- Carbon capture vital in primary steelmaking route
- Unavailability of natural gas for BF major hindrance
- Physical limit of hydrogen injection in BF 20%
The decarbonisation challenge for Indian steelmakers is tough, although it may well be expected that many of the breakthrough technologies will first be incubated in India, technocrat Alexander Fleischanderl, CTO Upstream and Head of Green Steel SVP, Primetals Technologies Austria GmbH, told SteelMint in a recent interview.
“Considering scope 1 and 2, on a global level the steel industry emits 2 tonnes (t) of CO2 per tonne of steel produced. Around 9% of global CO2 emissions come from steel,” says Fleischanderl while at the same time underlying the centrality of steel in the energy transition.
“The global energy transition will be built on steel. A new renewable energy installation – say a wind or a solar park – needs five to six times more steel build per specific energy unit output than a gas plant or a coal-fired power plant. Renewable energy installations are steel-intensive. More steel will be needed to build them. Also, the developing nations, led by India, will see huge growth in steelmaking capacity in the coming decades,” he says.
So, the decarbonisation challenge is a tough one. While Europe has taken the lead in decarbonising the steel industry, there will be different timelines for different countries.
Decarbonisation strategy
“Primetals has a decarbonisation strategy that, first of all, seeks to optimise energy and emission efficiency at existing steelmaking assets, mainly the integrated blast furnace-basic oxygen furnace (BF-BOF) route, by around 30%,” says Fleischanderl.
The next step in the transition involves integrating electric steelmaking (EAFs) into integrated steel mills and adopting other technologies such as Arvedi ESP, which obviates the need to reheat slabs and billets in fossil-fired reheating furnaces after they have cooled down by directly rolling them in a hot condition to near end-product stage. “We see huge potential for endless casting and rolling technology,” says Fleischanderl.
The transition phase will also involve carbon capture in different parts of the world, mainly installations of industrial carbon capture plants, most certainly at the BF for capturing large volumes of CO2.
The last stage is the green steel phase which involve carbon direct avoidance (CDA), switching from fossils to hydrogen, utilising hydrogen for DRI and HBI and also for injecting into BFs, large CCS installations and utilisation of captured carbon in the chemical industry for generation of new revenue streams such as the ArcelorMittal-Primetals-Lanza Tech partnership of producing bioethanol through a proprietary microbial technology.
CCUS vital for India
BF-BOF steel capacity enhancements in Asia are locking in CO2 emissions for the foreseeable future. What is the way out? The expert contends: “It is true that BF-BOF route steel capacity is growing in Asia. It is also true that these investments are going to stay for the next four to five decades. We are aware that steelmaking in India is still largely based on the traditional method and through extensive use of coal because of the paucity of natural gas reserves and high costs of imports. Our recommendation is first, optimization of existing processes and assets, use of HBI and hydrogen in the blast furnace and other technology improvement packages to reduce the carbon footprint. However, CCUS will be vital to reduce the carbon footprint of traditional steelmaking facilities.”
Hydrogen pathway
In India renewable energy is growing at a fast pace and the scope of its use in the EAF is significant but, most importantly, renewable energy can be used to produce green hydrogen for large-scale metallurgical use. The forecast is that renewable energy installations in India are expected to touch 450 GW by 2030. The transition in India is, therefore, likely to be from the existing traditional steelmaking route to widespread use of hydrogen.
In China, the pathway is more or less similar. The country has already put in DR facilities to run on hydrogen.
Hydrogen injection in BF
For blast furnace operations we need the stability of the burden but we need permeability too, which means the coke has many uses that cannot be totally replaced right now. Steelmakers can’t replace met coke, they can only minimise its use.
“The physical limit of hydrogen application into the BF should be around 20 kg per ton of hot metal. More than that and we’ll get into a very tight window of operations which would require shaft gas injection, not yet available, to keep the top gas temperature up,” states Fleischanderl.
“BF steelmakers have the option to use HBI in a major way,” the expert informs. “Primetals offers the Sequenced Impulse Process (SIP) technology, which is short-term impulsing of oxygen injection with the objective of better utilisation of PCI coal, which has an impact on carbon utilisation and stable operations”.
Steelmakers can run on a high level of automation. There are many opportunities to optimise the carbon consumption rate at the BF facility. Residual CO2 emissions from the BF need to be captured through available and emerging CCUS technology.
~ By Nirmalya Deb
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