Accident Handling 14: How to prevent the wear-resistant material in the worn areas of a circulating fluidized bed boiler from falling off?

pin； The design of the local anti-wear structure is reasonable ； Better anti-wear materials ； Process measures such as spraying can reduce wear.

Pay attention to the construction procedures and operate as closely as possible in accordance with the start-up and shutdown curves

In addition to the above measures, it is also necessary to control the primary air velocity; excessive primary air can cause severe erosion of the casting material, leading to its detachment.

Appropriate wear-resistant materials should be selected. The material must be a high-strength, fire-resistant, wear-resistant material with good flexural strength. Reinforcing metal pins are included in the fire-resistant and wear-resistant materials, with their length extending essentially through the thickness of the fire-resistant layer; or stainless steel fibers can be added to these materials. In this way, when cracks occur due to uneven expansion, large-scale detachment does not happen. The maintenance of fire-resistant and wear-resistant materials is also important. During furnace drying, it is crucial that the surface of the refractory layer reaches and exceeds the sintering temperature.

If the wear-resistant materials used in circulating fluidized bed boilers meet the required standards, then the reasons for the detachment of these materials in the areas subject to wear (the dense phase region and the transition zone between dense and sparse phases) are mainly due to inadequate construction techniques and improper operation during startup and shutdown. In the first case, the construction quality is poor and the drying process is not carried out correctly; the drying is not done in accordance with the prescribed guidelines. One reason for this is that the wear-resistant refractory castables are exposed to intense heat too early, resulting in rapid evaporation of the moisture inside them and the formation of cracks. Another reason is insufficient drying time – the boiler is put into operation before all the moisture in the castables has evaporated. Yet another issue is an excessive cooling rate when the boiler is shut down, or an overly rapid heating rate when it is started; the former poses the greatest risk, as it subjects the castables to excessive thermal stress, leading to cracks and eventual detachment.