CO2 GASIFICATICON OF IRON-LOADED CARBONS - ACTIVATION OF THE IRON CATALYST WITH CO

Carbon dioxide gasification of various iron-loaded carbon species such as Yallourn coal char, carbon black, and activated carbon were invest igated. Catalytic effect of iron was pronouncedly observed when less r eactive carbons such as carbon black or activated carbon was gasified at 800 degrees C. Cyclic gasification in which a gasification agent an d a product CO were fed alternately was carried out in order to enhanc e activities of iron catalyst. When appropriate intervals in the feedi ng of CO2 and CO was selected (CO2 75 s and CO 120 s), gasification ra te increased considerably, even with the shorter effective gasificatio n time. Moreover, instantaneous gasification of iron-loaded carbons oc curred, if the iron-loaded carbons were treated with CO at 780 to 800 degrees C for 120 s before introducing CO2. Such phenomenon is called rapid gasification and is only observed when highly dispersed alpha-ir on (elucidated by EXAFS) was produced on the carbon surface. The most significant rapid gasification was observed and about 70% of original carbon was gasified within 4 min at 800 degrees C, when 1.8 mmol of ir on was loaded on 1 g of carbon black (surface area 101 m(2)/g).