An Experimental Study of the Pyrolysis and the Oxidation of Ethylene Glycol and Propylene Glycol in a Jet-Stirred Reactor

This work investigates experimentally the pyrolysis and
oxidation
of ethylene glycol (EG) and propylene glycol (PG), two candidate molecules
as model surrogates of biomass-based pyrolysis oils, the structure
of which is included in sugars. This paper reports the first experiments
with these high boiling point (∼470 K for EG, 461 K for PG)
dioxygenated molecules performed in a fused silica jet-stirred reactor.
Pyrolysis and oxidation experiments are carried out for a 1% fuel/He
mixture over a temperature range T = 600–1200
K. EG oxidation experiments are performed at three equivalence ratios
(φ = 0.5, 1.0, and 2.0), while those for PG were only performed
under stoichiometric conditions. The residence time is 2 s, and the
pressure is quasi atmospheric (107 kPa). Experimental data clearly
show differences in the reactivity of both fuels. Results for EG are
compared to simulations using a literature detailed kinetic model
and indicate significant deviations and the need to further refine
the diol chemistry in detailed kinetic models. Rate-of-production
and sensitivity analyses point out important pathways that should
be further investigated for a better understanding of glycol combustion
chemistry, like concerted decomposition reactions of the fuel and
the consideration of ethenol instead of its analog aldehyde, acetaldehyde.