Optimal design of a simulated-moving-bed chromatographic process for high-purity separation of acetoin from 2,3-butanediol in a continuous mode.

For the high-purity production of acetoin or 2,3-butanediol (BD) from related fermentation processes, it is essential to accomplish a detailed separation between acetoin and BD in an economical mode. To address this issue, we aimed to develop a highly-efficient simulated-moving-bed (SMB) process for the continuous-mode separation of acetoin from BD with high purity and small loss. As a first step for this task, the adsorption and mass-transfer parameters of acetoin and BD on a proven adsorbent were estimated while assuming that BD isomers (meso-BD and DL-BD) would be identical in adsorption and mass-transfer behaviors. The resultant parameters from such estimation were applied to the optimal design of the acetoin-BD separation SMB. The designed SMB was then experimentally investigated, which revealed that some sign of BD isomerism occurred in the SMB column-profile data and thus had an adverse effect on the SMB separation performance. To resolve this problem, the individual parameters of BD isomers were determined on the basis of the SMB column-profile data and an inverse-method principle. The resulting parameters of BD isomers were used in the re-design of the target SMB, which was then experimentally checked for its separation performance. It was confirmed that such SMB re-designed in consideration of BD isomerism was quite effective in the continuous-mode separation of acetoin from BD with high purity (> 99.2%) and small loss (< 1.52%).