Papers by Keyword: Circulating Fluidized Bed (CFB) Boiler

Abstract: The compressed gas for ambient temperature in vortex tube can be separated into two streams of different temperature gas, which phenomenon is unapparent for non-compressed gas. However, for non-compressed high-temperature gas, it can produce temperature difference of more than 20°C in vortex tube, which has been ignored by researchers. In this paper, basic principle of temperature difference effect in vortex tube is described firstly, and cooling effect produced by different inlet temperature in the condition of low pressure ratio is analyzed, which results that obvious cooling effect can still be produced for high temperature and low pressure ratio. Combined with factual operation conditions of cyclone separator for circulating fluidized bed (CFB) boiler, a design and renovation method of cyclone separator is proposed firstly according to temperature difference effect principle of high-temperature gas in vortex tube. According to the analysis, the separation efficiency and boiler performance will be enhanced by using temperature difference effect in vortex tube to design and reconstruct the existing cyclone separator.

Abstract: The coatings for elevated temperature erosion resistance in circulating fluidized bed (CFB) boilers were fabricated by high velocity arc spraying process and CrB powder wire. The microstructure and phase component of the coating were examined by optical microscopy(OM) and Transmission electron microscopy (TEM). The properties including microhardness, adhesion strength and in-situ erosion rate of the coating were measured. The failure mechanism was also discussed based on the experimental data. The OM results showed that the coating consisted of individual flat lamella, thin oxide layer, porosity and very small amount of particle which characterized as different shape and color respectively. TEM results indicated that the phases within the lamella were mainly composed of α phase, amorphous phase and other nanosized particle phase of Fe23(C,B)6, Cr23C6 etc.. The amount of amorphous phase near the substrate was more than that in the other area indicating that the appearance of amorphous phase was related to the high cooling rate of the coating. The microhardness was about 860~1100HV0.2. The coating exhibited high erosion-corrosion resistance, which was about six times as 20G steel. The advantage of the coating with excellent performance, simple process and low cost made it possible to find potential application in power plants.