Steam reforming of cyclic model compounds of bio-oil over Ni-based catalysts: Product distribution and carbon formation

Steam reforming (SR) and oxidative steam reforming (OSR) of furfural, 2-methylfuran, and guaiacol have been investigated in the temperature range 400-800 degrees C at a steam to carbon (S/C)-ratio of 5 and oxygen to carbon (O/C)-ratio of 0.2-1.4 over Ni/CeO2-K/MgAl2O4. Carbon oxides and H-2 were the major products in the SR of 2-methylfuran and furfural, while the by-products were methane, ethanol, 2-propanol, and acetone. Temperatures of 500 degrees C or above were needed to minimize the formation of by-products in the SR of 2-methylfuran and furfural. Phenolics, like benzenediols and phenol, were produced in high yields in the SR of guaiacol and temperatures of 780 degrees C were needed to totally convert guaiacol to carbon oxides and H-2. Carbon deposition was observed in the SR of all three model compounds and was most severe for guaiacol followed by furfural and 2-methylfuran. The carbon deposition could be reduced significantly by adding oxygen to the feed at a cost of a lower yield of H-2. Stable operation was observed initially (first 4 h) in the OSR of all compounds, but experiments over 24 h showed signs of deactivation due to an accelerated rate of carbon deposition in the SR of furfural and guaiacol. Furthermore sintering was more severe in OSR. (C) 2014 Elsevier B.V. All rights reserved.