High quality bio-oil from catalytic flash pyrolysis of lignocellulosic biomass over alumina-supported sodium carbonate

• Na2CO3/γ-Al2O3 was very effective for de-oxygenation of pyrolysis liquid.
• Higher heating value of catalytic bio-oil increased from 17.8 MJ/kg to 36.1 MJ/kg.
• Phase separation of pyrolysis liquid yielded a bio-oil with 5.8 wt.% water content.
• Acids were completely removed leading to a pH neutral bio-oil.
• Catalyst can be implemented for in-situ upgrading of biomass pyrolysis vapors.

Performance of a novel alumina-supported sodium carbonate catalyst was studied to produce a valuable bio-oil from catalytic flash pyrolysis of lignocellulosic biomass. Post treatment of biomass pyrolysis vapor was investigated in a catalyst fixed bed reactor at the downstream of the pyrolysis reactor. In-situ catalytic upgrading of biomass pyrolysis vapor was conducted in an entrained flow pyrolysis reactor by feeding a premixed feedstock of the catalyst and biomass. Na2CO3/γ-Al2O3 was very effective for de-oxygenation of the pyrolysis liquid and oxygen content of the bio-oil was decreased from 47.5 wt.% to 16.4 wt.%. An organic rich bio-oil was obtained with 5.8 wt.% water content and a higher heating value of 36.1 MJ/kg. Carboxylic acids were completely removed and the bio-oil had almost a neutral pH. This bio-oil of high calorific low, low water and oxygen content may be an attractive fuel precursor. In-situ catalytic upgrading of biomass pyrolysis vapor produced a very similar quality bio-oil compared to post treatment of pyrolysis vapors, and shows the possible application of Na2CO3/γ-Al2O3 in a commercial type reactor system such as a fluidized bed reactor.