Looking at the use of hydrogen in steel-making and other industries would help complete the picture of hydrogen as a source of energy for propelling economic activities; after discussing the history of hydrogen and the use of hydrogen in the transport industry in the previous articles.
Let’s first discuss the basic question.
Why do we need Green Steel?
In the traditional way of making steel, steel plants use five major raw materials, iron ore, carbon, chromium, nickel, and most importantly, fossil fuels. The fossil fuel, mainly coal, is burnt in large quantities to raise the temperature to 1100 degrees to melt the iron ore and reduce the ferrous oxide to metallic iron. This directly produces flabbergasting amounts of carbon emissions. In fact, it produces 5% of total CO2 emissions and is the largest industrial emitter.
Next, carbon is added to the iron ore to give it strength, chromium and nickel are later added to give it rust-resistant capabilities. This process, though simple, is a matter of concern. If this continues, in the near future, we will face grave problems related to the environment and our physical health.
Major steel players are now facing this decarbonisation challenge, which if lost, would most definitely throw them off their throne. Especially considering that consumer sentiments are moving vehemently toward a greener future and boycotting products that leave a debilitating carbon footprint on our planet. Recent studies estimate that the global steel industry around 14 percent of steel companies’ value is at risk if they are not able to decrease their environmental impact. Therefore decarbonisation needs to be a top priority for all the major and micro steel producers to stay economically relevant.
What is Green Steel
Green steel or Fossil Fuel Free Steel is steel manufactured with absolutely no use of fossil fuels. One worthwhile thing to note is that Green Steel is also called DRI (Directly Reduced Steel). It is formed using HYBRIT, where HYBRIT stands for Hydrogen Breakthrough Ironmaking Technology. But one thing to note is that hydrogen is not the only method of producing green steel. We can also use electric arc furnaces which are making huge moves in the industry, but for this steel to be labelled green, the furnaces have to be powered by electricity sourced from renewable sources.
However, in this article, we will focus on the Hydrogen method which is discussed below.
Ways Hydrogen is being integrated into Steel Production
There are mainly two areas where hydrogen can be integrated to reduce carbon emissions:
1) Hydrogen can be injected into the blast furnaces which would then both generate heat and reduce the iron ore (reduce here means removing the oxygen from it). This area, however straightforward, is very inefficient and causes only a 20% decrease in carbon emissions compared to the traditional method. This reduction when compared to the sheer effort one would have to make and the money one would have to invest to obtain green hydrogen makes this undesirable.
2) Hydrogen can also be used as a reducing agent using DRI (Direct iron reducing) to form sponge iron. This sponge iron is then used to make steel in electric arc furnaces. This method is very successful in reducing emissions (i.e by 90-95%!). Furthermore, it is also carbon neutral. Carbon however not used in the first part of the process (i.e formation of sponge iron) will be used in the second part (formation of steel in the electric arc furnace) as carbon is alloyed into metallic iron to give it strength.
Deeper into HYBRIT
HYBRIT was founded by the collaboration of major Sweden players such as SSAB (Steel company), LKAB (mining company), and VATTENFALL (energy company) with an aim to revolutionise steel making. In this technology, fossil-free iron ore pellets from LKAB, and climate-neutral hydrogen from Vattenfall are used. This method is called Direct Reduction (DR) as oxygen is removed from the iron ore without melting it. Meaning it is reduced in the solid form itself.
The reducing agents in this method are hydrogen, (which is formed from water using electricity), and carbon monoxide (which reduces Iron Ore and produces carbon dioxide but if shaft furnaces are used, hydrogen can completely substitute carbon monoxide and CO would no longer be used, which means carbon dioxide would no longer be formed). This method emits water instead of carbon dioxide. After the formation of metallic iron using this process, it is then fed into an electric arc furnace.
The Electric Arc Furnace
Figure: “ULCOS hydrogen-based route to steel” by “Hydrogen Ironmaking: How It Works” written by Fabrice Patisson and Olivier Mirgaux, open access Creative Common CC BY licence
The electric furnace is cylindrical with thick walls made of heavy metal. It has a dome-shaped removable roof that shuts the furnace up. The dangerous metal dust is vented out using a duct that empties the dust into a drop-out box. The scrap loading and charging process is fully automated which vouches for its efficiency and safety. Once the metal scrap and iron sponge are loaded into the furnace, high-current electric arcs are used to melt the low carbon and potassium iron ore pellets into the steel of specific compositions.
Advantages and Disadvantages of Electric Arc Furnace
Some advantages are that this method allows for better thermal control which in turn allows for larger alloy additions. Furthermore, in this method (under general production of steel) the quality of steel scrap doesn’t matter. However, there are numerous disadvantages too. For example, due to weak oxidation, slag mixing is not as intense, and causes the resulting steel to be weaker, therefore we need to add more carbon (0.05% instead of 0.01% or 0.02% in blast furnaces) than we would generally have to add in the traditional method (a blast furnace).
