The Structure and Performance of a New Type of Industrial Circulating Fluidized Bed Boiler with a Circulating Ash Heat Exchanger

Contributed by excellent features of fuel flexibility, high combustion efficiency and controllable emission, circulating fluidized bed (CFB) combustion technology has been found wide application in burning coal, it is the only clean coal combustion technology of being commercialized in the world currently ([1]). However, with regard to the industrial area, the existing CFB boiler technologies are fail to meet the challenges of small scale industrial boiler, such as small capacity, low parameters of steam, artificial ignition, high combustion and desulfurization efficiency. Thereby, in this work, a new type of industrial CFB (ICFB) with a circulating ash heat exchanger has been proposed and developed. In this kind of ICFB, the immersed tube heat absorbing surfaces are located in the circulating ash heat exchanger (CAHE), instead of the furnace emulsion zone, so as to reduce the erosion of immersed tubes and extend the time of burning and desulfurization. The absence of immersed tubes in the bottom of the furnace facilitates the artificial ignition, and the fluidization air can be operated at a relative high velocity as well, which will contribute to keeping the upper region of the furnace in a fast fluidization state. This article summarizes some experiments and industrial tests conducted on a heat test rig and an ICFB respectively, the results demonstrate that this new type of ICFB can satisfy the industrial demands mentioned above.