PRODUCTION OF PRODUCER GAS WITH LOW TAR AND A HIGH HEATING VALUE FROM CONSTRUCTION WOODY WASTE BY AIR GASIFICATION IN A TWO‐STAGE GASIFIER USING ACTIVATED CARBON

摘要

Construction woody waste is one of precious energy resources. In this paper, we reports the experimental results of air gasification conducted using a two-stage gasifier that consisted of a fluidized bed zone (bottom-reactor) and a tar cracking zone (upper-reactor) filled with activated carbon. In the experiments, the effects of the experimental variables such as the equivalence ratio, upper-reactor temperatures and fluidization velocity were investigated. In addition, the results of the experiments with virgin, without and with spent activated carbon were compared. The producer gas that was obtained with the application of activated carbon at an ER of 0.25 was mainly composed of H_2 (7 vol. %), CO (41 vol. %) and CH_4 content (8 vol. %) respectively, and its lower heating value (LHV) was approximately 10 MJ/Nm~3. In all the experiments, the tar contents in the producer gases were found to be below 4 mg/Nm~3. In addition, the total amount of the tar was reduced threefold when activated carbon was applied in the upper reactor. Therefore, the producer gases seem to be appropriate for use as fuel gases in gas engines to produce electricity.