Approaches to determining the theoretical combustion temperature of fuel in a blast furnace furnace when varying the parameters of the blowing mode

Abstract: The study of blast furnace melting practice in a 5000 m³ furnace using pulverized coal fuel allowed us to establish the key factors that cause deformation and burnout of lances and coolers. The reasons are the asymmetry of the combustion zone in front of the lances and the violation of gas dynamics associated with the uneven supply of blast and fuel, which directly affects the temperature distribution and gas composition. The above processes, in turn, are caused by the uneven supply of blast and pulverized coal fuel to the lances, which causes variations in the theoretical combustion temperature and changes in the volume of furnace gas along the circumference and radius of the furnace. Accordingly, when determining the optimal consumption of blast additives, focusing only on the theoretical combustion temperature, as a universal indicator of the state of temperature-oxidative conditions in the lance zone, is methodologically limited. This is especially true in cases of significant changes in the initial melting parameters, when the use of standard methods does not allow to ensure the required accuracy of calculations. This work aims to create methodological principles for calculating the theoretical fuel combustion temperature, taking into account stoichiometric ratios and fuel characteristics based on the results of technical analysis, as well as actual blowing parameters in conditions of replacing part of the coke with natural gas and pulverized coal fuel. The developed method allows to determine the theoretical fuel combustion temperature in tuyeres of combustion zones when supplying natural gas and/or pulverized coal fuel, using operational information on the blowing parameters and fuel component consumption, which are recorded by automation systems and control and measuring devices on the blast furnace control panel. The introduction of this method provides the possibility of accurate calculation of the furnace gas output and theoretical combustion temperature, which is the basis for effective optimization of the blowing mode, with special emphasis on modes using pulverized coal fuel.