As shown schematically in FIG. 1, hot gases, containing
molecular oxygen, from generator elements, (14) and (19), pass through a
bed of
coal chunks in an ODD reactor chamber (2). The
molecular oxygen content of these hot gases is less than stoichiometric, relative to the
coal volatile matter content, so that
partial oxidation of only the volatile matter occurs within the ODD reactor chamber, (2), during devolatilization therein. Two products are thusly created, a partially oxidized, and hence cleaner burning, volatile matter
fuel gas, and a
solid devolatilized
coke. The hot
coke is transferred, by overfeed, into a
coke reaction chamber, (7), where counterflowing primary air, via air meter, (12), gasifies the coke into
carbon monoxide with some
carbon dioxide. Finally, the
carbon monoxide and the partially oxidized volatile matter, are admixed with overfire air, and burned fully to
carbon dioxide in overfire burner chambers, (23), (26). The resulting hot burned gases flow into the
nozzle inlet, where, after mixing with bypass air, they expand through the expander portion of a gas
turbine engine.
Coal ashes accumulate at the bottom, (9), of the coke
reaction chamber, (7), where the overlying coke chunks prevent ash particle carryover into the
turbine blades. Low cost
coal can thus be cleanly used as an
energy source for gas
turbine engines.