Study of combustion intermediates in fuel-rich methyl methacrylate flame with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry

A fuel-rich premixed laminar methyl methacrylate (MMA)/O2/Ar flame at low pressure (30 Torr) with the equivalence ratio (ϕ) of 1.60 is studied in this work. Synchrotron vacuum ultraviolet photoionization combined with molecular beam mass spectrometry is employed to identify the combustion intermediates including isomeric intermediates. The observed combustion intermediates can be classified as four types: radicals, non-cyclic hydrocarbons, cyclic hydrocarbons and oxygenates. Benzene is the unique aromatic hydrocarbon detected in this work, and several oxygenates with two oxygen atoms are identified. Mole fraction profiles of most intermediates are evaluated, which can help understand the MMA combustion mechanism under fuel-rich conditions. The similarities among rich flames of MMA and other oxygenated fuels, as well as the characteristics of rich MMA flame, are also discussed. The results show that combustion of MMA not only reduces soot emissions, but also has low concentrations of some potential toxic by-products. Copyright © 2008 John Wiley & Sons, Ltd