Comparative analysis of ammonia combustion for domestic applications

This article explores whether ammonia is a reliable fuel for heat and electricity generation in domestic applications. First, the ammonia combustion characteristics, including adiabatic flame temperature, ignition delay time, and laminar flame speed are analysed and compared with the conventional fuels such as natural gas, dimethyl ether, hydrogen, and syngas, under 12 kWe turbine and 45kWth boiler conditions. Furthermore, the combustion of ammonia at a conventional boiler and turbine combustor was numerically modelled, analysed, and compared with the available fuels. The finding demonstrates that ammonia provides inferior combustion characteristics in combustion heat releases, stability region, and ignition characteristics. The ammonia combustion characteristics including, laminar flame speed and ignition delay time, were comparable to those of methane. The flame temperature and exhaust gas composition of ammonia are rather different than those of methane which may vary the heat transfer during the operation of gas turbines and boilers. The combustion of ammonia in boilers may produce the required heat for heating purposes; however, it needs further modification to achieve better NOX control. In a gas turbine, on the other hand, combustion ammonia leads to remarkably higher temperatures if the same turbine inlet temperature is needed compared to other fuels, however, at the cost of significant NOX formation, which may go beyond 100 ppm with thermal NO formation on par of fuel NO.