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Operation regimes in catalytic combustion: H 2 /air mixtures near Pt
Author(s) -
Park Young K.,
Bui PierreAndré,
Vlachos Dionisios G.
Publication year - 1998
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.690440911
Subject(s) - flammability limit , combustion , flammability , catalysis , ignition system , catalytic combustion , platinum , homogeneous , chemistry , chemical engineering , range (aeronautics) , autoignition temperature , thermodynamics , materials science , composite material , organic chemistry , engineering , physics
The influence of a platinum catalyst on flammability limits and operation windows for catalytic and catalyst‐assisted homogeneous oxidation is studied, for the first time to our knowledge, as a function of H 2 in air composition in a stagnation‐point flow geometry. The results show that the coupling between the homogeneous and heterogeneous chemistries leads to relatively easy startup, the coexistence of catalytically (partially) and homogeneously (completely) ignited branches under certain conditions, and the expansion of the fuel‐lean and rich flammability limits. A strategy to attain virtually any desired operation regime is discussed. It is shown that synergism between homogeneous and heterogeneous chemistries leads to higher combustion efficiency and lower fuel emissions at elevated temperatures for fuel‐lean mixtures only. Analysis of the flammability limits indicates that heat generated by surface reactions is primarily responsible for expansion of the flammability limits. Finally, a direct transition to flames occurs over a wide range of composition upon catalytic ignition in the absence of surface heat loss.