Hayden With the closure of the Seneca mine in 2006, the Hayden Station power plant shifted to burning coal from Twentymile to generate electricity.
While unit two burned the coal efficiently, controllers noticed unit one had increased furnace slagging and increased levels of nitrogen oxides, or NOx, an air pollutant.
Slag is a build-up of residue in the furnace that must be removed by various processes, including the use of dynamite and high-pressure water blasting.
"We had increased maintenance costs for contractors removing the slag," Hayden Station Maintenance Manager Sid Arola said. "We also lost generation during those shut-down periods."
Arola spoke at the Northwest Colorado Energy Producers Association meeting Thursday evening at the Holiday Inn of Craig about the project to correct the problems encountered by the change in coal sources.
Investigations revealed the furnace design, along with the fuel system and burner designs, had to be adjusted to accommodate the hotter burning coal from Twentymile.
A combustion improvement project began with monitoring and measuring devices installed throughout the system, and cameras aimed at the inside of the furnace to monitor combustion and slagging.
As a result of adjustments made from the information gathered, slag and NOx levels decreased at the station, but the coal was still not burning efficiently.
General Electric and Utility Innovations showed interest in the work being done at the plant and became involved in improving the computerized system used for controlling plant operations.
Combustion experts were brought in and goals were set to reduce slag and NOx, as well as meet standards for the future without hurting plant efficiency.
"The slagging characteristics improved (with the adjustments)," Arola said. "Most of it sheds now, falling off on its own."
The difficulty keeping equipment running was remedied and maintenance resources were shifted to other areas, improving the efficiency of the generating station.
NOx levels were stabilized at readings seen before the switch to Twentymile coal, and station operators were receptive to the new system, Arola said.
"We're happy to have a reliable source of coal for the future," he said.
Dan Olsen can be reached at 824-7031, ext.207, or firstname.lastname@example.org