In the boiler system, the cyclone separator plays a vital role. It can effectively separate the fly ash and unburned carbon particles produced after fuel combustion from the flue gas. However, the problem of refractory castable falling off inside the cyclone separator often occurs, which brings considerable trouble to the normal operation of the boiler.What is the reason for the refractory material castable falling off in the cyclone separator?
First, it is shedding caused by thermal shock. When starting and stopping the furnace or when the load fluctuates violently, temperature cycle fluctuations will produce significant thermal shock. This rapid temperature change causes a large temperature gradient inside and on the surface of the refractory layer, which in turn induces large thermal stress. As the stress continues to accumulate and change, the surface of the refractory castable is prone to cracking, eventually causing the material to fall off.
Secondly, it is shedding caused by structural changes. During long-term use, the composition and crystal phase structure of refractory materials may undergo gradual changes. These microstructural changes will reduce the overall strength of the material, causing surface deterioration and cracking under relatively small temperature stress, leading to shedding.
Furthermore, mechanical stress is also an important cause of shedding. Due to the difference in thermal expansion coefficient between the refractory material castable and the metal penetrating the refractory lining, the expansion and contraction rates between the two are inconsistent when the temperature changes, resulting in mechanical stress. This stress can cause the bond between the refractory material and the metal to fail, ultimately causing detachment.
In addition, the quality issues of the refractory castable itself cannot be ignored. If the aggregate and powder ratio of the refractories castable is unreasonable, or the bonding force of the binder is insufficient, its performance will be seriously affected. These quality problems will cause the bonding force of the refractory material castable to gradually weaken during use, and eventually fall off.
At the same time, problems during the construction process are also an important factor causing the refractories castables to fall off. If the vibration is not sufficient during construction or the maintenance conditions are insufficient, the bonding strength between the refractory material castable and the inner wall of the separator will be seriously affected. This kind of construction defect will gradually be exposed during the operation of the boiler, manifested as the falling off of refractory castables.
Finally, physical and chemical erosion during operation is also an important reason for the shedding of refractory material castables. The high temperature and high speed flue gas generated during boiler operation will cause continuous erosion and wear to the refractories castables. At the same time, the chemical components in the flue gas may react chemically with the refractories castable, causing its structure to gradually loosen, reduce its strength, and eventually cause it to fall off.
