Soot generation in a turbulent diffusion flame generated during methane gas combustion is numerically explored. Moss-Brooke’s soot methodology is used for this purpose. The temperature field, mass fraction of soot, rate of soot surface growth, and soot formation were investigated in detail. This method takes into account several sub-processes, containing coagulation, nucleation, oxidation, and surface growth. The radiative transfer equation is approximated by employing the P1 method which involves the truncating series expansion in terms of spherical harmonics. The equilibrium-based method is applied to investigate the role of OH on soot oxidation and concentration on soot production using the Fenimore-Jones and Lee soot oxidation models. The obtained results indicate a higher estimation of soot generation from the Lee oxidation model as compared to the Fenimore-Jones model. Furthermore, neglecting the radiation from the wall results in significant temperature overestimations, which could potentially affect the distribution of species.