(320g) Process Innovation in the Sugar Industry: Chromatographic Sugar Separation Using Smb Technology

Chromatographic separation of sugar from raw juice is identified as a promising alternative for the current chemical purification process. The alternative process is based on chromatographic removal of sucrose from raw juice. Simulating moving bed technology (SMB) is chosen as the most suitable technology on the basis of purification level, limited degree of dilution and increased sugar yield. Experiments - up to the level of pilot scale – and process modelling are used hand in hand to develop the new process.

The selection of a suitable adsorbent is a key factor in designing a technically and economically feasible process. An adsorbent is selected which binds sucrose selectively compared to glucose, glutamine and betaine. The binding mechanism on a molecular scale (CH-p interaction) is weak enough to allow for a sensible desorption strategy. Sorption isotherms and mass transfer coefficients are fitted using experimental data. A SMB process model is used to evaluate the performance of the adsorbents.

The unit operations before (clarification and stabilisation) and after the SMB unit (concentration) as well as the the utilization of process water streams are also taken into account. Experiments on lab-scale are carried out using micro filtration and reverse osmosis. SMB experiments are carried out on pilot scale using the selected adsorbent. A temperature swing is used, resulting in a concentration step during adsorption / desorption. This lowers the energy costs for water evaporation prior to the crystallisation process.

The process is economical feasible when all identified savings are realised. Important issues are the reduction of sugar losses in the total process, a higher yield as result of a higher purity, and limited operational costs due to prevented dilution.