Last year, Goldman Sachs forecasted that by 2050, industrial hydrogen, including hydrogen-based steelmaking, will account for 18% of global hydrogen demand. Considering that demand for hydrogen for power generators is expected to be 42%, the proportion is higher than anticipated. Of course, various tasks should be preceded for hydrogen-based steel to be commercialized, such as R&D and demonstration of related technologies, adjusting the price of hydrogen for industrial use, and establishing a hydrogen supply chain. However, the future is bright for those endlessly challenging.

With the last article of the [Exploring Hydrogen with POSCO] series, Let’s go on a journey to the future hydrogen steelworks of 2050, constructed with POSCO’s unceasing strives and innovations. POSCO Newsroom introduces carbon-neutral steelworks where steel is produced without generating any CO₂ generation and the technology that makes this possible — Hydrogen-based Steelmaking.

l Good Bye CO₂: How Hydrogen-based Steelmaking Works

How does hydrogen-based steelmaking work? There is a reason why it is called hydrogen-based steelmaking and not just hydrogen steelmaking. The trick here is that hydrogen (H₂) acts as a reducing agent that separates oxygen from iron ore (Fe₂O₃). Through the process: (Fe₂O₃ + 3H₂ → 2Fe + 3H₂O), iron (Fe) is produced together with water (H₂O), and this iron is called Direct Reduced Iron (DRI).

So what reducing agents are being used as of now? It is carbon monoxide — gas generated from coal. When iron ore and coal are put into the blast furnace and melted at 1500°C or higher, the generated carbon monoxide (CO) triggers a reduction reaction (Fe₂O₃ + 3CO → 2Fe + 3CO₂) that separates oxygen from iron ore (Fe₂O₃), and CO₂ is generated at this stage.

Replacing the reducing agent coal with hydrogen might seem like a simple change, but it marks the beginning of a huge transformation. Needless to say, the steelworks will no longer generate any CO₂, a greenhouse gas, and great changes will be made to the conventional steel production process as well. So, what will the steelworks look like in 2050 once the hydrogen-based steelmaking technology is applied?

The first change is that the blast furnaces will disappear at the steelworks. Since the process of melting coal and iron ore in a single blast furnace is no longer needed, other attached facilities, such as the sintering plant and coke plant, will be eliminated along with the blast furnace. But, imagine a steelwork without a blast furnace. Where would the reduction reaction between hydrogen and iron ore take place then? This is where “Fluidized Reduction Furnace” steps in.

The fluidized reduction furnace, a facility that reduces iron ore to produce DRI, already exists in POSCO and can be found in its own FINEX (Fine Iron ore Reduction) process. In FINEX, iron ore fine and coal aren’t put into the blast furnace, but instead, they go through the fluidized reduction furnace and the melter gasifier to be processed into molten iron. This technology is the core technology in realizing hydrogen-based steelmaking. However, there is a difference between the two: FINEX uses 25% hydrogen and 75% carbon monoxide generated during the process as reducing agents, whereas hydrogen-based steelmaking (HyREX: Hydrogen Reduction) uses 100% hydrogen.

However, the blast furnace isn’t the only facility to disappear. Previously, molten iron produced in the blast furnace was converted into refined molten iron through a converter. However, in the case of hydrogen-based steelmaking, the DRI produced in the fluidized reduction furnace goes through an “electric furnace,” not a “converter,” hence the converter is expected to disappear as well. So it can be said that in hydrogen-based steelmaking, the fluidized reduction furnace and the electric furnace take the place of the conventional blast furnace and converter.

However, there is one thing to notice here — the use of power. Another significant difference between hydrogen-based steelmaking and the conventional blast furnace operation and FINEX is that it requires large amounts of external power. The blast furnace not only produces molten iron but also supplies the heat source required for post-processing and the by-product gas for power generation. The reason why by-product gas is created in the blast furnace operation is that carbon can not be used in 100% reduction. In fact, POSCO self-procures more than 60% of the power required for the steelworks by generating by-product gas power. However, in hydrogen-based steelmaking, hydrogen is used in 100% reduction so it does not create any by-product gas, meaning that all power for the steelworks must be supplied from outside. If so, once the blast furnace disappears, where do we get the power required at the hydrogen-based steelworks in 2050?

