Recently, Prestage AgEnergy of NC LLC, a division of Prestage Farms Inc., teamed up with Hurst Boiler & Welding Company Inc. to build a plant for transforming turkey-house waste into electricity. Ground for the 165,000-sq-ft, $25-million facility in Sampson County, east of Clinton, N.C., was broken during the summer of 2015; however, Michael Pope, vice president of Prestage AgEnergy, said the project had been in the works since 2011.
“It’s taken so long because we spent a lot of time in development and researching different technologies to make sure that the application and technology we were using would be successful,” Pope said.
According to Pope, fewer than six companies in the state have permits to use poultry litter, a blend of manure and bedding material, for fuel. He said the approved companies must adhere to certain guidelines.
“All the information we have is that no one else is even exceeding 40 percent poultry litter in their fuel source,” Pope said. “Many manufacturers have to supplement the majority of their fuel blend with wood chips, as the poultry litter they’re using is a certain type of poultry litter that comes from young polts and chicks.”
Pope said the plant in Sampson County will be the first in the country to use 100 percent poultry litter as a fuel source.
Poultry litter poses a challenge for many boiler systems because of its high ash content and ash characteristics.
“We are well aware of the many challenges and problems of litter as a fuel, which is why we spent an inordinate amount of time and resources making sure that we had measures in place to ensure success in the U.S. market,” Charlie Coffee, solid-fuel-boiler sales for Hurst Boiler, said.
Litter is significantly different than other biomass fuels. In the past, there were problems using poultry litter in boilers designed for biomass. To mitigate the challenges associated with using poultry litter, Hurst Boiler considered each aspect of the process, from the way litter arrives at a facility to the way litter is handled to the way emissions are treated. The result is the new 1600 HP poultry-litter-fueled biomass boiler.
Currently, turkey waste from Prestage Farms poultry houses is collected and transported to fields, where it is applied as fertilizer.
“We’ll go through about 50,000 to 55,000 tons of poultry litter per year,” Pope said.
When the new facility becomes operational, the wood-based turkey litter will go to the plant, where it will be used as fuel.
The cogeneration facility is scheduled to be commissioned mid-year.
In case you are wondering, Pope said there will not be a smell from the litter being burned. A negative draft in the boiler will pull odors from the building’s litter-storage area.
“We use it (the litter) to heat water and create high-pressure steam in our boiler,” Pope said. “And from there, we send it through some turbines to generate electricity.”
The system is capable of generating over 95,000 MWh a year. In addition to renewable power that will be sold back to the grid, Pope said, the boiler will generate steam that will be used to operate an existing mill that produces turkey feed and hog feed.
“Steam is used in the process to pelletize the feed, and they use natural gas to produce that steam,” Pope said. “Well, it’s a nice fit we can come in using renewable energy, renewable fuel source, generate steam, and supply the steam to that feed mill ... as well as displace natural gas at that site.”
The project, Pope said, helps to meet a 2007 state energy-policy mandate that utilities provide poultry-waste-generated power. No wastewater discharge is expected. Additionally, the plant is expected to create 16 jobs and up to a dozen indirect jobs related to the cleanout of litter from poultry houses and the transportation of waste to the facility.
The boiler will operate at 1,500°F, which, Pope said, is high enough to provide steam for the mill and low enough to generate an ash byproduct that can be repurposed as fertilizer.
The boiler system allows Prestage to take advantage of the many unique benefits poultry litter offers. For example, ash from the litter is particularly rich in potassium and phosphorous.
“By concentrating these nutrients in ash, these systems can transform the potential risk of phosphorous regulation into an economic asset for companies,” Coffee said. “At the end of the day, we take what’s left of that ash byproduct (which) can go into the fertilizer market, it can go to local blenders, and it can go straight into the field. It also allows us the ability to take a high-phosphate-rich product and export it out of this region. That’s an additional asset for us and the state.”