New insight into NH3-H2 mutual inhibiting effects and dynamic regimes at low-intermediate temperatures

The hydrogen effect as a “fuel enhancer” on ammonia oxidation features is a relevant topic for ammonia-based energy conversion systems. For the most, scientific literature is focused on high temperature ammonia-hydrogen oxidation chemistry, whereas few works focus on low-intermediate temperatures (900–1350 K), relevant for non-conventional low-temperature combustion processes. Recently, low-intermediate and the shift to high-temperature ammonia oxidation chemistry has been characterized through experimental tests in a Jet Stirred Flow Reactor (JSFR) by the same authors, with the identification of thermo-kinetic instabilities. In addition, the ammonia effect on hydrogen oxidation chemistry has been addressed through a mutual inhibiting interaction for low-intermediate temperatures. Given this background, this work investigates the hydrogen effects on ammonia oxidation and thermo-kinetic instabilities from low-intermediate to high temperatures in a JSFR, parametrically varying the H2 inlet concentration. Maps of combustion behaviours (Tin- ϕ) are then drawn up, on the basis of experimental evidences, in the range 1200K<1350 K, and 0.2