Spools of graphite fiber used in making rocket motor casings at Hercules' Clearfield plant are blamed for clogging the Davis waste-to-energy plant's pollution control equipment after the material was burned there.
Graphite string was apparently delivered to the burn plant along with other Hercules garbage and caused the plant to shut down for four days during the past month, said Jim Young, manager of the Davis Solid Waste Management and Recovery District.The string, when subjected to high temperatures, does not disintegrate and turns into lightweight fibers that coated the plant's electrostatic precipitators. The electrically charged precipitator probes attract particulates in the smoke coming from the plant's two furnaces and keeps them from going into the atmosphere.
"Graphite is electrically conductive so the it wreaks havoc in electrostatic precipitators. Those probes are electrically charged to gather particulate matter blowing around. When the graphite touched them it short-circuited the system," Young said.
Plant personnel have already cleaned the precipitators and hope the problem doesn't resurface. The shutdown has cost the waste district about $6,000 in revenue because it was unable to provide Hill Air Force Base about 22 hours worth of steam. The district has a contract to sell steam to the base to help offset the burn plant's operating costs.
Young said that graphite should have been delivered to the district's landfill in Layton instead of the to the burn plant. The fault could lie with either Hercules or the garbage hauler, Waste Management Systems Inc.
Jack DeMann, Hercules spokesman, said the company has been separating out graphite and other non-flammable materials into different trash bins. He suggested that the graphite made it to the landfill, but was transported to the burn plant by someone else.
"Graphite should not be incinerated. It should go to the landfill. We have a contract to take it to the landfill. Apparently someone is then going into the landfill and scooping material up and hauling material away to be incinerated." DeMann said.
He was unable to explain why new spools of graphite were being discarded by the firm.
DeMann said Monday that company officials were working to resolve the problem. A meeting has been scheduled between Hercules, Hill Air Force Base and district officials. Burn plant officials have said Hercules may be held liable. "I don't how it will be resolved, but our people are attempting to resolve it," DeMann said.
The $54 million plant was recently accepted by the waste district board from the contractor, a arm of Katy-Seghers Inc. An uneven burning problem has caused previous shutdowns at the plant.