In this article, the effects of operating temperature on the hydrodynamics of dense gas-solid flow inside the fluidized bed reactor are investigated systematically. To this end, 3D simulations have been carried out by incorporating the appropriate model parameters and using the well-known Euler-Euler two fluid methodology in ANSYS FLUENT. The methodology is validated against the experimental results available in the literature. Temperature, air velocity and particle sizes are varied systematically. Results show that the variation of minimum fluidization velocity with temperature depends upon the particle size. For small particles (Geldart's group B), the minimum fluidization velocity decreases with an increase in temperature and the trend is reversed when large particles (Geldart's group D) are fluidized. This behavior is explained by analyzing the modification in inter-phase momentum exchange coefficient due to temperature variation. Voidage profiles, particle velocity and bubble characteristics are also seen to be influenced by the thermal conditions of the fluidized bed reactor. Particle axial velocity tends to decrease with an increase in the operating temperature. For group B particles, temperature has negligible effect on bubble size and expanded bed height. On the other hand, bubble size and expanded bed height decrease with an increase in temperature for group D particles. © 2017 Elsevier Masson SAS