Our group has recently been developing a staged gasifier called
the ‘UOS gasifier’. First, a two-stage gasifier consisting of a fluidized
bed gasifier and a fixed bed reactor usually filled with activated
carbon in series was developed and applied in the gasification of
biomass and plastic waste [22e24]. With the help of the staged
configuration and Ni-impregnated activated carbon, a tar-free
producer gas was obtained for a ~4 h operation [25]. In this paper,
a recently developed three-stage gasifier was applied to effi-
ciently reduce tar. For the construction of the three-stage gasifier,
an auger reactor was added to the existing two-stage gasifier. The
auger reactor was expected to generate a considerably large
amount of tar in advance, which would enhance the tar destruction
in the fluidized bed gasifier and fixed-bed reactor. The aim of the
present work was to evaluate the efficiency of the three-stage
gasifier in the production of a clean producer gas. In particular,
the effect of the temperature of each reactor of the three-stage
gasifier on the producer gas development and evolution of impurities
(tar, NH3, and H2S) was investigated. Additionally, comparisons
of experiments were conducted between with and without
activated carbon