触媒担持によるバイオマスチャーのガス化速度向上機構に関する研究

抄録

The present study examined the mechanism underlying the enhancement of the gasification rate of biomass char when potassium (K) or iron (Fe) was supported on the char. The alkali metal catalysts were directly supported on the char with support ratios of 0, 2, 6, 10, and 20 wt%. When K was supported on the char, the gasification rate increased as the support ratio increased up to 10 wt%. Although the amount of the char-supported K catalyst slightly decreased due to heating during gasification (evaporation and scattering), the catalyst did not completely disappear, but remained on the surface and inside of the char and the remaining catalyst exerted its effect. When Fe was supported on the char, although the gasification rate increased as the support ratio increased, the gasification rate was markedly lower when Fe was supported than when K was supported. One reason for this low gasification reactivity was that the impregnation (infiltration) of the char with Fe was difficult when the catalyst supported by Fe solution and a large number of Fe crystals were laminated on the char surface only. Specifically, after heating under an Ar flow, the Fe content on the surface decreased because Fe oxide particles moved into mesopore, suggesting the decrease in the number of active sites and the restriction of the accessibility of CO₂ to active sites.