Modeling and simulation of carbon black synthesis in an aerosol flame reactor

Carbon black has diverse industrial applications such as a reinforcing agent in tires and as a black pigment in printing inks. Flame aerosol synthesis is the commonly employed route for large scale production of carbon black. A coupled flame dynamics – monodisperse population balance model for the synthesis of carbon black in an aerosol flame reactor is presented here. The population balance model was incorporated into the commercial computational fluid dynamics software CFX to simulate the effect of flame dynamics on particle synthesis. The model was tested with published experimental data for acetylene black synthesis through oxidative thermal decomposition of acetylene with oxygen in a premixed flame reactor. The predicted axial temperature profiles at different equivalence ratios (actual acetylene/oxidizer ratio divided by stoichiometric acetylene/oxidizer ratio) were reasonably close to experimental data. The effect of the equivalence ratio on process parameters like maximum temperature of the flame, specific surface area of particles and flame structure was investigated. It was observed that the maximum temperature of the flame and specific surface area of carbon black particles decrease upon increasing the equivalence ratio which is in agreement with published experimental studies. Simulation results are also presented for carbon black synthesis in a diffusion flame reactor with different burner designs.