing robustness to faulty measurements or conditions that violate process models. Moving horizon estimation (MHE) and unscented Kalman filtering (UKF) are two estimation techniques that permit incorporation of constraints prior to evaluating the a priori estimate. This paper evaluates both constrained nonlinear estimators versus the extended Kalman filter (EKF) using industrial process data provided by ExxonMobil Chemical Company. Results provide short-term insight into the fouling process, and parameter estimates produced by UKF and MHE are shown to be more accurate than EKF. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018116

Dynamic modeling to minimize energy use for CO2 capture in power plants by aqueous monoethanolamine / Sepideh Ziaii 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. 6105–6111 Titre : Dynamic modeling to minimize energy use for CO2 capture in power plants by aqueous monoethanolamine Type de document : texte imprimé Auteurs : Sepideh Ziaii, Auteur ; Gary T. Rochelle, Auteur ; Thomas F. Edgar, Auteur Année de publication : 2009 Article en page(s) : pp. 6105–6111 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CO2  capture  Dynamic  rate-based  model  Coal-fired  power  plants Résumé : A dynamic rate-based model was developed for stripping in CO2 capture from coal-fired power plants with 30 wt % monoethanolamine (MEA). The model, created in a flow sheet of Aspen Custom Modeler, was based on the film theory for liquid and vapor phases. It takes into account the impact of equilibrium reactions on the mass transfer, thermodynamic nonidealities, and the hydraulics of the structured packing. With this model, steady state analyses were carried out for the stripper to understand the effect of the lean loading and the height of the packing on total equivalent work and find optimum operating conditions that minimize power plant lost work. Two dynamic strategies with control configurations are proposed to run the stripper in a flexible operation during the period of electricity peak load and prices. Open loop responses demonstrated some differences in dynamic behavior and steady state values for proposed dynamic strategies. One of the approaches increased the CO2 removal by 1% at the reduced steam rate and provided faster response of the stripper to a step change in the reboiler heat rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801385q [article] Dynamic modeling to minimize energy use for CO2 capture in power plants by aqueous monoethanolamine [texte imprimé] / Sepideh Ziaii, Auteur ; Gary T. Rochelle, Auteur ; Thomas F. Edgar, Auteur . - 2009 . - pp. 6105–6111. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6105–6111 Mots-clés : CO2  capture  Dynamic  rate-based  model  Coal-fired  power  plants Résumé : A dynamic rate-based model was developed for stripping in CO2 capture from coal-fired power plants with 30 wt % monoethanolamine (MEA). The model, created in a flow sheet of Aspen Custom Modeler, was based on the film theory for liquid and vapor phases. It takes into account the impact of equilibrium reactions on the mass transfer, thermodynamic nonidealities, and the hydraulics of the structured packing. With this model, steady state analyses were carried out for the stripper to understand the effect of the lean loading and the height of the packing on total equivalent work and find optimum operating conditions that minimize power plant lost work. Two dynamic strategies with control configurations are proposed to run the stripper in a flexible operation during the period of electricity peak load and prices. Open loop responses demonstrated some differences in dynamic behavior and steady state values for proposed dynamic strategies. One of the approaches increased the CO2 removal by 1% at the reduced steam rate and provided faster response of the stripper to a step change in the reboiler heat rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801385q

