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<p>Plasma-assisted gas heating offers a controllable high-enthalpy heat source for upgrading metallurgical gases in low-carbon ironmaking, yet the discharge-heating behavior remains strongly dependent on gas composition and cathode durability. Here, a modular nontransferred arc plasma heating platform was developed, and the heating characteristics of five metallurgical gases (N<sub>2</sub>, CO, CO<sub>2</sub>, H<sub>2</sub>, and CH<sub>4</sub>) were systematically evaluated by varying working-gas flow (8–26 L/min), temperature-regulating gas flow (8–42 L/min), and current (30–50 A). Under optimized conditions, outlet temperatures exceeded 1700&#xa0;°C for N<sub>2</sub> and 1580&#xa0;°C for CO at 26 L/min, and the best controllability was obtained at a working-to-regulating flow ratio of approximately 1:1. To emulate industrial metallurgical-gas mixtures, CO–H<sub>2</sub>–N<sub>2</sub> mixed gases with constant N<sub>2</sub> dilution (20%) and varying H<sub>2</sub> fraction (0–25%) were further tested at 40 A (Vw = 18 L/min, VT = 8 L/min), showing a nonmonotonic response with a temperature maximum at 5–10% H<sub>2</sub> (1420–1390&#xa0;°C) and reduced outlet temperatures at higher H<sub>2</sub> fractions despite increased sustaining voltage/power. Electrode evaluation (Cu, Ag, and W) revealed strong atmosphere dependence: in 50%N<sub>2</sub>–50%H<sub>2</sub>, Cu failed within ~10&#xa0;min, Ag sustained ~30&#xa0;min, whereas W showed no ignition failure within 30&#xa0;min; under N<sub>2</sub> plasma heating, W achieved 1700+ &#xa0;°C at a lower flow threshold than Cu and far exceeded Ag in maximum temperature. These results establish composition-adaptive operating windows and electrode-selection guidelines for plasma upgrading of metallurgical gases toward energy-efficient, hydrogen-enabled ironmaking.</p> Graphical Abstract <p></p>

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Gas Characteristics and Electrode Erosion in Plasma Heating Metallurgical Gas Processes

  • 期刊论文

  • 发表日期：

    2026年5月17日

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  • Xingjian Deng,
  • Tian Gao,
  • Lianda Zhao,
  • Qingguo Xue,
  • Haibin Zuo,
  • Jingsong Wang

摘要

Plasma-assisted gas heating offers a controllable high-enthalpy heat source for upgrading metallurgical gases in low-carbon ironmaking, yet the discharge-heating behavior remains strongly dependent on gas composition and cathode durability. Here, a modular nontransferred arc plasma heating platform was developed, and the heating characteristics of five metallurgical gases (N2, CO, CO2, H2, and CH4) were systematically evaluated by varying working-gas flow (8–26 L/min), temperature-regulating gas flow (8–42 L/min), and current (30–50 A). Under optimized conditions, outlet temperatures exceeded 1700 °C for N2 and 1580 °C for CO at 26 L/min, and the best controllability was obtained at a working-to-regulating flow ratio of approximately 1:1. To emulate industrial metallurgical-gas mixtures, CO–H2–N2 mixed gases with constant N2 dilution (20%) and varying H2 fraction (0–25%) were further tested at 40 A (Vw = 18 L/min, VT = 8 L/min), showing a nonmonotonic response with a temperature maximum at 5–10% H2 (1420–1390 °C) and reduced outlet temperatures at higher H2 fractions despite increased sustaining voltage/power. Electrode evaluation (Cu, Ag, and W) revealed strong atmosphere dependence: in 50%N2–50%H2, Cu failed within ~10 min, Ag sustained ~30 min, whereas W showed no ignition failure within 30 min; under N2 plasma heating, W achieved 1700+  °C at a lower flow threshold than Cu and far exceeded Ag in maximum temperature. These results establish composition-adaptive operating windows and electrode-selection guidelines for plasma upgrading of metallurgical gases toward energy-efficient, hydrogen-enabled ironmaking.

Graphical Abstract