干旱区生态环境知识资源中心

Woody biomass (Eucalyptus camaldulensis) produced at our plantation site in the arid area of Western Australia was pyrolyzed by a fluidized bed reactor (FBR). Pyrolysis temperature range was between 300 and 1400 degrees C, and heating rate was rapid (100-1000 degrees C/s) or slow (10 degrees C/min). The influence of pyrolysis temperature and heating rate on char yield was investigated. Under rapid heating rate, char yield was almost constant at about 15%, between 500 and 900 degrees C, while it was decreased to several % with increased temperature, and char yield was decreased to 3% between 1000 and 1400 degrees C. In slow heating rate, char yield was almost kept at 22-17% between 500 and 1400 degrees C. Concentrations of alkali and alkaline earth metallic (AAEM) species (particularly Na, K, Mg and Ca) in produced char were analyzed using ICP-MS. Contents of Na, K, Mg and Ca in dry biomass basis were 0.10, 0.15, 0.29 and 1.01%, respectively, but when pyrolysis temperature was increased, their contents decreased. Especially in rapid pyrolysis, a significant decrease was seen from 800 to 900 degrees C, and even over 1000 degrees C, gradual decrease was also observed. SEM and SEM-EDX pictures were also given to elucidate the effects on its structure of pyrolysis temperature and heating rate.