Ohio-based R&A Energy Solutions said it has developed a unique solution to transforming a multitude of waste materials into renewable fuels.

Chief Executive Officer Joel Keller said the company integrated a commercial-sized, proprietary pyrolysis system with a modified internal combustion engine and generator set system. "We have successfully tested carpet scraps, sewage sludge cake, manure, wood waste, auto shredder residue, food waste and sorted municipal solid waste as feedstocks," he said.

One of the pyrolysis systems, which are available in different sizes, is capable of converting nearly 50 tons of waste per day into 600 to 1,280 British thermal units per standard cubic foot, according to Keller. "The syngas produced will generate between 1.5 and two megawatts," he said. "In addition, significant amounts of pyro-oils and pyro-char are produced. [Furthermore,] hot water, space heating or chilling, and steam can be made from the waste heat."

Before being processed, the feedstocks may need to be partially dried or mixed with drier materials such as crop waste, yard waste or forest residues. The feedstock is fed into the pyrolysis unit, where it's heated in a zero- or near-zero-oxygen environment.

The organic components rapidly vaporize to form a dry synthesis gas-consisting mainly of methane, ethane, propane and butane-which is then used as fuel to run an internal combustion engine and generator set, or in a boiler to make steam. "Waste heat is recycled to augment the energy from the syngas in the production of power or to dry additional fuel," Keller said. "The process is 85 percent to 90 percent efficient with ultra-low emissions."

Keller said depending on the feedstock, a variety of organic liquids may be produced through pyrolysis. "Many of these liquids may be used directly as transportation fuels," he said. The resulting sterile ash may be used as filler for concrete, mixed with liquid asphalt for road repair, used for certain industrial or manufacturing operations, or applied to farm fields, depending on exact content, local needs and regulations.

The systems are modular and scalable, he said. They may be applicable to the dairy cattle feedlot, waste hauling, municipal utility and auto shredding industries. Systems are available in 500-, 1,000-, 2,000- and 4,000-pound-per-hour sizes, producing between 20 kilowatts and six megawatts.

Keller said R&A Energy Solutions currently has three projects in the financing stage, and another five or six moving to the financing state within six months.