2014 年 93 巻 5 号 p. 521-530
Biomass has been recognized as a renewable energy source alternative to fossil fuels, because it doesn’t increase CO2 amount in the atmosphere. Among various ways of woody biomass use, IGCC power generation is known as the most possibly efficient technology. In the process, biomass is firstly pyrolyzed and the produced volatile and char are secondary converted; hence it is necessary to know the production process and yields of pyrolysis gas, tar, producing char and char gasification kinetics for effective energy conversion. In this study, many woody biomass species (four softwoods, nine hardwoods and four barks) were pyrolyzed at 1000 °C at the rapid heating rate up to around 1000 °C/s. Then the produced char is gasified in an experimental fluidized bed. After that, the produced char was gasified by CO2 at 1000 °C. We computed char conversion and its rate from CO production rate with time and conversion rate was plotted against conversion. Different gasification rate curves are found for various biomass samples. The gasification rate of char was evaluated by the first order rate constant based on the volume reaction model. Hardwood char gasification rates were faster than those of softwood samples. Most of the gasification rates of char from the bark samples were nearly same as those of woody part samples. As for the hardwood, the char produced from biomass with lower compressive strength generally gave faster reaction rate.
