Detailed kinetic modeling of the formation of toxic polycyclicaromatic hydrocarbons (PAHs) coming from pyrolysis in low-pressuregas carburizing conditions

Hydrocarbon pyrolysis in low-pressure gas carburizing conditions leads to gas phase reactions, whichproduce polycyclic aromatic hydrocarbons (PAHs), some of which, such as benzo[a]pyrene, are carcino-genic. Workers can be exposed to these PAHs during maintenance and cleaning operations of carburizingfurnaces. The aim of the study is the prediction of the formation of sixteen PAHs considered as prior-ity pollutants by the Environmental Protection Agency in the United States (US EPA). A model has beenimplemented in order to describe the reaction pathways leading to their formation. It was validatedusing experimental data from the literature, obtained during pyrolysis of different hydrocarbons such asacetylene and ethylene. Flux analyses were realized in order to determine main reaction pathways lead-ing to benzene depending on the reactant. Simulations were also performed to compare PAH formationbetween acetylene, ethylene and propane pyrolysis.