(657e) Aromatics/Alkanes Separation: Simulated Moving Bed Process Model Development By a Concurrent Approach and Its Validation in a Mini-Plant

SMB process design for multicomponent systems is often challenged by the difficulty of establishing a reliable adsorption model, especially when the adsorption equilibrium is governed by multi-component nonlinear isotherms. In this talk, we discuss a “concurrent” iterative approach to simultaneously determine the adsorption model while optimizing SMB process design, thereby greatly reducing the experimental effort for process development. Here we specifically focus on a concurrent approach for separation of multicomponent aromatics/alkanes mixtures that approximate hydrocarbon streams often encountered in petroleum refining. These multicomponent streams display strong competition for adsorption in mesoporous or microporous adsorbents. Using an approach that combines adsorption measurements and model fitting and SMB model predictions that allow targeted selection of compositions for adsorption measurements, we demonstrate convergence of the concurrent method with only a small number of multicomponent adsorption measurements. Then, we demonstrate a second iterative methodology to refine the SMB model by estimating the non-thermodynamic (i.e., mass transfer) and other (dead volume) system parameters, using only a small number of runs on a 16-column SMB “mini-plant” designed and constructed in-house at the Georgia Institute of Technology. The final process design, validated in the SMB mini-plant, maximizes the throughput while maintaining the desired aromatic purity and recovery.