Experimental and Kinetic Studies of Ethylene Glycol Autoignition at High Temperatures

As one of the simplest polyols with chemical properties of alcohol, ethylene glycol is considered as a renewable energy source and a model fuel for pyrolysis oil. In this work, autoignition characteristics of ethylene glycol have been investigated behind reflected shock waves. Experiments were conducted at pressures of 2, 5, and 10 atm, equivalence ratios of 0.5, 1.0, and 2.0, and temperatures ranging from approximately 1200 to 1600 K. The fuel concentration was also varied. Results show that the ignition delay time increases with decreasing the pressure or fuel concentration. A strong positive dependence upon the equivalence ratio was found. A quantitative relationship has been yielded by the regression analysis of the experimental data. Simulations were carried out using chemical kinetic mechanisms available in the literature to assess the reliability of mechanism. Reaction pathway and sensitivity analysis confirmed the importance of H-abstraction reactions in ethylene glycol oxidation process. Finally, a comparison between ethylene glycol and ethanol ignition was conducted. Ethylene glycol ignites faster than ethanol because of the early accumulation of H and OH radicals in the oxidation of ethylene glycol.

Automated summary

The autoignition characteristics of ethylene glycol were investigated in this study, showing that decreasing pressure and fuel concentration lead to an increase in ignition delay time, with equivalence ratio playing a significant role in ignition. The importance of H-abstraction reactions in ethylene glycol oxidation process was confirmed. Ethylene glycol ignites faster than ethanol due to early accumulation of H and OH radicals during its oxidation.