Industrial Chromatography - with the advent of new contactors like IXSEP-RDA and the demand for very high purity products, the use of chromatography as a purification technique is growing rapidly in the areas of food, pharmaceutical and fine chemical processing. In the past, batch chromatography was seldom used for production due to the large amount of dilution of products.

Definition – chromatography exploits the differences in affinity that similar chemical species have for an adsorbent. Using a solvent to carry and transport the species into the adsorbent bed, we find that each species interacts with the adsorbent more or less strongly and as they travel through the bed each species moves at a characteristic velocity. The more strongly adsorbed species move more slowly than the less strongly adsorbed ones. Consequently, at the effluent of the bed the species exit in a sequence which corresponds to inverse strength of their affinities for the adsorbent.

Process Considerations – in the last 40 years there have been a succession of efforts to make large scale chromatography continuous. It became clear that operating in the simulated moving bed (SMB) mode brought significant process benefits. The IXSEP system can easily be configured to effect a binary counter-current chromatographic separation. The benefits generated when using continuous systems include; more consistent product purity, lower consumption of effluent (often water), higher concentration products, continuous operation, and higher adsorbent productivity based on counter-current contacting technique.

Process Example

A large scale application of industrial chromatography occurs in the corn syrup industry where mixtures of fructose and glucose from the enzyme reaction are enriched to produce a 90% fructose pure stream from a 42% fructose feed. The systems typically use 10 or 20-bed systems containing a specially prepared strong acid cation resin. The resin has a narrow particle size distribution and smaller mean diameter. A typical flow s heet, representing a typical binary separation, appears below.

Chromatographic Separation Process Scheme