Petrochemical furnaces are used in the petrochemical industry for the preheating of crude oil, residue, gasoil, naphtha, kerosene, and diesel through refining operations. When the fluid flows inside the furnace pipes, thermal cracking occurs. During the heating process, a generation of lighter fractions of petroleum and coke formation takes place. Coke adheres to the wall of the pipes, increasing pressure drop and internally insulating the pipes. Consequently, heat transfer is affected. In most of these processes, during heating and thermal cracking, gases are generated, forming a liquid-gas two-phase flow in the pipe. In this work, thermal cracking and gas generation are represented by a kinetic net which takes into account the constituent fractions of the petroleum load, which are represented by six pseudo-components. The CFD model was able to predict the lighter petroleum fractions and the gas generation as well as the coke formation inside the tube. Coke concentration increases along the pipe as the average temperature of the mixture increases.