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Rapid pressure swing adsorption for reduction of bed size factor of a medical oxygen concentrator / Siew Wah Chai in Industrial & engineering chemistry research, Vol. 50 N° 14 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 14 (Juillet 2011) . - pp. 8703-8710 Titre : Rapid pressure swing adsorption for reduction of bed size factor of a medical oxygen concentrator Type de document : texte imprimé Auteurs : Siew Wah Chai, Auteur ; Mayuresh V. Kothare, Auteur ; Shivaji Sircar, Auteur Année de publication : 2011 Article en page(s) : pp. 8703-8710 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Network  hub  Pressure  swing  adsorption Résumé : Reduction of the adsorber size of a medical oxygen concentrator (MOC) employing a generic pressure swing adsorption (PSA) technology is an ongoing research and development activity. The MOC typically produces a 90―93% O2-enriched product gas from ambient air at a rate of ≤ 10 L/minute (LPM) for individual use. A common practice is to reduce the total cycle time (tc, seconds) of the PSA process in order to decrease the bed size factor [BSF, pounds of adsorbent in the PSA unit per ton of contained O2 per day production rate (TPDc)]. Adsorbent columns packed with very small adsorbent particles are used to enhance the adsorption kinetics for rapid PSA cycle operation. An experimental mini-PSA set up was used to measure the performance of a simulated Skarstrom-like PSA cycle using a commercial sample of LiX zeolite as the air separation sorbent. Different adsorbent particle sizes, adsorption pressures, and cycle times were tested. It was experimentally demonstrated that BSF cannot be indefinitely reduced by lowering tc because of finite adsorbate mass transfer and gas-solid heat transfer resistances, as well as column pressure drop during the desorption step. A BSF of ∼25―50 Ibs/TPDc with an O2 recovery of ∼25―35% for production of ∼90% O2 could be achieved by the PSA process using a dry, CO2-free air feed at a pressure of 3-4 atm, an adsorbent particle size of ∼0.35 mm, and a total cycle time of 3―5 s. A novel 'snap on' concept of a truly compact and portable MOC was proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24346910 [article] Rapid pressure swing adsorption for reduction of bed size factor of a medical oxygen concentrator [texte imprimé] / Siew Wah Chai, Auteur ; Mayuresh V. Kothare, Auteur ; Shivaji Sircar, Auteur . - 2011 . - pp. 8703-8710. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 14 (Juillet 2011) . - pp. 8703-8710 Mots-clés : Network  hub  Pressure  swing  adsorption Résumé : Reduction of the adsorber size of a medical oxygen concentrator (MOC) employing a generic pressure swing adsorption (PSA) technology is an ongoing research and development activity. The MOC typically produces a 90―93% O2-enriched product gas from ambient air at a rate of ≤ 10 L/minute (LPM) for individual use. A common practice is to reduce the total cycle time (tc, seconds) of the PSA process in order to decrease the bed size factor [BSF, pounds of adsorbent in the PSA unit per ton of contained O2 per day production rate (TPDc)]. Adsorbent columns packed with very small adsorbent particles are used to enhance the adsorption kinetics for rapid PSA cycle operation. An experimental mini-PSA set up was used to measure the performance of a simulated Skarstrom-like PSA cycle using a commercial sample of LiX zeolite as the air separation sorbent. Different adsorbent particle sizes, adsorption pressures, and cycle times were tested. It was experimentally demonstrated that BSF cannot be indefinitely reduced by lowering tc because of finite adsorbate mass transfer and gas-solid heat transfer resistances, as well as column pressure drop during the desorption step. A BSF of ∼25―50 Ibs/TPDc with an O2 recovery of ∼25―35% for production of ∼90% O2 could be achieved by the PSA process using a dry, CO2-free air feed at a pressure of 3-4 atm, an adsorbent particle size of ∼0.35 mm, and a total cycle time of 3―5 s. A novel 'snap on' concept of a truly compact and portable MOC was proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24346910

