Development and progress on hydrogen metallurgy

Abstract

Hydrogen metallurgy is a technology that applies hydrogen instead of carbon as a reduction agent to reduce CO2 emission, and the use of hydrogen is beneficial to promoting the sustainable development of the steel industry. Hydrogen metallurgy has numerous applications, such as H2 reduction ironmaking in Japan, ULCORED and hydrogen-based steelmaking in Europe; hydrogen flash ironmaking technology in the US; HYBRIT in the Nordics; Midrex H2™ by Midrex Technologies, Inc. (United States); H2FUTURE by Voestalpine (Austria); and SAL-COS by Salzgitter AG (Germany). Hydrogen-rich blast furnaces (BFs) with COG injection are common in China. Running BFs have been industrially tested by AnSteel, XuSteel, and BenSteel. In a currently under construction pilot plant of a coal gasification-gas-based shaft furnace with an annual output of 10000 t direct reduction iron (DRI), a reducing gas composed of 57vol% H2 and 38vol% CO is prepared via the Ende method. The life cycle of the coal gasification—gas-based shaft furnace—electric furnace short process (30wt% DRI + 70wt% scrap) is assessed with 1 t of molten steel as a functional unit. This plant has a total energy consumption per ton of steel of 263.67 kg standard coal and a CO2 emission per ton of steel of 829.89 kg, which are superior to those of a traditional BF converter process. Considering domestic materials and fuels, hydrogen production and storage, and hydrogen reduction characteristics, we believe that a hydrogen-rich shaft furnace will be suitable in China. Hydrogen production and storage with an economic and large-scale industrialization will promote the further development of a full hydrogen shaft furnace.