International Journal of Minerals, Metallurgy and Materials Accepted manuscript, https://doi.org/10.1007/s12613-020-2021-4 © University of Science and Technology Beijing and Springer-Verlag GmbH Germany, part of Springer Nature 2020 Development and Progress of Hydrogen Metallurgy Jue Tang1*), Man-sheng Chu2*), Feng Li1), Cong Feng1), Zheng-gen Liu1), Yu-sheng Zhou1) 1) School of Ferrous Metallurgy, Northeastern University, Shenyang 110819, China. 2) State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China. Corresponding author: Jue Tang, [email protected]；Man-sheng Chu, [email protected] Abstract: Hydrogen metallurgy was a technology that taking hydrogen as the reduction agent instead of carbon to reduce CO2 emission, which is beneficial to promote the sustainable development of steel industry. Lots of main projects of hydrogen metallurgy have been proceeded and planed, such as H2 reduction ironmaking in Japan, ULCORED and Hydrogen-based steel making in Europe, hydrogen Flash TM Ironmaking Technology in the US, HYBRIT in Nordic, Midrex H2 , H2FUTURE of Voestalpine, SALCOS Project of Salzgitter. The hydrogen-rich BF with COG injection is typical in China. AnSteel, XuSteel, and BenSteel have carried out the industrial tests in running blast furnaces. And the pilot plant of coal gasification-gas based shaft furnace with an annual output of 10,000 t DRI was under construction. The reducing gas of 57%H2 and 38%CO was prepared by ENDE method. The life cycle assessment of the coal gasification-gas based shaft furnace-electric furnace short process (30%DRI+70% scrap) was carried out with 1 t molten steel as the functional unit. It was found that the total energy consumption per ton steel was 263.67 kgce, and the CO2 emission per ton steel was 829.89 kg, which was superior to the traditional BF-converter process. Considering the domestic materials and fuels, the developing production and storage of hydrogen, the characteristics of hydrogen reduction, it was more suitable to develop hydrogen-rich shaft furnace in China, and the production and storage of hydrogen with an economic and large-scale industrialization would promote the further development of full hydrogen shaft furnace. Key words: hydrogen; hydrogen metallurgy; blast furnace; gas-based shaft furnace; low-carbon 1 Introduction According to IEA, the global energy-related CO2 emissions totaled 3.31 billion tons in 2018, which increased by 1.7% compared with the previous year and reached the highest level on record. China, the US, Europe and India accounted for more than 60% of the world's total CO2 emissions, which were 9481 Mt, 4888 Mt, 3956 Mt and 2999 Mt respectively [1]. In recent years, as for the global energy consumption and CO2 emissions, industry accounted for 33% and 40% respectively. CO2 emissions from steel industry accounted for a high proportion of about 33.8% of industrial emissions [2]. To combat global warming, the Paris Agreement was adopted in 2015. Its main goal was to limit the rise in global average temperature to less than 2℃ this century and to keep the global temperature rise to less than 1.5℃ above pre-industrial level. Countries around the world signed the agreement and put forward plans to reduce carbon emission. In 2016, China had launched 10 low-carbon demonstration zones, 100 mitigation projects and 1,000 training opportunities for climate change, with a view to reduce CO2 emission per unit of GDP by 60-65% by 2030 [3-5]. And in 2017, the carbon emission trading system had been launched in China [2]. The steel industry was the main target for that new trading system, and the mandatory CO2 emission reduction would force the steel enterprises to develop low-carbon technology. Based on the global warming and energy transformation, the governments had attached great importance to developing and utilizing the carbon-free or low-carbon energy. Hydrogen energy, with its diverse source, low-carbon emission, high efficiency, and wide application range, was regarded as the most promising clean energy in the 21st century and had been listed in the national energy strategic deployment by many countries [6,7]. Xu Kuangdi put forward the idea of achieving the reduction of iron ore by hydrogen in 1999 [8], and then he further put forward the idea of hydrogen metallurgy in 2002 [9]. In 2018, Gan Yong pointed out that 21st century was the era of hydrogen, and hydrogen metallurgy was the process that water was generated by hydrogen reduction instead of carbon reduction, with no emission and extremely fast reaction rate [10]. At present, the hydrogen metallurgy mainly included blast furnace (BF) ironmaking with adding hydrogen and production of direct reduction iron (DRI) by hydrogen [11-16]. The following topics including the development and progress of hydrogen metallurgy abroad and in China, and the challenges and opportunities of hydrogen metallurgy were