A novel optimization approach for material screening in the adsorption process separation context based on rigorous models: Separation of a mixture of N2 and CO2 in a Pressure Swing Adsorption Unit as a case study

Abstract

Adsorption material screening simultaneously with optimizing an adsorption-based process is a challenging problem with increasing attention in the literature. This is usually done in an uncoupled way, separated into two separated steps. The first step focuses on the materials' properties, followed by an optimization step where the focus is on the process behavior given a pre-selected material. It is observed in the literature an increasing demand for systematic optimization approaches that make use of materials science databases in a process systems engineering context. Therefore, providing a synergy between these two disciplines. Hence, the present work proposes the design of a looped optimization problem where the material and process operating conditions are used as decision variables to optimize a Pressure Swing Adsorption. An inner loop is used to screen the best material among the 12 options. An outer optimization loop is used to optimize de process operating variables. A case study presents the separation of the raffinate stream produced in the gaseous Simulated Moving Bed process to separate CH4/N2 using CO2 as the desorbent gas. Thus, the SMB raffinate stream is composed of a mixture of N2 and CO2. The results demonstrate that the proposed methodology can efficiently perform both tasks, identify the most suitable material and optimize the Pressure Swing Adsorption unit.