Model Validation for Mixer-Settler Units

• Type: Article in International Conference Proceedings Book
• Date: 2001

Authors

Gilberto António Pinto (Author) Other; Marília Baptista (Author) Other; Anabela M.F.M. Guedes (Author) Other; M. Guimarães (Author) Other; Carlos Novais Madureira (Author) FEUP; António Fiúza (Author) FEUP; J. Cruz-Pinto (Author) Other

Conference proceedings International

Title: Proceedings of 6th World Congress of Chemical Engineering, Conference CD

Other information

Abstract (EN): Mass transfer processes between immiscible liquid phases play an important technical and economical role in the chemical, mining and environmental industries, because of their large throughput capacity and reduced energy and environmental costs, small energy and environmental costs. The simplicity, flexibility and ease of construction and of operation of their mixer-settler implementation explain its worldwide popularity. Up to now, the complexity of the hydrodynamic sedimentation phenomena, however, have prevented the proper, first principles based, modelling approach to the design of their industrial set-ups and forced the use of the less flexible, empirical correlation based, scale-up approach, thus resulting in frequent oversizing of the industrial units. Associating two well-known, avaiable, sophisticated but fast, continuous flow, steady-state models, the Guimarães (i) thoroughly agitated mixer model based on moment generating functions and the Ruiz (ii) finite-differences shallow-depth settler model, we have developed a simple and effective combined model and algorithm (for the combination). The input parameters for the combination model are volumetric flowrates, initial solute concentrations and relevant physical properties of the phases, and the agitation power density in the mixer. In order to validate the combined model, we have built and used pilot-scale experimental set-ups in which mixer inner drop-size distributions and settler length and depth of the dispersion wedge may be optically measured. Results of the parameter optimisation are encouraging and further measurement of the dropsize distributions is contempled. Preliminary test results indicate the potentiality of the algorithm for the efficient sizing of the units and the prediction of their combined performances in complex networks involving roughing, cleaning and reclaiming stages.

Language: Portuguese

Type (Professor's evaluation): Scientific

No. of pages: 8