充填層式木質バイオマスガス化炉の反応挙動解明(熱工学,内燃機関,動力など)  [in Japanese] Reaction Behaviors in Packed-Bed Woody Biomass Gasifier(Thermal Engineering)  [in Japanese]

Gasification technology is recognized as one of the candidates to utilize the biomass effectively. From this viewpoint, this study focused fundamentals on woody biomass gasification, using a labscale packed-bed. In this experiment, pellets of black pine are gasified, using air as the gasification agent. The gasification tests were carried out under both updraft and downdraft conditions. The temperature distribution inside the gasifier and the compositions of gasified gas were measured and analyzed during gasification by thermo-couples inserted from a furnace wall and a micro gas chromatograph, respectively. The produced gasses before cooling were also sampled to analyze amount of tar generation in the gasses. As a result, the lower heating value of the produced gas under the downdraft condition was higher than that under the updraft condition. It was easier to operate under the downdraft condition than under the updraft. Under the updraft condition, bridging phenomenon happened. Amount of tar generation under the downdraft condition was lower than that under the updraft. This is because tar passes through a partial combustion zone or higher temperature zone in the downdraft gasifier.