The specific experimental conditions are shown in Table 3.
Runs 1 and 2 were conducted in the two-stage gasifiers, while
the other runs were conducted in the three-stage gasifiers. Runs 1 and 3 were performed without activated carbon in the fixed bed
reactor, whereas the other runs were performed with activated
carbon. The main experimental variables were the reaction temperatures
of the three reactors. The influence of the reaction temperatures
of the auger and fixed bed reactors on the producer gas
composition, tar removal efficiency, and gasification efficiency can
be found by comparing the results of Runs 4e6 and Runs 6e8. The
results of Runs 9 and 10 along with those of Run 4 can be compared
to find the influence of the fluidized bed gasifier temperature. The
comparisons of experimental results between Runs 1 and 2 (twostage
gasifier) and between Runs 3 and 6 (three-stage gasifier)
would reveal the role of activated carbon for tar removal. The
comparisons between Runs 1 and 3 and between Runs 2 and 6
would show the performance of the three-stage gasifier in tar
removal. For evaluating the performance of a gasifier, cold gas ef-
ficiency (CGE) and carbon conversion efficiency (CCE) are usually
applied. In this study, these parameters were calculated from the
following formulas: