cfb boiler main wear areas and wear hazards

　　Wear in the cfb boiler (circulating fluidized bed boiler) is widespread, with the increase in operating time, its harm will gradually become apparent, do not take measures or measures adopted when the boiler bursts frequently is difficult to avoid. Especially when burning poor quality coal or research stone and other high ash fuel, wear and tear problems are more prominent, will cause huge economic losses to the power plant.

　　A plant of three 135MW circulating fluidized bed boilers put into operation in 11 years a total of 125 shutdowns, including 38 planned shutdowns, 87 failures, water-cooled wall leakage shutdown 66 times accounting for 75.8% of the number of failures. Wear has a complex cause not only with the material concentration, flue gas speed, particle characteristics, but also by the boiler structure design, wear-resistant refractory material quality, construction and maintenance process, daily operation and maintenance and other factors.

　　(1) furnace water-cooled wall and wear-resistant refractory layer, including the dense phase area dense phase area and water-cooled wall tube junction of the transition zone, the four corners of the furnace area, the water-cooled wall tube in the middle of the furnace, the roof heating surface, screen heating surface through the wall area and temperature, pressure measurement points and other irregular areas, door hole area, etc.

　　(2) The water-cooled screen heating surface, screen superheater, screen reheater arranged in the furnace chamber, the lower end of the screen reheater.

　　(3)The coal feed port, return port, secondary air port, and bed burner area.

　　(4)Air cap and air distribution plate, slag drop pipe.

　　(5)Furnace exit flue window area, cyclone separator and its import and export flue inner surface.

　　(6)The inner surface of the riser and return device.

　　(7) Convection flue at the end.

　　In addition to the seventh item and the conventional pulverized coal boiler is basically the same, the other need to combine the circulating fluidized bed boiler furnace flow characteristics, through the design optimization, reasonable choice of anti-wear measures to avoid. For example, proper control of coal particle size, lower fluidization air volume to reduce wear, reasonable use of wear-resistant refractory materials, optimization of heating surface selection and layout, etc.