Effect of Biphenyl, Acetylene and Carbon Dioxide on Benzene Pyrolysis at Intermediate Temperatures

Benzene pyrolysis chemical kinetic mechanism has been of interest as benzene and phenyl radicals are important species for polycyclic aromatic hydrocarbons (PAHs) growth. Also, valuable industrial species such as biphenyl can be produced from benzene pyrolysis. This work aims to study the effect of additives (biphenyl and acetylene) on benzene pyrolysis at intermediate temperatures (900–1250 K). However, significant soot was noticed at high temperatures (1200–1250 K), which may affect the measurements. Nitrogen and a blend of nitrogen and carbon dioxide were used for dilution. The experiments were performed using a jet-stirred reactor (JSR) coupled with gas chromatography (GC) at atmospheric pressure. A residence time of 3 s was considered, as a long residence time is needed to collect enough samples at intermediate temperatures. The concentration-temperature profiles from the experimental measurements were compared with three selected models, Hamadi et al., Ranzi et al. and Sun et al. models. In general, Sun et al. model performs better than the other two models, especially for the prediction of light hydrocarbon concentrations. The results show an apparent influence of additives on benzene pyrolysis. The experiments and Sun et al. model illustrate a noticeable formation of methane and ethylene. Hamadi et al. and Ranzi et al. models demonstrate minor formation of light hydrocarbons under our experimental conditions. Sensitivity analyses of benzene, biphenyl, methane and ethylene were conducted at 1175 K using Sun et al. model.