Perspectives of Scaling Up the Use of Zeolites for Selective Separations from Lab to Industry

Abstract

Different synthetic zeolites can be obtained by varying the composition, porosity, and active centers, making them of great interest in industry, especially as adsorbents in gas separation and purification processes. On the other hand, adsorption separation processes are increasingly common in industrial applications due to the technical and economic advantages of this technology. In this context, zeolites have emerged as promising candidates for these processes due to their high temperature stability, resistance to harsh environments combined with unique molecular sieve characteristics, ion exchange, and selective adsorption. In this chapter, we will focus on two cases, paraffin/olefin separation (ethane/ethylene and propane/propylene) and carbon dioxide/methane separation.Some innovative alternatives to replace conventional distillation have emerged for paraffin/olefin separation, with emphasis on simulated moving bed (SMB) technology. A wide variety of zeolites has been studied for this process, such as zeolites 13X, 4A, and 5A. The second case study is the removal of carbon dioxide (CO2) from natural gas stream. Adsorption processes are considered a competitive solution, once the adsorbent can be regenerated either by TSA or PSA. Concerning the use of zeolites for CO2 removal, natural chabazite, zeolite 4A, H-mordenite, and zeolite 13X are the ones with more available information in literature.In this review, we will focus on the strategy and importance of the lab/pilot scale with perspectives of scaling up adsorptive gas-phase separations using zeolites. The main methods adopted in lab/pilot scale studies include adsorbent characterization, adsorption equilibrium, adsorption dynamic studies, and process simulation and optimization.