No.8 石炭ガス化炉模擬雰囲気における芳香族化合物の転換反応機構(改質・処理・クリーン化(2),その他)

抄録

Conversion characteristics of benzene and naphthalene as model tar compounds were studied with an atmospheric flow reactor at 1100-1400℃ in atmospheres that simulated the reducing section of two-stage entrained-flow coal gasifier in an air-blown or O_2/CO_2-blown mode. The experimental results showed that soot was one of the most important fates from the both aromatic hydrocarbons, but its yield decreased significantly as the inlet concentration of the aromatic hydrocarbons was lowered. It was also found that changing the mode from the air-blown to O_2/CO_2-blown suppressed the soot formation by promoting the reforming of the soot precursors when the inlet concentration of the aromatic hydrocarbons was below 8 g/Nm^3. Numerical calculation based on a detailed chemical kinetic model was performed for better understanding of the mechanism. The model predicted that the decrease of the inlet concentration leads to decrease of soot yield, and these trends were consistent with the experimental results. The model also indicated that hydroxyl radical (OH・) was a most important species for the pathways of decomposition of aromatics, and its concentration in O_2/CO_2-blown mode was higher than that in the air-blown mode. The model prediction was in agreement with the experimental result qualitatively.