Influence of an iron compound added to coal on soot formation

Abstract

Soot formation is one major challenge in developing clean and efficient utilizes based on hydrocarbon fuels. We report the physical and chemical characteristics of a set of soot samples obtained from coal and coal mixed with iron nitrate pyrolysis on a drop tube furnace at different reaction times. Yimin lignite was chosen for the experiments, using acid washing to remove its metals and adding iron by impregnation. The pyrolysis processes of the two coal samples were analyzed by TG-DTG, DSC and MS. Characterization was carried out with transmission electron microscopy(TEM), Raman spectrometer, X-ray photoelectron spectroscopy(XPS), and infrared spectroscopy (FTIR). The results show that the iron nitrate significantly reduces the yield of soot and decreases the sizes of the primary soot particles. This inhibition effect on soot production increase with reaction time. With the addition of iron nitrate, the carbon lamellae in soot are more graphitized, but the primary particle surface roughness increases. In addition, the addition of iron results in more aliphatic functional groups and C–O on the surface of the soot.