Experimental investigation on combustion characteristics of novel preheated air swirl burner operating on the heavy oil fired furnace for reducing NOx emission

Abstract

ABSTRACT This paper presents an experimental study carried out to evaluate the influence of air swirl vane angles on pollutants in a heavy oil fuel fired furnace with a recuperator. A novel burner system with a range of concentric air swirl generators (vane angles of 15°, 20°, 30°, 45°, 60°, and 90°) was ultimately incorporated to the combustion chamber of a 250 kg crucible furnace. This study examined the thermal efficiency and the polluting emission parameters of CO2, HC, CO, and NOx. According to the results, preheated air-fuel and air swirl generators with vane angles of 45° and 30° emit the least HC and CO, whereas air swirl vane angles of 90° emit the most. A preheated primary air swirl vane angle of 45° results in the lowest NOx emission (25 ppm) value. Furthermore, with larger air swirl vane angles of 45° results in increased temperature and premixed combustion, as well as a raise in NOx emission. To ensure accurate airflow for complete combustion, secondary air entry area kept twice the primary air entry area in the novel burner. The results showed that when the temperature of the preheated primary and secondary air and heavy oil fuel combination increased, so did the mean effective temperature of the combustion gases. Conversely, when the vane angle is reduced and no preheated air-fuel combination is present, the mean temperature of the combustion gas drops dramatically.