posted on 2020-05-14, 12:34authored byBrian R. Pinkard, Anmol L. Purohit, Stuart J. Moore, John C. Kramlich, Per G. Reinhall, Igor V. Novosselov
Ethanol is partially
oxidized in a continuous supercritical water
reactor at temperatures from 500 to 530 °C, constant pressure
of 25 MPa, initial ethanol concentration of 5 wt %, residence times
of 3–8 s, and oxidant-to-fuel stoichiometric equivalence ratios
of 5, 7.5, and 10%. The experimental conditions are selected to study
the regime where ethanol oxidation happens rapidly but below the temperature
necessary to initiate hydrolysis reactions. The reactions and interactions
of intermediate species can be analyzed, leveraging previous experimental
results and the existing body of literature on ethanol hydrolysis,
pyrolysis, and oxidation. Higher oxidant concentration increases ethanol
destruction and gasification efficiency, although significant coke/char
buildup is qualitatively observed within the reactor. Product yields
from the experiments are used to infer significant reaction mechanisms,
and a pathway is postulated for the counterintuitive formation of
char under the studied conditions.