Incorporation of parametric uncertainty into complex kinetic mechanisms: Application to hydrogen oxidation in supercritical water

Journal Article · Thu Jan 01 04:00:00 EST 1998 · Combustion and Flame

DOI:https://doi.org/10.1016/S0010-2180(97)81762-2· OSTI ID:570140

Phenix, B D; Dinaro, J L; Tatang, M A; Tester, J W; Howard, J B; McRae, G J ^[1]

---

1. Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering and Energy Lab.

In this study, uncertainty analysis is applied to a supercritical water hydrogen oxidation mechanism to determine the effect of uncertainties in reaction rate constants and species thermochemistry on predicted species concentrations. Forward rate constants and species thermochemistry are assumed to be the sole contributors to uncertainty in the reaction model with all other model parameters and inputs treated as deterministic quantities. Uncertainty propagation is performed using traditional Monte Carlo (MC) simulation and a new, more computationally efficient, probabilistic collocation method called the Deterministic Equivalent Modeling Method (DEMM). The results of both analyses show that there is considerable uncertainty in all predicted species concentrations. The predicted H{sub 2} and O{sub 2} concentrations vary {+-}70% from their median values. Similarly, the HO{sub 2} concentration ranges from +90 to {minus}70% of its median, while the H{sub 2}O{sub 2} concentration varies by +180 to {minus}80%. In addition, the DEMM methodology identified two key model parameters, the standard-state heat of formation of HO{sub 2} radical and the forward rate constant for H{sub 2}O{sub 2} dissociation, as the largest contributors to the uncertainty in the predicted hydrogen and oxygen species concentrations. The analyses further show that the change in model predictions due to the inclusion of real-gas effects, which are potentially important for SCWO process modeling, is small relative to the uncertainty introduced by the model parameters themselves.

• OSTI ID: 570140
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 112; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
CHEMICAL REACTION KINETICS
CONCENTRATION RATIO
FORMATION HEAT
HYDROGEN
HYDROGEN PEROXIDE
HYDRONIUM RADICALS
INDUSTRIAL WASTES
MATHEMATICAL MODELS
ORGANIC COMPOUNDS
OXIDATION
SUPERCRITICAL GAS EXTRACTION
WASTE PROCESSING