Analysis/control of in-bed tube erosion phenomena in the fluidized bed combustion (FBC) system. Technical progress report No. 14, (January 1, 1996--March 31, 1996)

摘要

The material wastage tests were continued to analyze erosion phenomena under the simulated erosion conditions of in-bed tubes in fluidized bed combustors. AISI 1018 steel and three thermal sprayed coating specimens were tested at an elevated temperature (300(degrees)C) using nozzle type erosion tester. Bed ashes retrieved from the operating biomass-fired boiler were used for erodent particles at a particle loading of 375 g, at particle impact angle of 30(degrees), at particle velocity 60 m/s for exposure periods of 4 hours. The specimens were water-cooled on the backside. The material wastage of specimens was determined by thickness measurements. Test results can be seen that the cooled specimen had greater material wastage than that of the uncooled specimens. In addition, all of thermal-sprayed coating specimens for both cooled and uncooled specimens could reduce the erosion wastage rates as compared with 1018 steel. Among the three thermal-sprayed coatings, a DS-105 specimen of high velocity oxygen fuel spraying exhibited the lowest erosion wastage rate. When tested a higher particle velocity (60 m/s), but at the same elevated temperature (300(degrees)C), the material wastage rate of all three coatings was about 6 to 18 times higher than that of the material wastage at a low particle velocity (2.5 m/s).