Throughout history, coal has been an important natural resource. There are many directions of coal research, but the main one is still the use of solid fuel as a resource for power plants. Coal gasification is becoming an attractive alternative for generating electricity, as it provides higher efficiency and improved environmental performance. However, because of the complex solid fuel system, the process of physical- chemical modeling is still a challenge. It is necessary to apply an accurate research method that will allow obtaining reliable data on the solid fuel conversion process and which has sufficient accuracy of fixing parameters. The analysis of the conversion of the coke residue by the TGA method in the nonisothermal regime in Ar and O2 is performed in this paper. Mechanisms for coal conversion have been studied and reaction ranges have been identified in which the process obeys the elementary reaction models. It is established that the TGA method allows obtaining initial data for mathematical modeling of coal conversion processes. Kinetic characteristics are obtained for pyrolysis processes in argon and air in the nonisothermal regime.