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Kinetically driven instabilities and selectivities in methane oxidation
Author(s) -
Park Young K.,
Vlachos Dionisios G.
Publication year - 1997
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690430816
Subject(s) - methane , anaerobic oxidation of methane , chemistry , chemical engineering , organic chemistry , engineering
Ignitions, extinctions, and Hopf bifurcations in methane oxidation were studied as a function of pressure and inlet fuel composition. A continuous stirred‐tank reactor was modeled with numerical bifurcation techniques, using the 177 reaction/31 species mechanism. Sensitivity and reaction pathway analyses were performed at turning points to identify the most important reactions and reactive species. Then, simulations were compared with experimental data. Multiple ignitions and extinctions as well as oscillations that are purely kinetically driven were found. Ignition to a partially ignited state with considerable reactivity of methane indicates possible narrow operation windows with high selectivities to partial oxidation products. At 0.1 atm, we found a selectivity of up to 80% to CO at 70% CH 4 conversion. The ignition to a fully ignited branch is associated with high selectivity to CO 2 and H 2 O. The C2 chemistry inhibits the ignition of methane to the partially ignited branch. The methane ignition temperature exhibits two branches with respect to pressure, with only the low‐pressure branch being dominant. Reaction path analysis at ignition conditions shows that the preferred pathway of CH 4 oxidation is to form CO and CO 2 through CH 2 O and CH 2 (s) intermediates. However, at intermediate to high pressures, the recombination of CH 3 to C 2 H 6 also becomes quite significant.