During the use of circulating fluidized bed boiler linings, they are greatly affected by thermal shock, erosion, wear, and oxidation spalling. Thinning of the refractory material layer in the furnace and redness of the furnace shell often occur, which leads to changes in the furnace type and affects the normal production of circulating fluidized bed boilers. Regular inspection maintenance and repair of worn parts of the furnace lining are of important means to extend the service life of the furnace lining. As an industrial kiln system service solution provider, Rongsheng Refractory Materials Manufacturer can provide a full range of refractory material services, including refractory material sales, maintenance, and the design of refractory lining materials.
Damage and Maintenance of Circulating Fluidized Bed Refractory Materials
Repairing the lining of circulating fluidized bed boilers is a powerful measure to extend the life of the lining, balance the damage to the lining, and reduce production costs. Circulating fluidized bed boilers use refractory materials as working linings, and their service life extension and maintenance vary according to their working conditions.
(1) Medium temperature. The working temperature of each part of the circulating fluidized bed boiler lining is 800~1000℃. From the perspective of refractory materials, this belongs to the medium-temperature range. When selecting refractory materials, first consider the medium-temperature physical and chemical properties of the material. For fired products, the sintering temperature is generally higher than this temperature range, so its physical and chemical properties at high temperatures can be directly used as a basis for selecting refractory materials. For unshaped refractory materials and unfired products, the physical and chemical properties at mid-temperature must be examined. Organically bonded materials or hydration-bonded hydraulic materials tend to have the worst strength at medium temperatures. These materials produce ceramic bonds at high temperatures and their strength is greatly improved, so their physical and chemical indicators at high temperatures cannot be used as a basis for selecting refractory materials.
(2) Thermal shock. Under normal operating conditions, circulating fluidized bed boilers start and stop 2 to 10 times a year. In the early stages of operation, due to improper operation, the refractory lining was subjected to a strong thermal shock every year when it was started and stopped. If the refractory material has poor thermal shock resistance, the spalling of the refractory material caused by thermal shock will become a fatal factor in its damage.
(3) Erosion and wear. The flue gas flow rate in circulating fluidized bed boilers is high (up to more than 29m/s) and the solid material concentration is high. At medium temperatures, high-speed flue gas entrains a large number of solid particles, causing strong erosion and wear to the refractory lining. Especially in the impact zone of the cyclone, the erosion is the most serious. For circulating fluidized bed boilers and cyclones with single-side return, the cyclic flow of materials causes wear areas on the refractory lining walls.
There are three main methods for lining maintenance and repair of circulating fluidized bed boilers:
One is to directly replace the broken and worn refractory materials and re-line them. This method of repair is thorough, but the cycle is long, the workload is large, and the production shutdown time is long, which has a greater impact on the normal production of the circulating fluidized bed.
The second is to use the hard material pressing method. Hard material pressing technology is used to repair the middle and lower furnace walls of the thickened blast furnace body without lowering the material line. However, the pressing of hard materials is only suitable for the material-filled parts of the middle and lower parts of the blast furnace and is not suitable for the material-free parts of the upper part of the blast furnace and large-area furnace wall repairs.
The third is to use the gunning and lining method. This method is suitable for repairing the upper part of the blast furnace where there is no material and large areas of furnace walls. Moreover, the gunmetal lining method is easy to use, has a short cycle, and has little impact on the normal use of circulating fluidized bed boilers.
Rongsheng Refractory Material Manufacturer has a complete technical team, construction team, and customer service team. The manufacturer is strong and can select appropriate maintenance and repair methods based on customer needs and the actual condition of the furnace lining to reduce the impact of furnace lining maintenance on normal production.
It is worth mentioning that the Rongsheng refractory material manufacturer can solve the problem of refractory lining for you based on the actual production situation of your circulating fluidized bed boiler lining. When the furnace lining is damaged or falls off, you can contact us. We will provide you with detailed product introductions, on-site repair and maintenance services, and provide furnace lining usage guidance and technical support.
Through trials of Rongsheng’s wear-resistant refractory castable products, many of our customers feel that the use of our refractory lining materials has extended the service life of their kilns and reduced the time for shutdown and repair. It saves production costs and improves economic benefits for enterprises.
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