Research on the heat supply of different sections in a rotary hearth furnace

To solve the urgent problems in the thermal system at the initial stage of producing direct reduced iron(DRI) in a rotary hearth furnace(RHF) in China,thermal parameters in different sections of RHF were analyzed by systematic analysis,thermal simulation experiments,and numerical simulation. The RHF mathematical model and heat supply model were established with 83 variables and 20 parameters. The result of numerical simulation indicates that producing every 1 t metalized pellet needs 1213 kg iron ore fines,283 kg pulverized coal,and 615 kg coal gas. Based on the systematic analysis on different sections of the rotary hearth furnace,thermal simulation experiments on preheating,heating,and reducing sections were studied separately. Under different conditions(n_C:n_O=0.8~1.2),the real-time reduction progresses of carbon-bearing pellets in these sections were confirmed. According to the matching of the self-reduction decalescence of carbon-bearing pellets and thermal parameters,the fuel supply parameters of each section were determined. Fluent simulation software was used to verify the thermal parameters of the three sections. And the results show that the designed parameters are reasonable,and can effectively implement the functions of all the sections of a rotary hearth furnace,which provide the theoretical basis for the optimization design of the rotary hearth furnace.