Effects of a malfunctional column on conventional andfeedcol-simulated moving bed chromatography performance

The effects of a malfunctional column on the performance of a simulated moving bed (SMB) processwere studied experimentally and theoretically. The experimental results of conventional four-zone SMB(2-2-2-2 configuration) and FeedCol operation (2-2-2-2 configuration with one feed column) with onemalfunctional column were compared with simulation results of the corresponding SMB processes witha normal column configuration. The malfunctional column in SMB processes significantly deterioratedraffinate purity. However, the extract purity was equivalent or slightly improved compared with thecorresponding normal SMB operation because the complete separation zone of the malfunctional col-umn moved to a lower flow rate range in zones II and III. With the malfunctional column configuration, FeedCol operation gave better experimental performance (up to 7%) than conventional SMB opera-tion because controlling product purity with FeedCol operation was more flexible through the use oftwo additional operating variables, injection time and injection length. Thus, compared with conven-tional SMB separation, extract with equivalent or slightly better purity could be produced from FeedColoperation even with a malfunctional column, while minimizing the decrease in raffinate purity (lessthan 2%).