TY - JOUR
T1 - Oxidation Kinetics of Methane and Methane/Methanol Mixtures in Supercritical Water
AU - Li, Guoxing
AU - Lu, Youjun
AU - Glarborg, Peter
PY - 2022
Y1 - 2022
N2 - Methanol-assisted
oxidation of organic compounds in supercritical water (SCW) is of
interest for wastewater treatment. To provide better predictive tools
for this process, it is important to develop kinetic models. This paper
investigated the oxidation kinetics of methane and methane/methanol
mixtures in SCW. A detailed chemical kinetic model was established,
drawing on the analogy between oxidation chemistry in SCW and the gas
phase. The model performance was evaluated against experimental data
from the literature. Species measurements in supercritical water
oxidation (SCWO) of methane and methane/methanol mixtures were
reproduced satisfactorily by the model. A sensitivity analysis indicated
that hydrogen abstraction from water by HO2 and CH3OO,
of minor importance in the gas phase, was important in the SCWO of
methane. Compared to the gas phase, SCW facilitated the oxidation of
methane by enhancing the production of OH radicals. Addition of methanol
promoted methane oxidation, especially at low temperature, by enhancing
the production of reactive radicals but had little influence on the
reaction pathways of the SCWO of methane. Both the present model and
AramcoMech 3.0 well predicted the experimental trends, but AramcoMech
3.0 underpredicted the methane oxidation rate at elevated temperature,
partly due to the omission of the reaction of CH3OO with H2O in the mechanism.
AB - Methanol-assisted
oxidation of organic compounds in supercritical water (SCW) is of
interest for wastewater treatment. To provide better predictive tools
for this process, it is important to develop kinetic models. This paper
investigated the oxidation kinetics of methane and methane/methanol
mixtures in SCW. A detailed chemical kinetic model was established,
drawing on the analogy between oxidation chemistry in SCW and the gas
phase. The model performance was evaluated against experimental data
from the literature. Species measurements in supercritical water
oxidation (SCWO) of methane and methane/methanol mixtures were
reproduced satisfactorily by the model. A sensitivity analysis indicated
that hydrogen abstraction from water by HO2 and CH3OO,
of minor importance in the gas phase, was important in the SCWO of
methane. Compared to the gas phase, SCW facilitated the oxidation of
methane by enhancing the production of OH radicals. Addition of methanol
promoted methane oxidation, especially at low temperature, by enhancing
the production of reactive radicals but had little influence on the
reaction pathways of the SCWO of methane. Both the present model and
AramcoMech 3.0 well predicted the experimental trends, but AramcoMech
3.0 underpredicted the methane oxidation rate at elevated temperature,
partly due to the omission of the reaction of CH3OO with H2O in the mechanism.
U2 - 10.1021/acs.iecr.1c04524
DO - 10.1021/acs.iecr.1c04524
M3 - Journal article
SN - 0888-5885
VL - 61
SP - 3889
EP - 3899
JO - Industrial and Engineering Chemistry Research
JF - Industrial and Engineering Chemistry Research
IS - 11
ER -