Performances and emission characteristics of NH₃-air and NH₃-CH₄-air combustion gas-turbine power generations

For the first time NH₃-air combustion power generation has been successfully realized using a 50-kW class micro gas turbine system at the National Institute of Advanced Industrial Science and Technology Japan. The combustor adopted gaseous NH₃ fuel and diffusion combustion to enhance flame stability. The emission of NO and unburnt NH₃ depends on the combustor inlet temperature. Emission data revealed the existence of NH₃ fuel-rich and fuel-lean regions in the primary combustion zone. It is presumed that unburnt NH₃ is released from the fuel-rich region while NO is released from the fuel-lean region. When diluted air enters the secondary combustion zone unburnt NH₃ is expected to react with NO through selective non-catalytic reduction. Furthermore NH₃-CH₄-air combustion operation tests demonstrated that the increase of the NH₃ fuel ratio significantly increasef the NO emission wheile it decreased the NO conversion ratio. To achieve low NO_x combustion in NH₃-air combustion gas turbines large quantities of NH₃ fuel should be burned and produce both rich and lean fuel mixtures in the primary combustion zone.