Abstract
We examined the pulverizing characteristics of woody biomass by three defferent sizes of dry mills with ring-type pulverizing media. This type of mills have many pulverizing rings in the inside of the pulverizing cylindrical chambers and these rings roll and rotate in me chambers by external vibration. Woody biomass are pulverized by this high rotational centrifugal force. Two kinds of woody biomass: cedar and douglas fir were used for pulverizing tests of these mills. Pulverizing energy consumption of each of mills was inversely proportional to the amount of input materials. When the amount was too large, the pulverizing was no longer proceeding. The study of the pulverizing characteristics of small and large dry mills leaded to the definite relationship between the pulverizing energy consumption and saccharification efficiency of woody biomass. The relationship was independent of the physical size of mills. Input power per area of pulverizing chamber is about 15 kw/m^2. Then, it was estimated that woody powder was heated by large pressure from pulverizing rings and the average temperature of this woody powder layer achieved at about 300 centigrade.
