Study On Clarification Of Syrup With Electrochemical Treatment

Clarification techniques is the most critical aspects of the sugar manufacturing process. Sulfurous acid method is the most common method in the domestic sugar-refinery, and the effect of clarification was not satisfactory. The electrolysis method has the advantage of simple manipulation, short disposal time, small land occupation,no secondary pollution, the wide sphere of application, etc. Treating of remelt syrup by electrolysis using aluminum as soluble anode was studied in this paper. The effect of electrolysis method on color value, apparent purity, colloid content of syrup was studied. And the electrolysis method on remelt syrup with ultrasonic was also studied. The main contents of studies were as follow:1. The effect of electrolysis method on color value of syrup was syudied. The optimum technological conditions by orthogonal experiment were determined: electrolytic time was 16 minutes, current density was 600 A·m^-2, the temperature was 60℃, inter-electrode distance was 5 mm and initial pH was 5. The decolorization rate of syrup on optimum technological conditions was 88.9%. Adding PAM after electrolytic reation can inhibit the decolorization rate of syrup. The decolorization rate decreased with increasing PAM addition.2. The effect of electrolysis method on apparent purity of syrup was studied. The optimum technological conditions by one-factor experimental were determined: electrolytic time was 18 minutes, current density was 700 A·m^-2, the temperature was 50℃, inter-electrode distance was 10 mm and initial pH was 4⁹. The apparent purity of syrup on optimum technological conditions was 88.7%. The percent of the raise of apparent purity was 4.12% with the blank experiment 85.0%.3. The effect of electrolysis method on colloid content of syrup was syudied. The optimum technological conditions by one-factor experimental were determined: electrolytic time was 16 minutes, current density was 600 A·m^-2, the temperature was 60℃, inter-electrode distance was 15 mm and initial pH was 6. The colloid content of syrup on optimum technological conditions was 1.462. The percent of the removal of colloid content was 58.2% with the blank experiment 3.5.4. The electrolytic treatment combined with ultrasonic and the ultrasonic treatment after electrolysis on decolorization of syrup was studied. The electrolytic clarificated syrup without ultrasonic wave assisted had been on standing for 50min, and the decolorization rate of syrup was 39.8%. The ultrasonic treatment after electrolytic clarificated syrup can greatly reduce the time of standing, the optimal conditions were: ultrasonic power was 195w, electrolytic time was 120s, and the decolorization rate of syrup was 36%. With ultrasonic treatment the decolorization rate was 32.7% on condition that ultrasonic power was 97.5w, electrolytic time was 6min, it higer than the decolorization rate with electrolytic treatment separately27.9%.