Generic Modeling Framework for Gas Separations Using Multibed Pressure Swing Adsorption Processes

System and Processes of Pre-combustion Carbon Dioxide Capture and Separation

In this chapter, the development of H2/CO2 separation technology, including a new CO2 chemical adsorbent, a pressure swing adsorption (PSA) reactor model, and the continuous operation of a pilot-scale test system for pre-combustion CO2 capture, are presented. Potassium-promoted Mg–Al layered double oxides (LDOs) are shown to be appropriate candidate adsorbents for elevated temperature (250–450 °C) PSA for pre-combustion H2/CO2 separation. The adsorption heat of CO2 on the surface of LDOs is only 2.5–60.4 kJ mol−1, which is beneficial for achieving isothermal desorption by a pressure swing. Further, methods for enhancing the CO2 capacity and the mechanical strength of adsorbent pellets are introduced. The single- and double-column fixed-bed experiments provided useful results for the development and validation of scalable modeling. The PSA model was built by coupling a non-equilibrium kinetic adsorption model and a column model. The effects of operating parameters on the H2 recovery ratio and CO2 capture ratio were studied. A 4-column pilot-scale elevated temperature PSA (ET-PSA) system was developed with a processing capacity of 4.0–6.6 Nm3 h−1 to determine the feasibility of such a system for industrial application. It achieved 1089 h of accumulated operation and 75 h of continuous operation, maintaining a CO2 removal ratio higher than 91.7%.

Advances in Pressure Swing Adsorption for Gas Separation

Pressure swing adsorption (PSA) is a well-established gas separation technique in air separation, gas drying, and hydrogen purification separation. Recently, PSA technology has been applied in other areas like methane purification from natural and biogas and has a tremendous potential to expand its utilization. It is known that the adsorbent material employed in a PSA process is extremely important in defining its properties, but it has also been demonstrated that process engineering can improve the performance of PSA units significantly. This paper aims to provide an overview of the fundamentals of PSA process while focusing specifically on different innovative engineering approaches that contributed to continuous improvement of PSA performance.