The second change at the steelworks is the increased dependency on renewable energy. “Green hydrogen” is a prerequisite for the basic concept of hydrogen-based steelmaking. This means that neither the hydrogen inserted into the fluidized reduction furnace nor the electricity production process that drives the facility should cause any carbon emission. However, as seen in [Exploring Hydrogen with POSCO #1], renewable energy, such as solar and wind power, is essential to produce green hydrogen. Therefore, those countries that cannot produce green hydrogen on their own will have to rely on imports in the future.

Solar and wind power are heavily influenced by geopolitical factors that determine sunlight and wind speed. As of 2019, the cost to generate solar energy in Korea is 163 KRW per kWh, which is 10 times more expensive than that of the Middle East. That is why Australia and the Middle East are expected to be areas to mass produce green hydrogen. According to data released by global research company Bloomberg NEF in March 2020, the global demand and supply outlook for green hydrogen in 2050 showed clear division by region. In particular, the dependence of Asian regions, including Korea, on Australia and the Middle East, which are relatively close geographically, is likely to increase. Thus, the importance of participating in green hydrogen production projects and finding partners with these regions will gradually grow more in the future.

▲ The forecast for green hydrogen trade in 2050 according to countries (Source: Bloomberg NEF, Hydrogen Economy Outlook, 2020.3.30)

The close connection between hydrogen-based steelmaking and renewable energy was also found in the HYBRIT project of SSAB, a Swedish steelmaker that operated a pilot plant for hydrogen-based steelmaking in August 2020. The HYBRIT project was participated by LKAB, the largest iron ore producer in Europe, and Vatenfall, a Swedish multinational electric power company.

In Europe, the proportion of low-carbon power generation, such as renewable energy, hydropower, and nuclear power, is already large. Germany, which announced its national hydrogen strategy last year, already covers more than 50% of its total power consumption with renewable energy, including solar and wind power. In January 2021, the European Union also announced that the proportion of renewable energy (38%) exceeded fossil fuels (37%) for the first time. European steelworks have a history of over 150 years, thus possessing many blast furnaces and related equipment that have already reached the end of their lives. Also, small-sized facilities with an annual production of fewer than 1 million tons account for a large quantity, making the transition to hydrogen-based steelmaking more active than others. On the contrary, most of the blast furnaces in Asian steelworks, including those in Korea and Japan, are of large scale with an annual production of 5 million tons, and their history is shorter, so there are many cases where the lifespan of the blast furnace remains to be several decades or more.

l Developing Technology to Advance Hydrogen-based Steelmaking: CO₂ Reduction Hybrid Steelmaking Technology

Currently, there are 15 ultra-large blast furnaces with an internal volume of 5500㎥ or more worldwide. Among these, POSCO possesses six units in total, including the world’s largest, Gwangyang Works no.1 blast furnace (6000㎥). Two-thirds of POSCO blast furnaces are ultra-large blast furnaces. Once the blast furnace starts burning, it produces molten iron until the fire goes out completely, and POSCO Pohang Works no.1 blast furnace, which produced the first molten iron in 1973, is still in operation. Considering this, rather than implementing the change suddenly at once, it would be much more realistic to promote the transition to hydrogen-based steelmaking in stages, according to the situation of each country and steelworks, while simultaneously conducting CO₂ reduction activities for existing blast furnaces.

Currently, POSCO is participating in the government-led development of the CO₂ reduction hybrid steelmaking technology based on blast furnaces, which has been underway since December 2017, and seeking various ways to reduce CO₂, such as partially replacing coal with hydrogen-containing resources or carbon-neutral reducing agents such as biomass*, and partially reducing iron ore before putting them into the blast furnace. By applying this technology to blast furnaces, it becomes possible to reduce CO₂ emissions by about 10% compared to conventional blast furnaces. POSCO Newsroom will cover this CO₂ reduction hybrid steelmaking technology next time.

