Paper Submission
10. Combustion and Reacting Flows
Stabilization of non-premixed hydrogen-rich gas flame in hot air coflow
The traditional steel industry produces substantial CO2 emissions through burning pulverized coal in the blast furnace (BF). To address the urgent requirement for achieving carbon neutrality by 2050, developing low-carbon BF technology, such as utilizing hydrogen-rich gas injection in the existing system, is a promising approach for decarbonization. Coke oven gas (COG), a valuable hydrogen-rich by-product from the carbonization process of coke production, can be recovered and injected into BF for combustion, simultaneously reducing overall CO2 emission. However, the stabilization of COG jet flames in convective hot air surroundings is still lacking. Based on this, three hydrogen-rich gases (COG, CH4, and 50%COG/50%CH4 blends) under 0–5 kW thermal input across a wide range of jet velocity and coflow air temperatures (30–650°C) were investigated by using a jet-in-coflow (JIC) burner. COG composition was simulated as 55%H2 + 30%CH4 + 5%CO + 10%N2. Results indicate that increased H2 concentration within the fuel mixture decreases the luminosity of non-premixed sooty flames. For a fixed air velocity (Va), the laminar flame height of COG increases linearly with increasing fuel velocity (Vf), but it becomes shorter and remains unchanged under turbulent conditions. A blue-white, lifted turbulent flame was observed at a higher Vf value under lower Va. However, Vf beyond a critical value under higher Va leads to blowoff. Furthermore, the blowoff velocity follows COG > 50%blends > CH4, indicating that the higher reactivity of H2 enhances flame stabilization. In addition, elevating temperature significantly extended blowoff velocity. Three distinct flame regimes were identified based on the jet velocities: nozzle-stabilized flame, lifted flame, and blowoff. Finally, optimum operating conditions were found according to the stabilization maps. This study provides valuable insights into flame stabilization mechanisms of hydrogen-rich fuel in the energy transition towards low-carbon blast furnace operations.
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Author Information
Dr.
Hsien-Tsung Lin
Mr.
Si-Rui Chen
Presenting author
Prof.
Fang-Hsien Wu
Corresponding author
Prof.
Guan-Bang Chen