(55b) Standing Wave Design of Simulated Moving Beds for the Recovery of Sugars From Biomass Hydrolysate

Authors: 
Wang, N. L., Purdue University


Simulated Moving Bed (SMB) is more economical than batch adsorption for large scale purification. They have been used to produce para-xylene since 1970’s, high-fructose corn syrup since 1980’s, and chiral pharmaceuticals since 1990’s. However, SMB has not been widely used for multicomponent separation. A major barrier is the difficulty in designing zone flow rates and port velocity to ensure high purity and high yield in systems with significant diffusion effects.  SMB has three or more zones, which have different zone flow rates. Design the flow rates and port velocity by trial and error using either experiments or process simulations will require a large number of trials. A second barrier is the lack of design method to control the split of a mixture of three or more components. To overcome these barriers, a design method based on the concept of standing concentration waves in SMB was developed. A difference between port velocity and wave velocity is designed to focus a key wave in each zone to control product purity, yield, and the split. When intrinsic adsorption and diffusion parameters are known, the necessary flow rates and step times can be found quickly using minimal calculations. This method also reduces optimization search space by four dimensions or more. This talk will discuss how this method was used to develop a nine-zone SMB to recover glucose and xylose from a three component mixture and a five-zone SMB to recover six sugars with high purity (>95%) and high yield (>99%)from biomass hydrolysate (a complex mixture with 10 components).