Sandia LabNews

Team developing viable biofuel for military aircraft


Coming soon: New biofuel for military jets.

That’s what Sandia researchers are working on as part of a Defense Advanced Research Projects Agency (DARPA) funded team led by UOP LLC, a Honeywell company.

The team is looking at the production of military Jet Propellant 8 (JP-8) fuel based on renewable biomass oil feedstocks, including oil crops, unconventional sources like algae, and various forms of waste vegetable and animal oils.

The goal of the 18-month effort, backed by a $6.7 million project award from DARPA, is to develop, demonstrate, and commercialize a process by October to produce the JP-8 fuel used by US and NATO militaries.

Sandia researchers are working with team members at UOP and Cargill to evaluate technical, economic, and environmental interdependencies. The team is conducting comparative life-cycle analyses and tradeoff assessments and assessing the scale-up feasibility of high-volume bio-oil feedstock and JP-8 fuel production from suitable oil crops and other sources.

At the same time, Sandia, UOP, Honeywell Aerospace, Cargill, and Southwest Research Institute researchers are working to evaluate, develop, and commercialize the processes and biofeedstock and biofuel production scale-up pathways needed to enable reliable, high-volume, competitively priced jet fuel production based on feedstock rather than petroleum.

A new complementary DARPA biofuel program announced in November is specifically focused on the production of JP-8 from algae and lignocellulosic materials. Sandia partnered on six different teams that submitted proposals to this program. Proposal funding decisions are expected to be made in late April, with funded projects expected to begin by late summer.

Systems analysis

According to Sandia project leader Ron Pate (6313), Sandia researchers are addressing issues and options for the necessary expansion of reliable and cost-competitive oil crop production and oil feedstock processing. This includes evaluation of promising oil crops that will not directly compete with food and feed markets, can avoid the use of higher-quality agricultural land, and may also allow for reduced demand for energy, fresh water, and other inputs.

“National scale-up of oil crop-based aviation fuel production at the volumes, supply availability, reliability, and competitive costs desired is a complex and dynamic ‘system of systems’ challenge,” says Ron. “We are leveraging our capabilities and expertise in systems dynamics modeling, simulation, and assessment to help provide insight and decision support to the project.”

Several key issues and interdependencies for bio-oil feedstock and biofuel production scale-up include land use, water demand and availability, soil and climate conditions, energy, and other critical inputs.

Conversion processes under development are expected to yield high fractions of liquid biofuel product in the form of JP-8 and green diesel, along with other useful coproducts. Mass conversion yields to JP-8 are process- and feedstock-dependent, but can be well above 50 percent, says Ron.

Oils derived from plants like soy, oil palm, sunflower, and numerous others provide an easy-to-handle material with high energy density and chemical structures that can more easily be converted into high-performance liquid fuels than other forms of biomass. Production of conventional oil crops for biofuel will face limits due to competing markets for oil crop products and competing uses for the land and water required to grow the crops, Ron says.

Algae that create oil in the form of triacylglycerols (TAGs) and fatty acids have long been seen as a promising option for producing liquid transportation biofuels, Ron says. Algae can be grown using land not otherwise suitable for agriculture, and can use lower quality water sources such as inland brackish ground water, various waste waters, desalination concentrate, by-product water from oil, gas, and coal-bed-methane energy mineral extraction, and coastal sea water.

Despite the high productivity potential of algae, Sandia’s preliminary techno-economic assessment reveals several major areas where innovation will be required before affordable algal biofuel production is possible.

These include less energy-intense processes associated with algal biomass harvesting, dewatering, and neutral lipid extraction. Costs of algal oil production need to be brought down by at least an order of magnitude to be competitive with other alternatives, says Ron. Currently, Sandia has several internally funded projects underway to address issues associated with algae for biofuel.

Lignocellulosic biomass represents a widely available biofuel feedstock source. Lignocellulosic materials come from forest industry residues, including sawmill and paper mill discards, municipal solid waste that includes discarded wood and paper products, agricultural residues, including corn stalks, straw, and sugarcane bagasse, and biomass from dedicated energy crops that include fast-growing herbaceous grasses and woody trees.

Outlook

Fuel produced using the new processes will have to meet stringent military specifications.

The processes are expected by the military to achieve high-energy efficiency in the conversion of renewable bio-oil feedstock to JP-8 fuel and other valuable coproducts that can include green diesel fuel and other industrial chemicals, Ron says.