Combustion characteristics by reversed air injection as a flameless combustion

Abstract

The effort to reduce pollution emission from industrial combustors have been researched through combustion control such as multi staging and flue gas recirculation. Recently, flameless combustion, which is referred as various words such as MILD combustion, HiTAC, etc., has been developed to reduce NOx and CO simultaneously and to increase heat transfer performance. Meanwhile, those technologies need new concept burner including heat recycling media to heat up combustion air which makes the burner system complicated and expensive. In this research, we introduced a new flameless combustion phenomena generated with reversed air injection technology, which consists of two high speed air nozzles without additional heat recycling media, so it can be operated in a steady mode without alternating flow direction. Experimental study was carried out to investigate the phenomena of reversed air injection. LPG was applied as the fuel. The premixed combustion with metal fiber mat is the relative partner for comparison. As the conclusion, the NOx emission of the reversed air injection is less than one third of NOx emission of the premixed combustion. The operation range of heat load increases at the reversed air injection. The CO emission of the reversed air injection at the exit does not increase comparing to the premixed combustion. Aspect ratio of the furnace chamber appears as a main design parameter.