Anti-wear treatment of wear-resistant castables refractory for CFB boiler

July 11, 2018

Circulating fluidized bed boiler is used as the most important boiler in the thermal power plant, in the overhaul process of circulating fluidized bed boiler, it may be worn out on key equipment such as cyclone separator, boiler wear-resistant castable and fuel recovery device, which will affect the economy and safety of CFB boiler, directly affects the comprehensive target of the thermal power plants.

The funtion of wear resistant castable refractory

The wear-resistant castable in the boiler is the key material that regualte the internal temperature of the circulating fluidized bed boiler,improve the economic operation capactiy of the CFB, and optimzes the internal structure of the CFB. It is the key link during the installation and overhaul of the CFB. The construction of wear resistant castables of boiler is directly related to the stable operation of the CFB, and various problems of the wear-resistant castable of the boiler will lead to the friction and loss of CFB,and cause the safety problems and economic operation of the circulating fluized bed boiler. 

Causes for abrasion of wear-resistant castables during overhaul process

In the overhaul process of boiler wear-resistant castables refractory, if insufficient temperature, frequent start and stop occurs, the peeling and falling off of the wear-resistant castable refractory of the boiler will occur, which will not only cause the protection of the wear-reistant castable refractory, but also affect the whole of the circulating fluidized bed boiler. During overhaul, if the wear-resistant castable refractory projects does not follow the necessary technology and targets, it will cause cracks and detachment of the wear-resistant refractory castable. During the casting process of the wear-resistant castable refractory of the boiler, the loosening and detachment of the nails occur,and the fixing and connecting functions of the nails can not be exerted,and the vibration of the wear-resistant castable refractory of the boiler will also cause to excessive wear. In the second time pouring of the wear-resistant castable, if the secondary treatment is not carried out, the wear-resistant castable of the boiler will fall off during operation, which will bring a huge safety hazard to the normal operation of the circulating fluidized bed boiler.

Prevention of wear resistant of boiler wear-resistant castables

In order to prevent the abrasion of the boiler wear-resistant castables during the overhaul, it is necessary to combine the engineering characteristics and operation of the circulating fluidized bed boiler, standardize the details of the overhaul, pay attention to the construction of the boiler wear-resistant castable, establish the new standards and new requirements for refractory castable construction to prevent wear and tear caused by wear-resistant castables of the boiler.

1. It is necessary to control the frequent ignition and cease-fire of the boiler during the overhaul, so as to ensure the effective oven and temperature control, and to prevent the wear-resistant castables refractory from peeling and falling off due to the excessive temperature changes.

2. In the process of wearable castable ratio, test and casting, it’s necessary to strictly followed by the details and indicators of the process and technology, especially the key factors such as controlling the proportion, mixing and time of the wear-resistant castable refractory of the boiler, so as to ensure the quality and safety of the construction of the wear resistant castable refractory of the boiler.

3. It’s necessary to reserve the expansion joints and temperature expansion joints of the boiler wear resistant castables to prevent the layered and falling off caused by internal stress and temperature stress.

4. We must strictly check the firmness of the nails, and timely weld and make up the loosening and detached nails to enhance the strength of the wear-resistant castables refractory. In the construction of wear-resistant castable refractory at the high temperature part of the CFB, two pouring methods should be adopted to prevent the spalling that may occur at the bottom, control the overall stability of the CFB, and prevent occurence and expansion of the wear problem.