China’s govt lays out low-carbon steel technology roadmap

• Carbon peaking by 2030 integral to dual carbon policy
• Proper standards system, sustainability data collection vital
• Lowering hydrogen cost key to energy transition in industry

The Iron and Steel Industry Low-Carbon Work Promotion Committee held a meeting recently to discuss suggestions for low-carbon transformation of China’s steel industry. Understanding the process and mechanism of climate change will help to more fully understand the background and significance of the country’s dual-carbon goal. China’s steel industry should make a contribution to the low-carbon development of world steel.

Steel and metals are the basis of sustainable development and in the near future the market will choose more steel as a green material. The low-carbon challenges confronting China’s iron and steel industry need to be addressed objectively in the context of national development.

Policymakers are emphasising on achieving energy efficiency and technology breakthroughs. It is essential to create a low-carbon value chain and industrial ecosystem as well as cross-industry collaboration. Strengthening the formulation and implementation of standards to promote a green manufacturing system is also essential.

However, the level of energy conservation and emissions reduction in some iron and steel enterprises is not high enough and there are weak links in the standardisation of data and management systems and the improvement of the standards system.

Dual carbon goal

The Ministry of Industry and Information Technology has floated several ideas on emissions reduction and high-quality development of the iron and steel industry: Companies need to strengthen top-level design and make practical layouts. It is strictly forbidden to add new steel production capacity. It is vital to strengthen the adjustment of industrial structure and the steel industry, an important basic industry of the national economy, is carbon and energy-intensive, and is therefore one of the main battlefields for energy conservation and carbon reduction.

The Ministry of Ecology and Environment has pointed out that the country’s efforts to address climate change have made progress, and the intensity of carbon emissions has continued to decrease. In 2021, the national carbon dioxide emissions per unit of GDP will decrease by 3.8% y-o-y, a cumulative decrease of 50.3% from 2005.

The ‘Carbon Neutral Vision and Low-Carbon Technology Roadmap for the Iron and Steel Industry’ proposes a dual-carbon technology pathway for China’s iron and steel industry – system energy efficiency improvement, resource recycling, process optimisation and innovation, smelting process breakthroughs, product iterative upgrade and capture and storage utilisation.

The Roadmap proposes four stages of implementation of the dual-carbon project: the first stage (before 2030) is for actively promoting the steady realisation of carbon peak; the second stage (2030-2040) will focus on innovation-driven realisation of deep de-carbonisation; the third stage (2040-2050) will have to be a major breakthrough in limiting carbon emissions; and the fourth stage (2050-2060) will integrate development of carbon neutrality.

The key tasks are deepening the supply-side structural reforms, continuing to optimise the process structure, developing low-carbon technologies, building a green and low-carbon industrial chain, and strengthening global low-carbon industry innovation cooperation.

Hydrogen metallurgy

As a major carbon emitter, the steel industry accounts for about 15% of the country’s total carbon emissions. Raw material or fuel substitution is an important measure to reduce emissions. Hydrogen metallurgy technology uses hydrogen as a reducing agent to replace carbon, which is an important way of reducing emissions from long-process steelmaking and ensuring sustainable development.

In February 2022, the Ministry of Industry and Information Technology, the National Development and Reform Commission, and the Ministry of Ecology and Environment jointly issued the ‘Guiding Opinions on Promoting the High-Quality Development of the Iron and Steel Industry’, which clearly stated that the promotion of hydrogen metallurgy, low-carbon metallurgy, clean steel smelting, and development of advanced technology such as strip casting and endless rolling is a priority.

Technology processes

Hydrogen energy is an effective way to eliminate carbon emissions from traditional steel and ironmaking. Hydrogen energy can replace fossil fuels in blast furnace ironmaking, sintering, hot blast furnaces, lime kilns, steel rolling and heating furnaces and other production processes.

Typical hydrogen metallurgical processes mainly include hydrogen plasma direct steelmaking, hydrogen smelting reduction and hydrogen direct reduction, etc. Among them, the two main ones are blast furnace hydrogen-rich smelting and gas-based direct reduction shaft furnace ironmaking.

Blast furnace hydrogen-rich smelting is to inject hydrogen-rich gas (coke oven gas, natural gas) or hydrogen into the blast furnace, which is a low-carbon ironmaking technology. Blast furnace injection of H2 or hydrogen-rich gas helps to increase pig iron production, achieve coke saving to a certain extent and reduce carbon emissions.

At present, the process has become mature and has many advantages such as improving blast furnace operating conditions, energy utilisation efficiency, reducing the use of coal and coke and reducing emissions. However, due to the limited amount of injected hydrogen, the carbon emission reduction of blast furnace hydrogen-rich reduction is 10-20%, and the effect is limited.

The gas-based direct reduction shaft furnace uses the mixed gas of H2 and CO to convert iron ore into direct reduced iron, which is then put into electric furnace for smelting; this process can control carbon emissions from the source, and the carbon reduction rate can reach more than 50%.

In order to achieve the goal of dual carbon steel enterprises actively participate in the research and development of hydrogen metallurgy technology and some enterprises have built or will build related hydrogen metallurgy production lines one after another. However, the hydrogen metallurgy process has not yet achieved large-scale development and application.

Roadblocks

The cost of hydrogen is a major factor. The production scale of the iron and steel industry is huge, and the large-scale implementation of hydrogen metallurgy requires a large number of low-cost, environmentally friendly hydrogen sources with high environmental performance and energy conversion efficiency. At present, hydrogen is a relatively expensive secondary energy with high price. Therefore, the future development of hydrogen metallurgy technology depends to a large extent on the large-scale, economical, green production and economic storage and transportation of hydrogen.