Emission and performance of a micro gas turbine combustor fueled with ammonia-natural gas

Abstract

Ammonia as a carbon-free fuel has great potentiality to be utilized in power generation sectors such as micro gas turbines (MGT) to mitigate carbon dioxide emission from combustion systems. It is also easy to store and transport at room temperature compared to hydrogen, and in liquid form has equal volumetric energy density to liquid hydrogen. However, some challenges regarding its NOx pollution and flame stabilization inhibit its usage in these areas which requires further studies. In the present study, thermal performance and NOx emission of an MGT combustor fueled with ammonia-natural gas blends has been analyzed numerically through chemical reactant networks (CRN). The combustor’s inlet conditions are at atmospheric conditions and diffusion flame is stabilized using air swirler. In the first part of the paper, the CRN model has been developed based on empirical and semi-empirical equations. Series of experiments have been carried out to find the required parameters for the CRN model. Also, the results of NOx emission and temperature distribution have been validated with the experimental results. In the second part, effects of ammonia addition to the natural gas fuel are studied for various ammonia percentages using the CRN. The results show that by increasing ammonia molar percentage in the fuel, NO emission rises dramatically and reaches up to 330 PPM, but after a certain threshold (about 12.5 molar percent of ammonia) further ammonia addition reduces NO emission. Moreover, the overall temperature of the combustor decreases with ammonia addition due to lower LHV (lower heating value) of ammonia relative to natural gas. However, the overall efficiency of the combustor does not change significantly. The results also reveal that most of the NO is produced in the primary and secondary zones of the combustor. NO2 is mostly created in the secondary zone of the combustor and comprises about 10% of total NOx emission.

Experimental performance and emissions of additively manufactured high-temperature combustion chambers for micro-gas turbines

“…There has been considerably more work conducted on MGT combustion chambers not involving AM. This ranges from the use of synthetic and ammonia mixed gaseous fuels in MGTs, 3,[25][26][27][28] to the use of flameless or MILD combustion to reduce emissions 4,[29][30][31] and the development of porous burners and other injection research. [32][33][34][35] All such research further confirms that numerous different industries are recognizing the potential of MGTs to become viable power generating solutions in the coming years.…”

Impact of Fuel Quality on Gas Turbine Components

“…Within the recirculation zone, the fuel vaporizes, partially burns, and gets ready for rapid combustion in the remaining burning zone. Ideally, at the end of the burning zone, all fuel should be burned so that the function of the dilution zone is solely to mix the hot gas with the dilution air [5].…”

Internal cooling sensitivity analysis to improve the thermal performance of gas turbine blade using a developed robust conjugate heat transfer method

“…As well known, gas turbines are numerously used to convert energy of combustio gases into mechanical work. [1][2][3][4][5][6] One main goal in gas turbine engine development is to increase its thermodynamics efficiency, of which the turbine inlet temperature plays a very important role. Evidently, this temperature should not exceed the allowable design temperature of metal parts.…”