This paper presents a numerical simulation of dehydrogenation of isobutane to isobutene in a bubbling fluidized bed reactor using the three-phase model. The effects of the operating conditions on the isobutane conversion and the rate of energy consumption in the reactor are investigated. For this purpose, a numerical algorithm is developed to solve the coupled system of nonlinear governing equations of the model in an iterative manner. It is found that the energy consumption in the bed shows a reverse trend to the isobutane conversion with increase in the initial pressure of isobutene and the entering superficial velocity of isobutene while both of them show the same trend with increase in the bed temperature. The simulation results also show that the volume flow rate of the feed stream (the entering superficial velocity of isobutane) strongly affects the energy consumption in the bed. From a design viewpoint, quantitative energy analysis presented makes it possible to evaluate the right operating conditions for the fluidized bed reactor. (C) 2018 Elsevier Ltd. All rights reserved.