CFB boiler water-cooled wall anti-erossion technology solutions and applications

      Circulating fluidized bed boilers (CFB boilers) are more efficient and cleaner than other kinds of boilers and more in line with the requirements of thermal power plants. However, because of the characteristics of circulating fluidized bed boilers themselves, the problem of wear and tear of circulating fluidized bed boilers has always restricted their better application and development. Especially for thermal power plants such as enterprises, if the wear problem is serious will directly affect the enterprise production safety and economic efficiency.

　　For enterprises that use circulating fluidized bed boilers, it is of great significance to solve the circulating fluidized bed boiler anti-wear. Anti-wear measures in place, not only can improve the smooth operation rate of the boiler, and even improve the efficiency of enterprises.

　　Circulating fluidized bed boiler water-cooled wall wear causes

　　Our common circulating fluidized bed boiler wear is mainly water-cooled wall wear, water-cooled wall wear serious will lead to boiler burst tube shutdown.

　　In general, the most serious wear area is mainly concentrated in the following parts.

　　1, the furnace wall castings on the edge of the water-cooled wall root parts. Because it is located in the edge of the dense phase of the furnace material, not only by the serious high-speed high concentration of bed material strong scouring, wear, and the existence of serious vortex effect, cutting effect. The reason is because the top of the top edge of the furnace wall casting material provides a platform, when the material to a higher speed down to the platform when the bounce, which water-cooled wall tube side bounce part, the water-cooled wall tube on the serious cutting effect.

　　2, the lower water-cooled wall of the furnace chamber and the central water-cooled wall combined with the weld part. This is also located in the chamber material dense phase edge area, due to the installation of the boiler construction of the weld butt is not smooth, and the weld relative to the smooth water-cooled wall will form a step effect, in close to the water-cooled wall downward high-speed flow of material under long-term scouring, the upper edge of the weld will appear serious scouring wear.

　　3, the furnace chamber exit water-cooled wall back wall parts. Here due to particle operation by the flue gas inflection centrifugal inertia caused by wear and scour, in the flue gas outlet on both sides of the water-cooled wall local wear performance is particularly obvious.

　　Anti-wear technology solution

　　After years of research, we found that the grille anti-wear is the most effective solution to the water-cooled wall wear. Grating anti-wear technology is mainly in the water-cooled wall surface along the horizontal and vertical direction, installed alloy grating plate to form a mesh grating, blocking the formation of high-speed wall flow, optimize the surface flow field of the water-cooled wall, eliminate local vortex, reduce the velocity of gas-solid two-phase flow against the wall, reduce the cutting force of material particles on the water-cooled wall, so as to effectively control the water-cooled wall wear problems of an active anti-wear technology.

　　This technology is mature and has been applied to more than 200 circulating fluidized bed boilers. Other boilers including supercritical boilers and even ultra-supercritical boilers also apply this technology, and the feedback so far has been relatively good, not only solving the anti-wear problem but also improving the energy efficiency of the boiler.