| As the most abundant category of PAHs in diesel fuel, alkylated naphthalenes are closely related to PAH and soot formation during combustion. To understand the procedure of PAH and soot formation so that the combustion technologies could be promoted to decrease PAH and soot emission, it is important to investigate the thermal decomposition and growth of shortly-alkylated naphthalenes. This study aims at a better understanding of: the mechanisms of short-alkylated naphthalenes decomposition in high temperature conditions and PAHs/soot formation therein; the comparison of the mechanisms with those of homolog bearing a single aromatic ring, such as toluene and ethylbenzene. Experiments were conducted in a semi-isothermal tubular flow reactor at different temperatures ranging from 550 to 1000°C. Products including gaseous hydrocarbons, aromatic hydrocarbons, CO, and soot were collected by the product collection system. Then the products were identified and quantified. The major products of those compounds at high temperatures and their profiles versus reaction temperature were presented. The routes of reactant decomposition and product formation were discussed based on experimental results and reaction mechanisms were postulated. In addition, the research has also discussed: the effects of intrinsic chemical structure, such as the 1 vs. 2 positions of the methyl group, and the resultant product distributions; the difference of 1-methylnaphthalene decomposition in pyrolysis and oxidation conditions. The global kinetic analysis method was employed to simulate reactant decomposition, and formation of some products and kinetic parameters were obtained. The simulation results were in good agreement with experimental data. |
