In this paper, 3-D-CFD simulation using an ANSYS-Fluent package in a 4m diameter kiln with 40 m length firing methane (CH4) gas is applied to avoid undesirable thermal behaviour (wall hot spots; peak wall temperatures) in industrial rotary kilns. New influencing parameters are introduced, including primary air ratio, burner configuration (two configurations with different fuel jet momentums), and burner power. The influence of these parameters on the peak kiln flame and on wall temperatures, flame radiation heat flux, radiative heat transfer coefficient, temperature contours, and pathlines are investigated and discussed. Preliminary comparison of jet flames with available experimental data is carried out to select and validate the proper turbulence model for the present simulations. Results reveal that the peak flame temperature, flame radiation heat flux, and radiative heat transfer coefficient increase with higher fuel jet momentum, lower primary air ratio, and higher burner power. On the other hand, the wall hot spots emerge when operating the kiln at higher burner power or by lowering the jet momentum (larger fuel inlet diameter). Stable flames and a higher recirculation size can be obtained by operating the kiln under a higher primary air ratio and higher jet momentum (narrower fuel inlet diameter). Based on these results, operators are shown a way to adjust controllable kiln parameters to reduce wall hot spots and to improve product quality, in addition to controlling the ringing problems.