^*Biomass: living organisms in general, including plants that synthesize organic matter by receiving solar energy, and animals & microorganisms that feed on these plants

POSCO has declared to achieve carbon neutrality by 2050 last year. Accordingly, in the short term, it plans to develop technology to reduce CO2 emissions and expand its low-carbon product portfolio while, in the long term, achieving carbon reduction by realizing hydrogen-based steelmaking. Since hydrogen-based steelmaking technology requires a long time and enormous cost, POSCO is promoting joint R&D for hydrogen-based steelmaking technology with domestic and foreign steelmakers. In his speech at the World Steel Dynamics (WSD) conference last October, POSCO CEO Jeong-Woo Choi called for joint action of the steel industry, such as promoting the Green Steel Initiative and sharing information & collaborative technologies regarding carbon reduction.

Hydrogen society is fast approaching. And at the center of this is POSCO, which continues to pioneer and innovate towards carbon-free steelworks with its world-class steel technology.

In June 2020, Germany’s Minister of Economic Affairs and Energy, Peter Altmaier, said the above when briefing the national strategy. According to the National Hydrogen Strategy, Germany is to develop all technologies for producing, transporting, storing, and utilizing hydrogen in Germany. Investment in hydrogen power generation alone reaches 12 trillion KRW. How far are Asian countries leading in this area then? Korea established an hydrogen economy master plan in 2004 and announced a hydrogen economy roadmap in 2019. Japan fabricated a hydrogen fuel cell strategy roadmap in 2014, while China announced the China Hydrogen Initiative in 2017. Additionally, in July 2020, Korea announced the “Korean New Deal” and plans to invest about 73 trillion KRW (43 trillion KRW at government expenditure) for the Green New Deal, out of a total investment of 160 trillion KRW. And 24 trillion KRW will be invested at government expense for new renewable energy.

The announcement of Germany to develop all hydrogen technologies from production to utilization has two implications. One is that the hydrogen business model is considered as an entire process that works as a value chain rather than viewed as in individual phases of production, transport, storage, and utilization. The other is that the success of the hydrogen business ultimately depends on the technology that deals with hydrogen.

In December 2020, POSCO announced plans to achieve “Carbon Neutrality” by 2050 and a green hydrogen business model. By 2030, POSCO will focalize on equipping itself with hydrogen production capabilities and core technologies and nurture the hydrogen business as the group’s growth engine. And for this, strengthening its technological capacities for hydrogen is essential, which includes developing steel products for producing, transporting, storing, and applying hydrogen, increasing byproduct hydrogen production facilities, developing core technologies for hydrogen, and also hydrogen-based steelmaking technology.

Then what are some of the technologies related to hydrogen? In the first part of “Exploring Hydrogen with POSCO,” we looked at the relationship between hydrogen production and steel. In the second part today, we will look at steel products for hydrogen transport applied according to the different states of hydrogen and the key material in hydrogen production and application technology — the stainless steel separator.

First, the most crucial factor when dealing with hydrogen in a gas state is “pressure”. When the pressure rises, hydrogen penetrates and degrades the metal, causing “hydrogen embrittlement,” which eventually breaks the metal. Molecular hydrogen (H₂) cannot penetrate metal, but atomic hydrogen (H) is so fine that it can penetrate metal. Thus, when the pressure increases, the number of these atoms increases, resulting in hydrogen embrittlement.

However, as the pressure of hydrogen increases, its volume decreases and results in better transport efficiency. So the technology is evolving to enable materials to endure the increasingly high pressure of hydrogen better. For example, the simple pipeline for hydrogen transport can currently withstand around 20 bar but extends to 100 bar to increase transport efficiency. In general, fuel cell electric vehicles should be able to withstand 700bar and hydrogen stations 99 bar. Then, what does 700bar mean? “Bar” is one of the units to measure pressure, and it refers to the air pressure 100m above sea level. For instance, if your waterproof wristwatch reads 10bar, it means that it can withstand a depth of about 100m. So, 700bar is an unimaginable amount of pressure — the pressure you experience at 7,000m. Converting 700bar into weight is 713.8kg/㎠, so in other words, it is similar to the pressure received when ten adults weighing 71kg stands on a small area the size of 1㎠.

