The reduction of NOx and CO2 emissions is of great importance in
practical combustors (such as gas-fired turbines) due to the stringent NOx emissions
regulations and the forthcoming legislation on greenhouse gases such as CO2
Two hetero-/homogeneous combustion technologies (the “fuel-lean” catalytically stabilized
combustion, and the “fuel-rich catalytic, fuel-lean homogeneous” combustion) have
been pursued lately in gas turbines. In those approaches, partial fuel
conversion is accomplished heterogeneously in burners with a suitably large
surface-to-volume ratio, such as catalytically-coated honeycomb monoliths, and complete
fuel conversion is attained in a post-catalyst homogeneous combustion zone.
This process leads to substantial reduction of NOx emissions (typically < 3
ppm). Moreover, catalytic combustion technologies allow for stable combustion even
under heavy dilution (e.g. use of large exhaust gas-recycle, EGR). Combustion
with large EGR is of interest in power generation as it allows for a twofold
increase in the CO2 content of the exhaust gas, thus facilitating
the capture and further sequestration of CO2.
At PSI the catalytic combustion processes are investigated experimentally
and numerically in channel flow configurations. Particular emphasis is given in
the study of the heterogeneous/homogeneous chemical and thermal interactions
which are responsible for the onset of gaseous ignition. In situ measurements
(laser based) are carried out over the catalyst boundary layer at pressures and
temperatures relevant to those encountered in practical systems.
Large Scales (Gasturbines)
Small Scales (Microreactors)
Direct Numerical Simulation