Al2O3-Cr2O3复合砖 危废焚烧探索 brick research
Medical waste refers to the waste that is directly or indirectly infectious, toxic, and other harmful produced by medical institutions in medical treatment, prevention, health care, and other related activities.Nowadays, there are a variety of technologies that can be used for the disposal of medical waste, and the incineration method is applicable to various infectious medical waste, which is the mainstream technology in the field of medical waste treatment.The rotary kiln waste incinerator is one of the incineration treatment equipment, which can fully ensure the stability, safety, reduction and harmless environmental protection requirements of medical waste, and is also in line with the development trend of contemporary medical waste treatment.
The temperature in the garbage incinerator is usually 1400~1600℃, locally 1700℃; the slag contacting the heat surface area in the furnace includes Na2O, K2O, Cl-, SO2-4, base degree 0.3~1.5; the rotary kiln is positive and reverse swing; the atmosphere in the furnace is changing; the garbage type and water content change greatly.Therefore, refractory materials are required to have excellent resistance to slag erosion, permeability, high strength, erosion resistance, wear resistance and good thermal shock resistance to meet the impact of mechanical stress and thermal stress.At present, the refractory incinerator mainly use high chromium, magnesium chromium, aluminum and chromium, high aluminum, silicon carbide and other materials, but due to the atmosphere in the furnace, use temperature, the uncertainty of calcium and silicon ratio and the variability of garbage types, make the above performance of better materials is difficult to achieve the expected use effect.
In this study, Al2O3-Cr2O3 composite bricks with compact structure, high pressure resistance strength and good heat shock resistance were prepared and their application in straight cylinder rotary kiln incinerator for medical waste.
各层的内径分别为R1=1.83 m、R2=2.08 m、R3=2.15m,钢壳外半径为R=2.178 m,设各层的内表面温度分别为t1、t2、t3,钢壳外壁温度为tw,热导率分别为λ1=3.1 W·(m·K)-1,λ2=1.3 W·(m·K)-1,λ3=37.5 W·(m·K)-1,传热计算选取燃烧室附近的高温区域,工作温度约1 400℃,外界极限温度为t=40℃。
The inner diameter of each layer is R1=1.83 m, R 2=2.08 m, R3=2.15m, the steel shell outer radius is R=2.178 m, so that the inner surface temperature of each layer is t1, t2, t3, the temperature of the outer wall of the steel shell is tw, the thermal conductivity is 1=3.1 W · (m=K W-1,2=1.3 W · (3 · K) -1,3=37.5 W · (m · K) -1. The heat transfer calculation selects the high temperature area near the combustion chamber, the working temperature is about 1 400℃, and the external limit temperature is t=40℃.
(2)当耐火砖侵蚀剥落60 mm时,即工作面内径R1=1.89 m,此时外壁温度约为281℃。
(3)当耐火砖侵蚀剥落200 mm时,即工作面内径R1=2.03 m,此时外壁温度约为355℃。
Using iterative method, the data calculation are as follows:
(1) When the refractory brick is basically without obvious erosion, that is, the inner diameter of the working surface is R1=1.83 m, and the temperature of the outer wall is about 260℃.
(2) When the refractory brick is peeled off for 60 mm, the inner diameter of the working surface is R1=1.89 m, and the temperature of the outer wall is about 281℃.
(3) When the refractory brick eroded and strips 200 mm, the inner diameter of the working surface is R1=2.03 m, and the temperature of the outer wall is about 355℃.
It shows that the view of the operation of the rotary kiln, the damage of the working surface is basically normal.According to the heat transfer formula calculation and combined with the temperature of the kiln outer wall and the thickness theoretically available for use, it is speculated that under normal conditions, there is no problem with using the refractory bricks for another 6 to 10 months.