In the end, the key to commercializing hydrogen energy lies in the technology to develop a material that withstands high pressure. In addition, fuel cell electric vehicles and transport tube trailers have the issue of material weight reduction. This is why composite materials, such as carbon fiber, are currently used in hydrogen vehicles. However, composite materials are expensive, and if the price competitive steel handles hydrogen better, it will not only become a material that can compete with composite materials but also accelerate the commercialization of hydrogen.

Unlike hydrogen vehicles that require weight reduction, the transport pipes and storage containers of hydrogen stations can withstand 990 bar pressure even with carbon steel, and the steel pipes used here are seamless pipes. Seamless pipes withstand pressure better than conventional welded pipes. The reason for this is because seamless pipes are made with round hollow steel pipes without welding, so they have no seams. High-pressure hydrogen storage containers are manufactured by expanding the diameter of seamless pipes, and the 990 bar containers use large-diameter seamless pipes that are currently not manufactured in Korea and depend entirely on imports. It shows that the localization of materials, parts, and equipment is paramount. Accordingly, POSCO plans to cooperate with seamless pipe manufacturers not only in Korea but overseas as well to prepare for the expanded steel demand of hydrogen pipes and containers.

The most important factor when dealing with liquid hydrogen is “temperature”. When hydrogen is cooled to -253°C, its volume is reduced to 1/800 compared to its gaseous state, so transporting it in large quantities becomes possible. This also means that the tank containing liquefied hydrogen must be fabricated with cryogenic steel that can withstand -253°C. Liquefied hydrogen transport vessels have not yet been demonstrated worldwide, and Japan has built the only 116m long demonstration small ship.

Another way to transport and store hydrogen is by making hydrogen chemically react with other substances to form hydrogen compounds. Hydrogen compounds include organic hydrogen compounds (MCH, room temperature) that combine hydrogen with toluene, liquefied ammonia (NH₃, -33°C) that combines nitrogen, and liquefied methane (NHx, -160°C) that combines carbon dioxide. Compared to liquid hydrogen, hydrogen compounds can be stored at a higher temperature, making transport easier. As POSCO has already developed steel materials that can handle hydrogen compounds, the demand is expected to gradually increase if research and demonstration on making hydrogen compounds are complete.

l Singing Hydrogen in Stainless Steel

Green Hydrogen is the ideal energy source for a “Zero CO₂” society. The most important part when producing this Green Hydrogen is the “Water Electrolytic Separator”. A separator is a metal that plays a crucial role when producing and utilizing hydrogen as a fuel. The separator is a passage for hydrogen and oxygen, and it should be highly conductive and corrosion-resistant. Hence, outstanding technology is required. There are two types of separators: “Fuel Cell Separator,” which is used to utilize hydrogen as fuel, like in fuel cell electric vehicles, and “Water Electrolytic Separator,” which is used to produce hydrogen.

Since the Water Electrolysis Separator is in charge of producing hydrogen from water (2H₂O → 2H₂ + O₂), it operates in a reverse reaction (2H₂ + O₂ → 2H₂O) from the Fuel Cell Separator of a fuel cell electric vehicle or generator. Since the applied environment has higher temperature and humidity and is overall harsher than in the fuel cell, the Water Electrolysis Separator requires better corrosion resistance and conductivity than the Fuel Cell Separator.

The “Fuel Cell Separator” is a separator put on the fuel cell of a vehicle and is equivalent to an engine of conventional engine vehicles. The fuel cell converts hydrogen injected into the car into electric energy. POSCO began developing fuel cell separators in 2006 and succeeded in developing and commercializing the world’s first ultra-high corrosion-resistant stainless steel separator material, Poss470FC, which was applied to the fuel cell electric vehicle Nexo in 2018.

In the past, the separator was coated with gold or carbon material to prevent corrosion, but Poss470FC, which is evaluated as an innovative material, shows better corrosion resistance and conductivity, lowers manufacturing cost, and reduces product size without such coating. Poss470FC was awarded the Gold Prize in the 2018 New Technology Award category by the International Stainless Steel Forum (ISSF) and was selected as one of the “15 Industrial Technology Achievements Leading the Korean Industry” by the National Academy of Engineering in Korea in 2019.

