Hydrogen metallurgy process under the background of carbon neutrality may be popular

In contrast, the gas-based direct reduction shaft furnace process plays an important role in controlling the input of carbon-containing raw materials from the source and the final output of carbon dioxide. A gas-based direct reduction shaft furnace converts iron ore to direct reduced iron (DRI) by using a mixture of hydrogen and carbon monoxide instead of carbon monoxide as a reducing agent, which is then fed into an electric furnace for further smelting. Obviously, because hydrogen is the main reducing agent, its final product, carbon dioxide emissions will be effectively controlled. Compared with the hydrogen rich reduction blast furnace, the carbon dioxide emission per ton of iron ore smelting using the gas base direct reduction shaft furnace process is reduced by more than 50%. Taking the existing traditional long process iron making technology as an example, carbon dioxide emissions per ton of steel have dropped from the existing nearly 2 tons to less than 1 ton, which undoubtedly brings new possibilities for China to achieve carbon peak and carbon neutrality goals.

In addition to the existing use of hydrogen-carbon monoxide mixture for iron ore smelting, the exploration of pure hydrogen iron making in the industry has also been actively promoted. This process will reduce CO2 emissions by 98% compared to the long process, once again creating new possibilities for cleaner production in the steel industry. Of course, under the existing conditions, due to the strong endothermic effect of hydrogen reduction, the gas volume of the full hydrogen shaft furnace will increase significantly, the reduction rate will also be affected, and the full hydrogen has high requirements for equipment and operation, etc., and the full hydrogen metallurgy technology can not be promoted and applied in a large area in a real sense.

In summary, under the background of carbon peaking and carbon neutrality, the gas-based direct reduction shaft furnace process will be the mainstream hydrogen metallurgy technology means in China in the short term, and the further maturity of the process will also be the main exploration direction of the industry.

Analysis of important factors restricting the development of hydrogen metallurgy process

Gas-based direct reduction shaft furnace process undoubtedly brings a new idea for carbon control and emission reduction in China, but there are many problems in front of us. In addition to the equipment line production of the process, operator training and other factors, the source of hydrogen has a direct impact on the actual promotion and application of this technology.

The existing hydrogen production process is mainly divided into three categories: hydrogen production from fossil energy, industrial by-product hydrogen, and hydrogen production from electrolytic water. Fossil energy hydrogen production mainly includes coal hydrogen production and natural gas hydrogen production, of which the former as a low cost hydrogen production technology in the domestic development is more mature, it is estimated that in the case of raw coal (carbon content of more than 80%) 600 yuan/ton, the production cost is 8.85 yuan /kg, of which the raw material cost accounts for only 15%-20%. Compared with the 70% raw material cost ratio of natural gas hydrogen production, the cost of coal hydrogen production technology is more controllable. However, because the process of coal to hydrogen will extend more carbon footprint, this feature is contrary to low-carbon goals such as energy conservation and emission reduction. In recent years, coke oven gas hydrogen production, light cracking hydrogen production, chlor-alkali by-product hydrogen production as the main industrial by-product technology has been developed. These three hydrogen production processes theoretically produce high purity hydrogen, but the key to restricting its development is whether its raw materials are in sufficient supply. In the existing relatively mature electrolytic cell technology, proton exchange membrane (PEM) and alkaline electrolytic cell (AE) although the technology is not a problem, but due to the high cost of electricity, it has not been widely used. According to market electricity price estimates, the cost of hydrogen production by electrolytic water is about 30-40 yuan /kg.

In the above three hydrogen production processes, the purity of the finished hydrogen obtained by electrolytic water hydrogen production can be as high as 99% in theory, compared with other ways, electrolytic water hydrogen production undoubtedly has an absolute advantage in the key indicator of hydrogen purity. Of course, with the existing power supply situation, it is obviously impossible to popularize electrolytic water hydrogen production in a large area, but considering the development of clean energy power generation in China, the future use of such as biological energy, nuclear energy as a source of electrolytic water hydrogen production power may bring more possibilities for the further development of the process.

Sum up

For a long time, China's hydrogen metallurgy process has not ushered in rapid development due to technical, cost and other factors. However, in the new situation of carbon neutrality, the development of hydrogen metallurgy process has once again gained new momentum. At the same time, with the maturity of the relevant hydrogen production process and the reduction of the cost of hydrogen production brought about by the development of the new energy industry, it will also provide a strong guarantee for the development of hydrogen metallurgy process in China.