Home > News > Content
Wear Factors And Material Selection Of Refractory Castables For CFB Boiler Lining
Jan 14, 2019


In CFB boilers, the wear of lining refractory castables is mainly manifested by erosion wear. Erosion wear refers to the wear caused by the impact of fluid or solid particles on the surface of the lining at a certain speed and angle. There are two basic types of erosion wear: erosion wear and micro impact wear (cut wear).



 


The wear of refractory castables for CFB boiler lining is a very complicated failure process. It is not only affected by mechanical reasons, but also closely related to various factors such as lining materials, environment and medium. Specifically, it can be divided into the following categories:


(1) Wear caused by thermal stress and thermal shock


This wear is mainly manifested by temperature cycle fluctuations and thermal shocks as well as mechanical stresses causing cracks and flaking of the refractory castable. When the temperature cycle fluctuates, internal stress is formed due to the difference between the refractory castable aggregate and the thermal expansion system between the binders, thereby destroying the refractory castable layer, often causing cracks and flaking of the refractory castable lining. The thermal shock caused by the rapid temperature change causes the stress in the refractory castable to peel off beyond the tensile strength. The damage of the refractory castable caused by mechanical stress is mainly due to the difference between the refractory castable and the thermal expansion system between the metal parts passing through the lining of the refractory castable.



 


(2) Wear caused by solid material scouring


The wear is mainly manifested by the damage caused by the material being strongly washed against the refractory castable lining. The easy-wearing area of the refractory castable in the circulating fluidized bed boiler includes a corner zone, a cyclone separator and a solid material returning system. In general, refractory castable wear increases as the impact angle increases.


(3) Wear caused by changes in properties of refractory castables


The wear is mainly caused by the deterioration of the refractory castable and the deterioration caused by the decrease of physical and chemical properties. For example, the deterioration of the refractory castable due to the aging of the alkali metal, the refractory castable and the binder may not be able to reach the specified sintering temperature, the strength may be lowered, or the baking may not be achieved. The furnace standard requires that the moisture in the material is not completely converted into water vapor. After the boiler is ignited, the water vapor pressure in the refractory castable exceeds the tensile strength of the material, causing lining and collapse of the liner.



 


To understand the main factors of wear of refractory castable lining in CFB boiler, take preventive measures in material selection and construction, which can effectively reduce the wear of the lining and prolong the service life of the boiler. Here, it is recommended to use high-strength wear-resistant refractory castables and wear-resistant refractory plastics. This material combination has been well used in domestic CFB boilers.


Related News

SUBSCRIBE TO OUR SPECIAL OFFERS

Please send us your requirement by email.

Copyright © Greenergy Refractory and Insulation Material Co.,Ltd All Rights Reserved.