Company: Westwood Generating Station, Integrys Energy Services
Location: Tremont, PA
Industry: Electrical Generation
Plant Capacity: 39 Megawatts
Energy Source: Waste Coal
Operational Since: 1986
Preventative maintenance is serious business at the Westwood Generating Station, a 36MW waste coal- red power plant in Eastern Pennsylvania. Because the plant burns highly corrosive legacy coal left over from long-ago coal mining operations, an aggressive maintenance schedule is required to maximize plant output.
“The waste coal we burn is actually more rock than coal,” explains Ron Graver, maintenance planner at the Westwood Generating Station, which is part of Integrys Energy Services. “Because the type of coal we burn puts added stress on the crushers in our fuel system, we take one of our two fuel lines down every three weeks to replace the hammers in the crus
Replacing the hammers can be completed in five hours. But before Westwood Generating installed Plattco valves, the scheduled maintenance project typically had to be extended beyond five hours to perform additional maintenance work on the rotary valves installed on the fuel line when the plant went online in 1986.
According to Graver, it took the maintenance team eight hours every three weeks to complete work on the rotary valves and, as a result, the Westwood Generating plant was required to keep one fuel line down an extra three hours every three weeks.
“But the biggest problem with the rotary valves was the unscheduled down time,” he explains. “We were having problems with the rotary valves because they have many working parts and require very tight tolerances in order for them to work properly,” Graver said. “The rotary valves were constantly getting plugged and this was throwing off the timing for the entire fuel system, causing it to shut down.”
“It was also a safety issue for us,” Graver says. “The valves are located next to the boiler so our maintenance staff was spending a lot of extra time working in an extremely hot environment.”
To address the problem, Westwood Generating decided to try Plattco’s patented Double Flap Airlock® valve. According to Graver, a 16-inch H-1699 valve was installed on one fuel line during an outage. “The H-1699 worked so well that we replaced the remaining rotary valves with the same Plattco H-1699 valves,” Graver says. The Plattco H-1699 valves are hydraulically actuated and run at six cycles per minute. They feed 55 tons of coal per hour into the boiler.
Two years later, Westwood Generating replaced the two rotary valves on the plant ash system with Plattco 10-inch H-1075 valves. “We liked the way the Plattco valves worked in the fuel system, so we decided to put them on the ash system, too,” Graver explains. “It was the same situation in the ash system. The rotary valves required too much maintenance and they weren’t holding up.”
Since installation in the early 1990s, the Plattco valves have required virtually no unscheduled maintenance time. “Over the years, the Plattco valves have really helped us maintain an efficient operation,” Graver says. “They have reduced our downtime greatly. Because we aren’t spending time working on the valves, our maintenance team can work on other projects that help with our overall efficiency.”
Westwood Generating replaced the original 16-inch valves on the fuel line after 15 years and a year later chose to upgrade the new valves with mechanical seals that will further reduce the maintenance requirements. “Because the fuel we burn is very corrosive, the packing on the seals wears out sooner than in a conventional coal red system,” Graver explains. “Our Plattco representative recommended installing the mechanical seals, which eliminate the need to replace the packing seal and bearing.”Download the Case Study