SIMULATED MOVING BED REACTORS - AN INSTRUCTIONAL MODULE FOR INCORPORATION OF PROCESS INTENSIFICATION CONCEPTS INTO THE SENIOR REACTOR DESIGN COURSE

摘要

The combination of reaction and separation in a single process unit is one of the basic tenets of process intensification. With this coupling, constraints arising from thermodynamic equilibrium may be avoided and the combined process may be more efficient as well as more economical in terms of capital expenditures as well as operating costs. With rising energy prices and the need for the chemical industry to remain globally competitive, consideration of process alternatives including these hybrid processes will be required of practicing chemical engineers in the coming years. Due to the compartmentalized mode of instruction in most chemical engineering departments, separations and reactor design are typically taught in different courses. As a result, hybrid processes combining reaction and separation are generally relegated to coverage during the senior year, either in a capstone design course or in a reactor design course. Fogler examined membrane reactors as well as reactive distillation in his text, Elements of Chemical Reaction Engineering, and has developed web modules for instruction on these topics. The availability of the instructional content in the text as well as the web modules provide other instructors with tools that can be easily incorporated into their courses. The simulated moving bed reactor (SMBR) exemplifies process intensification through the coupling of separation and reaction. The separation process is adsorption, with separation accomplished using a solid phase adsorbent that has an affinity for one or more reaction products. As the reaction proceeds in the SMBR, products are removed from the reaction phase, and in the case of an equilibrium-limited reaction, this allows the reaction to proceed and achieve greater conversion. The simulated moving bed (SMB) technology for separation has been successfully employed commercially since the 1960s by UOP. Use of SMB as a platform for coupling reaction with separation is relatively recent. This module provides instruction on the basic configuration of a simulated moving bed reactor, constraints/limitations on its use, and also contains an overview of representative technology applications. Through comparison of process variables such as relative affinity of the adsorbent for reactants/products, process flow rates, reactor temperature, and feed stoichiometry, students gain insight into the impact of these variables on SMBR performance compared to a conventional packed bed reactor.