A methodology has been developed for the analysis of operational flexibility of a continuous processing plant. An application has been demonstrated for a multipurpose plant with uncertain operating conditions. A practical flexibility analysis procedure using a direct search optimization algorithm is proposed to solve the problem. The method provides a heuristic screening technique that makes it possible to avoid the exhaustive enumeration of every constraint vertex, while the direct search optimization offers a simple and effective means to identify bottlenecks. A refinery multiperiod plant problem has been investigated in order to highlight the procedures which lead to the construction of flexibility indices for each operating mode.
A dynamic simulation model for the bioleaching of uranium ore in a stope leaching process has been developed. The model incorporates design and operating conditions, reaction kinetics enhanced by Thiobucillus ferrooxicfuns present in the leaching solution and transport properties.3 %. The model is sensitive to small errors in the estimates of fragment size and ore grade. Because accurate estimates are difficult to obtain a parameter estimation approach was developed to update the value of fragment size and ore grade using on-line plant information.Model predictions agree well with experimental data with an average deviation of about On a rnis au point un modele de simulation dynamique pour le biolessivage du minerai d'urdnium dans un procCde de lessivag.: ttage. Le modttle inclut des conditions de conception et d'operation, les cinetiques de riaction entrainees par 7'hiobucillus ferroxiduns presentes dans la solution de lessivage ainsi que les proprietes de transport.Les prkdictions du modkle concordent bien avec les donnees experimentales avec un Ccart moyen d'environ & 3 % . Le modkle est sensible aux petites erreurs dans les estimations de la taille des fragments et de la qualit6 du minerai. Etant difficile d'obtenir des estimations exactes, on a mis au point une mCthode d'estimation de paramtttres pour mettre B jour la valeur de la taille des fragments et de la qualite du minerai B partir d'une information mesurke en ligne dans I'usine.
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