▲ A Fuel Cell Separator made with POSCO stainless steel, Poss470FC, on display at POSCO’s booth at the North American International Auto Show in 2016

On the other hand, unlike the case for fuel cell electric vehicles, which operate under 100°C, the Fuel Cell Separator for power generators operates at 600 to 800 °C for a long period of time. So it requires high oxidation resistance and conductivity accordingly. As of present, stainless steel produced in Germany and Japan adopting pricey rare-earth elements is being applied. Accordingly, POSCO is striving to activate the domestic industry of fuel cells for generators with source materials by developing the low-cost, high-conductive steel, Poss460FC, that can replace expensive import materials.

Jules Verne (1828-1905) is a French science-fiction novelist who achieved fame for his books “20,000 Leagues Under the Sea” and “Around the World in 80 Days”. The passage above is from his book, “The Mysterious Island,” published in 1874. The Mysterious Island is where Captain Nemo of “20,000 Leagues Under the Sea” spent the rest of his life after being caught up in the vortex of the Arctic Ocean. “The Mysterious Island” is about how five prisoners captured in the American Civil War steal a hot air balloon and flee to a desert island. Thanks to the main character, who is a master of all things, the escaped survivors live in abundance by making daily necessities such as bombs, wind power plants, and electricity on the uninhabited island. Using water as an energy source must have been what Jules Verne had imagined. However, 150 years later, his imagination is about to become reality. The era of the hydrogen economy is approaching before us.

POSCO Newsroom would like to present to you the story of the encounter of “steel” and “hydrogen,” an Sustainable material of the future. The “Exploring Hydrogen with POSCO” series will present to you the details!

l Steel, the Partner of Hydrogen (Sensitive to Pressure & Temperature)

Hydrogen is element number 1 on the periodic table and is also the first element to be created in the Big Bang about 14 billion years ago. It is abundant enough to account for 75% of the universe and 90% of the elements. Water (H₂O) is a combination of ^*hydrogen, a word meaning “making water,” and oxygen, and occupies 3/4 of the earth. Since it is possible to decompose and combine hydrogen and oxygen through electrochemical reactions, hydrogen, when used as an energy source, can indeed become a near-infinite energy source, just as Jules Verne imagined.

^*Hydrogen is a combination of the Latin words “Hydro (water)” and “-gen (make)”

However, utilizing hydrogen as a raw material is not as easy as it sounds. This is because hydrogen is very sensitive and difficult to handle. In a gaseous state, the pressure of hydrogen is high, and when hydrogen is mixed into the air at a certain percentage, it explodes due to various external stimuli such as heat, flame, or sunlight. Therefore, materials used to transport and store gaseous hydrogen must be pressure-resistant and safe.

If gases are difficult to handle, what about liquids? Hydrogen in liquid form is cold enough to cause frostbite even in brief contact. The boiling point of hydrogen is -252.88°C, so the material used to transport and store liquid hydrogen must withstand -253°C.

A material that can withstand high pressure, reduce the risk of explosion, and endure cryogenic temperatures. The invisible force to develop a hydrogen society lies in the technology to make high-performance hydrogen materials. In the center of all this stands POSCO, the steelmaker that continues to challenge and innovate in new sectors.

l Different Types of Hydrogen

To find out about steel for hydrogen application, it is first necessary to understand “hydrogens” produced in various ways.

The first is “By-product Hydrogen,” which is made by purifying hydrogen from by-product gases generated on industrial sites, like steelmaking, petrochemical, and oil. The manufacturing cost is lower than half compared to other production methods. However, the purity of the produced hydrogen is not high, so high refining costs are required to produce hydrogen with a purity of 99.999% for hydrogen-electric vehicles. Currently, POSCO possesses an annual hydrogen production capacity of 7,000 tons, utilizing the Cokes Oven Gas generated during the steelmaking process and natural gas (LNG). Among them, around 3,500 tons of by-product hydrogen are extracted and used to control temperature and prevent oxidation while steelmaking.

