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In order to define a kinetic scheme and to calculate the kinetic parameters of the thermal cracking of petroleum residues, a vacuum residue of Belaym crude was thermally cracked at 410, 430, 450 and 470 °C for reaction times up to 120 min. The concentration of three pseudo-components, namely vacuum residue, distillate and coke, was detected during conversion and the data from these experiments were used for the definition of the kinetic model. Distillate production can be described as a simple first-order reaction while coke formation seems to be the consequence of consecutive reactions, in particular involving asphaltenes. A study of the structural changes of asphaltenes as a function of severity was also performed and the variations of the average molecular parameters with conversion were correlated. The results of this work have been used as reference data for a subsequent study of residue conversion in the presence of hydrogen-donor solvents.