An Industrial-Scale Cement Rotary Kiln CFD Model to Characterise Alternative Fuel Combustion Profiles

Abstract

This work proposes a Computational Fluid Dynamics (CFD) model of a cement rotary kiln capable of reproducing some 3D effects which cannot be solved by simpler models. Specifically, flight behaviour and falling position of fuels particles are captured. Furthermore, detailed combustion chemistry (devolatilization, char combustion and moisture evaporation) is solved. The 64-meter-long kiln burns a blend of petcoke and Refuse Derived Fuel (RDF). Both were characterized and their properties introduced in the model. The clinker bed was simplified by fixing a temperature profile, a typical approach in literature. Different air excess numbers (λ) were simulated to assess the impact on flight of particles and combustion profiles. The resulting combustion profiles give a valuable input to simpler models in which a much larger and faster set of simulations can be performed, allowing kiln operators to run several different operational scenarios.