Experimental and Numerical Analysis of Ammonia Cracking on a Ruthenium Based Catalyst for Maritime Fuel Cell Systems

Description

To use ammonia as an energy source for fuel cells, pre-cracking can be useful. The aim is to increase the efficiency and durability of the fuel cells. In order to perform the decomposition on the required scale, a catalyst for thermal cracking is needed. Ruthenium has proven to be a promising material in previous research. However, to design an ammonia cracker, the reaction kinetics for the specific catalyst is required.

This project shows how different operating conditions affect the conversion of the decomposition reaction and develops a reaction kinetics for the ruthenium-based catalyst. In order to obtain the kinetics, experiments are carried out and a CFD model is developed. The analyzed catalyst consists of ruthenium nanoparticles anchored to aluminum oxide particles. The experiments show that the conversion increases with temperature, but decreases with a higher volume flow or a higher ammonia concentration in the input mixture. Additional hydrogen also has a negative impact on the conversion. The kinetics developed is able to emulate the characteristics of the catalyst. The results indicate the high activity of ruthenium even at comparatively low temperatures. They also show that even small amounts are sufficient to achieve the desired decomposition rate, which is particularly important with regard to material costs.

This work demonstrates that the pre-cracking of ammonia in fuel cell systems is possible. The high activity of the catalyst and consequently the compact design of the cracker also allows mobile use. Therefore, these systems can make a significant contribution to the energy transition in the transportation sector.

Period	Apr 2023 → Oct 2023
Degree of Recognition	International