Steam reforming of different biomass tar model compounds over Ni/Al2O3 catalysts

This work focuses on the removal of the tar derived from biomass gasification by catalytic steam reforming on Ni/Al2O3 catalysts. Different tar model compounds (phenol, toluene, methyl naphthalene, indene, anisole and furfural) were individually steam reformed (after dissolving each one in methanol), as well as a mixture of all of them, at 700 °C under a steam/carbon (S/C) ratio of 3 and 60 min on stream. The highest conversions and H2 potential were attained for anisole and furfural, while methyl naphthalene presented the lowest reactivity. Nevertheless, the higher reactivity of oxygenates compared to aromatic hydrocarbons promoted carbon deposition on the catalyst (in the 1.5–2.8 wt.% range). When the concentration of methanol is decreased in the feedstock and that of toluene or anisole is increased, the selectivity to CO is favoured in the gaseous products, thus increasing coke deposition on the catalyst and decreasing catalyst activity for the steam reforming reaction. Moreover, an increase in Ni loading in the catalyst from 5 to 20% enhances carbon conversion and H2 formation in the steam reforming of a mixture of all the model compounds studied, but these values decrease for a Ni content of 40%. Coke formation also increased by increasing Ni loading, attaining its maximum value for 40% Ni (6.5 wt.%)

Nitrogen monoxide reduction over ZSM-5 zeolite-supported catalysts / by Fakhry Seyedeyn-Azad.

Bibliography : leaves 210-222.xxvii, 243 leaves : ill. ; 30 cm.Shows how ZSM-5 zeolites can be synthesised under different conditions, and highlights the effect of zeolite properties on the activity of zeolite-supported catalysts for direct decomposition and selective catalytic reduction of nitrogen monoxide.Thesis (Ph.D.) -- University of Adelaide, Dept. of Chemical Engineering, 199

Steam reforming of carboxylic acids for hydrogen generation: Effects of aliphatic chain of the acids on their reaction behaviors

The paper investigated the effects of molecular structures on the conversion of the carboxylic acids (formic acid, acetic acid, propionic acid and butyric acid) during the steam reforming reactions. In essence, molecular structures determined catalytic behaviors of the organics during the reforming reactions. The acids with a C–C bond were more stable than formic acid during the homogenous decomposition reactions. However, the steam reforming of formic acid was much easier than that of the heavier acids due to the absence of cracking of the C–C bond during reforming. The difficulty for reforming of the carboxylic acids increased with the increase of the length of the aliphatic carbon chain (from acetic acid to butyric acid). The carboxylic acids with a longer aliphatic carbon chain (propionic acid and butyric acid) also had a higher tendency towards coking than acetic acid and formic acid. The coke formed in steam reforming of formic acid was the lowest compared with other acids. The C–C bond and the number of C–C bond in the carboxylic acids affected the reactivity of the carboxylic acids, their tendencies towards the formation of coke and the properties of the coke. The coke had larger aromatic ring systems and oxygen–containing functionalities during steam reforming of acetic acid. The amorphous coke formed in reforming of acetic acid, while the fibrous coke formed during the reforming of the heavier carboxylic acids