Numerical evaluation of temperature and concentration profiles obtained from petroleum waste pyrolysis

The petroleum industry generates various residues, such as oil sludge, throughout the production chain. To mitigate the environmental impacts, diverse technologies are developed to convert these residues into less harmful materials or materials with added energy value. To study and understand treatment alternatives for these wastes, the present work proposes a kinetic analysis using the Arrhenius equation of the species involved in Oil Sludge pyrolysis, a thermochemical conversion process in inert atmosphere. A one-dimensional and isothermal numerical model is developed in Mathematica for a downdraft bed (DB) reactor. The article describes a kinetic model of a single devolatilization phase for the pyrolysis of petroleum residues, where non-condensable gases, char, and heavy hydrocarbons such as Phenol (C6H6O), Naphthalene (C10H8) and Benzene (C6H6) are produced, which are subsequently thermally cracked. The composition of the devolatilization product is predicted by elemental mass balances of the feedstock CxHyOw, given by experimental values correlated to the elemental analysis of the material. This model allows for the analysis of product formation for certain fixed temperatures and elemental composition of the residue supplied. The presentation of results provides information on the behavior of species, including their consumption and generation, which are analyzed through the fundamental laws of mass conservation, allowing for an understanding of the formed product’s behavior and subsequent use in other industry processes. The model is validated and verified in the literature using process software and experimental works, following parameters of Root Mean Square Error (RMSE) analysis. 
 
Keywords: Pyrolysis, Petroleum residues, Kinetic analysis, Thermochemical conversion, Downdraft bed.