BROOKSVILLE — Cemex is one step closer to making alternative fuels such as peanut hulls and wood chips a permanent part of its energy supply.
The Florida Department of Environmental Protection is poised to grant the company a permit to burn the fuels in the No. 2 kiln at its Brooksville South Plant, off Cobb Road.
Cemex has been testing some of the fuels in the kiln on a temporary permit since last year. The company has had success burning peanut shells, pine wood chips, chipped pallet wood and tire fluff, the polyester cord harvested from old tires when the steel belts and rubber are removed, said company spokeswoman Sara Engdahl.
"Cemex is pleased with the FDEP's support of our successful alternative fuels program at Brooksville," Engdahl said in an email. "Our innovative alternative fuels program not only directly supports the state of Florida's initiative to increase recycling and reduce the use of landfills, but also decreases carbon emissions and conserves natural resources."
Cutting coal usage will help the company shrink the kiln's carbon footprint and reduce mercury emissions, but the main driver is cutting fuel costs, company officials have said.
One day earlier this year, the company saw its use of alternative fuels crank up to 47 percent of total use, Engdahl said. The company expects to eventually reduce its coal use by about 60 percent by burning new alternative fuels. That would increase to 70 percent when including whole tires, which the company has burned for decades.
According to the federal Environmental Protection Agency, tires deliver 25 percent more energy than coal, with an emission profile of greenhouse gases and other pollutants that is about the same, making them acceptable as an industrial fuel. Environmentalists criticize this practice, however.
Peanut hulls are examples of biogenic fuels. Others are corn husks, citrus peels, animal bedding and cotton. Biomass fuels include wood chips, green wood, forest thinnings, sawdust, trees trimmings, clean woody land-clearing debris and clean construction debris. All are included in the permit.
The permit would also allow for a wide range of other fuels deemed nonhazardous, including plastics, carpet, roofing materials and wood treated with creosote. Included, too, are so-called engineered fuels such as cleanup debris from natural disasters, processed municipal solid waste, dried and sanitized sewage bio-solids, noninfectious hospital materials, expired pharmaceuticals and confiscated narcotics.
It's impossible to predict how much of, or how often, those kinds of materials will be burned because their use depends on availability, Engdahl said.
As for concerns about emissions from burning plastic and drugs, she said: "The nature of the cement manufacturing process completely consumes chemical compounds or residues that could be found in the material."
The permit does not change the plant's existing emissions limits. Among them is 200 pounds of mercury per year.
In 2008, EPA reports indicated that the Brooksville Cemex operation emitted 134 pounds of mercury, placing it among the top 20 cement kiln mercury polluters in the nation. That was the year Kiln No. 2 was put into operation. Burning coal accounts for only a portion of a cement kiln's total mercury emissions, though. The chemical reaction caused by heating the raw materials also produces mercury.
Cemex has four kilns in Hernando County: two at the Brooksville South plant and two at the Brooksville North plant off U.S. 98. Two of the four have been shut down, and another is idle.
The newest of the four, Kiln No. 2 was operating at about two-thirds capacity last fall because of a sharp drop-off in market demand. Now, Engdahl said, the kiln is operating at about 90 percent of its daily capacity of 3,500 tons of clinker, the pebble-sized pieces that are ground into Portland cement.
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Meanwhile, the owners of the Central Power & Lime power plant just steps away from Cemex's kiln are making progress on their own efforts to ditch coal.
Florida Power Development LLC, an affiliate of Arroyo Energy and J.P. Morgan Chase, plans to convert the 150-megawatt plant so that it is fueled entirely by woody biomass. The plant would produce between 70 and 80 megawatts.
DEP issued the permit earlier this year, and now the owners are accepting bids from contractors, said Rick Jensen, owner of FB Energy, a St. Petersburg-based renewable energy development company and a minor partner in the project.
Built in 1984, years before Cemex bought the cement and quarry operations, the plant does not provide power directly to the Cemex operation. Rather, it sells electricity for use by utility companies. When operational, the power plant, not Cemex's kiln, uses most of the coal trucked onto the property.
The plant has been idle for the last couple of months, Jensen said. The goal is to have the project completed and the plant online by early next year.
A spokeswoman for J.P. Morgan Chase did not return messages seeking comment.
Tony Marrero can be reached at firstname.lastname@example.org or (352) 848-1431.