Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
66145 | Journal of Molecular Catalysis A: Chemical | 2012 | 6 Pages |
Decomposition of pyrrole or pyridine with iron catalysts supported on carbons has been studied with a cylindrical quartz-made pulse reactor, into which liquid pyrrole or pyridine is injected as a pulse, in order to develop a novel hot gas cleanup method of removing the nitrogen present in tar as N2. The catalyst is mainly prepared by heating FeOOH precipitated onto powdery cellulose from FeCl3 solution. Nanoscale iron catalysts with the average particle sizes of 25–30 nm can promote decomposition reactions of the N-containing heterocyclic compounds in inert gas at >500 °C and provide N2 yields of 40–45% after the almost complete decomposition of pyrrole at 600 °C or pyridine at 650–700 °C. Iron catalyst with the mean size of 100–500 nm, prepared from Fe(NO3)3 impregnated with a commercial activated carbon, is also active for the decomposition of the heterocyclic N-compounds, but it is almost inactive for N2 formation, the yields being as low as less than 2% in all cases. The increase in the number of pulses lowers the catalytic activity of iron nanoparticles for N2 formation, whereas in situ H2 treatment at 500 °C after reaction can restore it to the almost original state. On the basis of the above-mentioned results, it is likely that the activity of iron catalyst for N2 formation from pyrrole or pyridine is very sensitive to the iron particle size, and the in situ H2 treatment is effective for recovery of the decreased catalytic performance.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (92 K)Download as PowerPoint slideHighlights► Fe catalysts supported on carbons have been utilized to decompose the N in pyrrole or pyridine to N2. ► The catalyst is mainly prepared by heating FeOOH precipitated onto powdery cellulose. ► Nanoscale iron particles promote N2 formation from pyrrole or pyridine at temperatures of >500 °C. ► N2 yields are 40–45% after the almost complete decomposition of these heterocyclic N-compounds. ► The activity of Fe catalyst for N2 formation is very sensitive to the iron particle size.