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Flow reactor studies and kinetic modeling of the H 2 /O 2 reaction
Author(s) -
Mueller M. A.,
Kim T. J.,
Yetter R. A.,
Dryer F. L.
Publication year - 1999
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1999)31:2<113::aid-kin5>3.0.co;2-0
Subject(s) - chemistry , thermodynamics , reaction rate constant , kinetic energy , kinetics , reaction rate , reaction mechanism , chemical kinetics , limit (mathematics) , explosive material , flow (mathematics) , mechanics , catalysis , physics , organic chemistry , mathematical analysis , mathematics , quantum mechanics
Profile measurements of the H 2 /O 2 reaction have been obtained using a variable pressure flow reactor over pressure and temperature ranges of 0.3–15.7 atm and 850–1040 K, respectively. These data span the explosion limit behavior of the system and place significant emphasis on HO 2 and H 2 O 2 kinetics. The explosion limits of dilute H 2 /O 2 /N 2 mixtures extend to higher pressures and temperatures than those previously observed for undiluted H 2 /O 2 mixtures. In addition, the explosion limit data exhibit a marked transition to an extended second limit which runs parallel to the second limit criteria calculated by assuming HO 2 formation to be terminating. The experimental data and modeling results show that the extended second limit remains an important boundary in H 2 /O 2 kinetics. Near this limit, small increases in pressure can result in more than a two order of magnitude reduction in reaction rate. At conditions above the extended second limit, the reaction is characterized by an overall activation energy much higher than in the chain explosive regime. The overall data set, consisting primarily of experimentally measured profiles of H 2 , O 2 , H 2 O, and temperature, further expand the data base used for comprehensive mechanism development for the H 2 /O 2 and CO/H 2 O/O 2 systems. Several rate constants recommended in an earlier reaction mechanism have been modified using recently published rate constant data for H + O 2 (+ N 2 ) = HO 2 (+ N 2 ), HO 2 + OH = H 2 O + O 2 , and HO 2 + HO 2 = H 2 O 2 + O 2 . When these new rate constants are incorporated into the reaction mechanism, model predictions are in very good agreement with the experimental data. ©1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 113–125, 1999