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Show ~AFRC Initial Operating Results of Coal-Fired Steam Generator Converted to 100% Refuse-Derived Fuel Presented at the American Flame Research Committee 1987 International ymposium of Hazardous, Municipal, and Other Wastes Palm Springs, California November 2-4, 1987 ABSTRACT J. A. Barsin Manager, Industrial Prolects Babcock & Wilcox Barberton, Ohio P. K. Graika Senior Production Engineer Northern States Power Company Minneapolis, Minnesota The convers~on of Northern States Power Company's (NSP) Red Wing Qnd Wilmarth steam generators to fire refu~e-derived fuel (RDF) is a unique project -- a retrofit repowering from coal to RDF is a first-of-a-kind. The use of the ex~st~ng plar.t with the necessary modifi,ations to the boilers has allowed NSP to effectively incinerate the fuel as required by Wash~ngton and Ramsey Counties. This paper covers the six-month start-up of Red Wing No.1, commencing in January 1987, and the o perating results since the plant went commercial ~n June 1987. A preceding ~aper g~ven at the 1986 Joint Power Generation Conference discussed the backgrcund, evaluations, and final designs of the conversion proJect (1). This presentation summarizes that background and presents operating issues, actual performance, and evaluations of how early design decisions turned out in actual operation. BACKGROUND ~wo coal - f~red power plants in Red Wing and Mankato, M~nnesota, have been converted to burn 00% RDF. Four boilers, two each at Red Wing and W~lmdrth steam plants, were selected for the conversion by the ut~lity, Northern States Power Company. NSP's evaluation of future power- J. A. Gonyeau Red Wing Plant Superintendent Northern States Power Company Red Wing, Minnesota T. M. Bloomer. PE Prolect Engineer CRS Sirrine, Inc. (North Carolina Division) Research Triangle Park, North Carolina generation needs indicated an opportunity to supplement conventional fuels, extend the life of older plants to delay adding new stations, and alleviate a waste disposal problem. The utility had capacity within its system (relative t o more modern NSP plants) that was used for peaking service only. The two plants were 35 years old and had two steam generators each rated at 125,000 Ib/hr, while firing coal on a stoker. They operated at pressures and tempe ratures similar to new units being sold to burn waste fuels. Burn trials conducted at both plants demonstrated the ability to burn RDF. Solid-waste disposal is a particular problem in the Minnesota counties of Ramsey and Washington, which includes the city of St. Paul. A state mandate issued in 1980 declared that all waste must be delivered to a resource recovery facility by 1990. Existing landfills were full or nearly full and carving out new ones was costly because of environmental restrictions and controls. Also, hauling distances increased as landfills were being located well away from metropolitan areas. It was clear to NSP that a energy and material recovery program involvir.g municipal wastes was needed. Thus, they began to consider proposals for processing municipal solid wastes (MSW). The RDF Solution In mass burning, refuse in its as-received, |