Parametric study for an ammonia decomposition reactor design using computational fluid dynamics simulation

Ammonia is a promising carbon-free hydrogen carrier for solid oxide fuel cell (SOFC) systems, requiring efficient pre-decomposition before stack supply. This study combined experimentally derived reaction kinetics of ammonia decomposition with computational fluid dynamics (CFD) to evaluate the effects of reactor operating conditions and geometry. Using a commercial Ru/Al 2 O 3 catalyst, the reaction order, activation energy, and pre-exponential factor were determined as 0.5153, 102.7 kJ mol −1 , and 4.96 × 10 8 mol 1−n ·m 3n−3 ·s −1 , respectively, and the simplified reactor model incorporating these parameters showed high agreement with experimental results (R 2 = 0.9832). Parametric analyses were then performed on heat supply, feed-gas temperature, inlet velocity, channel aspect ratio, and reactor length. A normalized sensitivity analysis showed that heat supply and inlet velocity were the most dominant variables. Combining the optimal geometry with optimized operating conditions achieved a maximum thermal efficiency of 80.4960%, providing direction for reactor design in SOFC ammonia pre-treatment systems.