Study on the actual operation characteristics of fluidized bed heat exchanger in a supercritical CFB boiler

Abstract

On the basis of measurements on the fluidized bed heat exchanger (FBHE) in a 600MW supercritical CFB boiler fueled by lean coal under different boiler load, the actual operation characteristics of the FBHEs, such as post-combustion characteristics and heat absorption shares in the FBHE were obtained in this paper, as well as ash flow rate through the FBHE. The measured and calculated results indicate that the post-combustion phenomenon exists in the FBHEs of the boiler fueled by lean coal. As steam parameter raises from subcritical to supercritical parameter, heat absorption share of heating surface in the FBHEs are quite different from each other regardless of boiler load. Moreover, as the boiler load decreases, ash flow rate through FBHE arranging reheater is almost the same, while ash flow rate through FBHE arranging superheater changes significantly. These results can provide referential materials for the optimized design and operation of the FBHE in large-scale CFB boilers.