Characterising premixed ammonia and hydrogen combustion for a novel Linear Joule Engine Generator

A novel ammonia/hydrogen dual-fuelled Linear Joule Engine Generator (LJEG) is developed for medium to large scale power generations and electrification of ship propulsion systems. The characteristics of premixed ammonia/hydrogen combustion of the LJEG are investigated through chemical kinetic modelling. Three representative mechanisms are compared based on their accuracy of reproducing experimental results. With robust combustion and low NO_x emission as the primary targets, laminar burning velocity, ignition delay and flame species concentration are investigated over a wide range of equivalence ratio (0:8 - 1:6), hydrogen blending ratio (0:0 - 0:6), oxygen content (0:21 - 1:00), inlet temperature (300 K - 700 K) and pressure (1 bar - 20 bar). Rate of production (ROP) analysis is carried out to gain in-depth understanding of critical NO_x production and consumption pathways. The results indicate that an equivalence ratio around 1:1 is beneficial for both combustion robustness and NO_x emission reduction. Both adding hydrogen in the fuel (40% Vol) and enriching oxygen in the oxidizer (60% Vol) promote burning velocity to the similar level of methane (37 cm/s). Explicit reduction of NO emission is observed when pressure increases, which can be attributed to the combination of NH_i radicals. The findings show the potential of the ammonia and hydrogen fuelled LJEG for ultra-low emission power generation.