Thermogravimetric char reactivities

The char was ground, sieved and a particle size fraction of 0.5-1.0 mm was selected for physical activation with carbon dioxide. Previously, char reactivity was evaluated in a CO2 atmosphere, in order to optimise the operating temperature for the activation process. A thermogravimetric analyser (TGA) was used for this purpose. Approximately 25 mg of sample was heated at 15 °C min " from room temperature up to 1200 °C under 50 mL min" of CO2. The reactivity test revealed that the char is a very stable carbon material, that does not begin to react until 900 °C. Thus, an activation temperature of 925 °C was selected, at which point mass loss started to be significant (5% of the initial mass). 

In the present paper investigation are made in order to produce operational data for the gasification reactivity for biomass chars and coal chars. Furthermore the differences between chars derived from biomass and coal is illustrated. Thermogravimetric analyses have been used to obtain information about the kinetic values of the C-CO2 reaction. 

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