Kinetics of carbochlorination of chromium (III) oxide

摘要

Kinetics of the carbochlorination of Cr{sub}2O{sub}3 has been studied with Cl{sub}2+CO gas mixtures between 500°C to 900°C using thermogravimetric analysis. The apparent activation energy is about 100 kJ/mol. Mathematical fitting of theexperimental data suggests that the shrinking sphere model is the most adequate to describe the carbochlorination mechanism of chromium oxide and that is controlled by the chemical reaction.In the temperature range of 550°C to 800°C, the reaction order is about 1.34 and is independent of temperature. Changing the Cl{sub}2+CO content from 15 pct to 100 pct increases the reaction rate and does not affect the reaction mechanism. Similarly,changing the ratio of Cl{sub}2/(Cl{sub}2+CO) from 0.125 to 0.857 do not modify the carbochlorination mechanism of Cr{sub}2O{sub}3. In these conditions, the reaction rate passes through a maximum when using a chlorinating gas mixture having aCl{sub}2/(Cl{sub}2+CO) ratio of about 0.5.