SUGAR SEPARATIONS ON A PILOT SCALE BY CONTINUOUS ANNULAR CHROMATOGRAPHY

A pilot‐scale continuous annular chromatograph has been developed for scale‐up and optimization studies. The chromatographic apparatus consists of a slowly rotating annular bed of sorbent material. The feed mixture which is to be separated is continuously introduced at a stationary point at the top of the bed, while eluent flows over the remainder of the annulus. The rotation of the sorbent bed coupled with the elution development induced by the downflow of eluent causes the feed components to appear as individual helical bands, each of which has a characteristic, stationary exit point. The separation of sucrose, glucose, and fructose, using the calcium form of a cation‐exchange resin, was investigated using water as the eluent. Experiments were carried out both with a synthetic mixture of the sugars as well as with an industrial feedstock. The separation was explored first in a bench‐scale conventional fixed‐bed column and then in the pilot‐scale continuous chromatograph. Factors such as column loading, feed‐to‐eluent ratio, and feed concentration were investigated both experimentally and theoretically. The results of bench‐scale experiments were carried out in the limit of infinite dilution, almost perfectly scaled to the pilot unit when loading was low and feed mixtures were of low viscosity. Very significant deviations from ideality were, however, observed at high feed loadings, when the feed viscosity exceeded that of the eluent by more than a factor of 2. Copyright © 1990 American Institute of Chemical Engineers (AIChE)