SYNTHESIS OF SILICON CARBIDE BY FUEL-RICH COMBUSTION IN CERAMIC SURFACE BURNER

多孔陶瓷表面燃烧器是沿多孔陶瓷板表面沿着形成火焰的燃烧器，其燃烧极限在宽的当量比范围内。如果甲烷-氧气混合物在高温下的燃烧可以在相当富燃料的当量比下发生，则二氧化硅可以转化为碳化硅。本文提出了将表面燃烧器应用于燃烧合成碳化硅的方法，并对其可行性进行了初步探讨。获得了以下认识：1）采用蜂窝陶瓷组装表面燃烧器，通过燃烧极限试验没有观察到回火现象。2)燃烧器的富油燃烧当量比达到3.0，但碳烟生成变得显着。3)蜂窝表面附着的火焰当量比小于1.5，火焰长度小于1.5w 关于我们 当当量比大于1.5时，火焰长度增大。4)根据31个物种的基元反应，分析了化学反应动力学模型。分析结果表明，当当量比大于2.0时，反应物的组成和温度满足二氧化硅碳化反应的条件。5)一片石英玻璃被检查以在燃烧器的富燃料火焰中在板坯上合成碳化硅膜。然而，由于与燃烧热负荷相比，辐射热损失大，样品不能保持反应所需的足够高的温度，因此通过XRD分析没有检测到产物。这意味着，实现这一过程的一个关键因素应该是减少辐射热损失相比，燃烧热负荷。这意味着实现这一目标的关键是减少板坯的辐射热损失和保温。少

The porous ceramic surface burner, in which flame is formed along the surface on a porous ceramic plate, has flammability limit in wide region of equivalence ratio. If the combustion of a methane-oxygen mixture at high temperature can take place under a fairly fuel-rich equivalence ratio, silicon dioxide may be converted to silicon carbide. In the present study, an application of the surface burner to the combustion synthesis of silicon carbide was proposed and the possibility was investigated fundamentally. The following knowledge was obtained : 1) The surface burner was assembled by using ceramic honeycomb and flashback was not observed from the test of flammability limit. 2) The fuel-rich combustion of the burner achieved up to 3.0 in equivalence ratio, but soot generation became significant. 3) The thin flame attached on the surface of honeycomb in less equivalence ratio than 1.5 while the length of the flame attached on the surface of honeycomb in less equivalence ratio than 1.5 w … More hile the length of the flame was enlarged with elevation of the equivalence ratio beyond 1.5. 4) The chemical reaction kinetic model was analyzed on the basis of the elementary reactions with 31 species. The analytical result showed that the composition and temperature satisfied the condition required for the carbonizing reaction of silicon dioxide in the higher equivalence ratio than 2.0. 5) A piece of quartz glass was examined to synthesize a film of silicon carbide on the slab in the fuel-rich flame of the burner. However the production was not detected by XRD analysis because the sample could not maintain sufficiently high temperature necessary for the reaction due to large radiant heat loss compared with the combustion heat load. The fact means that a key factor for realizing this process should be to reduce the radiant heat loss compared with the combustion heat load. The fact means that a key factor for realizing should be to reduce the radiant heat loss from slabs and maintain temperature. Less