Powerfeed process

Figure 5. Comparison of (a) the average mj and m3 among the 5-colunm SMB, the Varicol and the PowerFeed processes and (b) Values of m3 in the 4 subintervals of the PowerFeed process corresponding to the points in...

Our results show that the Varicol and the PowerFeed operations improve the performance of the SMB process, particularly when the total number of columns is small and the separations are difficult. The optimal design of the Varicol and PowerFeed processes can be replaced by the optimal design of the corresponding SMB process given by the equilibrium theory, followed by the search of the optimal ports switching and flow rates variation schemes within the switching period, respectively. 

As reported by Zhang the performance of the PowerFeed processes is similar to VariCol with respect to product purities, productivity and eluent consumption and thus better than classical SMB processes. However, this improved performance is achieved with increased complexity of operation and design. 

These results show that both the Powerfeed and the Varicol processes provide a performance that is significantly improved compared to that of the conventional SMB process, and that the extent of the improvement achieved is larger for more difficult separations. A rigorous comparison between the Varicol and the Power-feed processes in general terms is not possible, but it seems fair to say that they are equivalent in terms of potential performance, although the implementation of the Varicol process may be simpler than that of the Powerfeed process. 

Kawajiri, Y. and Biegler, L. (2006b). Optimization strategies for simulated moving bed and powerfeed processes, AIChE Journal 52, 4, pp. 1343-1350. 

Figure 7.32 Nominal and robust Pareto curves for four-column SMB, Varicol, and PowerFeed processes ( ) the robust Pareto curves (reproduced from Mota, Araujo, and Rodrigues, 2007).

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