Effectiveness of intravenous infusion algorithms for glucose control in diabetic patients using different simulation models / Terry G. Farmer Jr. 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. 4402–4414 Titre : Effectiveness of intravenous infusion algorithms for glucose control in diabetic patients using different simulation models Type de document : texte imprimé Auteurs : Terry G. Farmer Jr., Auteur ; Thomas F. Edgar, Auteur ; Nicholas A. Peppas, Auteur Année de publication : 2009 Article en page(s) : pp. 4402–4414 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Insulin  infusion  algorithms  Glucose  dynamics  Diabetes  patient  Proportional  integral  derivative  control Résumé : The effectiveness of closed-loop insulin infusion algorithms is assessed for three different mathematical models describing insulin and glucose dynamics within a type I diabetes patient. Simulations are performed to assess the effectiveness of proportional plus integral plus derivative (PID) control, feedforward control, and a physiologically based control system with respect to maintaining normal glucose levels during a meal and during exercise. Control effectiveness is assessed by comparing the simulated response to a simulation of a healthy patient during both a meal and exercise and establishing maximum and minimum glucose levels and insulin infusion levels, as well as maximum duration of hyperglycemia. Controller effectiveness is assessed within the minimal model, the Sorensen model, and the Hovorka model. Results showed that no type of control was able to maintain normal conditions when simulations were performed using the minimal model. For both the Sorensen model and the Hovorka model, proportional control was sufficient to maintain normal glucose levels. Given published clinical data showing the ineffectiveness of PID control in patients, the work demonstrates that controller success based on simulation results can be misleading, and that future work should focus on addressing the model discrepancies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800871t [article] Effectiveness of intravenous infusion algorithms for glucose control in diabetic patients using different simulation models [texte imprimé] / Terry G. Farmer Jr., Auteur ; Thomas F. Edgar, Auteur ; Nicholas A. Peppas, Auteur . - 2009 . - pp. 4402–4414. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4402–4414 Mots-clés : Insulin  infusion  algorithms  Glucose  dynamics  Diabetes  patient  Proportional  integral  derivative  control Résumé : The effectiveness of closed-loop insulin infusion algorithms is assessed for three different mathematical models describing insulin and glucose dynamics within a type I diabetes patient. Simulations are performed to assess the effectiveness of proportional plus integral plus derivative (PID) control, feedforward control, and a physiologically based control system with respect to maintaining normal glucose levels during a meal and during exercise. Control effectiveness is assessed by comparing the simulated response to a simulation of a healthy patient during both a meal and exercise and establishing maximum and minimum glucose levels and insulin infusion levels, as well as maximum duration of hyperglycemia. Controller effectiveness is assessed within the minimal model, the Sorensen model, and the Hovorka model. Results showed that no type of control was able to maintain normal conditions when simulations were performed using the minimal model. For both the Sorensen model and the Hovorka model, proportional control was sufficient to maintain normal glucose levels. Given published clinical data showing the ineffectiveness of PID control in patients, the work demonstrates that controller success based on simulation results can be misleading, and that future work should focus on addressing the model discrepancies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800871t

In Vivo Simulations of the Intravenous Dynamics of Submicrometer Particles of pH-Responsive Cationic Hydrogels in Diabetic Patients / Terry G. Farmer Jr. ; Thomas F. Edgar ; Nicholas A. Peppas in Industrial & engineering chemistry research, Vol. 47 n°24 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°24 (Décembre 2008) . - p. 10053–10063 Titre : In Vivo Simulations of the Intravenous Dynamics of Submicrometer Particles of pH-Responsive Cationic Hydrogels in Diabetic Patients Type de document : texte imprimé Auteurs : Terry G. Farmer Jr., Auteur ; Thomas F. Edgar, Auteur ; Nicholas A. Peppas, Auteur Année de publication : 2009 Article en page(s) : p. 10053–10063 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dynamics  Submicrometer  Simulations Résumé : A mathematical model describing glucose-dependent pH swelling and insulin release is developed for pH-sensitive cationic hydrogels in which glucose oxidase and catalase have been immobilized and insulin imbibed. Glucose-based swelling and insulin release are simulated for intravenously injected particles at various design conditions. The effects of particle size, the number of injected particles, insulin loading, enzyme loading, monomer functional group loading and pKa, and hydrogel cross-linking ratio on insulin release and glucose sensitivity are investigated to optimally design the device for use. Increased insulin infusion is shown to result from increasing the number of circulating gels, increasing the collapsed particle size, or decreasing the cross-linking ratio of the system. Release duration is shown to be dependent only upon the particle size and the achievable diffusion coefficient of the system. Glucose sensitivity, as measured by gluconic acid production and by the system pH, is a function of glucose oxidase loading and the concentration and pKa of the monomer used in the hydrogel. The necessary submicrometer particle size results in very rapid device insulin depletion. When the device is designed without considering constraints, the resulting release profile resembles that of an on/off switching mechanism. Future work will focus on simulations of swelling and release when the device is implanted in an alternative administration site. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070957b [article] In Vivo Simulations of the Intravenous Dynamics of Submicrometer Particles of pH-Responsive Cationic Hydrogels in Diabetic Patients [texte imprimé] / Terry G. Farmer Jr., Auteur ; Thomas F. Edgar, Auteur ; Nicholas A. Peppas, Auteur . - 2009 . - p. 10053–10063. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°24 (Décembre 2008) . - p. 10053–10063 Mots-clés : Dynamics  Submicrometer  Simulations Résumé : A mathematical model describing glucose-dependent pH swelling and insulin release is developed for pH-sensitive cationic hydrogels in which glucose oxidase and catalase have been immobilized and insulin imbibed. Glucose-based swelling and insulin release are simulated for intravenously injected particles at various design conditions. The effects of particle size, the number of injected particles, insulin loading, enzyme loading, monomer functional group loading and pKa, and hydrogel cross-linking ratio on insulin release and glucose sensitivity are investigated to optimally design the device for use. Increased insulin infusion is shown to result from increasing the number of circulating gels, increasing the collapsed particle size, or decreasing the cross-linking ratio of the system. Release duration is shown to be dependent only upon the particle size and the achievable diffusion coefficient of the system. Glucose sensitivity, as measured by gluconic acid production and by the system pH, is a function of glucose oxidase loading and the concentration and pKa of the monomer used in the hydrogel. The necessary submicrometer particle size results in very rapid device insulin depletion. When the device is designed without considering constraints, the resulting release profile resembles that of an on/off switching mechanism. Future work will focus on simulations of swelling and release when the device is implanted in an alternative administration site. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070957b

