Industrial TSA separations

Physical sorbents for carbon dioxide separation and removal were extensively studied by industrial gas companies. Zeolite 13X, activated alumina, and their improved versions are typically used for removing carbon dioxide and moisture from air in either a TSA or a PSA process. The sorption temperatures for these applications are usually close to ambient temperature. There are a few studies on adsorption of carbon dioxide at high temperatures. The carbon dioxide adsorption isotherms on two commercial sorbents hydrotalcite-like compounds, EXM911 and activated alumina made by LaRoche Industries, are displayed in Fig. 8.F23,i24] shown in Fig. 8, LaRoche activated alumina has a higher carbon dioxide capacity than the EXM911 at 300° C. However, the adsorption capacities on both sorbents are too low for any practical applications in carbon dioxide sorption at high temperature. Conventional physical sorbents are basically not effective for carbon dioxide capture at flue gas temperature (> 400°C). There is a need to develop effective sorbents that can adsorb carbon dioxide at flue gas temperature to significantly reduce the gas volume to be treated for carbon sequestration. 

The general guidelines for developing a gas separation process based on adsorption are reviewed. Two important industrial cases based on adsorption processes are selected the separation of propane/propylene mixtures and n/iso-paraffins mixtures. The 13X zeolite and Ag -Amberlyst were used as adsorbent for propane/propylene mixture taking into account information from the open literature. The 5A zeolite was selected for n/iso-paraffins system the adsorption equilibrium and diffusivity data were obtained from gravimetric and ZLC techniques respectively. A mathematical model for the bulk separation in fixed bed upon non-isothermal non-adiabatic conditions is formulated and solved numerically. The simulated results are compared with the available experimental breakthrough curves. Finally, a cyclic process based in the PSA-VSA and TSA concepts is proposed for these systems. 

DPA), or by reducing the total pressure, as in pressure swing adsorption (PSA). Industrially, PSA is the predominant type of adsorption cycle used for gas separation, although TSA is also quite common. These processes are alternatives to other traditional and more energy-intensive cryogenic and distillation processes. 

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