Factors Affecting the Service Life of Refractories in Waste Incinerator

The technical performance and economic benefit of MSW incinerator are mainly affected by the lining refractories, while the atmosphere, service temperature, erosion of molten matter and stress in the furnace affect the service life of refractories to varying degrees, thus affecting the service life of the whole incinerator. Therefore, it is very important to analyze and explore its influencing factors.

(1) Effect of atmosphere in furnace. Different furnace atmosphere has different erosion degree to refractories, most of waste incinerators are oxidation atmosphere. When selecting material, it is difficult to define the operating atmosphere limit of non-oxide refractories (such as SiC), which is not only due to the concentration of some gases (including alkali vapor), but also due to subtle changes in temperature, pressure and so on. According to the research, the corrosion resistance of SiC brick is about 10 times larger than that of reducing atmosphere.

(2) Effect of temperature used. Incinerator. High temperature is 1400℃, generally with the increase of temperature erosion rate increases sharply. more so when the temperature exceeds 1400℃, especially clay, high-aluminum refractories are more susceptible to temperature.

(3) Impact of CaO/SiO₂. Slag as a residue from incinerator incineration, its main components are Al₂O₃、SiO₂、CaO、Fe₂O₃ and alkaline oxides, carbonate and alkaline earth metals, CaO/SiO₂ become its main influencing factors. Al₂O₃-Cr₂O₃ and other neutral refractories are more vulnerable to its influence than alkaline refractories. With the increase of CaO/SiO₂ and the increase of erosion, C-SiC brick is more uncomfortable and CaO/SiO₂ than SiC brick. Usually CaO/SiO₂=1.0 is the critical point, above this point, can choose MgO、 spinel, C series refractories; below this point, choose Al₂O₃、Cr₂O₃、SiC series refractories is good.

(4) Effect of stress. The main stress of the incinerator is as follows :1) the thermal stress caused by the temperature gradient; 2) the mechanical stress caused by the expansion difference between the metal frame and the refractory at the contact site (including friction); 3) stress induced by oxidation, corrosion (HCI、CL₂), chemical changes caused by foreign components and crystal transfer; 4) corrosion, pillar failure caused by the loss of support stress. Experience shows that, In several stress regions of the incinerator, The magnitude of stress depends on the process. With the steady improvement of lining requirements for refractories for incinerators, There are several ways to resist stress :1. Optimizing the operation of incinerator, such as by regulating excess air coefficients and garbage mixtures; Improvement of refractories to improve lining life; Use high quality refractories.