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Evaluation of Biomass Gasification to Produce Reburning Fuel for Coal-Fired Boilers
LEE, C., N. D. HUTSON, BOB E. HALL, AND R. E. Maurer. Evaluation of Biomass Gasification to Produce Reburning Fuel for Coal-Fired Boilers. Presented at 33rd International Technical Conference on lCoal Utilization and Fuel Systems, Clearwater, FL, June 01 - 06, 2008.
Gasification and reburning testing with biomass and other wastes is of interest to both the U.S. EPA and the Italian Ministry of the Environment & Territory. Gasification systems that use biofuels or wastes as feedstock can provide a clean, efficient source of synthesis gas and pyrolysis liquids (tars/oils), while reducing the volume of wastes and minimizing adverse boiler emissions. EPA has performed reburning tests in the past and both parties are interested in biomass and waste fuels due to the low cost of the fuel source, the impact on our landfills, and the reduction of CO2 emissions through the cost-effective biofuels. EPA will perform tests on a 4-million Btu/hr pilot-scale combustor that is capable of firing a variety of fuels to evaluate the gasification of biomass and bio wastes for reburning to control NOx emissions and displace fossil fuels. Ansaldo Ricerche of Italy designed a pilot scale gasification unit and syngas line that will connect to EPA's combustor. The design utilizes uses a fixed-bed gasifier. The project will examine the feasibility of using syngas and pyrolysis liquids (tar fog) from gasification of biomass and bio-waste as a reburning fuel to reduce emissions from coal-fired industrial and utility boilers. A key aspect of this project will be the continuous monitoring of the product gas and the pyrolysis liquids being fed to the reburning zone of the boiler in order to quantify the impact and significance of the tar fog as a contributor to NOx reduction. A NOx reduction of 50 to 65% or greater is anticipated in existing boilers.