"Using hydrogen instead of coal" to make iron, how much do you know about hydrogen metallurgy technology?



Basic principles of hydrogen metallurgy

Carbon metallurgy is the representative development mode of iron and steel industry, the basic reaction formula of smelting is Fe2O3+3CO=2Fe+3CO2, carbon as a reducing agent and produce product carbon dioxide. The concept of hydrogen metallurgy is based on the concept of carbon metallurgy, the basic reaction formula of hydrogen metallurgy is Fe2O3+3H2=2Fe+3H2O, hydrogen acts as a reducing agent and the product is water, carbon dioxide emissions are zero.

From the perspective of hydrogen metallurgy thermodynamics, according to Fe-O-H system equilibrium, below the critical temperature (about 570℃), the order of H2 reduction of Fe2O3 is Fe2O3-Fe3O4-Fe; Above the critical temperature, the order of reduction of Fe2O3 by H2 is Fe2O3-Fe3O4-Feo-Fe. The thermodynamics of hydrogen reduction in the reaction process includes two technological routes: low temperature reduction and high temperature melting reduction. From the perspective of hydrogen metallurgy kinetics, the kinetic condition of hydrogen reduction of iron oxide is better than that of CO, and the mass transfer rate of hydrogen is obviously higher than that of CO. Compared with the reduction kinetic conditions of CO, the reduction kinetic conditions of hydrogen-rich gas or pure hydrogen are improved [1].

Hydrogen metallurgy process

At present, there are mainly two kinds of hydrogen metallurgy processes: hydrogen rich reduction blast furnace and gas base direct reduction shaft furnace. Hydrogen rich reduction blast furnace technology is an improvement of the existing long process process, and the emission reduction potential is limited. Gas base direct reduction shaft furnace is a direct reduction technology, which does not need coking, sintering, iron making and other links, and has great emission reduction potential. The exploration of pure hydrogen iron making has also been actively promoted. Carbon dioxide emissions will be reduced by 98% compared to the long process. However, under the existing technical conditions, it can not be widely applied, and the high cost is the main reason.

Development of hydrogen metallurgy at home and abroad

In the application of hydrogen metallurgy, the domestic is still in the research and development test stage, and in the international community, has begun ultra-high temperature gas furnace and smart atomic furnace hydrogen smelting technology closely related technology research, ThyssenKrupp has achieved the use of hydrogen in blast furnaces.

Foreign demonstration project

(1) ThyssenKrupp "Blast Furnace hydrogen steelmaking" project

On November 11, 2019, German steel producer ThyssenKrupp officially launched the test of hydrogen metallurgy. According to ThyssenKrupp, this is the first time in the world that a steel company has used hydrogen instead of coal in a steelmaking process to reduce carbon dioxide emissions. On February 3, 2021, ThyssenKrupp successfully completed the first phase of the hydrogen utilization test for blast furnace No. 9 in Duisburg. Due to the COVID-19 pandemic, the start of the second phase of the trial was delayed until 2022. The second phase of the experiment will focus on the influence of hydrogen utilization technology on the blast furnace metallurgical process.

(2) Sweden's HYBRIT project - the world's first fossil fuel-free sponge iron pilot line

HYBRIT is Sweden's "breakthrough hydrogen ironmaking technology" technology research project, by three industry giants (SSAB, Europe's largest iron ore producer LKAB company and one of Europe's largest power producers, Sweden's Great Falls Power company) to create a joint venture HYBRIT Development Limited responsible for promoting. SSAB, LKAB and Vattenfall plan to create the world's first value chain with "fossil-free steel manufacturing". SSAB aims to be the first in the world to achieve fossil-free smelting technology through HYBRIT technology by 2026. By 2045, SSAB will manufacture steel entirely along fossil-free process lines.

(3) Voestalpine H2FUTURE Project

In early 2017, the H2FUTURE project, co-launched by Voestco, aims to reduce CO2 emissions in steel production by developing breakthrough hydrogen alternative to coke ironmaking technology, with the ultimate goal of reducing CO2 emissions by 80% by 2050. Members of the H2FUTURE project include Voestalpine, Siemens, VERBUND (Austria's leading electricity supplier and Europe's largest hydropower producer), the Austrian Grid (APG), and the Austrian K1-MET (Metallurgical Competence Center) Central Group.

Domestic hydrogen metallurgy development

(1) China Baowu nuclear energy - hydrogen production - metallurgical coupling technology

On January 15, 2019, China Baomu, China National Nuclear Group and Tsinghua University signed the "Nuclear Energy - Hydrogen production - Metallurgy coupling technology Strategic Cooperation Framework Agreement", and the three parties will cooperate to jointly build the world's leading nuclear hydrogen metallurgy industry alliance. Based on the world's leading fourth-generation high-temperature gas cooled reactor nuclear power technology, the research and development of ultra-high temperature gas cooled reactor nuclear hydrogen production technology is carried out, and coupled with iron and steel smelting and coal chemical process, relying on the development needs of China's Baowu industry, to achieve ultra-low carbon dioxide emissions and green manufacturing in the steel industry. Among them, nuclear hydrogen production is the coupling of nuclear reactor and hydrogen production plant using advanced hydrogen production technology to carry out large-scale H2 production. According to preliminary calculations, a 600,000-kilowatt high-temperature gas-cooled reactor unit can meet the demand for hydrogen, electricity and part of oxygen for 1.8 million tons of steel, reduce about 3 million tons of carbon dioxide per year, and reduce energy consumption about 1 million tons of standard coal, which will effectively alleviate the carbon emission reduction pressure on China's steel production.

In July 2020, Baowu carried out a hydrogen-rich carbon cycle oxygen blast furnace process experiment in Baogang, and connected the decarbonized gas to the hydrogen-rich carbon cycle blast furnace. Compared with the access to the decarbonized gas of the European metallurgical furnace, the ton iron fuel ratio of the hydrogen-rich carbon cycle blast furnace decreased by nearly 45 kg, and the emission reduction of CO230% compared with the traditional blast furnace. In July 2021, Bachang's hydrogen-rich carbon cycle blast furnace has completed the oxygen enrichment target of 50% of the second stage (35% of the first stage), and the later stage of Bachang's hydrogen-rich carbon cycle blast furnace will achieve the goal of full oxygen smelting through technology upgrading and optimization. In January 2021, Baowu announced that it would achieve carbon peak in 2023, reduce carbon by 30% in 2035, and achieve carbon neutrality in 2050.

(2) Hesteel Group hydrogen rich utilization project

On November 22, 2019, Hesteel Group and Italy Tenion Group signed a memorandum of understanding, agreeing that the two sides would carry out in-depth cooperation in hydrogen metallurgy technology, use the world's most advanced hydrogen production and hydrogen reduction technology, and join hands with MCC Jingcheng to jointly develop and build the world's first 1.2 million tons of hydrogen metallurgy demonstration project, which would be applied to the transformation and upgrading project of Hesteel Xuansteel. In May 2021, Hesteel Xuangang Hydrogen energy development and utilization project demonstration project officially started construction. The project makes full use of the advantages of Zhangjiakou's national renewable energy demonstration zone to create an innovative development model of synergistic complementarity between "zero carbon" hydrogen production and hydrogen energy industry development that can be promoted and replicated. The new hydrogen reduction process developed by the project relies on independent and integrated innovation, adopts the model of combining production, learning and research, and the core technology is Tenova's Energiron-ZR (zero reforming) technology, which can replace the traditional blast furnace carbon metallurgy process, and is expected to reduce carbon by 60% per year.