Cofiring Woody Biomass at Allegheny Energy: Results from Willow Island and Albright Generating Stations

摘要

Allegheny Energy Supply Co., LLC, with support from the US Department of Energy (USDOE) National Energy Technology Laboratory (NETL) and the Office of Energy Efficiency and Renewable Energy (EERE), has constructed and operated two cofiring demonstrations at the Willow Island Generating Station and at the Albright Generating Station. This program has demonstrated cofiring at both a 188 MW cyclone boiler and at a 140 MW tangentially fired (T-fired) pulverized coal boiler. Between the two units, more than 6,000 tons of sawdust have been fired with Eastern bituminous coals. In the case of Willow Island, cofiring was performed with tire-derived fuel (TDF) as well. These 6,000+ tons of sawdust represent generation of nearly six million kWh of renewable energy; and they represent a total reduction in greenhouse gas emissions equivalent to some 18,000 tons of fossil CO_2. The Willow Island program was designed to develop a designer opportunity fuel combining sawdust with TDF to achieve a highly volatile, low nitrogen and low sulfur opportunity fuel for cyclone firing. The Albright program was designed to test the cofiring of sawdust in a pulverized coal boiler equipped with close coupled overfire air (CCOFA) and separated overfire air (SOFA) to evaluate the ability of biomass to reduce NO_x emissions in a boiler with low-NO_x firing capability. Both test programs have been successful. This paper reviews the operational and environmental results of both programs, providing an evaluation of biomass cofiring as a fuels-based tool for addressing environmental issues including NO_x, SO_2, and mercury emissions. It addresses future test programs that are planned for these units as well.