ABERDEEN PROVING GROUND, Md. – For 90 days in 2008, Camp Victory in Baghdad was home to the first TGER unit, a deployable machine tactically designed to convert military field waste into immediate usable energy for forward operating bases. The bio refinery system is a trailer-mounted hybrid technology that can support a 550-person unit that generates about 2,500 pounds of trash per day, and convert roughly 2,000 pounds of that garbage—paper, plastic, packaging and food waste---into electricity via a standard 60-kilowatt diesel generator.
“We picked Iraq as a forward operating base because we wanted to really stress the system. All other energy systems had been tested in laboratories or under ideal conditions and temperature climates. What we really wanted to do was stress it with heat and sand in a low infrastructure environment,” said James Valdes, Ph.D., a senior technologist for Biotechnology at the U.S. Army Edgewood Chemical Biological Center (ECBC) located at the Edgewood Area of Aberdeen Proving Ground, Md.
“You know that old saying, ‘Be careful what you wish for, you might get it’? Well, we got it. We learned an awful lot over there for 90 days about what works, what doesn’t work and what’ll break.”
As ECBC project director for TGER, Valdes is responsible for leading a team that has successfully implemented the necessary adjustments in the new prototype, TGER 2.0. Among them is an automated interface that uses a touch-screen panel that makes it easier for workers to input information and monitor every part of the machine, from oxygen levels to the status of the gasifier. What used to take three technicians to operate the machine now takes two people: one person to feed the garbage and another person to monitor the progress. But Valdes hopes that as the prototypes advance, TGER could eventually be used by one technician or soldier.
One of ECBC’s most valuable lessons learned while the TGER was deployed in Iraq was the realization that the downdraft gasifier had the tendency to get clogged and melt if there was too much plastic in the ground-up garbage pellets, which produced an inert, non-energetic synthetic gas that could not be used as viable fuel. To fix the problem, Valdes and his team developed a horizontal gasifier with an auger device that uses a cylindrical casing to rotate the trash, eliminating the need to turn the cardboard and plastic into fuel pellets and avoiding a problematic mechanical step.
The TGER 2.0 prototype also enables steam to be injected into the gasifier, which allows a larger conversion of output gas to become energetic. According to Valdes, only 24 percent of the output gas of the original prototype was usable energy, a number that has tripled to 75 percent in the new TGER 2.0 prototype. It is also environmentally friendly with a zero carbon footprint.
The advanced prototype was shipped back to the manufacturer for modifications after undergoing a final field trial on Sept. 20 at the Edgewood Area of Aberdeen Proving Ground, where the green technology was tested to see how long it could run at the highest levels of garbage input before breaking down. Within two hours of powering on, TGER 2.0 can make synthetic gas that enables a generator to be run on about ¾ power. Within 12 hours, alcohol is produced and blended to run on full power at a steady state if the machine is continually fed.
One of the innovations Valdes said he would like to capitalize on is recapturing the excess heat that the machine produces with a heat exchanger that can apply the energy to field sanitation and heating water. The new TGER prototype could also be transitioned into the commercial sector, said Valdes.
“Longer term, we will be talking to the PMs (project managers) about transitioning it but we’ll also be talking to some companies that do things like support oil and gas operations in places like Mongolia and parts of the world that are difficult to have camps in,” explained Valdes.
Oil and mining operations, camp sites, hospitals, mess halls and even post-natural disaster events like Hurricane Katrina or Superstorm Sandy are just a few of the places the green technology could prove beneficial.
ECBC and contracting firm SAIC recently entered into a cooperative research and development agreement—an agreement between a government agency and a private company—to speed the commercialization of the technology.