50.石炭チャー燃焼・ガス化時の無機成分の放出と低温表面への析出に関する検討(石炭利用における科学と工学の接点)

抄録

The release of inorganic matters from coal char as volatile matters and aerosols at high temperatures and their deposition on lower temperature surfaces were investigated fundamentally. Taiheiyo, Datong and Blair Athol coal char smaller than 250μm held in a ceramic basket were rapidly inserted into an electronic furnace and burned, gasified or pyrolyzed at 1500℃ to release vapor and aerosols of inorganic matters. A packed bed of glass beads of 2.25-3.25μm was placed in the downstream of the reactor. The temperature of the bed was controlled in the range of 100-500℃ to form deposit on the glass beads. The morphological features and chemical compositions of deposits were evaluated by means of SEM and EDAX. The release and formation of ash deposits depends on gaseous environments. It was found that deposition temperature significantly influenced the morphology and composition of deposits. In combustion, the ash deposits consists of volatile components such as alkali, calcium, sulfur and halogen, though in gasification, the ash deposits contains iron in addition to alkali, calcium and sulfur. It is proposed that inorganic vapors heterogeneously deposited on the glass beads surfaces at 500℃, while homogeneous nucleation and growth predominantly occurrs and resultant aerosols are captured on the beads surfaces at 100℃.