Multivariate image analysis (MIA) for industrial flare combustion control / David Castiñeira in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12642-12652 Titre : Multivariate image analysis (MIA) for industrial flare combustion control Type de document : texte imprimé Auteurs : David Castiñeira, Auteur ; Blake C. Rawlings, Auteur ; Thomas F. Edgar, Auteur Année de publication : 2012 Article en page(s) : pp. 12642-12652 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Combustion  Image  analysis Résumé : A new approach for flare monitoring is proposed so that flare combustion efficiency can be predicted online in industrial plants. Multivariate image analysis (MIA), which is based on principal component analysis (PCA) and projection to latent structures (PLS), has been applied to flare combustion systems in order to predict their resulting combustion efficiencies as a function of the crosswind velocity, using simulated results, and as a function of steam or air flow rates, using experimental tests of a full-size flare. The results show that a multivariate regression model based on flare color images can be used to predict the flare performance over a range of operating conditions for steam-assisted flares. Therefore, simple two-dimensional color images of industrial flares may be a fast, accurate, and inexpensive approach for online monitoring of these industrial combustion systems. This would allow for developing effective flare control and mitigation strategies. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419219 [article] Multivariate image analysis (MIA) for industrial flare combustion control [texte imprimé] / David Castiñeira, Auteur ; Blake C. Rawlings, Auteur ; Thomas F. Edgar, Auteur . - 2012 . - pp. 12642-12652. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12642-12652 Mots-clés : Combustion  Image  analysis Résumé : A new approach for flare monitoring is proposed so that flare combustion efficiency can be predicted online in industrial plants. Multivariate image analysis (MIA), which is based on principal component analysis (PCA) and projection to latent structures (PLS), has been applied to flare combustion systems in order to predict their resulting combustion efficiencies as a function of the crosswind velocity, using simulated results, and as a function of steam or air flow rates, using experimental tests of a full-size flare. The results show that a multivariate regression model based on flare color images can be used to predict the flare performance over a range of operating conditions for steam-assisted flares. Therefore, simple two-dimensional color images of industrial flares may be a fast, accurate, and inexpensive approach for online monitoring of these industrial combustion systems. This would allow for developing effective flare control and mitigation strategies. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419219

Nonlinear model identification for temperature control in single wafer rapid thermal processing / Wonhui Cho in Industrial & engineering chemistry research, Vol. 47 n°14 (Juillet 2008) 

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PCA combined model-based design of experiments (DOE) criteria for differential and algebraic system parameter estimation / Yang Zhang in Industrial & engineering chemistry research, Vol. 47 N°20 (Octobre 2008) 

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