• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>Per Kofstad Memorial Symposium on High Temperature Corrosion and Materials Chemistry Nov 1999, Honolulu, Hawaii >MECHANISMS OF SILICA REFRACTORY CORROSION IN GLASS-MELTING FURNACES: EQUILIBRIUM PREDICTIONS
【24h】

MECHANISMS OF SILICA REFRACTORY CORROSION IN GLASS-MELTING FURNACES: EQUILIBRIUM PREDICTIONS

机译：玻璃熔窑中二氧化硅耐蚀性的机理：平衡预测

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Corrosion of refractory silica brick used to line the roof or "crown" of many-glass-melting furnaces is a serious problem in furnaces using oxygen-fuel rather than air-fuel. In this work, we report equilibrium calculations for the Na_2O-SiO_2 system that predict the formation of a variable-composition liquid-solution phase as a function of key furnace variables. Since thermodynamic data for the relevant liquid phases are unavailable in standard compilations, new data generated using the associate species model are included in the calculations. The calculations indicate that gas-phase NaOH concentrations less than ～15 ppm will not react with the silica refractory under either air-fired or oxy-fired conditions, since this is the smallest equilibrium NaOH partial pressure in a system containing crystalline SiO_2 (either cristobalite or tridymite) in equilibrium with a variable-composition sodium-silicate liquid phase at refractory temperatures in the range 1400 - 1700 ℃. The high water content (～65%) of oxygen-fired furnaces results in measured NaOH(g) concentrations as high as 300 ppm, which greatly exceeds the 1600 C maximum of 68 ppm NaOH(g) for oxy-fired equilibrium with a liquid-SiO_2(crystalline) system. This indicates that there is a thermodynamic driving force for NaOH(g) to react with silica refractories in oxy-fired furnaces. The results of the calculations are used to define a "critical temperature," above which corrosion is not expected to occur for a given NaOH(g) partial pressure.
机译：在使用氧气燃料而不是空气燃料的熔炉中，用于衬砌许多玻璃熔炉的炉顶或“皇冠”的耐火硅砖的腐蚀是一个严重的问题。在这项工作中，我们报告了Na_2O-SiO_2系统的平衡计算，该计算可预测作为关键炉变量的函数的可变组成的液相溶液相的形成。由于相关液相的热力学数据在标准汇编中不可用，因此使用缔合物种模型生成的新数据将包括在计算中。计算结果表明，小于约15 ppm的气相NaOH浓度在空气或氧气燃烧条件下都不会与耐火硅石反应，因为这是含有结晶SiO_2（方石英）的体系中最小的NaOH平衡分压在1400-1700℃的耐火温度下与可变组成的硅酸钠液相平衡。氧气炉的高水含量（〜65％）导致测得的NaOH（g）浓度高达300 ppm，大大超过了1600℃最高的68 ppm NaOH（g）的含氧平衡的液体-SiO_2（晶体）体系。这表明在氧气燃烧炉中，NaOH（g）与二氧化硅耐火材料有热力学驱动力。计算结果用于定义“临界温度”，在该温度以上，对于给定的NaOH（g）分压，预计不会发生腐蚀。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号