From the viewpoint of minimizing environmental impact, waste incineration facilities are expected to reduce NOx emissions. In stoker incinerators, exhaust gas recirculation is combined with selective non-catalytic reduction to decrease NOx levels. With the aim of reducing the cost for the denitrifying agent, a low NOx combustion system using a novel gas injection method for exhaust gas recirculation has been developed. In this system, gas from exhaust gas recirculation is used to induce the flow of recirculation in the primary combustion zone, thereby expanding the area of reduction. A swirling flow is also formed in the secondary combustion zone to facilitate complete combustion, which decreases the total air ratio. This system produced half the NOx compared to that by conventional methods, and is summarized in this report.
