Catalytic Behavior of Co-Based Catalysts in the Kinetic Study of Acetic Acid Steam Reforming

A kinetic model of acetic acid steam reforming is presented in this work on Co-based catalysts, accounting for the products distribution due to the main and side reactions. The Cr-promoted catalyst exhibited enhanced hydrogen yield and reduced methane selectivity in comparison to the chromium-free samples. The kinetic study was carried out in the presence of the chromium-containing catalyst between 500 and 600 degrees C, varying the contact time in the range 18-270 ms. The model developed over Co-Cr/SBA-15 was based on elementary kinetics and involved the following pathway: acetic acid decomposition, acetic acid ketonization, methane and acetone steam reforming. A good agreement between the predicted concentration and the experimental data was observed as a function of reaction temperature as well as contact time, thus validating the hypothesis on the reactions set and allowing a potential description of the acetic acid steam reforming reaction pathway, rarely investigated in the recent literature. The comparison with the kinetic model recorded over the monometallic catalyst demonstrated that Cr increases the rate of methane steam reforming and ketonization reaction, leading to acetone formation and its subsequent conversion to H-2 and CO2 via reforming; thus, an increase in hydrogen yield above 500 degrees C was assured.