Abstract
Gasification technologies enable conversion of low-grade
resources to clean gases, and can generate electricity through gas
turbine. However, gasified fuels contain nitrogenous compounds of
NH3 and HCN that cannot be removed in the case of employing a
hot/dry-type synthetic gas cleanup for improvement of plant
thermal efficiency and are oxidized into fuel-NOx in combustion
processes. Fuel-NOx emissions constitute the majority of NOx
emissions in exhaust. In combustion processes of the CO, H2 and
CH4 mixture fuels, the oxidation characteristics of nitrogenous
compounds are different from cases of conventional hydrocarbon
fuels, and influenced by fuel constituents and combustion methods.
Author had clarified influence of gasified fuel constituents on
fuel-NOx emissions through experiment. This paper clarifies that
conversion rate of nitrogenous compounds to fuel-NOx is decided
by both a CH4 concentration and primary equivalence ratio in the
case of using two-stage combustion, while conversion rate is
greatly affected by an H2 constituent in the case of gasified fuel
containing no CH4. Consequently, a prediction methodology of
conversion rate of fuel-N is established in the case of air-staging
two-stage combustion.
