Control of Fan Erosion in Coal-Fired Power Plants:Phase 1

摘要

This EPRI sponsored project examines ways of controlling fly-ash erosion in power plant fans. Computer calculations of particle trajectories and resulting erosion damage show the relative erosion tolerance of various fans. Airfoil centrifugal fans commonly used for induced-draft service have the highest fly-ash erosion tolerance. The erosivity of fly ash from burning bituminous coals, subbituminous coals, and lignites was studied. Fly ash of the highest silica content showed nearly the full range of erosivity indicating that silica content by conventional chemical analysis is not a reliable predictor of expected erosion rates. Work is continuing to speed commercialization of field-replaceable erosion armor for electric utility fans. If the equivalent added protection of 0.2-0.3 in. of steel is required, chrome-plated steel shields can be used and still be within the weight limits that will not overstress most fans. If the erosion rates are so high that the equivalent of 0.3-0.6 in. of steel are required, shields with advanced coatings will be required. The factors in obtaining highly erosion resistant coatings are shown and the erosion resistances of promising advanced coatings compared.