Military forward operating bases generate large amounts of solid waste, including everything from kitchen scraps to packaging. A new research and development project is helping Defense Logistics Agency Energy turn that waste into fuel. The mobile waste-to-liquid-fuel project, developed in conjunction with the Community Power Corporation, has produced a prototype system that can extract 40 gallons of fuel from a ton of dry waste
“We wanted to develop a mobile system that could be applied to FOBs overseas to take advantage of any type of carbonaceous waste, such as paper, plastic, cardboard and wood, they regularly generate,” said Lindsey Hicks, chemist and strategic energy program manager in DLA Energy. “It’s not only a waste management system for them, but it also produces enough usable fuel to supplement DLA Energy’s deliveries to those FOBs, easing some of the burden of getting fuel to those locations.”
The project is one of several the agency procured using funds from the 2009 American Recovery and Reinvestment Act, Hicks said.
“Originally the project was a cooperative effort … for the Army, but the project fell through,” he said. “Once we had ARRA funds, we applied them to the new effort and put out a competitive statement of work for a bid. CPC won, and we had a contract signed in September 2010. Although the CPC waste-to-fuel study was our only project developed in-house that was covered by ARRA funding, there were four procurement contracts for fuels derived from algae oil that were also funded through ARRA.”
Although the waste-to-liquid-fuel process is unique, the quest to explore alternative waste management options is not a new one, said Jeanne Binder, strategic energy analyst and former research and development program manager in DLA Energy.
“CPC had done previous work with the Army converting waste to synthetic gas and to energy, like electricity, but this DLA Energy project was specifically to take that technology and modify it so that we could produce a fuel we can use in the battlefield environment,” she said. “To be able to go from doing a simple waste-to-energy [conversion] to making a fuel wasn’t simple, but it was feasible. To do that, they built additional modules for the fuel conversion.”
In developing the prototype, which can produce about 25 gallons of fuel per day, DLA Energy and CPC had to consider several factors, such as size and mobility.
“The method CPC uses is the most viable way to do it,” Hicks said. “Although the process is open technology, the configuration CPC uses is proprietary, so we had to look at the overall cost of development and the type of materials we could work with, like if it could handle many types of material or only one or two. Plus the size of the module being developed: Could it be handled by base personnel or did it require technical expertise to handle it?”
Housed at CPC’s Littleton, Colo., facility, the prototype consists of four modular containers. The first, the waste processing module, is known as the drier. It ensures the waste, such as wood chips, walnut shells or cardboard boxes, is dried properly, then sends it to a compressor where it’s compressed into small pellets called briquettes.
“Even though the materials [in the demo] wouldn’t be particularly what you would find overseas, the main issue is the ability to pelletize different types of waste materials into a form that can be handled by the system,” Hicks said. “You don’t want to use too much food waste, because when you have too much water involved, the oxygen in the water interferes too much during the conversion. But this basically simulates what you would be doing overseas once you would apply this system.”
After they are pelletized, the briquettes are passed to the second module, the biomass gas production module. There, at operating temperatures of 700 to 900 degrees Celsius, the briquettes are converted to a synthetic gas made up of carbon monoxide and hydrogen. In a regular waste-to-energy project, that gas would go directly into generators to produce energy. Instead, the gas goes onto the next module, called “LiquiMax.” This module uses the “Fischer–Tropsch process,” a set of chemical reactions, to turn the gas into a liquid fuel.
“Basically we’re heating the material without combustion in the presence of controlled oxygen under pressure,” said Jose Maniwang, engineer and strategic energy program manager in DLA Energy. “The carbon and the hydrogen separate out, and you’re producing two gasses: carbon monoxide, which is carbon and oxygen, and straight hydrogen gas. This mixture of gas can be used as a fuel or can be processed under the Fischer–Tropsch system to produce a liquid hydrocarbon fuel, which is what we’re doing. Depending on how you mix those [gases] together, you can come up with the proper fuels you need, whether it be gasoline, diesel or jet fuel.”
The last step, the LiquiMax support module, contains a compressor and liquid fuel distillation subsystem that cools the liquid fuel, making it usable.
“We’re not producing a whole lot of fuel, not the large amounts to fly planes or to operate convoys of vehicles, because this is a mobile system,” Hicks said. “You want it at a scale where you can get it in and out in a fairly rapid pace, so it’s producing relatively small volumes. This is basically a smaller scale of other alternative fuel initiatives that use municipal solid waste generated by local and state governments. In fact, the fuel produced will mostly be used just for generator operations, but it beats trucking in the additional fuel.”
During CPC’s six-month demonstra-tion phase, the module was tested for its ability to produce small amounts of fuel from three types of waste, with hopes that the fuels produced could meet the commercial specifications of the fuels they are meant to replace, Hicks said.
“The results were positive; everything passed,” he said. “They were able to produce samples of commercial [aviation] fuel and commercial diesel fuel. Those samples were tested by our contractor lab in San Antonio, and we’ve sent the [results] to CPC for their review and input. Now we’re just waiting on CPC to develop their final report.”
As for now, any plans for the program to move from an R&D project into a program of record, with further production and deployment, depends on the military services, which will be able to access the report through the Defense Technical Information Center, Binder said.
“DLA doesn’t have the ability to create a program of record for this equipment; the services have that ability,” she said. “With a lot of our research that involves systems, we share the data from our research with the military services and then they decide whether they want to pick it up and move forward with it or not. We’re a facilitator for them in a way.”
With the major developments of biodiesel and ethanol in recent years, DLA Energy is no stranger to the procurement of alternative fuels, Binder said.
“DLA Energy has been procuring alternative fuels for quite a while for the military services to meet their Energy Policy Act of 2005 goals, which started the big push to buy the alternative fuels we have,” she said. “But [earlier fuels] require a different type of infrastructure to handle them, and only certain engines can burn them. These next generation fuels, the advanced ‘drop-in’ replacement biofuels and alternative fuels, can be burned without any modifications. They’re used in blends with petroleum, and the end user doesn’t notice a difference. Eventually, once these fuels are certified and able to be produced in sufficient quantities, they have the potential to become competitive with petroleum.”
With promising results and a need to explore alternative “greener” fuels, DLA Energy plans to support several initiatives aimed at finding the best fit for the military services, Binder said.
“A lot of different services are looking into alternative energy using waste, algae, alcohol to jet, etc.,” she said. “There are a lot of different ways, especially depending on the type and nature of the feedstock, to do that. Although biomass fuels are not new, they’ve been evolving. I think you’ll see these advanced alternative fuels become increasingly available over the next five, 10, 20 years. Most, but not all, emit less greenhouse gasses, so they’re environmentally friendlier. They’ll never 100 percent replace petroleum, but some of their sources, like crops, are more sustainable, renewable and well managed. For me, working with R&D projects, it’s an eye opener. It’s amazing technology.”
To further support the advancement of the Army’s renewable energy goals, DLA Energy issued a competitive request for proposal for biomass power to be delivered to Fort Drum, N.Y., home of the 10th Mountain Division. Under a long-term power purchase agreement, the RFP included a requirement for the design, installation, test, commission, operation and maintenance of an on-site or contiguous biomass generation facility that can deliver at least 100,000 megawatt hours of electric energy annually. As an alternative to the on-site biomass power requirement, the RFP also included a request for the 10-year supply and transmission of electricity generated from other renewable energy facilities. DLA Energy is currently reviewing and evaluating proposals.
— Amanda Neumann