International Society for Industrial Process Tomography

Liquid Mixing Time and Solid Dissolution in Slurry Stirred Tanks

A.Paglianti^1*, G. Montante²

¹ Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Alma Mater Studiorum – Università di Bologna, Bologna, Italy

² Dipartimento di Chimica Industriale "Toso Montanari", Alma Mater Studiorum – Università di Bologna, Bologna, Italy

^*Email: alessandro.paglianti@unibo.it

ABSTRACT

Electrical Resistance Tomography is adopted for analysing salt particles dissolution in dense solid-liquid stirred tanks. The process provides an ambitious challenge for the application of ERT in the process industry, because the presence of high inert particles loadings requires a not trivial analysis of the experimental data. For the optimization of the working conditions of the stirred tank, two characteristic Arial are required: the time for the liquid homogenization in the tank and the time required for the complete dissolution of the salt particles. The former time has been experimentally determined in previous investigations both in stirred tanks working with single-phase and well as with multiphase mixtures. The latter characteristic time has not been analysed so far, due to the lack of experimental procedures for distinguishing it from the former one. In this work, a novel approach for the simultaneous identification of the homogenization and the dissolution time is presented. The impact of the new procedure is significant for the production processes, because it allows to distinguish when the process is influenced by the dissolving particle size, and therefore a reduction of the particle size has an impact on the dissolution dynamics, and when the stirred tank dynamics is influenced only by the liquid homogenization, and therefore a reduction of the particle size doesn’t influence the process accomplishment.

Keywords Electrical Resistance Tomography, Mixing time, Mass transfer, Slurry stirred tanks, Solids dissolution

Industrial Application Chemical and Pharmaceutical Industry