Power Conversion

The Ottumwa Generating Station (OGS) has a dry-bottom, tangentially-fired, pulverized coal boiler with a twin furnace configuration and two fireballs. Two biomass burners, designed by Foster Wheeler Energy Corporation, were installed in opposite corners (one burner per corner) of the East furnace. The burner inserts are low NOx design and are attached to the coal burner tilt mechanism. The biomass burner inserts are installed between the third and fourth level of coal burners. Processed switchgrass particles less than one-quarter inch in length are blown about 1000 feet from the switchgrass processing facility, through the biomass burners, and into the furnace. The particles are burned in suspension along with pulverized low-sulfur coal. The West furnace has no switchgrass injection ports. Particulate emissions are controlled by a hot-side electrostatic precipitator. The burning fuel in the furnace releases heat that is captured by water-filled tubes. This heat converts the water into steam, which is passed through steam turbines causing the turbine blades to rotate. The turbines share a common shaft with an electric generator which produces electricity as the spinning turbine blades force the shaft to rotate.

Switchgrass burner outside OGS boiler (Click to E

Pipes transporting switchgrass to OGS boiler (Cli

To view other steps in the Chariton Valley Biomass Project’s “cofiring cycle,” click on one of the links below:

Establishing and Growing Switchgrass
Transportation and Storage
Green Power Sales