Hydrothermal stability of Na-LTA shaped with clay binder

Gas drying by adsorption on molecular sieves is one of the first unit operations in natural gas processing. Nevertheless, the thermal swings during regeneration combined with the presence of a complex gas mixture may lead to early adsorbent fouling. The shaping of adsorbent materials is crucial not only to reduce pressure drop in columns, but also for enhanced thermal and mechanical properties. In this work, synthesized sodium-based zeolite Linde Type A (Na-LTA) in powder was shaped by extrusion into cylindrical pellets using a clay binder followed by calcination at 673 K for 24 h. The produced 2-mm pellets had binder contents of 15 and 20% (w/w). Thereafter, the shaped pellets were subjected to an accelerated aging procedure, which exposes the samples to conditions analogous to those of Temperature Swing Adsorption drying processes with a higher severity. High-resolution water vapor isotherms at 313 K were measured before and after the simulated aging process. Results show that the sample with 20% of binder had an average decrease in water uptake (mol kg-1) of 1.2% after aging, whereas the aged zeolite in powder presented a decrease of 8.1, evidencing a protective effect of the clay binder against thermal fouling.