In these calculations, the possibility for the consumption of
activated carbon during gasification was excluded, because a previous
work performed using the UOS gasification process revealed
that the difference of rates of tar adsorption on activated carbon
and the tar cracking appeared to be not significant [27]. In all the
experiments, 800 g of DSS was used, and silica sand with particle
sizes between 150 and 300 mm was used as the bed material in the
fluidized bed gasifier. The amount of activated carbon applied in the
fixed bed reactor was 0.5 kg. The operation time was ~1 h. The feed
rates were therefore 11.8e13.6 g/min. The flow rate of air as a
gasifying agent was almost kept at ~15 L/min. The equivalence ratio
(ER) in this study was defined as the air to fuel weight ratio used in
the gasification process divided by the air to fuel weight ratio for
stoichiometric combustion; it was maintained at 0.29e0.33 for all
experiments. The calculated gas residence time in the fluidized bed
was ~1 s. The contact time between the producer gas and the
activated carbon bed ranged from 0.9 to 1.2 s