Effect of operating conditions on the sorption enhanced steam reforming of blends of acetic acid and acetone as bio-oil model compounds

Hydrogen production by sorption enhanced steam reforming (SESR) of bio-oil model compounds was thermodynamically and experimentally studied by mixing acetic acid (AcH) and acetone (AcCO), in a fluidized bed reactor. In the SESR process the catalytic reforming reaction and CO2 removal by sorption were carried out simultaneously in a single reactor. The SESR of the model compounds and their blends was performed under atmospheric pressure over a Pd/Ni–Co hydrotalcite-like material (HT) catalyst using dolomite as CO2 sorbent. The effects of the reaction temperature (475–725°C), steam/C molar ratio and weight hourly space velocity (WHSV) were studied. For the SESR of acetic acid, acetone and their blends it was observed that the H2 yield and H2 concentration increase as the temperature increases, reaching a maximum value, and then they decrease with the temperature. It was also found that the CH4 concentration decreases as the temperature increases, while the CO and CO2 concentrations increase with the rise in temperature. High steam/C molar ratio values and low WHSV values favor the H2 yield and H2 concentration, while they lead to a decrease in the CH4 concentration. Hydrogen purities as high as 99.2–99.4% with small amounts of methane, CO and CO2 were obtained for the SESR of the model compounds of bio-oil and their blends at a temperature of 575°C at atmospheric pressure. The effect of temperature on the SESR of the blends of model compounds of bio-oil is similar to that of the individual model compounds studied, except in the fact that lower H2 yield values are obtained by the SESR of the blends (83.3–88.6%) compared to the individual model compounds (90.2–95.9%), a decrease which becomes more noticeable as the proportion of acetone in the blend is increased.