(371e) Fundamental Understanding of Carbon Black Formation – a Study on Gas Phase Chemistry

Carbon black (CB) is a powdery form of elemental carbon that is produced in highly controlled process to produce particles of varied structure and surface chemistry. Approximately 90% of the carbon black produced worldwide is utilized in tire industry and for manufacturing of mechanical rubber goods. The remaining 10% finds application in manufacturing of products such as plastics, printing inks, paints, coatings, toners and electronics. The furnace black process accounts for more than 90% of carbon black production worldwide. In this process, the carbon black feedstock (CBFS) is injected, into the highly turbulent gases at high temperature, through nozzles/atomizers to achieve optimum atomization and distribution of the droplets in the gas. The atomization and droplet distribution processes significantly affect vaporization of CBFS droplets, the subsequent gaseous pyrolysis process and ultimately carbon black particle formation. The reactor process conditions are adjusted to control the size and shape of the particles, aggregates and agglomerates, thus determining the grade of the carbon black formed. Fundamental understanding of the carbon black particle formation inside the reactor can help in achieving high yields and wide range of grades.

Gas phase chemistry inside the reactor is one of the key step in the complete carbon black formation process. The gas phase chemistry involves the pyrolysis of the vaporized components of CBFS, combustion and formation of CB precursor species. The present work is aimed at studying this gas phase chemistry involved in the carbon black formation process with the help of computational fluid dynamics (CFD). A suitable reaction mechanism is used to model the gas phase reactions involved in the carbon black formation. Steady state simulations have been performed using the commercial solver, ANSYS Fluent. A parametric study has been performed using the validated model to evaluate the effect of temperature, CBFS composition and flow rates of CBFS and high temperature gas. Depending on the governing conditions, different reaction pathways lead to the formation of CB precursor species. Thus, the model can be used to gain key insights about the gas phase chemistry involved in formation of CB precursor species.