The gasification activities of three kinds of Binxian chars with carbon dioxide were studied at 1000-1300 degrees C and under atmospheric pressure in self-made thermal balance. The specific surface area of coal or chars was determined with BET methods during gasification. The results showed that the reaction rate of two rapid pyrolysis chars increases at the beginning and decreases subsequently with increasing carbon conversion at relatively high temperatures. The heating rate of coal has a significant effect on the gasification process. The activation energy of slow pyrolysis char varies between 160 kJ/mol and 180 kJ/mol during gasification. The activation energy of the two rapid pyrolysis chars displays a linear trend when the carbon conversion is less than 40% and decreases slowly afterwards. (c) 2007 Elsevier Ltd. All rights reserved.