Abstract
Under high temperature combustion, it is foreseen that very high levels of NOx are generated. In order to suppress the NOx increase, the Exhaust Gas Recirculation (EGR) system is applied to heavy duty gas turbine. The EGR system in a Gas Turbine Combined Cycle recirculates exhaust gas from the Heat Recovery Steam Generator outlet to the compressor inlet. This reduces the oxygen content of the mixed products of combustion with fresh air and therefore, reduces the NOx formation in the combustor. Unfortunately, the lower burning velocity of the mixture causes flame holding problems that may lead to unstable combustion. A novel combustor has been developed that provides good flame holding characteristics and reduces NOx. Intermediate pressure tests were carried out to confirm the NOx reductions in a simulated EGR environment. The results indicate a sharp decrease in NOx compared to a conventional Dry Low NOx combustor operating at similar high temperature.
