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

Abstract

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 NOx 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 (300K−700K) and pressure (1bar−20bar). Rate of production (ROP) analysis is carried out to gain in-depth understanding of critical NO production and consumption pathways. The results indicate that an equivalence ratio around 1.1 is beneficial for both combustion robustness and NOx 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 (37cm/s). Explicit reduction of NO emission is observed when pressure increases, which can be attributed to the combination of NHi radicals. The findings show the potential of the ammonia and hydrogen fuelled LJEG for ultra-low emission power generation.