In order to explore the formation and evolution of soot during the combustion of coal

this paper uses Pingdingshan coal as combustion material

and uses the light scattering method coupled with the thermophoretic sampling article diagnostic method to measure the soot mass in flame. A light scattering measurement system capable of precise vertical movement is constructed to measure the light scattering intensity at different heights of the flame. The particle size distribution is obtained by the thermophoretic sampling particle diagnostic method

and the soot mass at different heights when the flame is calculated by Mie scattering theory. The results show that as the flame rises

the median mass diameter of soot firstly increases and then decreases. When the flame burns stably

a large amount of soot is formed at a height of H=10 mm. As the flame rises

the mass of soot decreases rapidly in the H=10～30 mm range. In the range of 10～20 mm

the soot mass of Pingdingshan coal decreases by 58.62%. When H40 mm

the soot mass of Pingdingshan coal slowly decreases.