About – Accomplishments

Since its inception, the Chariton Valley Biomass Project (CVBP) has completed a wide range of valuable research studies and achieved a number of significant technical successes. The following list provides a brief summery of some of these activities to date and provides links to more detailed information:

First Cofire Test

After several years of planning, the Chariton Valley Biomass Project successfully completed two months of switchgrass co-fire testing at the Ottumwa Generating Station (OGS) in Chillicothe, Iowa. From November 30, 2000, through January 25, 2001, the switchgrass team co-fired 1,269 tons of switchgrass at rates up to 16.8 tons/hour, representing about 3% heat input to the 725 MW power plant. Stack testing was completed when co-firing switchgrass and when burning only coal. Fuel and ash samples were collected for analysis and boiler performance and emissions data was collected. Numerous improvements were made to the feed-handling equipment during testing and the testing was completed with no environmental incidents, no injuries to personnel, and no loss in electricity output from OGS.

The goals of this test—the first of three rounds of co-fire tests—were: to identify the effects of co-firing on boiler performance, to measure any changes in emissions during co-firing, and to gather information to improve the design of the switchgrass handling equipment. All three of these goals were met. The design target for the switchgrass handling system was 12.5 ton/day, which was exceeded after a redesign of the secondary grinder in our system. During several days in January, the project team burned more than 100 tons of switchgrass. For a complete report on the First Cofire Test results, click here.

Interim Cofire Test Burn

The interim cofire test, the second round of co-fire testing, was conducted during the first two weeks of December 2003. Pre-testing of biomass processing equipment and sampling techniques occurred between November 21 and 26, 2003. This test was performed using an improved switchgrass handling system and was done to verify air emissions, obtain large samples of co-fired fly ash for testing, and further analyze the technical feasibility of switchgrass co-firing at OGS. To meet the objectives of the Interim Test Burn, it was only necessary to burn an estimated total of 781 tons (1,673 bales) of switchgrass during the pre-test and testing periods combined. The average switchgrass feed rate during the December cofire testing was about 8.9 tons per hour, representing about 1.9 percent of the boiler’s heat input.

The interim test burn was successful in showing measurable decreases in sulfur dioxide emissions and no significant change to the carbon monoxide, particulate, and nitrogen oxide emissions while co-firing. Subsequent concrete testing using the co-fired fly ash by Iowa State University has shown the concrete with the co-fired fly ash can meet the ASTM requirements as concrete with the coal fly ash.