High-pressure conversion of ammonia additivated with dimethyl ether in a flow reactor

The oxidation of ammonia (NH 3 ) mixed with dimethyl ether (DME) was investigated from experimental and modeling points of view using a quartz flow reactor with argon as bath gas from 350 K to 1225 K, for two different DME/NH 3 ratios (0.05 and 0.3), three oxygen excess ratios (λ = 0.7, 1 and 3) and various pressures (1, 10, 20 and 40 bar). The effect of pressure, oxygen stoichiometry, temperature, and DME/NH 3 ratio has been analyzed on DME, NH 3 , NO, NO 2 , N 2 O, N 2 , O 2 , H 2 , HCN, CH 4 , CO, and CO 2 concentrations. The present study indicates that oxygen availability, DME/NH 3 ratio, and pressure are important variables that shift NH 3 and DME conversion to lower temperatures as their values increase. Under certain conditions, the pressure effect can avoid NO and HCN production, which would represent a benefit for pressure applications. The main products of ammonia/dimethyl ether oxidation are N 2 , N 2 O, CO, and CO 2 , and under certain conditions, NO, H 2 , CH 4, and HCN are also produced. NO 2 is always detected below 5 ppm for all the conditions considered. The N 2 O formation is favored by increasing the O 2 stoichiometry, pressure, and/or DME/NH 3 ratio. The experimental results are interpreted and discussed in terms of an updated detailed chemical kinetic mechanism, which captures, with a general good agreement, the main trends of NH 3 and DME conversion under the considered conditions. Despite this, some calculated species present discrepancies with the experimental results. The main challenge is the consideration of the C-N interactions that can be present in the combustion of DME/NH 3 mixtures.