Thermally Assisted Simulated Moving Bed Systems

The principles of simulated moving bed (SMB) and thermal swing adsorption (TSA) are combined to develop a traveling wave mode, thermally assisted SMB. The four-zone, thermal SMB and the corresponding one-column, thermal Analog to the SMB are studied for separating binary systems with linear isotherms. Design parameters and operating conditions are determined using the local equilibrium theory and detailed simulations are done with the commercially available chromatography/SMB software package Aspen Chromatography v12.1. Simulations were performed for the separation of toluene/xylene with silica gel as the adsorbent and n-heptane as the desorbent. The SMB and Analog are operated with a heat exchanger heating or cooling the fluid before it enters each adiabatic column. The advantage of the traveling wave mode compared to the direct mode of heat transfer is since heat transfer rates are not limiting, the SMB and Analog systems can be scaled up easily.