Research On Wear Mechanism And Resistant Measures Of CFB Boiler

At present, the wear of water wall tube is the major bottleneck which restrict the development of CFB boilers. It has become the focus of CFB research to study the wear mechanism and look for effective anti-wear measures. In order to analyze the wear mechanism of CFB boiler tube, this paper first simulate the internal flow field of the furnace on the basis of actual data of Baima Power Plant. Simulation results revealed a typical core-annulus flow pattern along the radical direction. The particles flow upward with high velocity at the central region and downward with low velocity near the wall, forming the inner circulation of gas-solid flow. The axial distribution profile of particle concentration show high value at the bottom of the furnace while low in the upper zone. In addition, much higher particle concentration and velocity were observed at the corner of the funace and the bottom part. That is why the tubes in such areas are subject to wear. The computational results agreed with the experimental data reported in the literature. In this study, the anti-abrasive coatings were prepared by using a self-made TIG cladding system. Rapid water cooling condition was applied in order to decrease the deformation during welding process, thus enhanced the performance of the coatings. The micro-hardness and heat affected depth of the coatings were compared under different operation current with the aim of obtaining optimal operation parameters. Further analysis showed that the microstrutures of the coatings are uniform. Metallurgical bonding was formed between the coating and the substrate. Moreover, the micro-hardness of the coating is up to 1200HV, which is six times higher than that of 20G. Therefore, the coating has perfect wear resistance under the environment of high temperature.