Variation of Char Structure during Anthracite Pyrolysis Catalyzed by Fe2O3 and Its Influence on Char Combustion Reactivity

Effects of Fe2O3 on the pyrolysis reactivity of demineralized anthracite were investigated by a thermogravimetric analyzer, indicating that pyrolysis reactivity of Fe2O3 loaded demineralized anthracite was higher than that of raw demineralized anthracite when temperature is over 500 degrees C, Chars were prepared from the two coal samples in muffle with heating progress, and their structures were analyzed using SEM, FTIR, XRD, and Raman. FTIR results showed that absorption peaks of functional groups on the surface of char from catalytic pyrolysis at 700 T were more than that of char from noncatalytic pyrolysis. Raman results demonstrated values Of (I-D3 + I-D4)/I-G,I- of chars from catalytic pyrolysis and noncatalytic pyrolysis were 4.76 and 3.86, respectively, indicating that ordering of the char was decreased by Fe2O3. XRD analysis revealed that diffraction angle of the 002 peak did not shift; however, 1,,, and 4, decreased, indicating degree of graphitization for microcrystalline structure of char from catalytic pyrolysis was decreased, The results of FTIR, XRD, and Raman of the chat, showed that catalytic pyrolysis improved the formation of free radicals, while hindered polymerization and forming of basic structure units. Finally, combustion reactivity of the three chars, including char of raw demineralized anthracite (char-A), char Of Fe2O3-loaded demineralized anthracite (char-B), and char. Of Fe2O3-loaded demineralized anthracite washed by HCl (char-C), was investigated using TG and indicated that their active order was char-B > char- C > char-A, The results corroborated that Fe2O3 changed structure of anthracite char and improved combustion reactivity