A kinetic model for air-steam reforming of bio-oil over Rh–Ni/γ-Al2O3 catalyst: Acetol as a model compound

Abstract

A new kinetic model is proposed for catalytic reforming of acetol to synthesis gas over a Rh–Ni/γ-Al2O3 catalyst. Acetol is one of the most important bio-oil model compounds formed under reactive flash volatilization reaction conditions. The model was implemented in the Aspen Plus simulation package and used to predict the product gas composition at different reaction temperatures and steam and oxygen ratios. The contributions of the reactions both in the reactor freeboard and the catalytic bed were assessed using CSTR and PFR reactor models, respectively. The reaction scheme included decomposition, steam reforming, and water-gas shift reactions. The results from the model predicted the product distribution within an acceptable degree of tolerance. This study confirms that thermal decomposition and partial oxidation of acetol precede the catalytic reactions involving steam. The effects of temperature, oxygen concentration in the feed, the volume of the freeboard, and the catalyst bed height can all be evaluated with this new kinetic model. This work suggests that bio-oil decomposed into different fractions of molecules like acetol can be successfully modelled by a series of decomposition reactions followed by partial oxidation and catalytic steam conversion. The heat transfer within the catalyst bed is found to be critical for achieving a good match with the experimental results.