Documents disponibles écrits par cet auteur

Comparing the performance of recirculating cyclones applied to the dry scrubbing of gaseous HCl with hydrated lime / Vania Chibante in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 1029–1035 Titre : Comparing the performance of recirculating cyclones applied to the dry scrubbing of gaseous HCl with hydrated lime Type de document : texte imprimé Auteurs : Vania Chibante, Auteur ; Ana M. Fonseca, Auteur ; Romualdo L. R. Salcedo, Auteur Année de publication : 2009 Article en page(s) : p. 1029–1035 Note générale : chimical engineering Langues : Anglais (eng) Mots-clés : Recirculating  cyclone  systems Résumé : Recirculating cyclone systems, combining a numerically optimized reverse flow gas cyclone (RS_VHE geometry) with a straight-through cyclone concentrator, were employed as reaction chambers for the dry scrubbing of gaseous hydrogen chloride with solid hydrated lime particles. The performance of this technology was tested at laboratory scale with two differently sized RS_VHE cyclones (0.020 and 0.026 m internal diameter) coupled to the same recirculator of 0.020 m internal diameter. The experimental conditions were the following: reaction temperature ≈ 326 K, gas flow rate ≈ 2.9 × 10−4 m3·s−1 at STP, and relative humidity of the gas ≈ 8.5%. The experimental variables were the solids feed rate [(1.0−9.2) × 10−7 kg·s−1] and HCl concentration in the inlet gas [(0.35−2.8) × 10−2 mol·m−3], giving different values for the ratio between the amount of fresh hydrated lime and HCl feed at the inlet of the recirculating cyclone systems (R) and that corresponding to the stoichiometric quantity (SR). The acid removal efficiencies ranged from 10 to 96%, and the best performances were obtained for high values of the ratio R/SR. Increasing the cyclone diameter while maintaining cyclone geometry improved the performance of the acid gas removal as well as the solid reactant conversion, but the average particle collection efficiency was lowered from (98.0 ± 0.7)% to (89.3 ± 1.7)%. [article] Comparing the performance of recirculating cyclones applied to the dry scrubbing of gaseous HCl with hydrated lime [texte imprimé] / Vania Chibante, Auteur ; Ana M. Fonseca, Auteur ; Romualdo L. R. Salcedo, Auteur . - 2009 . - p. 1029–1035. chimical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 1029–1035 Mots-clés : Recirculating  cyclone  systems Résumé : Recirculating cyclone systems, combining a numerically optimized reverse flow gas cyclone (RS_VHE geometry) with a straight-through cyclone concentrator, were employed as reaction chambers for the dry scrubbing of gaseous hydrogen chloride with solid hydrated lime particles. The performance of this technology was tested at laboratory scale with two differently sized RS_VHE cyclones (0.020 and 0.026 m internal diameter) coupled to the same recirculator of 0.020 m internal diameter. The experimental conditions were the following: reaction temperature ≈ 326 K, gas flow rate ≈ 2.9 × 10−4 m3·s−1 at STP, and relative humidity of the gas ≈ 8.5%. The experimental variables were the solids feed rate [(1.0−9.2) × 10−7 kg·s−1] and HCl concentration in the inlet gas [(0.35−2.8) × 10−2 mol·m−3], giving different values for the ratio between the amount of fresh hydrated lime and HCl feed at the inlet of the recirculating cyclone systems (R) and that corresponding to the stoichiometric quantity (SR). The acid removal efficiencies ranged from 10 to 96%, and the best performances were obtained for high values of the ratio R/SR. Increasing the cyclone diameter while maintaining cyclone geometry improved the performance of the acid gas removal as well as the solid reactant conversion, but the average particle collection efficiency was lowered from (98.0 ± 0.7)% to (89.3 ± 1.7)%.

A coupled strategy for the solution of NLP and MINLP optimization problems / Helder G. Silva in Industrial & engineering chemistry research, Vol. 48 N° 21 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 21 (Novembre 2009) . - pp. 9611–9621 Titre : A coupled strategy for the solution of NLP and MINLP optimization problems : benefits and pitfalls Type de document : texte imprimé Auteurs : Helder G. Silva, Auteur ; Romualdo L. R. Salcedo, Auteur Année de publication : 2010 Article en page(s) : pp. 9611–9621 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nonlinear  programming  problems  Mixed-integer  nonlinear  programming  problems  Stochastic  optimizers Résumé : This paper presents a strategy for the solution of nonlinear programming (NLP) and mixed-integer nonlinear programming (MINLP) problems, based on the coupling of the equation-oriented simulator ASCEND IV with the stochastic optimizers MSGA and MSIMPSA. Both NLP and MINLP formulations of a reactive distillation example were explored. The results show that the connection between the two software blocks was successfully established. Despite the highly nonlinear behavior of the proposed example, the results presented generally agree with those previously obtained for the same case study using other approaches, namely, SIMOP, which is a FORTRAN 77-based NLP simulation tool developed for optimization problems. Increasing the column dimension or switching the vapor−liquid equilibrium (VLE) description to a nonideal situation, which produces nonlinear models with a much larger number of equations that must be solved simultaneously, show that the results deteriorate. This is attributed to the lack of user control over the subsystems’ structures (viz, tearing variables). This problem was partially circumvented through the application of a more elaborate scheme initialization for the column variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801613e [article] A coupled strategy for the solution of NLP and MINLP optimization problems : benefits and pitfalls [texte imprimé] / Helder G. Silva, Auteur ; Romualdo L. R. Salcedo, Auteur . - 2010 . - pp. 9611–9621. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 21 (Novembre 2009) . - pp. 9611–9621 Mots-clés : Nonlinear  programming  problems  Mixed-integer  nonlinear  programming  problems  Stochastic  optimizers Résumé : This paper presents a strategy for the solution of nonlinear programming (NLP) and mixed-integer nonlinear programming (MINLP) problems, based on the coupling of the equation-oriented simulator ASCEND IV with the stochastic optimizers MSGA and MSIMPSA. Both NLP and MINLP formulations of a reactive distillation example were explored. The results show that the connection between the two software blocks was successfully established. Despite the highly nonlinear behavior of the proposed example, the results presented generally agree with those previously obtained for the same case study using other approaches, namely, SIMOP, which is a FORTRAN 77-based NLP simulation tool developed for optimization problems. Increasing the column dimension or switching the vapor−liquid equilibrium (VLE) description to a nonideal situation, which produces nonlinear models with a much larger number of equations that must be solved simultaneously, show that the results deteriorate. This is attributed to the lack of user control over the subsystems’ structures (viz, tearing variables). This problem was partially circumvented through the application of a more elaborate scheme initialization for the column variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801613e