Influence of a self-formed three-stage dual-wing-shaped carbon on reduction of soot emission from acetylene diffusion flame

Abstract

This paper reports the formation of a self-formed three-stage dual-wing-shaped carbon (TSDWSC) from acetylene diffusion flame for the first time. The TSDWSC grows naturally from the protrusion at the outlet of the nozzle, while the emission of soot can be greatly reduced. The evolution of the TSDWSC involves three stages: the first unclosed dual-wing, the second unclosed dual-wing and the unmatured third dual-wing. The effects of protrusion, the flow rate of acetylene and various burner nozzle diameters on the formation of the TSDWSC are investigated. The experimental results show that with the increase of the protrusion height, the time when the first stage begins to appear decreases. With the increase of the acetylene flow rate, the stage number of the final dual-wing-shaped carbon increases. The TSDWSC can only be generated when the nozzle inner diameter is 2 or 3 mm. Using a two-color thermometer, the flame temperature distribution along the flame centerline is measured after the complete growth of the TSDWSC. The results show that the temperature of the TSDWSC area in the lower part is remarkably lower than that of the flame area in the upper part. The efficiency of reducing soot emission increases gradually with the evolution of the TSDWSC and reaches 100%, while the temperature of the flame area in the upper also rises gradually. X-ray diffraction (XRD) result indicates the formation of carbon crystals.