Steady state recycling chromatography with an integrated solvent removal unit - separation of glucose and galactose.

A process concept where a solvent removal unit is integrated to a steady-state recycling chromatography process (SSR-SR) offers a possibility to significantly increase the performance of single column chromatographic separation. The advantages of solvent removal for a difficult separation task at conditions typical for industrial scale chromatography were demonstrated by investigating the performance of SSR-SR in separation of glucose and galactose. Two limits for the extent of solvent removal were imposed: maximum total concentration of the solution fed into the column (viscosity limit) and the maximum total concentration achievable in the solvent removal unit (solubility or osmotic pressure limit). The process was optimized using numerical simulation. Three SSR-SR configurations with different positions of the solvent removal unit were compared with (1) the conventional batch process, (2) SSR without solvent removal, and (3) batch process with solvent removal. SSR-SR was found to always improve the productivity. In addition, solvent removal reduced eluent consumption in most cases. The concentration limits and the concentration of the fresh feed were shown to determine which SSR-SR configuration yields the best performance.