Minimization of NO during staged combustion of CH₃NH₂

Monomethylamine (CH₃NH₂), serving as a source of fuel-bound nitrogen, has been burned in air with ethylene (C₂H₄), the primary fuel, in a two stage turbulent flow reactor. The NO emission from the first stage dramatically decreased as the fuel equivalence ratio (φ) was increased. For fuel-rich feeds, air was injected into the secondary stage to achieve an overall fuel-lean system φ. Optimum fuel-rich feed values (φ(m)) were identified which yielded minimum NO emissions from the second stage. These φ(m) values are a function of the CH₃NH₂ concentration in the feed. Compared with an all fuel-lean base case, the NO emission was reduced by at least 60% with staged combustion. Two elementary reaction mechanisms, drawn from the literature, have been used with a two-zone reactor model to successfully simulate the experimental data. Rate-or-production analyses, based upon the successful modeling, have illuminated the key pathways to NO formation and destruction.