Ken-ichi Aika, Tokyo Institute of Technology, Japan
15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting
ABSTRACT
The ammonia synthesis reaction is considered to involve several elementary steps [1]:
N2 + 2＊ → 2N(a) (1)
H2 + 2＊ → 2H(a) (2)
N(a) + H(a) → NH(a) + ＊ (3)
NH(a) + H(a) → NH2 (a) + ＊ (4)
NH2 (a) + H(a) → NH3(a) + ＊ (5)
NH3(a) → NH3 + ＊ (6)
Here, the symbol ＊ indicates empty sites. For most metal catalysts, the dissociative adsorption of dinitrogen (step 1) is the rate-determining step, and all the other steps and its reverse step (from 2 to 6) are fast enough to be almost in equilibrium for each reaction step. The synthesis rate is considered to be the same as the rate for step (1), and is proportional to the dinitrogen pressure and square of the empty site concentration. Continue reading
