Among the global energy consumption and CO2 emission, industry accounts for 33% and 40% respectively, among which CO2 emission from steel industry accounts for a high proportion of industrial emission, which is about 33.8%. Hydrogen metallurgy has become a high point of ambition for leading steel companies because of its huge potential for emission reduction.
The steel industry is one of the most carbon-intensive and difficult to decarbonize industries, accounting for about 7.2% of global carbon emissions. According to the data of China Metallurgical Industry Planning and Research Institute, the carbon emission of the steel industry will account for about 15% of the country in 2020, which is the largest carbon emission industry among 31 categories of manufacturing industries in China.
Decarbonization of the steel industry cannot rely on electrification alone, but also requires more targeted solutions. Green hydrogen, as a high calorific value low carbon reducing gas, can be used to treat emissions caused by burning fuel to provide high temperatures, as well as emissions from reactive processes where coal is the primary reducing agent. In addition, steel production facilities generally have long lifetimes and low replacement rates. China, for example, has an average blast furnace life of 13 years, and other related facilities can operate for more than 20 years before being decommissioned. Therefore, on the one hand, rapid transition may bring a certain degree of stranded asset risk; on the other hand, both clean smelting technology and supporting infrastructure need to be steadily promoted from now on to gradually build up scale.
The current major global hydrogen metallurgy technology routes are as follows.
Technology | Notes | Advantages | Limitations |
Blast furnace ironmaking in a hydrogen-rich environment | Injection of hydrogen-rich gas in a conventional blast furnace ironmaking plant | Low cost of equipment renovation, economical, with a yield-enhancing effect | Limited theoretical reduction potential, technically difficult to achieve all-hydrogen metallurgy |
Gas-based direct reduction ironmaking | Direct reduction of iron making using reducing gas, the proportion of hydrogen directly boosted in the reducing gas | High theoretical abatement potential, up to 90% or more | High difficulty of equipment transformation, high quality requirement of iron ore raw material, insufficient existing process level |
Melt reduction ironmaking with hydrogen | Injection of hydrogen-containing gas in the melt reduction ironmaking process |
Blast furnace ironmaking in a hydrogen-rich environment technology is an improvement on the existing blast furnace ironmaking process. At present, most of the blast furnace hydrogen-rich smelting technologies are based on the reduction gas obtained from coke oven gas reforming or natural gas cracking to produce hydrogen for blast furnace air vent blowing. The reaction of coke reduction of iron ore in the traditional blast furnace process is exothermic, and although hydrogen reduction is more efficient, it is a heat-absorbing reaction, which will cause the temperature in the blast furnace to drop if it is carried out in large quantities, resulting in a decrease in reduction efficiency.
Gas-based direct reduction ironmaking uses coke-free reduction gas to make iron, which can significantly reduce the carbon emissions in the ironmaking process. The original technical route mainly used natural gas as the reduction gas. The hydrogen metallurgy route uses green hydrogen instead of natural gas, and almost no carbon is introduced into the ironmaking process in the pure hydrogen shaft furnace, and the carbon emission reduction capacity can reach 95%.
Melt reduction ironmaking can start with the lowest cost coal as the reductant and add carbon capture facilities to ensure low or zero carbon emissions, gradually move to a coal+gas mix, and eventually use hydrogen plasma melt reduction technology to achieve green hydrogen reductant substitution.
At present, the research of hydrogen metallurgy process has shown the innovative development trend of "blossoming". Since the traditional blast furnace smelting process cannot avoid the use of coke and therefore has limited potential to reduce CO2, many enterprises in China have made direct reduction in gas-based shaft furnace the focus of hydrogen metallurgy process research. The domestic hydrogen metallurgy situation is as follows.
Enterprise | Projects | Start-up time | Hydrogen Source |
Bayi Iron & Steel | Blast furnace hydrogen-rich reduction low carbon ironmaking | 2017 | Coke oven gas |
Xingtai Iron & Steel | Low carbon hydrogen-rich ironmaking technology transformation project | 2020 | Furnace top gas |
JInnan Steel | 2000 cubic meter blast furnace scale up hydrogen injection project | 2020 | Coal to ethylene glycol by-product hydrogen |
TaiHang Mining | Hydrogen-based direct reduction project with an annual capacity of 300,000 tons of direct reduced iron | 2013 | Coke oven gas |
Mintal Group | Gas-based shaft furnace direct reduction ironmaking project with an annual capacity of 1.1 million tons of pig iron | 2019 | Coal to gas |
JISCO | Coal-based Hydrogen Metallurgy Project | 2019 | Coal to gas |
Huaxin Steel | Direct iron reduction hydrogen-rich gas-based shaft furnace demonstration project with an annual production capacity of 10,000 tons of pig iron | 2018 | Coke oven gas |
HBIS Group | Hydrogen energy development and utilization of engineering demonstration construction projects | 2020 | Coke oven gas |
Baowu | 1 million tons/year hydrogen-based shaft furnace direct reduction demonstration project | 2021 | Natural Gas, Coke oven gas |
Rizhao Steel | Hydrogen-based gas direct reduction ironmaking project with an annual capacity of 500,000 tons of pig iron | 2020 | Hydrogen by-product from vinyl acetate production |
Hydrogen metallurgy in China is facing the challenges of immature technology, high cost of end-use hydrogen and low policy support. In order to speed up the promotion and application of green hydrogen in the steel industry, China must actively promote the basic research of hydrogen energy preparation, storage, transportation and application in the steel industry according to the local conditions and improve the relevant technology level. Actively carry out the layout of hydrogen energy industry and build hydrogen energy development and utilization engineering demonstration projects. Strive for the high point of technology and enhance the international discourse. Ultimately achieve the goal of carbon peaking and carbon neutrality in China's iron and steel enterprises.
