Upgrading bio-oils—the next step in developing renewable fuels
Breaking down biomass into bio-oil is no easy task. But finding a way to upgrade bio-oil into biofuels that can be plugged into the existing petroleum infrastructure is considered the holy grail of developing renewable transportation fuels. In the thick of the search for the holy grail, Pacific Northwest National Laboratory is a key player in three new research projects aimed at upgrading bio-oils.
PNNL is leading one new biofuels project and participating in two others that are aimed at achieving a process that can produce and upgrade pyrolysis oil to produce biofuels at a commercial scale. Pyrolysis is a process used to convert biomass into bio-oil, also called pyrolysis oil. All three of these awards are part of a $16.5 million U.S. Department of Energy effort to grow the production of renewable transportation fuels and will bring as much as $4.3 million in funding to PNNL over the next three years.
Why it matters:
Developing a biofuel that can be produced, distributed and stored in the same facilities as petroleum fuels will reduce the overall cost of biofuels, and allow them to be more readily accepted into the market as a direct replacement for petroleum. Another advantage of refinery-ready biofuels is increased fuel density. While ethanol-enhanced fuels have less density than conventional fuels, PNNL envisions biofuels having the same energy density as gasoline, thus getting the same mileage.
The biomass process begins with breaking down biomass into bio-oil through a process called pyrolysis, and then upgrading the oil to hydrocarbon fuel. In all three projects, PNNL will focus on the hydroprocessing (hydrogen reactions) to upgrade bio-oil, or pyrolysis oil. Pyrolysis uses heat to break down biomass, and the resulting oil contains high levels of oxygen and acids, making it unstable at the high temperatures used in refinery processing. The instability makes it difficult to convert the oil into hydrocarbon fuels and causes the catalysts used in hydroprocessing to be degraded more quickly.
PNNL is leading a project with UOP LLC, a Honeywell Company, and Albemarle Corporation to improve catalysts used in the standard fixed bed hydroprocessing reactors that convert bio-oil into hydrocarbon fuel.
In the other projects, PNNL will team with W.R. Grace to develop an entirely new reactor system for converting bio-oil into fuel as well as new catalysts specific to that system. In a third project, PNNL is teaming with Battelle to develop a catalyst that will produce a higher quality bio-oil right from the start. The higher-quality oil may prove easier to finish to biofuel in the hydroprocessing step.
"These projects are critical to DOE's efforts to shift our country to a renewable source of hydrocarbon fuel," said John Holladay, who manages biomass activities for PNNL. "Improving pyrolysis and upgrading the resulting oil are the next steps in moving technology from the laboratory to the marketplace, and it is becoming a key focus of DOE's Office of the Biomass Program. All three projects are different tactics to arrive at the same place—a process that is stable enough, and a catalyst that lasts long enough to run at a larger scale.
In another related project, DOE is funding the construction of a demonstration-scale bio-fuels plant in Hawaii. The project, which UOP is leading and which involves PNNL, will result in new catalysts and a method that can be incorporated into a commercial process for producing biofuels.
Acknowledgements: The research projects mentioned in this highlight are funded by the U.S. Department of Energy Office of the Biomass Program.