Reduction of NOx emissions by staged combustion in a high intensity spray combustor.

Abstract

NOx reduction effects by staged spray combustion in a high intensity swirl combustor have been investigated using kerosene with a pyridine content of 0-1.7%. The secondary air was radially injected into the combustion chamber through a multi-holed tube which was axially inserted from the rear side of a cylindrical combustor. Experiments have been carried out while varying the secondary air injection point, the primary to secondary air ratio, the pyridine content and the fuel flow rate. The main experimental results are as follows: (1) By effective mixing of a fine fuel spray with an air flow, with a large swirl degree, in the primary combustion zone, and by maintaining a suitable supply of secondary air, low NOx emission can be realized even in a high intensity combustion state. (2) The secondary air supply at a point where the primary combustion is almost completed is effective for reducing NOx emissions. (3) The primary to secondary air ratio for a suitable low NOx emission has a tendency to increase with a decrease in combustion intensity.