Furthermore, steel produced by EAF (electric arc furnace) method usually has a higher nitrogen percentage due to it dissolving from the air into liquid steel. About 40 to 120 parts per million of nitrogen are found as compared to 30 to 50 parts per million in BF (Blast Furnace) steels. This is problematic because nitrogen by property makes steel brittle so this increase in nitrogen percentage could affect the overall strength of the EAF steel. However, by introducing other gases (which do not have an embrittling effect) in the vicinity, applying a carbon monoxide boil, or applying an argon stir to the melt, this percentage can be decreased.
Why Sweden and Finland are suitable for the application of HYBRIT
This method of production using hydrogen hasn’t been tested on an industrial scale, but technically seems economically and environmentally attractive for future generations. According to a pre-feasibility study conducted in 2017, this route is the most economically feasible for northern parts of Sweden and Finland due to government policy and support.
This is due to the fact that after the Paris agreement, the parliament put forth a new climate law that aims to have no net greenhouse emissions by 2045. Same way, Finland put forth a climate plan to be carbon neutral by 2030. Now, SSAB accounts for 10 percent of CO2 emissions in Sweden and 7 percent in Finland so considering its huge role in the countries’ carbon footprint, they collaborated with LKAB for low phosphorus iron ores in pellet form and VATTENFALL to come up with HYBRIT and reduce their negative impact as that is the only way to reach the goals that the countries have set.
Furthermore, due to extensive electrical power, close vicinity to iron ore mines, top research centres, and close cooperation in the industry, Sweden and Finland are more than ideal for HYBRIT.
Now that we have discussed science and technology, let’s talk numbers. After the pre-feasibility study results, a plan for a pilot plant was made. Construction started in 2018 and the plant produced its first fossil-free steel in 2021. The 1 ton/hr plant had a production cost of SEK 1.1 billion split between the three companies. On top of this, they saw financial support of SEK 599 million from the Swedish Energy Agency.
Now let’s talk about the production economy of steel itself. The main reason for a large increase in fossil-free steel costs is due to the high cost of the electricity itself (which is used to make hydrogen), but by using green energy sources such as wind and by optimising/reducing the production time of electrolysis would cause a 6-7% decrease in electricity cost. i.e efficiency increase causes a decrease in cost. But in the current scenario, compared with the traditional way of making steel using blast furnaces, HYBRIT costs 20-30% more to produce.
However, in the future, this gap will most likely reduce due to a drop in the cost of electricity and an increase in the cost of coal and other fossil fuels (due to a decrease in supply). Furthermore, due to countries putting a cap on CO2 emissions, most steel plants would have to switch to this method eventually to ensure compliance.
Current and future application
In August 2021, SSAB made the world’s first customer delivery of fossil-free steel to Volvo group for trial before it is used commercially. Estimates show that we could see Volvo vehicles made with fossil-free steel as soon as 2026! Volvo has announced that small-scale production of vehicles made from green steel will start in 2022.
In the future, it is predicted that traditional steel-making processes would be completely replaced by this new HYBRIT technology. This will completely revolutionise the industry and have a hugely positive effect on the environment.
Hydrogen use in other industries
Now that we have gone deep into the use of hydrogen in the steel industry, it’s only fair we discuss some ways hydrogen is used in other industries. Major industries where hydrogen is being integrated are namely, the chemical industry, the cement industry, and in refining.
A description of them seems apt.
Use of Hydrogen in the Chemical Industry
Hydrogen has always been a big player in the chemical industry. Mostly for the manufacturing of ammonia which is then used in various fertilisers. But that’s not all, hydrogen is also used to make methanol, polyurethane, and nylon. To make ammonia, hydrogen is mixed with nitrogen in a ratio of 3:1 under very high pressure. However, the hydrogen used currently is produced from fossil fuels (i.e coal or natural gas), so a switch to low-carbon hydrogen would result in a decrease in about 30Mt of CO2 per ton of ammonia produced.
Although the process of making ammonia is relatively “clean”, it still produces excess N20 which disturbs the natural nitrogen cycle of the environment and can cause a disturbance in the life cycles of various species of animals and even plants.
Use of Hydrogen in Refining
Hydrogen is also known to be used for the desulphurisation of fossil fuels. The hydrogen used here is fossil hydrogen and a switch to green hydrogen would reduce emissions but not by much as any real decrease in emissions cannot happen if fossil fuels are still used.
Use of Hydrogen in the Cement Industry
The use of hydrogen in the cement industry isn’t as prominent as it is in other industries. In the cement industry, the only place where it can be integrated is as a fuel. It can replace the use of coal and natural gas as source of heat. The use of green hydrogen could reduce emissions from the cement industry but not by a lot. However, the day hydrogen replaced fossil fuels in the burner still seems far as hydrogen is a fuel with different properties and heat dispersing rate therefore, it might not be enough to heat the cement kiln. In the future, this method of cement production could be beneficial but in the current scenario, it is not very realistic.
This is part 3 of the 4-part series on understanding Hydrogen.
Read Part 1 of the series ‘History of Hydrogen as a Fuel’ here.
Read Part 2 of the series ‘Use of Hydrogen in Modern Transport’ here.
Read Part 4 of the series ‘The many shades of Hydrogen’ here.
Snigdha Singh, a 12th grade student from Mumbai, is an intern here at CFA and is passionate about economics and finance.
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