Title

Hot metal production in the blast furnace from an ecological point of view

Hot metal production in the blast furnace from an ecological point of view

Authorship

SCHMÖLE, PETER; LÜNGEN, HANS BODO

SCHMÖLE, PETER

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LÜNGEN, HANS BODO

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DOI

10.5151/2594-357x-34Red-239-254

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Abstract

Against the backdrop of current efforts to reduce greenhouse gas emissions and the imminent launch of CO₂ emission trading schemes within the EU, the blast furnace process too has therefore come under review regarding existing CO₂ emission reduction potentials. Possible options for reducing the reductant input and hence, CO₂ emissions, were evaluated by means of a blast furnace balance model developed by ThyssenKrupp Stahl AG. The calculations examined an "ideal" blast furnace as compared with its real-life industrial counterparts. In this ideal blast furnace, the thermodynamically unrealistic "ideal operating point" for the wustite reduction is directly on the equilibrium curve of the Baur-Glassner diagram, apart from being achieved at a lower reaction temperature. It emerged from the calculations that the reductant rate of the "ideal blast furnace" is only 5% below the average obtained with blast furnaces currently operating in Germany. To assess the possible reduction potentials for reducing agent consumption and CO₂ emissions, two alternative variants of the blast furnace process were evaluated against the "conventional" blast furnace using the balance model. The alternatives considered were nitrogen-free blast furnace and the plasma-heated blast furnace. A characteristic feature of both variants is that each involves the removal of CO₂ from a portion of the blast furnace top gas. Both process variants bring down the consumption of reductants but require a substantially higher input of electrical energy, especially in the case of the plasma-heated process.

Against the backdrop of current efforts to reduce greenhouse gas emissions and the imminent launch of CO₂ emission trading schemes within the EU, the blast furnace process too has therefore come under review regarding existing CO₂ emission reduction potentials. Possible options for reducing the reductant input and hence, CO₂ emissions, were evaluated by means of a blast furnace balance model developed by ThyssenKrupp Stahl AG. The calculations examined an "ideal" blast furnace as compared with its real-life industrial counterparts. In this ideal blast furnace, the thermodynamically unrealistic "ideal operating point" for the wustite reduction is directly on the equilibrium curve of the Baur-Glassner diagram, apart from being achieved at a lower reaction temperature. It emerged from the calculations that the reductant rate of the "ideal blast furnace" is only 5% below the average obtained with blast furnaces currently operating in Germany. To assess the possible reduction potentials for reducing agent consumption and CO₂ emissions, two alternative variants of the blast furnace process were evaluated against the "conventional" blast furnace using the balance model. The alternatives considered were nitrogen-free blast furnace and the plasma-heated blast furnace. A characteristic feature of both variants is that each involves the removal of CO₂ from a portion of the blast furnace top gas. Both process variants bring down the consumption of reductants but require a substantially higher input of electrical energy, especially in the case of the plasma-heated process.

Keywords

Conventional, nitrogen-free and plasma-heated blast furnace, reductant consumption and CO₂ emissions

Conventional, nitrogen-free and plasma-heated blast furnace, reductant consumption and CO₂ emissions