The second is “Extracted Hydrogen,” which is made with fossil fuels. It accounts for more than 90% of the hydrogen currently produced. In general, the extracted hydrogen is called Grey Hydrogen (H₂). The steam reforming method (CH₄ + 2H₂O → CO₂ + 4H₂), where hydrogen is extracted with a high-temperature reactor using methane (CH₄) — a major component of natural gas — is the most common production method of extracted hydrogen. However, during this process, a large amount of carbon dioxide (CO₂) is inevitably generated. It brings about an ironic situation where CO₂, a greenhouse gas, should be reduced, but rather increases due to hydrogen production. Therefore, a new technology, which is Carbon Capture & Storage (CCS) technology, is becoming more important. CCS Technology enables the capture, compression, transport, and storage of CO₂ underground. Extracted hydrogen can be classified into two. Hydrogen that utilizes coal and lignite is called Brown Hydrogen (H₂), and hydrogen applied with CCS technology is called Blue Hydrogen (H₂).

To efficiently transport large amounts of CO₂ extracted in the process of blue hydrogen production, liquefaction is required, and steel for liquefied CO₂ application must be of high-strength, thick, and able to withstand -60°C. Also, the storage tank will have to become larger to increase the efficiency of long-distance transportation. Last year, POSCO has already developed a steel product of 500MPa with a tank capacity of 51,000m³, a steel thickness of 80mmt, and the ability to withstand -60°C, in preparation for the demand for liquefied CO₂ steel.

The third is “Hydrogen from Water Electrolysis,” aka Green Hydrogen (H₂), which uses water as fuel, just as imagined by Jules Verne. It produces hydrogen by electrolyzing water (2H₂O → 2H₂ + O₂) and does not emit any CO₂. However, it cannot be said to be CO₂ free entirely, since electricity is required in the first place to electrolyze water. Therefore, when discussing green hydrogen production, the production of renewable energy, like solar and wind power generation, is inevitable.

l Steel for Solar & Wind Power Generation: A Must for Green Hydrogen

POSCO is also actively responding to market demand for steel products applied to solar and wind power generation. In the case of solar power structures, condensate corrosion caused by daily temperature difference influences the life of the structure. POSCO expanded into the market by applying its own PosMAC (POSCO Magnesium Aluminium alloy Coating Product) that has a tensile strength of 540MPa, stronger than conventional materials, and is up to 10 times more corrosion resistant. POSCO is also making continuous efforts to make more durable structures by increasing the strength of the material. As for steel products for wind power generation, POSCO already developed a full range of steel grades as of October 2019. Currently, one out of 10 wind turbines worldwide is made of POSCO steel. Also, POSCO is accelerating its response to the trend of large scale wind power generation and revised standards.

Hydrogen is produced in a variety of ways, from gray hydrogen, brown hydrogen, blue hydrogen, to green hydrogen! In December last year, POSCO supported the Korean government’s 2050 Carbon Neutrality Declaration, and began establishment for its own hydrogen production system. The plan is to boost the production capacity of by-product hydrogen to 70,000 tons by 2025, and produce up to 500,000 tons of Blue Hydrogen by 2030 and 2 million tons of Green Hydrogen by 2040. The ultimate goal is to lead the decarbonization era by completing a hydrogen production capacity of 5 million tons by 2050 and achieving 30 trillion KRW in hydrogen sales.

Did you know that “Green Hydrogen,” the most ideal energy source for the CO₂ Zero society, is created through stainless steel? The most important component when producing green hydrogen is the “water electrolysis separator,” and it is this metal called the “separator” that plays a very important role when decomposing water to produce hydrogen and using it as fuel. The separator is a passage for hydrogen and oxygen, and since it must have high electrical conductivity and highly resistant to corrosion, producing a separator requires high-end technology. The key material of this separator is none other than stainless steel!

There are two types of separators: one is the “Water Electrolysis Separator,’ which is required when producing hydrogen, and the other is the “Fuel Cell Separator,” which is required when utilizing hydrogen. More details about these separators will be provided in the upcoming series.