Comparative study of carbon formation on supported in catalysts during CH₄ reforming using TEOM, TPO-IR, TPD-IR and TGA techniques

Four different methods (TEOM, TPO-IR, TPD-IR, and TPO-TGA) were used comparatively for more accurate and reliable measurements of carbon formation on used Ni/Al₂O₃ reforming catalysts with and without Ca-promotion. TPO-TGA could not discriminate carbon burn off and Ni oxidation, especially when only a trace amount of carbon was formed that needs to be detected. TEOM was run on-line during methane reforming, it could avoid any other effects besides the reforming reactions. There was a fairly good correlation between the two techniques. The un-promoted C11-9-09 showed a better consistence between the two methods, noting that the slope of the linear trend line is very close to 1, while G-91 showed larger amount of carbon detected by TEOM than by TPO-IR.