Steam Reforming of Raw Bio-oil in a Fluidized Bed Reactor with Prior Separation of Pyrolytic Lignin

The effect that operating conditions (temperature, steam/carbon molar ratio, and space-velocity) have on the steam reforming of raw bio-oil has been studied in a two-step reaction unit. In the first step (operated at 500 °C), a carbonaceous solid (pyrolytic lignin) deposits by repolymerization of certain bio-oil components, and the remaining volatiles are reformed in the second step (fluidized bed reactor) on a Ni/La 2 O 3 –αAl 2 O 3 catalyst. Under suitable reforming conditions (700 °C, S/C = 9, space-velocity = 8000 h –1 ), the yields of H 2 and CO were 95% and 6%, respectively. Catalyst deactivation was very low, whereby the H 2 yield decreased by only 2% over 100 min of reaction. By using dolomite as adsorbent in the reforming reactor, CO 2 was effectively captured, and the raw bio-oil was reformed at 600 °C without adding water (S/C = 1.1), thus avoiding its vaporization cost. The yields of H 2 and CO were 80–82% and 1%, respectively, for a space-velocity (G C1 HSV) of 7000 h –1 and catalyst/dolomite ratio of 0.25, although a high yield of CH 4 (7%) was obtained due to the cracking capacity of the dolomite. The coke content on the catalyst was high (7.7 wt % in 2 h) because of the limited gasification of coke precursors under the operating conditions (low temperature and low S/C ratio) used in the process with CO 2 capture.