Bio-oil Production through Fast Pyrolysis and Upgrading to “Green” Transportation Fuels

Abstract

Fast pyrolysis process produces a high yield of liquid (a.k.a. bio-oil) and has emerged as one of the techniques to produce transportation fuel from different types of biomass. Nonetheless, some of the properties inherent by the bio-oil create significant challenges for its potential application as transportation fuel. The current research was focused on understanding the effect of fast pyrolysis process parameters on the bio-oil quality and upgrading to “drop-in”, non-ethanol, and “green” hydrocarbons. This study was divided into five specific objectives. The first objective examined the effect of temperatures on bio-oil yield from pine wood and its properties produced using a bench scale auger reactor. The second objective analyzed the effect of process parameters (temperature, heating rate and biomass types) of fast pyrolysis, and the study showed that the yield of each group of compounds could be tuned by changing process parameters based on the final application of the bio-oil. The third objective compared a catalytic pyrolysis of biomass with ZSM-5 catalyst under different gas environments (helium and hydrogen). The high ratio of catalyst to biomass (9:1) mixtures could produce high amount of aromatic hydrocarbons, which was around 50% its stoichiometric yield. In fourth objective, a new catalytic system (bifuctional – acid/metal) was introduced for catalytic pyrolysis under hydrogen pressure, and found that the hydrocarbon yield increased with new catalysts. Finally, a green fresh water micro-algae (low lipid content) was utilized for catalytic and non-catalytic pyrolysis. A high liquid yield with high hydrogen index bio-oil showed the possibility of using algae residue for bio-oil production. This study showed that hydrocarbons can be directly produced from terrestrial and algal biomass using catalytic pyrolysis.