The Danish Sugar Corporation (DDS) has developed a system for reverse osmosis and ultrafiltration which is now in use for many processes.
Experiments with ultrafiltration of raw juice from beet show promising results. The juice is filtered through a membrane which allows sugar and salts to pass, but proteins, pectines, etc. are removed. The protein-pectine concentrate from the filtration is diluted with water, and the ultrafiltration is continued. In this way it is possible to divide a raw juice with a purity of 89 into a fraction with a purity of 55 and a fraction with a purity of 92. The low purity fraction can be dried with the pulp. The high purity fraction is almost without colour.
A normal lime-CCL juice purification with a lime consumption of 1% CaCOs on beet gives a thin juice with a purity 1.5 higher than with our normal juice purification system with a lime consumption of 2.5 % CaCOs on beet. Ion-exchange juice purification after ultrafiltration gives very promising results.
The colour removal is increased considerably by ultrafiltration, both with lime-COa juice purification and ion-exchange as second step in the process.
The system was tried in a pilot plant in the 1970 campaign. The results were promising, but some technical problems have to be solved before the process is used in practice.
Some preliminary investigations were made on cane juices.
Proceedings: CITS 1971
pdf download: CITS1971-435-443.pdf