Study on the pyrolysis characteristics of sawdust catalyzed by spent FCC catalyst and blast furnace ash

Two industrial wastes, spent FCC catalyst (sFCCc) and blast furnace ash (BFA), were used as catalysts in the fast pyrolysis of sawdust, and the catalytic pyrolysis reaction characteristics of sawdust in the temperature range of 400−700 ℃ were explored. The results showed that both catalysts promoted the conversion from liquid products to gaseous products, and the highest gas yield was 52.60% at 700 ℃ catalyzed by BFA. The sFCCc had stronger deoxygenation activity at 500−600 ℃, resulting in higher CO and CO₂ production in gaseous products. While BFA had higher polycondensation and dehydrogenation activity at 600−700 ℃, and promoted the formation of polycyclic aromatic compounds and H₂. Pyrolysis oil was mainly composed of phenols. The sFCCc promoted the conversion of methoxy phenol to benzenediol. FT-IR analysis of pyrolysis oil showed that sFCCc promoted the removal of C−O and C=O, resulting in decreased acid and ester compounds and increased CO₂ yield.