PHG Energy of Nashville is designing and building the new waste-to-energy facility for the city of Lebanon, Tennessee. The installation will mark the 14th commercial downdraft gasification unit going online for that company, and will include use of a downdraft gasification unit with a full capacity throughput of 64 tons per day.
Tens of thousands of tons of sewer sludge, used tires and industrial wood waste will be processed there each year, producing electricity to help power the treatment plant and diverting those materials from area landfills.
Gasification is a clean thermo-chemical process that breaks down biomass-based material in a high-heat and low-oxygen environment. There is no incineration or burning involved in the process. The only residue after production of synthetic fuel gas is a carbon biochar that has multiple agricultural, industrial and direct fuel uses.
The syngas is used to power an Organic Rankine Cycle generator that will provide for the gasification operation’s internal needs, and deliver up to 200 Kw directly to the operation of the waste plant.
Tom Doherty, Environmental Specialist with the Tennessee, Department of Environment and Conservation, said the new facility is an important step forward in efforts Tennessee and his department are fostering across the state.
“When we look at the thousands of tons of wood waste and sludge this plant will cleanly process, that is a tremendous step forward,” Doherty said. “One of the most exciting parts of deploying this technology in Lebanon is that hundreds or tons of scrap tires will be put to beneficial use while saving Wilson County a considerable portion of their previous disposal expense.”
TDEC has awarded the project funding of $250,000 through the Clean Tennessee Energy Grant program, and facilitated a subsidy of 70 percent of the $3.5 million financing’s interest cost through the Federal Qualified Energy Conservation Bonds program.