PENGARUH SUHU SATURATOR TANK DAN FLOWRATE FEED TERHADAP KADAR IMPURITAS Fe DALAM PRODUK KRISTAL PADA PROSES KRISTALISASI ASAM SITRAT

Abstract

Citric acid - C6H8O7 is an organic compound which widely used as an additive in food and beverage as well as in pharmacy industries. In industries, Citric acid is produced by fermentation process and after separation-purification processes, the end product is in the form of crystals. For pharmacy purpose, the quality of citric acid crystals is very important aspect, and the impurity substance which difficult to separate is iron-Fe. The purpose of this study was to determine the influence of flow rate feed and temperature of saturator tanks against impurity of Fe in the products of citric acid crystals and to know the relationship between the crystal product rates with impurity of Fe in the product citric acid crystal. This research has used 4 liters MSMPR crystallizer, continuously operated, temperature of the crystallizer was keep constant at 20oC using refrigeration system. Concentration of Fe in the feed was 40 ppm. Feed flow rates was variated (0,5;1;1,5;2;2,5;3)ml/sec. Temperature of saturator tank was variated (30,40,50) oC. Fe content in the citric acid crystal was analyzed using spectrophotometer. This research concludes that greater flow rate feed, the higher concentration of Fe impurity trapped in the product of citric acid crystal. Meanwhile, the higher the saturator temperature, concentration of Fe impurity in the product citric acid crystals became lower. The best condition was reached at flow rate feed 0.5 ml / sec and at a temperature of saturator tank 50oC. Weight of crystal produced in the best conditions is 101.62 g with impurity concentration of Fe 0.3 ppm. In addition, product rate of crystal influenced the level impurity of Fe contained in the citric acid crystals products. The greater product rates , the greater the impurity of Fe that were trapped in the citric acid crystals. The influence of crystal product rates to the concentration of Fe trapped in the products of citric acid crystals, can be expressed by equation y = 0.0834x + 0.338 for saturator tank temperature of 30oC, y = 0.074x + 0.2793 for saturator tank temperature of 40 ° C, and y = 0.0769x + 0.2227 for saturator tank temperature of 50 ° C.