Design of a Micromix Fuel Injector for High Temperature Hybrid Concentrated Solar Power Plants

The hybrid air Brayton concentrated solar power plant (CSP) combines a natural gas fired combustor in series with a traditional CSP system. The combination boosts turbine inlet temperature above the receiver temperature and reduces output variability. However, a combustor operating in this mode must tolerate an inlet air temperature equal to the solar receiver outlet temperature, which is expected to be as much as 1,000°C for next generation designs. High inlet temperature hybrid combustors must achieve low NO_x emissions in spite of the increased risk for autoignition and flashback. In addition, the hybrid injector must be able to adjust to the variability inherent to the solar source. The design of a multibank micromix injector that meets these challenges is described with emphasis on its NO_x and CO emissions characteristics.