systematically discussed in this work. 2 Development and progress of hydrogen metallurgy abroad 2.1 Hydrogen metallurgy in Asia 2.1.1 H2 Reduction ironmaking in Japan The route of the COURSE50 project was shown in Fig 1, involving two main technologies of hydrogen-rich reduction and CO2 capture and recovery from BF exhaust to achieve the CO2 emission. The former was based on the reforming technology of coke oven gas (COG) and water and the novel coking technology to make coke with a high strength and a high reactivity. The latter was on the base of CO2 efficient absorption technology to utilize the waste heat. Through the experimental BF of 12 m3 with a productivity of 35 tons/d built by Nippon Steel, the project emission reduction target was confirmed as: 10% reducing by hydrogen reduction ironmaking, and 20% reducing by CO2 recovery, so as to achieve the overall emission reduction target of 30% [17,18]. Hydrogen reduction ironmaking was a method that replaced part of coke with hydrogen to reduce CO2 emissions during BF process. From 2014 to 2016, the first stage of experimental BF operation with H2 injection was carried out. It was indicated that the carbon emission reduced by 9.4% compared with that of non-H2 injection. Due to the small density of H2 and the hydrogen reduction accompanied by endothermic reactions, the adjustable position in the stack and raceway of BF and the preheating of H2 before injection were conducted to ensure the maximum reduction performance and stable inner temperature respectively. In the second stage, an expanded test would be carried out to gradually simulate the practical BF of 3 4000-5000 m . The first BF was expected to be operated with H2 reduction by 2030 and the technology would be available around Japan by 2050. In addition, the COURSE50 project had also developed the technology for producing hydrogen from COG. When COG left the carbonization chamber, the temperature reached 800℃, which could make full use of its sensible heat to achieve the catalytic cracking of tar and hydrocarbon substances to produce H2. The specific technical route was described in Fig 2. At present, the industrial trial of this technology had been completed. Through this modification, the H2 content of COG increased from 55% to 63-67%，and the gas volume was to be double. [20]. Sinter BF gas without CO2 CO2 separation BF gas equipment Coke Hot metal Slag Other CO2 Improvement of coke Unused waste heat recovery Increase of hydrogen Utilization of CO2 capture, separation concentration in COG unused waste heat and recovery Hydrogen reduction Technology to decrease Technology to CO2 capture, CO2 emissions separation and recovery Fig. 1. Route of the COURSE50 project Hydrogen concentration: 55%→63-67% Gas volume: to be double Enriched H2 (derived from Catalytic chemical reaction field sensible heat) Coke ex: CH4+H2O→3H2+CO COG COG H2 sensible heat H2 (water vapor) Waste heat Hydrocarbons Hydrocarbons (Sensible heat) (methane, etc.) (methane, etc.) CO, etc CO, etc H2 reduction COG H2 enrichment COG H : 65% of iron 2 (dried gas) ore H2 Enriched H2 H2 reduction process flow H2 enrichment concept (converted from tar and light oil) Fig. 2. Process of H2 enrichment from COG According to the report on the 12th CSM Steel Congress by Akihiko Inoue who was the vice president of Nippon Steel Co., the roadmap for super innovative technologies development by JISF (Japan Iron and Steel Federation) was given as Fig 3. COURSE50 was just the first step. Actually, a series of relevant hydrogen metallurgy technologies, such as H2 reduction in BF (internal H2 and external H2), H2 reduction without BF, CCS, and CCU, had been undertaken or planned in Japan [20]. Development of technologies specific to iron and steel sector 2010 2020 2030 2040 2050 2100 COURSE50 H2 reduction in BF (internal H2) R&D Introduction Super COURSE50 H2 reduction in BF (external H2) R&D H2 reaction ironmaking H2 reduction without using BF R&D Introduction CCS Recovery of CO2 from BF gas, etc. R&D Introduction CCU Adding value to CO2 from steel plant R&D Introduction Development of common fundamental technologies for society Zero-emission electricity Zero-emission electricity though R&D Introduction nuclear, renew ables, etc. Carbon-free H Low cost, large quantity production 2 R&D Introduction with nuclear and renew ables, etc. CCS/CCU Cheap storage, location, adding R&D Introduction value, etc. Fig. 3. Roadmap for super innovative technologies development by JISF 2.1.2 H2 metallurgy projects in Korea The hydrogen reduction ironmaking was developed through the public-private cooperation in Korea. There are three steps: starting the trial operation in test furnace from 2025; putting into production in two BFs from 2030, the CO2 emission decreased by 1.6%; achieving the complete hydrogen reduction [40] ironmaking in twelve BFs will be by 2040, the CO2 emission decreased by 8.7% .