LAUSR

This paper presents the results of an experimental study on the combustion process of methane mixed with ammonia (NH3) in flameless mode. At a time of striving for CO2-free power, ammonia became a potential energy storage carrier fuel from renewable sources. Flameless combustion features low emissions and is a very efficient technology used in the power sector, as well as steel production, ceramics, etc. Industrial furnaces were tested in the context of pure methane combustion with an addition of ammonia, up to 5%. Flameless combustion conditions were achieved with a regenerative gas burner system (High Regenerative SystemHRS). The burner consists of four ceramic regenerators allowing for continuous preheating of air, even up to 50K lower than the temperature of the combustion chamber wall. Constant power of the introduced fuel was kept at 150kW and the fuel-air equivalence ratio ranged from 0.75 to 0.95. The results have shown a growth of molar fraction of nitric oxides in flue gases when ammonia content in the fuel rose. The increase is more significant for the tests with a higher amount of oxygen in the combustion chamber (a lower fuel-air equivalence ratio). An addition of 5% of NH3 into the fuel caused an emission of nitric oxide at the levels of 113 ppmv and 462 ppmv (calculated to O2 = 0%), respectively for low and high fuel-air equivalence ratios. The calculated conversion factor (CF) of NH3 to fuel nitric oxide has shown extremely low values, equal to 2% (φ = 0.95) and 8.4% (φ = 0.75), which indeed confirmed that ammonia can be burned with low emissions in flameless combustion technology.