Chemical Structure Analysis of Coal Char Surface Based on Fourier-Transform Infrared Spectrometer

Coal char samples,partly burnt under different environments and temperatures,were prepared using a drop tube furnace with the combustion conditions similar to those in actual pulverized-coal boiler furnace.Micro structures and chemical groups of coal char surfaces were analyzed based on Fourier-transform infrared(FTIR) analyzer.Research results show that chemical structure such as C—H and C—O groups would be released combined with volatile matters emission during pyrolysis or combustion process.Especially for group contained O— and aliphatic structure,it would be eliminated clearly during thermal process,presented decreased FTIR spectrum peaks.Compared with aromatic groups,aliphatic structures would be decompounded easily,which caused increases of the relative contents of aromatic carbon and the aromaticity(fa) of thermal treated chars.For chars prepared under CO2 environments,the ratio of aromatic hydrogen and aliphatic hydrogen(Har/Hal) and aromaticity(fa) were always smaller than chars prepared in N2 environments.It can be concluded that thermal treated environments and temperature may be the key factors which effect chemical groups emission process and prepared chars reactivity.