Experimental characterization of dynamic behavior of lab scale vibrating sieve using identified models

Many industrial operations involve the separation of suspensions of particulate systems, being the vibrating screen, one of the most versatile equipment available for this task. Despite its large scale use in several areas, there are few experimental studies related to the dynamics of the operation of this equipment. The purpose of this study was to characterize the dynamic behavior of the sieve, evaluating the moisture of the retained solid. Using an experimental unit and a simulating fluid formed by sand, water and xanthan gum, semi empirical identified models for transient responses were obtained. The dynamic models were obtained by the analysis of the sieve response to individual step changes in independent variables g-force and concentration of solids fed considering two values of feed flow and first order plus dead time transfer functions. The moisture content in the retained stream was evaluated after the stabilization of the system response considering the new steady state. The best operating point of the sieve that permits the lowest moisture content was identified as 3.0 g-force; 5.0% concentration and 13 kg/min flow rate. Considering the experiments realized, it was verified that a fed stream solids concentration decrease promotes an increasing in the amount of moisture of the retained solid. On the other hand, feed flow had little influence on the response of the equipment. The semi empirical identified models represented adequately the system dynamics.