Biomasa este un termen generic care cuprinde o ... - ICECHIM

292. MODELLING THE AMMONIUM SULFATE SOLUTION ELECTRODIALYSISSiminiceanu Ilie & Coteţ Ioan LucianTechnical University of Iaşi , Faculty of Chemical Engineering , Bd. Mangeron 71, 700050Iaşi,Tel. 0232278685/2241; 0232 213331, e-mail: isiminic@ch.tuiasi.roThe experimental study was carried out on a laboratory-scale electrodialysis (ED) unitmodel TS2-5 (Eurodia-Tokuyama) equipped with five cell pairs. The membranes used wereAMX type anion-exchange membranes, and CMS type cation-exchange membranes, each of0.02 m 2 surface area. The feed was an ammonium sulfate aqueous solution with 88-92 mol/m 3 .The evolution with time of the solution concentration in dilute and in concentratecompartments has been determined for two flow rates and four voltages, at 300 K. Aphenomenological mathematical model was derived to describe the concentration evolutiontime. The integrated model contains two semi-empirical constants which have been identifiedby confronting the experimental data with the computed ones.τ zFVD0= ⎡ bC ln0.13 i X D − a ( 1 − X D ) ůUQ ⎣ű , (1)D100C i8060402005 V7,5 V10 V12 V0 5 10 15 20 25 30 35τ, minFig.1. Comparison of the experimental (points) and calculated values.The relative errors of the model including the average values of the constants havebeen estimated. The validated model was finally used to extrapolate the ED process in order todetermine the necessary time for an almost complete (over 98%, or less then 1.5 mol/m 3residual salt in the final dilute) removal of ammonium sulfate.