Pinzon Correa, Laura Tatiana (2018-08). Reaction Rate Measurement of C2H5OH->C2H4+H2O During Ethanol Pyrolysis Using H2O Time History Measurements Behind Reflected Shock Waves. Master's Thesis.
The thermal decomposition of ethanol has been studied under pyrolytic conditions behind reflected shock waves in the 1250 to 1677 K temperature range, at an average pressure of 1.31 atm for a mixture highly diluted in Ar. A laser absorption technique was utilized to measure Hv2O time histories, and the detailed kinetics mechanism (Aramco2.0) was selected among various models from the literature based on its a priori agreement with the experimental data in the present study. Sensitivity and rate-of-production analyses were performed and showed that the Cv2Hv5OH->Cv2Hv4+Hv2O (R1) decomposition pathway is almost the sole reaction contributing to Hv2O formation at the early times under the present conditions, allowing an a priori direct measurement of its rate coefficient kv1. The rate coefficient was determined to be defined as the Arrhenius equation kv1 (s^-1) = 3.37x10^11 exp (-27174 K/T), which is in very good agreement with (Kiecherer et al., Proc. Combust. Inst. 35 (2015) 465-472) where kv1 was also directly determined under similar conditions. Secondary chemical reactions taking place in the thermal decomposition have very low influence in the Hv2O formation during the time-frame selected, leading to an uncertainty for kv1 of approximately 20%. The full Hv2O time histories under oxidation conditions at 0.5, 1.0 and 2.0 equivalence ratios were measured to validate the full ethanol detailed kinetics mechanism. The rate coefficient found in this study was utilized in the Aramco 2.0 model and was compared against experimental data and well-known detailed kinetic mechanisms.