The Effect of Ultrafiltration Process on Purity and De-colorization Indexes of Thin Sugar Beet Juice

The main objective in sugar industry is to remove the colorants and other non-sucrose compounds in order to obtain thin sugar juice with high purity and quality. The aim of this research was to study the potential of ultrafiltration process and its operational conditions (process time، transmembrane pressure & temperature) on improving the purification and de-colorization performance of thin sugar beet juice. Experimental data was obtained using the pilot plant UF membrane system equipped to a spiral wound module and a polysulfone amide membrane with MWCO 20kD. In this work، the effect of transmembrane pressure (at levels of 1، 2 & 3 bar)، process temperature (at levels of 30، 40 & 50oC) and operation time (at levels of 15، 30 and 45 minutes) on the purification indexes in sugar industry (Brix، polarization، purity، hardness & color) has been investigated. The results showed that the increase of duration of UF process decrease the separation degree of CaO content and turbidity، whereas the purity ratio and color removal increased for the same condition. It was found that increasing process temperature led to decrease the separation degree of CaO content، turbidity and color removal، however the purity ratio increased in this case. Increasing transmembrane pressure also improved the separation performance of non-sucrose compounds for all the UF conditions studied. The trials displayed satisfactory separation with an average purity rise of 0. 72 unit، 7. 2% lower CaO content، 72. 5 % lower turbidity and 12. 62 % lower color in the permeate.