Low-temperature combustion

such as combustion of solid fuels (low-rank coals

biomass etc.) in grate furnaces or fluidized bed combustors

can make NH3 (fuel-nitrogen) conversion

which is an important source of NOx and N2O. To understand deeply on NH3 oxidation and production of nitrogen oxides in low-temperature combustion process

the effect of combustible gases (CO

CH4

or H2) and NO on ammonia oxidation reaction was experimentally investigated in a tubular flow reactor at temperature range 600-1000℃

and the concentrations of NO

NO2

NH3

CO

CH4 and O2 were monitored continually with online Fourier-transformed infrared gas analyzer (Gasmet DX-4000). The results obtained were analyzed to clarify the chemical reaction mechanism. It was found that trace amounts of CO

CH4

or H2 could promote the oxidation of ammonia and enhance the emissions of NOx and N2O significantly under the condition of low temperature and oxidizing atmosphere. At equal concentration

the effect of H2 on ammonia oxidation was the greatest

following was CH4 and CO. As concentration increase of the combustible gas

the ammonia concentrations in combustion product decreased and approached rapidly zero

while the emissions of NOx and N2O increased firstly and then arrived at a stable value. When there was NO in initial gas mixture

oxidation reaction of ammonia could be enhanced too.