A mathematical model is developed for simulation of dynamic behavior of coke-burning process in a hydrocracker reactor with an array of 4 fixed beds. The model is used for parametric study of the coke burning process. Results show that the effective parameters are inlet oxygen concentration, the flow rate of carrier gas and temperature within the beds. The effect of referred parameters on performance of regeneration of an industrial hydrocracker reactor is investigated for a real case and the optimum values of operating conditions are predicted. The optimum value for oxygen concentration during regeneration obtained as 0.85 mol%, with a predicted regeneration time of around 76h. (C) 2011 Elsevier Ltd. All rights reserved.