Combustion studies with a metallurgical coke have been carried out in batch experiments in an electrically heated fluidized bed reactor. Different experiments were carried out in air at temperatures ranging from 750-degrees-C to 950-degrees-C and coke particle diameters between 0.675 and 3.500 mm. The reactor outlet concentrations of O2, CO2 and CO were monitored continuously. A methodology for estimating the kinetic parameters of char combustion has been developed. From the response of gas outlet concentrations to the batch amount, a parameter to estimate the mean oxygen concentration in the bed was deduced. The overall rate constants at each burnoff stage were also obtained. Particle size of irregular coke particles at different stages of the combustion process were determined by means of image analysis technique. This makes it possible to evaluate the real importance of the external mass transfer resistance during combustion and to estimate the chemical rate constant. The results indicate that the coke particles studied react under Regime II in the size and temperature ranges analysed, though moving to Regime III as long as bed temperature and particle size increase. The estimated mean oxygen concentration around the char particles was in every case lower than that estimated by applying the two-phase theory. The dependence of the chemical rate constant on temperature can be described by the equation k(p)[g/(cm2 s atm 02) = 30 exp(- 22,340/RT(p)), where the activation energy is expressed in units of cal/mol.