Woody biomass samples were pyrolized at different temperatures and heating rates in a fluidized bed reactor (FBR). Only under the conditions of rapid pyrolysis between 600 and 1000 °C, porous alumina particles as the bed material adhered on the surface of the obtained char. The amount of particles adhering on the char derived from softwood was larger than that derived from hardwood.

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 ℃ at the rapid heating rate up to around 1000 ℃ /s. Then the produced char is gasified in an experimental fluidized bed.After that, the produced char was gasified by CO 2 at 1000℃ . 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.

Gasification characteristics were evaluated for various biomass samples such as softwoods and hardwoods. They were pyrolyzed at 1000 °C in a small scale fluidized bed under rapid heating condition with N 2 flow. After keeping 10 min at the temperature, the produced char was gasified with 25% CO 2 at 1000 °C. Char gasification characteristic was investigated by monitoring CO producing rate and the effects of woody biomass species on gasification rate and its time variation were examined. The conversion rate, dX/dt was plotted against the value of conversion. As a result, the following characteristic curves were observed mainly for softwoods; at nearly conversion X = 0.05, high reactivity peak was found, CO production was decreased first rapidly and then slowly until X = 0.5, and then almost followed volume reaction behavior. In order to elucidate the cause of this phenomenon, the high temperature char with bed material of alumina in the bed was cooled down under the N 2 flow to the room temperature and the char and alumina particles were separated by sieving. The alumina particles became black which suggests existence of some carbonaceous materials. Then each sample was introduced into the fluidized bed and separately gasified in the same bed. The gasified gas analyses showed that gasification rapidly proceeded for alumina particles only at the first stage of its gasification which explained the peak of gas evolution at low conversion of the continuous in situ pyrolysis/gasification experiments. In case of hardwoods, the amount of carbonaceous materials remaining in bed materials was quite small and it does not affect the results of the in situ pyrolysis/gasification experiments. Gasification difference of the char separately collected depended on their own properties rather than the common properties in their group.