AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Impacts of Co-firing Biomass on Emissions of Particulate Matter to the Atmosphere
IBRAHIM AL NAGHEMAH, Elizabeth Stone, University of Iowa
Abstract Number: 249 Working Group: Combustion
Abstract Biomass co-firing is the process of replacing part of the coal supplied to the boiler with biomass. Co-firing in existing boilers is a practical approach for increasing the use of biomass as fuel because it draws upon widely-available, existing infrastructure and presents immediate opportunity for the production of low cost renewable energy. Biomass is renewable and sustainable source of energy that holds significant potential for electricity generation, and has environmental benefits of reducing the emissions of carbon dioxide and other air pollutants.
In this study, gas and particle emissions from co-firing coal with two types of biomass compared to coal only was evaluated in a circulating fluidized-bed boiler at the University of Iowa Power Plant. Coal only and co-firing either 50% oat hulls or 3.8% wood chips (by weight) were fueled to the boiler at a constant energy input. Co-firing 50% oat hulls with coal significantly reduced the emission of atmospheric pollutants, including particulate matter by 90%, polycyclic aromatic hydrocarbons by 40%, and metals by 51%. In addition, co-firing oat hulls reduced fossil carbon dioxide emission by 40%. In contrast, co-firing small fraction of wood chips shows a negligible impact on theses atmospheric pollutants. Meanwhile, the emissions of two biomass burning markers—levoglucosan and retene—increased with addition of biomass. Fuel-based emission factors for PM, metals, and organic species were determined for each fuel condition. Other changes to the metal composition and distributions across PM, fly ash, and bottom ash are discussed. Co-firing oat hulls as a renewable source of energy offers several benefits to air quality.