Production of fuel-cell grade H2 by sorption enhanced steam reforming of acetic acid as a model compound of biomass-derived bio-oil

Fuel-cell grade H-2 has been produced by the sorption enhanced steam reforming (SESR) of acetic acid, a model compound of the bio-oil obtained from the fast pyrolysis of biomass. A Pd/Ni-Co catalyst derived from a hydrotalcite-like material (HT) with dolomite as CO2 sorbent was used in the process. A fixed bed reactor with three temperature zones was employed to favor the catalytic steam reforming reaction in the high-temperature segment, the SESR reaction in the intermediate-temperature part, as well as the water-gas shift (WGS) and CO2 capture reactions in the low-temperature segment. Different conditions of pressure, temperature, steam/C molar ratio and weight hourly space velocity (WHSV) in the feed were evaluated. Higher steam/C molar ratios and lower WHSV values facilitated the production of H-2 and reduced the concentrations of CH4, CO and CO2 in the produced gas. A fuel-cell grade H-2 stream with a H-2 purity of 99.8 vol.% and H-2 yield of 86.7% was produced at atmospheric pressure, with a steam/C ratio of 3, a WHSV of 0.893 h(-1) and a temperature of 575 degrees C in the intermediate part of the reactor (675 degrees C in the upper segment and 425 degrees C in the bottom part). At high pressure conditions (15 atm) a maximum H-2 concentration of 98.31 vol.% with a H-2 yield of 79.81% was obtained at 725 degrees C in the intermediate segment of the reactor (825 degrees C in the upper segment and 575 degrees C in the bottom part). Under these conditions an effluent stream with a CO concentration below 10 ppm (detection limit) was obtained at both low and high pressure, making it suitable for direct use in fuel cell applications. (C) 2015 Elsevier B.V. All rights reserved.