NH3 in H2 for FC, breakthrough technology

NH3 as the H2 Carrier and breakthrough Method of NH3 decomposition

Author: David Judbarovski, systems engineering, principle inventor, retired

Abstract

Here I suppose to offer the method of the hydrogen extraction from ammonia by its oxidation partly,  at moderate temperatures. Such hydrogen can be served as a clean and cheap  and non- poisoning fuel for H2-air Fuel Cells for high energy effective engines’  powering without any harmful exhaust being the water vapor and nitrogen only.

At present, decomposition of ammonia needs noble metal catalysts, being very expensive and rare ones, so such hydrogen is very expensive, and it is a big obstacle for large-scale introducing it as a common technology in the world practice. .

The problem of substitution the noble metal catalyst by something more cheap and common is a hot engineering problem being now  not solved.

(see Bell, T.E., Torrente-Murciano, L. H₂ Production via Ammonia Decomposition Using Non-Noble Metal Catalysts: A Review. Top Catal 59, 1438–1457 (2016). https://doi.org/10.1007/s11244-016-0653-4 )

Here just below I suppose a following chemistry offered by me:

NH3 + 0.2 O2 = 0.5 N2 + 0.4 H2O  + 1.1 H2.

So effectiveness of the chemistry by hydrogen production would be

K = 1.1 * 2 / 3 =  73%, and supposing Fuel Cell energy efficiency as 67 %,

the system’s total energy efficiency would be 73% * 67% ~= 50 % by NH3 as a fuel

Its Gibbs free energy is –

dG = dH – T * dS, hence

dG = 0.4 * 242,000 – 46,000  - T * (0.5 * 200 + 0.4 * 189 + 1.1 * 131 – 193 – 0.2 * 205) =

dG = 51,000 -  T * (320 – 234) = 51,000 – 86 * T, 

Supposing dG =< - 35,000,  so

T >= 1000 K ~= 700 C

The higher temperature T, the higher a productivity our chemistry offered.

Note: The problems of very cheap ammonia and very cheap & abundant & inexhaustible renewable energy of any designed supply schedule can be used for the said cheap ammonia production, it was and is my especial affords and numerous results..