High Temperature Materials and Processes (Nov 2024)
Analysis of carbon emission reduction capacity of hydrogen-rich oxygen blast furnace based on renewable energy hydrogen production
Abstract
Iron and steel industry is the pillar industry of the national economy, but it is also the source of highest carbon emission in manufacturing industry. With the proposal of China’s goal of peaking carbon emissions and achieving carbon neutrality, the steel industry urgently requires substantial technological breakthroughs in carbon reduction. About 90% of China’s crude steel production is produced through the blast furnace-basic oxygen furnace process, and blast furnace carbon consumption accounts for more than 70% of steel process carbon consumption. Therefore, blast furnace carbon reduction is the focal point of China’s steel industry’s efforts to mitigate carbon emissions. The hydrogen-rich gas injection to blast furnace and blast furnace with top gas recycling process are effective ways to reduce carbon emissions. However, these approaches still rely heavily on the fossil fuel coal-dominated energy structure. With the rapid development of renewable energy hydrogen production in China, hydrogen-rich oxygen blast furnace technology, which replaces carbon with hydrogen, can significantly reduce carbon emissions from ironmaking at the source. This article establishes a multizone constrained mathematical model for hydrogen-rich oxygen blast furnaces, calculates energy balance based on the constraint conditions of each zone, and systematically studies the influence of hydrogen injection, burden metallization rate on the coke ratio, top gas recycling injection volume, reducing gas composition, and CO2 emission reduction of hydrogen-rich oxygen blast furnaces. The research results show that at maximum hydrogen injection rate of about 600 N·m3 H2·t−1-HM (ton-hot metal), a replacement ratio of about 0.4 kg-coke·(N·m)−3-H2 was achieved with about 27% CO in the reduced gas of the shaft, 68% H2, 90% burden metallization rate. Coke ratio of the hydrogen-rich oxygen blast furnace is reduced to 203 kg and the CO2 emission is reduced to 501 kg·t−1-HM, 55% lower than that without hydrogen injection with a very significant CO2 reduction at the source.
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