In a bid to reduce the number of dangerous and expensive convoy missions trekking to remote base camps in Iraq and Afghanistan and to dispose of trash at those bases, the Army is backing an industry project aimed at turning solid waste into diesel.
Covanta Energy Corp. is using the $1.5 million boost from the Army Corps of Engineers to develop technology for converting garbage into diesel that would be indistinguishable from crude oil-based diesel fuel and usable for military vehicles and generators.
"If you could make fuel and eliminate a waste stream at the same time, that's pretty attractive," said the Army Corps of Engineers' Stephen Cosper, an environmental engineer who will help oversee the project. If successful, the technology would be especially useful overseas, he added.
The military's overseas fuel needs are massive. In 2008, the Defense Department supplied more than 68 million gallons of fuel every month, on average, to support forces in Iraq and Afghanistan, according to the Government Accountability Office. And the numbers rise when fuel used by diesel-toting convoys is included.
The escalation of U.S. forces in Afghanistan means fuel costs will likely grow in a landlocked, rugged country with spotty road networks watched by robbers and enemy forces. In June 2008 alone, 44 trucks and 220,000 gallons of fuel were lost due to attacks or other events during efforts to deliver fuel to Bagram Airfield in Afghanistan, according to GAO.
Processing trash at remote, temporary base camps in Iraq and Afghanistan is inherently tricky because setting up incinerators designed for long-term use is expensive, but burn pits -- ideally used to dispose of trash on a short-term basis -- have been linked to health problems for those exposed to them (Greenwire, Dec. 22, 2009). In Iraq and Afghanistan, where no base camps are permanent, the reasoning behind when to bring in incinerators can be murky.
Any technology that could help large, semipermanent bases meet some of their own fuel needs on-site could help reduce fuel costs, health risks and inherent dangers to fuel envoys. That is where Covanta Energy's project may help the Army get ahead.
To make diesel from trash, Covanta Renewable Fuels LLC, a subsidiary of Covanta Energy, would take solid waste, blend it with heavy oil and a catalyst, and then heat the stew to 500 degrees in a specialized turbine reactor that could convert the organic trash into liquid diesel fuel, said Steve Goff, vice president of research and development at Covanta.
"It is a catalytic depolymerization process that would depend on a patented catalyst purchased from German company AlphaKat," Goff said. To his knowledge, he added, no one else is working on this type of technology.
The key parts of this project that make converting waste into diesel possible are the catalyst -- which contains silicon, aluminum and sodium -- and the turbine, which spins at 3,000 rpm.
The turbine, unlike most pumps and mixers, is designed to handle all liquids, solids and vapor and do so at a relatively high temperature for rotating machinery, Goff said. Most pumps and mixers handle only liquids or a mix of liquid and solids while compressors handle vapors, but this turbine reactor is a pump, a mixer and a reactor that can work well with all matter, he said.
The turbine "concept and overall design are unique," Cosper noted.
Meeting U.S. EPA requirements
Unlike combustion or gasification technologies that require extremely high temperatures -- and large amounts of power -- to break down waste, this project would operate at relatively moderate temperatures, Cosper said. That means less power resources would need to be put into the project.
Another benefit of the lower temperature, Cosper said, is avoiding undesirable chemical reactions that can occur at higher temperatures and produce toxic chemicals.
The waste-based diesel, unlike biodiesel, would be molecularly identical to crude oil-based diesel. Therefore, Covanta's Goff said, "it will not have some of the handling issues often experienced with biodiesel."
This year, the company plans to test the system at a new facility in West Wareham, Mass., with different types of trash ranging from paper and food waste to plastics and tires, since municipal solid waste is very heterogeneous. Based on the results of the tests, Covanta hopes to be able to gauge the project's economic viability by the end of the year.
Though the company will put "millions" of its own money into the project, the Army funds will be put toward testing the technology to meet U.S. EPA requirements and to apply desulfurization technology to the process to ensure it could meet ultra-low EPA sulfur requirements. Covanta declined to release the specific dollar amount it plans to invest in the project this year, citing competitive reasons.
Most of the company's business lies in energy-from-waste facilities that depend on burning trash to turn water into steam. That steam, in turn, powers turbines that continuously generate electricity. The company operates 44 plants, 41 of which are in the United States.
'Some refinement' needed
For this diesel project, Covanta secured a two-year permit with Massachusetts to operate a plant as a R&D site, but the company would need to apply for a commercial permit to continue to operate the plant if it is successful.
This project is not the first DOD effort to try to convert trash into a power source, but marks the only attempt at making diesel from trash.
In recent years, the Army has explored gasification technology and ways to make ethanol out of specific kinds of trash that could run generators, but currently, this is the only waste-to-energy project funded with Army Corps research dollars. Cosper said the gasification technology is sound, but "some refinement" is required to make it usable in the field.
A 2009 GAO report suggested that systemic obstacles keep DOD from reducing its dependence on petroleum-based oil and effectively addressing fuel demand management issues at forward-deployed locations.
"DOD faces difficulty in achieving these goals because managing fuel demand at forward-deployed locations has not been a departmental priority and its fuel reduction efforts have not been well coordinated or comprehensive," GAO said. There are no waste-to-energy programs in wide use at military installations overseas.