Scholarlink

<p>Understanding coke post-degradation characteristics within the high-temperature zones of blast furnace is critical for optimizing ironmaking processes. Given the inherent "black box" nature of blast furnace, tuyere sampling technology has emerged as an essential tool for analyzing coke degradation behavior during operations. Nevertheless, the sampling accuracy limitations of the core sampling methods, along with the insufficient spatial analysis of microstructural evolution, leave the degradation mechanism of coke particle size in the tuyere zone remaining incompletely understood. This study employs a multipoint mobile sampler to collect uncompressed coke samples along the tuyere radial positions of a large-scale blast furnace, systematically analyzing the relationship between coke particle size distribution and multi-scale structural evolution including carbon microcrystalline structure, pore structure, and optical texture. Results reveal a 56.4&#xa0;pct average particle size degradation in the sampling coke from the centerline of blast furnace tuyere with distinct radial zonation. Coke particle size remains stable within 0 to 1.7 m from the furnace wall (Region I), followed by an accelerated degradation through 1.7 to 3.2 m (Region II), ultimately stabilizing at reduced dimensions within 3.2 to 5.2 m (Region III). Structural analysis reveals intensified graphitization in the tuyere zone, showing thermal-driven graphitization in Region I and slag-iron catalytic graphitization in Region III. Region II exhibits maximal macro-pore expansion and micro-pore volume reduction, indicating severe gasification reactions in this region. Crucially, coke anisotropic microstructures demonstrate poor gasification resistance in the alkali-rich environment of blast furnace, challenging conventional views that coke with higher optical texture index exhibits better thermal properties. Correlation analysis reveals a rapid increase in average macro-pore area accompanied by continuous micro-pore connection and optical texture index reduction in Region II, demonstrating that pore evolution and optical texture degradation collectively drive the rapid particle size reduction. Based on the degradation characteristics of coke along the tuyere radial direction, operational modifications including adopting central coke charging technology and strategic low-rank coal blending are proposed, aiming to enhance the gas and liquid permeability of the deadman and reduce coking cost in iron production.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Insights into Particle Size Degradation and Structural Evolution of Native-State Coke Extracted Above the Tuyere Centerline in a Large-Scale Blast Furnace

  • 期刊论文

  • 发表日期：

    2025年7月14日

查看全文
  • Jingbo Chen,
  • Shengfu Zhang,
  • Hao Chen,
  • Hua Zhang,
  • Liguo Zhang,
  • Wei Ren,
  • Jianming Wang,
  • Xianyou Huang

摘要

Understanding coke post-degradation characteristics within the high-temperature zones of blast furnace is critical for optimizing ironmaking processes. Given the inherent "black box" nature of blast furnace, tuyere sampling technology has emerged as an essential tool for analyzing coke degradation behavior during operations. Nevertheless, the sampling accuracy limitations of the core sampling methods, along with the insufficient spatial analysis of microstructural evolution, leave the degradation mechanism of coke particle size in the tuyere zone remaining incompletely understood. This study employs a multipoint mobile sampler to collect uncompressed coke samples along the tuyere radial positions of a large-scale blast furnace, systematically analyzing the relationship between coke particle size distribution and multi-scale structural evolution including carbon microcrystalline structure, pore structure, and optical texture. Results reveal a 56.4 pct average particle size degradation in the sampling coke from the centerline of blast furnace tuyere with distinct radial zonation. Coke particle size remains stable within 0 to 1.7 m from the furnace wall (Region I), followed by an accelerated degradation through 1.7 to 3.2 m (Region II), ultimately stabilizing at reduced dimensions within 3.2 to 5.2 m (Region III). Structural analysis reveals intensified graphitization in the tuyere zone, showing thermal-driven graphitization in Region I and slag-iron catalytic graphitization in Region III. Region II exhibits maximal macro-pore expansion and micro-pore volume reduction, indicating severe gasification reactions in this region. Crucially, coke anisotropic microstructures demonstrate poor gasification resistance in the alkali-rich environment of blast furnace, challenging conventional views that coke with higher optical texture index exhibits better thermal properties. Correlation analysis reveals a rapid increase in average macro-pore area accompanied by continuous micro-pore connection and optical texture index reduction in Region II, demonstrating that pore evolution and optical texture degradation collectively drive the rapid particle size reduction. Based on the degradation characteristics of coke along the tuyere radial direction, operational modifications including adopting central coke charging technology and strategic low-rank coal blending are proposed, aiming to enhance the gas and liquid permeability of the deadman and reduce coking cost in iron production.