(617e) Ammonia Absorbents with High Stability and High Capacity for Fast Cycling

Ammonia absorption is an alternative separation to condensation in ammonia production. Metal chloride salts selectively incorporate ammonia into their crystal lattices with remarkably high capacity. Regeneration and stability of these salts are further improved by dispersing them onto a porous silica support. Here, we discuss the optimal preparation methods of supported metal halides, as well as optimal conditions for uptake and release of ammonia. The metal halide salt particle size, support particle size, support composition and preparation methods are optimized for material stability, speed of uptake and release, and maximum ammonia capacity. An automated system was used to rapidly screen absorption and desorption conditions, to access material stability, and to identify optimal cycling conditions. Temperatures and pressures during absorption and desorption were designed to use minimal energy for maximum uptake and release of ammonia within a reasonable time. These results provide a basis for utilizing these supported metal halide salts as sorbents for small scale ammonia synthesis.