Rugged, reliable rotary valves seal the deal
A coal-fired power plant solves a feeding problem by installing ceramic-lined rotary valves in a limestone injection system.
AC Power manages and operates a coal-fired power plant near Colver, Penn., that burns high-sulfur bituminous coal to generate more than 100 megawatts of electricity for use by consumers in the surrounding area. To maintain EPA air-quality standards and regulate furnace emissions, the plant uses a dilute-phase pressure pneumatic conveying system to inject pulverized limestone into the furnace to absorb the sulfur and convert it into an inert material. The limestone injection system includes two rotary valves used as feeders and four rotary valves used as airlocks. Soon after starting operations in 1995, the plant found that the limestone continually abraded and damaged the rotary valves, necessitating their replacement every 3 to 6 months. In 2007, the plant decided to redesign the entire power-generation system to improve performance and lower operating costs. As part of the project it needed to find more robust and reliable rotary valves for the limestone injection system.