Catalytic Steam Reforming of Biomass-Derived Acetic Acid over Two Supported Ni Catalysts for Hydrogen-Rich Syngas Production.

The catalytic steam reforming (CSR) of biomass-derived acetic acid over the commercial Ni-based catalyst (CNC) and the maize stalk ash-supported Ni catalyst (Ni/MSA) for hydrogen-rich syngas production was studied by means of a bench-scale fixed-bed unit combined with NDIR/TCD techniques. A maize stalk ash-supported Ni catalyst was developed for steam reforming of HOAc. The chemical composition and structural characteristics of CNC and Ni/MSA catalysts were compared. Evolution characteristics of H and CO during CSR of HOAc were explored. Between 600 and 900 °C, the yields of H and CO showed a similar trend over time, which first increased rapidly to the peak value, then began to decrease and finally tended to stabilize. The optimal reaction conditions were as follows: temperature = 800 °C, water to carbon molar ratio (WCMR) = 3, and weight hourly space velocity (WHSV) = 5 h. Elevating the reforming temperature up to 900 °C gave rise to the continuously increased H yield and enhanced catalyst ability for selective hydrogen production. The percentage of coke deposited on the catalyst decreased by 49.8% with the rise of temperature from 600 to 900 °C. The CO yield continued to decrease with increasing WCMR from 1 to 7. Ni/MSA gave similar CO yield to the CNC. The Ni/MSA exhibited better ability to selectively generate hydrogen than the CNC, resulting in significantly higher hydrogen yield.