Synthesis of stabilizing antiwindup controllers using piecewise quadratic lyapunov functions / Tiwari, Pradeep Y. in IEEE transactions on automatic control, Vol. 52 N°12 (Decembre 2007) 

Public ISBD [article]  in IEEE transactions on automatic control > Vol. 52 N°12 (Decembre 2007) . - 2341-2345 p. Titre : Synthesis of stabilizing antiwindup controllers using piecewise quadratic lyapunov functions Titre original : La synthèse de stabiliser d'anti contrôleurs de remontage employant le lyapunov par morceaux quadratique fonctionne Type de document : texte imprimé Auteurs : Tiwari, Pradeep Y., Auteur ; Mayuresh V. Kothare, Auteur ; Mulder, Eric F., Auteur Article en page(s) : 2341-2345 p. Note générale : Automatique Langues : Anglais (eng) Mots-clés : Actuator  saturation  Antiwindup  Bilinear  matrix  inequalties  (BMI)  Constrained  control  Optimal  control  Piecewise  linear  system  Saturation  de  déclencheur  Anti  remontage  Inequalties  bilinéaires  de  matrice  (BMI)  Commande  contrainte  Commande  optimale  Système  par  morceaux  linéaire Index. décimale : 629.8 Résumé : We consider the problem of antiwindup controller synthesis based on the general antiwindup framework presented in Kothare (Automatica, vol. 30, no. 12, pp. 1869–1883, 1994) applicable to linear time-invariant systems (LTI) subject to a saturating actuator. Our synthesis approach takes advantage of the fact that the antiwindup system is a piecewise affine system and thus, we can utilize piecewise quadratic Lyapunov function theory Johansson and Rantzer (IEEE Trans. Autom. Control, vol. 43, no. 4, pp. 555–559, Apr. 1998), Rantzer and Johansson (IEEE Trans. Autom. Control, vol. 45, no. 4, pp. 629–637, Apr. 2000), and Johansson (Proc. 14th World Congr., Beijing, China, 1999, pp. 521–5260) to determine a stabilizing antiwindup control law. The synthesis problem is expressed in terms of bilinear matrix inequalities (BMIs) and is solved using an iterative approach as well as using commercial software. The performance of the system is optimized by minimizing an upper bound on the induced $L_2$ gain of the system. The proposed approach is demonstrated using examples. DEWEY : 629.8 ISSN : 0018-9286 RAMEAU : Liapounov, Fonctions de En ligne : PYT2@lehigh.edu, MAYURESH.KOTHARE@lehigh.edu, eric.f.mulder@exxonmobil.com [article] Synthesis of stabilizing antiwindup controllers using piecewise quadratic lyapunov functions = La synthèse de stabiliser d'anti contrôleurs de remontage employant le lyapunov par morceaux quadratique fonctionne [texte imprimé] / Tiwari, Pradeep Y., Auteur ; Mayuresh V. Kothare, Auteur ; Mulder, Eric F., Auteur . - 2341-2345 p. Automatique Langues : Anglais (eng) in IEEE transactions on automatic control > Vol. 52 N°12 (Decembre 2007) . - 2341-2345 p. Mots-clés : Actuator  saturation  Antiwindup  Bilinear  matrix  inequalties  (BMI)  Constrained  control  Optimal  control  Piecewise  linear  system  Saturation  de  déclencheur  Anti  remontage  Inequalties  bilinéaires  de  matrice  (BMI)  Commande  contrainte  Commande  optimale  Système  par  morceaux  linéaire Index. décimale : 629.8 Résumé : We consider the problem of antiwindup controller synthesis based on the general antiwindup framework presented in Kothare (Automatica, vol. 30, no. 12, pp. 1869–1883, 1994) applicable to linear time-invariant systems (LTI) subject to a saturating actuator. Our synthesis approach takes advantage of the fact that the antiwindup system is a piecewise affine system and thus, we can utilize piecewise quadratic Lyapunov function theory Johansson and Rantzer (IEEE Trans. Autom. Control, vol. 43, no. 4, pp. 555–559, Apr. 1998), Rantzer and Johansson (IEEE Trans. Autom. Control, vol. 45, no. 4, pp. 629–637, Apr. 2000), and Johansson (Proc. 14th World Congr., Beijing, China, 1999, pp. 521–5260) to determine a stabilizing antiwindup control law. The synthesis problem is expressed in terms of bilinear matrix inequalities (BMIs) and is solved using an iterative approach as well as using commercial software. The performance of the system is optimized by minimizing an upper bound on the induced $L_2$ gain of the system. The proposed approach is demonstrated using examples. DEWEY : 629.8 ISSN : 0018-9286 RAMEAU : Liapounov, Fonctions de En ligne : PYT2@lehigh.edu, MAYURESH.KOTHARE@lehigh.edu, eric.f.mulder@exxonmobil.com