Herein, C and M represent activated carbon and metals.
In the present work, the adsorptivity of activated carbon for H2S
could be confirmed; when activated carbon was applied, the H2S
contents in the producer gases obtained with the two-stage and
three-stage gasification could be reduced from 1342 (Run 1) to 346
(Run 2) ppmv and from 562 (Run 3) to 324 (Run 6) ppmv, respectively.
The introduction of the auger reactor operated above 500 C
in this study appeared to have an adverse effect on the H2S
removal; the H2S content in producer gas increased from 1342 (Run
1) to 1541 ppmv (Run 3) and from 346 (Run 2) to 664 ppmv (Run 6).
A high auger reactor temperature appeared to promote the release
of H2S from DDS. As indicated previously, the H2 production was
enhanced with the three-stage gasifier. The abundance in H2 in the
producer gases obtained from the three-stage gasifier then promoted
the H2S evolution by accelerating the reverse reactions of
Eqs (11) and (12). As in the case of the auger reactor, the high reaction
temperatures of the fluidized bed and fixed bed reactors
resulted in an increase in the H2S content in producer gas. The
increased H2S evolution according to the reaction temperature
could be observed in the work carried out at various temperatures
ranging from 473 to 1273 C