Análise e otimização da gaseificação de borras de petróleo utilizando modelagem CFD

Abstract

The gasification of petroleum sludge is a relatively new and underutilized technology, especially when compared to disposal techniques such as incineration and landfilling. This study presents the gasification of petroleum sludge using air as the gasification agent, through Computational Fluid Dynamics (CFD) modeling, with the optimization of gasifier characteristics and operating parameters aimed at maximizing the heating value of the resulting gas. Characterization of this material included the calculation of its activation energy and pre-exponential factor, and a modeling method was developed for the devolatilization reaction of petroleum sludge. These data were incorporated into the CFD model for adjustment to the material. The geometry used was developed based on the gasifier present in the Laboratory of Solid Fuel Gasification at UNIFEI. A two-dimensional Euler-Lagrangian multiphase reactive model was developed, using the species transport model to describe chemical kinetics within the gasifier. Initially, the air factor was varied within the gasification range, and the highest heating value was found with an air factor of 0.38, resulting in a gas with 3.8 MJ/Nm3. After the initial analysis, the operational parameters were optimized to find the point of maximum heating value, varying the gasifier height, fuel particle diameter, wall temperature, and air factor. The highest gas heating value was found for a gasifier height of 1.85 m, a fuel particle with a 0.1 mm diameter, a wall temperature of 337 °C, and an air factor of 0.23. At this point, the heating value was increased to 5.32 MJ/Nm3, a 42% increase compared to the best result obtained before optimization. The optimization showed how these parameters variation can help increase the energy produced in this system, even when using only air as the oxidizing agent. It also provides a starting point for future scale-up in the production of combustible gas from petroleum industry waste.