Biomass materials, such as switchgrass and cornstovers, are very potential to be used as renewable resources for producing energy, chemicals, and liquid fuels. The utilization of biomass, however, is limited by the cost of transporting. In addition to the location for collecting biomass, which is generally far away from the production facilities, biomass has a low energy density thus it is expensive to transport. Fast pyrolysis has been seen as a promising approach to improve the efficiency of biomass utilization by reducing the cost of transportation. In this approach biorenewable materials, such as cornstovers, are collected and preprocessed locally to yield energy-rich biooil and porous char via fast pyrolysis. The char can be injected back to the soil or used for producing heat. The biooil, which can be thought as densified biomass (density is 1280 kg/m3 compared to approximately 160 kg/m3 for original biomass), is transported by tanker trucks to a centralized facility where it is used as feedstock to produce energy, chemicals, and/or liquid fuels. The potential benefits of this system include: 1). Efficient and economically profitable utilization of abundant biomass which is otherwise considered waste, 2) Reduction in the consumption of expensive fossil fuel and natural gas which potentially reduces the emission of CO2. The use of biooil is not without problem, however. Biooil contains a good number of functional groups, such as carbonyl, carboxyl, phenolic, and hydroxyl, which renders the oils reactive and thermally unstable. In addition, often time bio-oil needs to be separated into components/fractions to be used as feedstock for certain applications. Iowa State University has developed a fast pyrolysis process for producing bio-oil from biorenewable materials, such as cornstovers and switchgrass. The fast pyrolysis unit consists of a 16.2 cm diameter fluidized bed reactor, a burner to externally heat the reactor, a two-stage auger to feed the solid, two cyclones to remove particulate matter, and a vapor-condensing system consisting of four condensers and an electrostatic precipitator. The condenser system enables collection of high water content biooil fractions of bio-oil with very low lignin content and high lignin fractions with low water content. Effects of reaction conditions and condenser temperatures on the bio-oil product distribution will be discussed. Also discussed are factors that affect bio-oil product stability and steps that can be taken to improve bio-oil stability. Finally, the potential utilization processes of these fractions for producing energy, chemicals, and fuels will be addressed.

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