α‐Fe layer formation during metal dusting of iron in CO‐H2‐H2O gas mixtures
α‐Fe layer formation during metal dusting of iron in CO‐H2‐H2O gas mixtures
复制标题
CO-H2-H2O气体混合物中铁金属粉化过程中α-Fe层的形成
DOI：
10.1002/maco.200303740
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
G. Inden
中科院分区：
文献类型：
--
作者：
Jianqiang Zhang;A. Schneider;G. Inden
在600°C和700°C的CO - H2 - H2O混合气体中，观察和研究了铁的金属粉尘在渗碳体和石墨之间形成α - Fe层。形成这种现象的条件是由气体成分决定的，而气体成分又取决于温度。600℃时CO含量小于1%，700℃时CO含量小于5%，铁层形成。随着CO含量的增加，光学显微镜下在渗碳体/石墨界面未检测到α - Fe层。在这种情况下，渗碳体直接与焦炭层接触。还分析了低CO气体混合物中焦炭的形态。在600°C时，在1% CO的条件下，石墨有三种形态：丝状碳、具有柱状结构的块状致密石墨和嵌有许多含铁微粒的石墨团簇。在700℃、5% CO条件下，反应初期的焦炭主要由石墨颗粒团簇和一些丝状碳组成。焦炭的X射线衍射分析表明，焦炭中同时存在α - Fe和Fe3C。本文讨论了渗碳体与石墨之间α -铁的富集机理。
The formation of an α‐Fe layer between cementite and graphite was observed and investigated during metal dusting of iron in CO‐H2‐H2O gas mixtures at both 600°C and 700°C. The condition to form this phenomenon is determined by the gas composition which depends on temperature. The iron layer formation was observed for CO content less than 1 % at 600°C and less than 5 % at 700°C. With increasing CO contents, no α‐Fe layer was detected at the cementite/graphite interface by optical microscopy. In this case cementite directly contacts with the coke layer. The morphologies of the coke formed in the gas mixtures with low CO contents were also analysed. Three morphologies of graphite have been identified with 1 % CO at 600°C: filamentous carbon, bulk dense graphite with columnar structure, and graphite particle clusters with many fine iron containing particles embedded inside. At 700°C with 5 % CO the coke mainly consists of graphite particle clusters with some filamentous carbon at the early stage of reaction. Coke analysis by X‐ray diffraction shows that both α‐Fe and Fe3C are present in the coke. The mechanism of α‐Fe accumulation between cementite and graphite is discussed in this paper.