Reforming Bio-Oil for Hydrogen Production

Researchers at the Department of Energy’s National Renewable Energy Laboratory (NREL), in collaboration with the Colorado School of Mines and Chevron, are developing a process for the low-temperature, partial oxidation, and catalytic autothermal reforming of bio-oil for the production of hydrogen.

The project, which began in 2005 and now runs through 2012, has a 2012 target of hydrogen produced at a cost of US$3.80/gallon gasoline equivalent with 72% energy efficiency. Currently, the practical yield is about 10 wt% H2 with 65% overall energy efficiency.
The fast pyrolysis of biomass—the chemical decomposition of organic material by heat in the absence of oxygen—produces liquid bio-oil (about 75% of the end products), bio-carbon or char (13%) and gas (12%). By comparison, gasification results in about .1 to 5% bio-oil, 10% char and 85% gas.

Bio-oil, while combustible, is not miscible with hydrocarbons. It has a heating value of about 17 MJ/kg and density of about 1.2 kg/. Its viscosity can increase with time.

Although bio-oil can be used directly in some applications (such as power generation), it can also serve as an intermediate for higher grade chemicals and fuels produced via subsequent processing.

Since shipping a liquid bio-oil is much more convenient and cost-effective than shipping the original biomass, bio-oil increasingly is being explored as a key element in a number of biorefinery projects.

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