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

陶瓷表面燃烧器富燃料燃烧合成碳化硅

基本信息

批准号：
10650743
负责人：
ITAYA Yoshinori
金额：
$ 2.24万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

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

多孔陶瓷表面燃烧器，其中火焰沿着多孔陶瓷板的表面形成，如果甲烷-氧气混合物在相当的燃料条件下能够在高温下燃烧，则其在较宽的当量比范围内具有可燃性极限。丰富的当量比，二氧化硅可以转化为碳化硅。在本研究中，提出了表面燃烧器在碳化硅燃烧合成中的应用，并从根本上研究了这种可能性，获得了以下知识：1）表面燃烧器。刻录机采用陶瓷蜂窝组装而成，燃烧极限测试中未观察到回火。 2) 燃烧器富燃料燃烧当量比达到3.0，但烟灰产生明显。 3) 燃烧器火焰附着较细。当量比小于 1.5 的蜂窝表面，当量比小于 1.5 w 的蜂窝表面附着的火焰长度……更多，火焰长度随蜂窝体高度的增加而增大当量比超过1.5。4)基于31种基元反应进行了化学反应动力学模型分析，分析结果表明，其组成和温度满足二氧化硅在较高当量比下的碳化反应所需的条件。 5) 一块石英玻璃在燃烧器的富燃料火焰中在板坯上合成了一层碳化硅薄膜，但由于样品无法保持足够高的温度，因此 XRD 分析未检测到该薄膜。由于辐射热损失与燃烧热负荷相比较大，因此反应所需的温度这一事实意味着实现该过程的关键因素应该是降低与燃烧热负荷相比的辐射热损失。减少板坯的辐射热损失并保持温度较低。