Comparison of Recycle Chromatography and Simulated Moving Bed for Pseudobinary Separations

• Published in: Industrial & engineering chemistry research 2009-08, Vol.48 (16), p.7724-7732
• Main Authors: Lee, Ju Weon, Wankat, Phillip C
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical engineering; Exact sciences and technology; Separations
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie900092y

The simulated moving bed (SMB) process has been extensively used in industrial separations for binary and pseudobinary separations. The SMB has been reported to have higher productivity and requires less desorbent than batch chromatography; however, in pseudobinary separations these advantages are dependent on the difference of adsorption behaviors of the nontarget components. In this research, the performance of batch chromatography with a single recycle stream was compared to SMB processes for pseudobinary separations of ternary nucleosides, a model system with competitive Langmuir isotherms. To compare the performances of SMB and recycle batch chromatography, detailed dynamic simulations of each process were performed with optimized operating conditions. The desorbent to feed ratio, D/F, of recycle chromatography was at least 2 times smaller than that of a four-column SMB process for most retained solute separations. For one case of least retained solute separation (2′-deoxycytidine/2′-deoxythymidine/2′-deoxyadenosine), minimum D/F of the four-column SMB process is approximately 15 times larger than that of recycle chromatography. The maximum productivity of recycle chromatography is 1.5−2 times larger than that of the four-column SMB process. When eight columns are used in the four-zone SMB process (two columns per zone), the performance (productivity, D/F, and pressure drop) is improved compared to the four-column SMB. The eight-column SMB has higher maximum productivity, and at the same productivity, it also has lower D/F and lower pressure drop compared to recycle chromatography. However, the recycle chromatography system is simpler and has fewer columns.