Characterization of an electrochemical industrial size filterpress reactor by hydrodynamic and mass transport studies

Abstract

This work deals with the study of the influence of turbulence promoters in hydrodynamic and mass transport behaviour of a filter-press type electrolyser with 3250 cm2 of electrode area (model REIM 3300 supplied by “I.D. Electroquímica”) in undivided configuration. A simple experimental arrangement was used to generate data from electrolytic conductivity measurements in a series of impulse-response experiments. The experimental curves has shown a strong influence of the presence or absence of turbulence promoters inside the reactor in the hydrodynamic behaviour. In previous papers, we used a new approach to analyse the different residence time distributions (RTD) in other smaller reactors. In those studies a new parameter, the turbulence factor, given as Nαθβ, was defined and employed to classify the turbulence promoters. The model used in those papers assumes plug flow with dispersion and flow exchange with stagnant zones and uses three parameters: Nα, θβ and Pe. Nα characterises the rate of exchange between the stagnant zones and the dispersed plug flow, θβ is the ratio between volume in dispersed plug flow/total volume and Pe is the Peclet number. In this present work a new complication has been taken into account due to the presence of two peaks in the RTD curves. Then a model with two paths has been used in order to describe the hydrodynamic behaviour of this electrochemical industrial size filterpress reactor. The optimised values of the parameters provided by the model give a plug-flow hydrodynamic behaviour with low axial dispersion for the reactor with turbulence promoters and more mixing for the empty configuration. The classification obtained by electrochemical method (mass transport enhancement factor) for the turbulence promoters (plastic nets) is compared with the obtained from hydrodynamic study.