Article

Partial-discard strategy for obtaining high purity products using simulated moving bed chromatography.

Department of Chemical Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea.
Journal of Chromatography A (Impact Factor: 4.61). 08/2006; 1122(1-2):161-73. DOI: 10.1016/j.chroma.2006.04.040
Source: PubMed

ABSTRACT A new "partial-discard" operation strategy was developed to improve the performance, especially purity, achievable in simulated moving bed (SMB) chromatography. This strategy was applied to the four-zone SMB process with two columns per zone for binary separation within the linear range. The "partial-discard" strategy significantly enhanced the purity or enrichment when the discard time and discard length were controlled. In addition, the "partial-feed with partial-discard" strategy improved remarkably the extract and raffinate purities at an intermediate feed time compared with the "partial-feed" operation. Adjustments of the discard length and discard time played key roles in achieving the desired product purity in SMB chromatographic performance.

0 Bookmarks
 · 
75 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The prior removal of isoleucine from valine has been a key issue in the stage of valine crystallization, which is the final step in the valine production process in industry. To address this issue, a three-zone simulated moving-bed process for the separation of valine and isoleucine has been developed previously. However, the previous process, which was based on a classical port-location mode, had some limitations in throughput and valine product concentration. In this study, a three-zone simulated moving-bed process based on a modified port-location mode was applied to the separation of valine and isoleucine for the purpose of making a marked improvement in throughput and valine product concentration. Computer simulations and a lab-scale process experiment showed that the modified three-zone simulated moving bed for valine separation led to more than 65% higher throughput and more than 160% higher valine concentration compared to the previous three-zone simulated moving bed for the same separation.This article is protected by copyright. All rights reserved
    Journal of Separation Science 03/2014; · 2.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The three-zone simulated moving bed (SMB) chromatographic process for separation of succinic acid and lactic acid, which has been developed previously, was based on a classical port-location arrangement (desorbent→extract→feed→raffinate) and a classical feeding mode (full-feeding). To improve the performance of the three-zone SMB process, it is worth utilizing the strategy of either a port-location rearrangement (desorbent→feed→raffinate→extract) or a partial-feeding. To investigate which of the two strategies is more effective, the three-zone SMBs based on the port-location rearrangement (PR) and the partial-feeding (PF) were optimized each under equal conditions and then the two strategies were compared in terms of product purities or throughput. The result showed that the PR strategy led to higher purities or higher throughput than the PF strategy in regard to the previously reported three-zone SMB system. To check whether such trend is still valid in other separation systems, the above optimization works were repeated while varying only the selectivity between two feed components. It was confirmed that the PR strategy is definitely superior to the PF strategy. However, such superiority of the PR over the PF strategy is lessened as the selectivity becomes lower. If the selectivity is significantly low, the PR strategy is rather outperformed by the PF strategy.
    Journal of Chromatography A 03/2014; · 4.61 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new operating method, namely three-port operation in a three-zone simulated moving bed (TT-SMB), was developed to improve the separation performance of simulated moving bed (SMB) chromatography. In the TT-SMB, the switching period consists of two steps; extract outlet port is closed at the first step for raffinate production and raffinate outlet port is closed at the second step for extract production. As a result, three ports were used in each step of the three-zone SMB operation. The separation performance of TT-SMB was compared with conventional three- and four-zone SMBs in terms of purity, recovery, productivity, and eluent consumption. A conventional three-zone SMB operation usually produced the contaminated portion at the product outlet node during the switching period. However, such phenomenon could be prevented by using the TT-SMB operation because one product outlet port was closed at each step. Compared to the conventional three-zone SMB, all performance parameters improved with the use of TT-SMB, and the improvement in purity and recovery was significant (up to 7%). Adjusting the step ratio played a key role in the trade-off between the performance parameters. The purity, recovery, and productivity of TT-SMB at well-designed step ratio conditions are up to 3% higher than those of the conventional four-zone methods (1-1-1-1 configuration).
    Journal of Chromatography A 03/2014; · 4.61 Impact Factor