Under the background of “ carbon peaking and carbon neutrality” ,the innovation of efficient and clean coal utilizationtechnologies has become a significant research direction in the energy sector. The coal purification-combustion coupling technology,as anovel thermal conversion process,focuses on the efficient removal of fuel nitrogen through a pre-purification process,offering a newpathway for the source control of NOx in subsequent combustion stages. To investigate the influence of reaction temperature on thenitrogen release and transformation characteristics during coal purification,experiments were conducted at varying temperatures on aself-constructed 1700 ℃ four-temperature zone drop-tube furnace,based on high-temperature thermochemical conversion mechanisms.The results indicate that as the reaction temperature increased from 900 ℃ to 1300 ℃,the proportions of H2 and CO in the coal gassignificantly increased,along with the gas yield and composition. The conversion rates of various components also increased,with theconversion rate of nitrogen to the gas phase jumping from 48.26% to 83.14%. A considerable portion of coke nitrogen was transformed athigh temperatures,leaving only 16.86% of fuel nitrogen in the solid phase coke,which would be the primary source of NOx in subsequent combustion processes. When the temperature reached 1000 ℃,the conversion rate of fuel nitrogen to N2 exceeded 50%,and highertemperatures further increased the proportion reduced to N2,while also increasing the proportions converted to NH3 and HCN.Promoting the release and reduction of fuel nitrogen to N2 before combustion is crucial for NOx emission reduction in coal combustion.On the other hand,after the purification reaction,the specific surface area and pore volume of Shenmu bituminous coal significantlyincreased,up to 66.3 times and 10.5 times that of the raw coal,respectively,with a decrease in average pore diameter. The stability of thefuel carbon framework decreased,and the number of reactive sites increased,improving the combustion characteristics of the fuel. Thisimprovement was further enhanced with increasing temperature,demonstrating that the purification reaction is beneficial for thesubsequent clean and efficient combustion of the fuel.