Activated carbon is widely used as an additive or catalyst in
commercial processes because of its high activity in impurities
reduction [29]. As shown in Table 4, activated carbon led to an
observable increase in the producer gas yield, inducing a decrease
in other product yields. The comparisons between Runs 1 and 2
(two-stage gasification) and between Runs 3 and 6 (three-stage
gasification) showed that activated carbon had a strong influence
on tar removal: it reduced the tar content in producer gas by ~4e5
times and the total tar by ~4e14 times. The tar content in the
producer gas of Run 6 was only 22 mg/Nm3
. Along with tar
reduction, the activated carbon brought about a significant change
in the producer gas composition; it significantly increased the H2
content and decreased the CO, CO2, and H2S contents in producer
gas