Optimal synthesis of rotating packed bed and packed bed: a case illustrating the integration of PI and PSE

Abstract

Abstract The rotating packed bed (RPB) that is a novel process intensification (PI) reactor has been successfully adopted in the chemical industry in recent decades. Unlike sheer process optimization, PI aims to break the bottleneck of transfer processes at the micro level, like mixing and reaction kinetics, such that the process shifts to be governed by its innate reaction rate rather than by mass transfer. This work demonstrates a superstructure synthesis approach for evaluating PI device through a case study involving an RPB and a packed bed (PB). A multi-scale model links the micro-mechanisms of intensification in the RPB with the macro-level decisions of equipment selection and interconnection. The proposed superstructure considers configurations of an RPB and PB in series, in parallel, and in between, allowing quantification of their synergy. The overall model is formulated as a nonlinear programming problem and is demonstrated with the case of H2S removal from refinery tail gas. The computational results show that the configuration of both RPB and PB in parallel is optimal under the assumption of linear investment and operating costs. Over a wide range of possible electricity prices, the hybrid system of both units is shown to be more cost-effective than a single RPB or PB. This synergistic effect is uncovered with the integration of process intensification and superstructure optimization, illustrating a new way for both PI and PSE to incorporate.