The paramenters of specific surface area

total pore volume

and aperture etc.of Yanzhou bituminous coal and pyrolyzed carbocoal under nitrogen atmosphere in the atmospheric circulating fluidized bed(CFB)have been measured by using nitrogen adsorption method

the results of study show that more abundant porous structure

larger total pore volume

and much smaller aperture have been formed during the process of coal pyrolysis;along with the temperature rise

the specific surface area and porosity of carbocoal being substantially increased

but the average aperture of carbocoal being evidently decreased.