Experimental and kinetic modeling study of tetralin pyrolysis at low pressure

Abstract

The pyrolysis of tetralin was studied from 850 to 1500K in an electrically heated laminar flow reactor at 30Torr. Synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry was used for isomeric identification and mole fraction measurements of pyrolysis products, especially free radicals. A kinetic model with 149 species and 554 reactions was developed in this work and validated by measured mole fraction profiles of pyrolysis species. Rate of production (ROP) analysis and sensitivity analysis were performed for mechanistic analysis of tetralin decomposition and aromatic growth processes. Contributions of four overall decomposition pathways of tetralin proposed in previous high-pressure pyrolysis studies were evaluated at the low-pressure condition based on both experimental observations and ROP analysis. It is concluded that tetralin mainly decomposes to dihydronaphthalenes, naphthalene, indene, indenyl radical and styrene via unimolecular decomposition reactions and H-abstraction reactions in low-pressure pyrolysis. Special modeling efforts on the formation pathways of indene were made to explain its high concentration in tetralin pyrolysis. Because of the high concentration levels in the pyrolysis of tetralin, indenyl radical and naphthalene play significant roles in the formation of large polycyclic aromatic hydrocarbons (PAHs), which explains the high sooting tendency of tetralin compared with alkylbenzenes.