First of all, please tell us about the location and purpose of the plant.

Kai Girod: I work in a technical research center next to thyssenkrupp Steel Europe’s industrial site in Duisburg. Here, metallurgical gases from the adjacent industrial site are purified in vast quantities in a gas purification system belonging to thyssenkrupp Industrial Solutions and supplied to the laboratories as gas streams. My plant is in a lab operated by Fraunhofer UMSICHT.

We conduct experiments using the gases provided so as to be able to produce specific products in a targeted manner. In my case, methanol. The main objective is testing the catalysts. We are using an already established catalyst for a process that can also be implemented in the short term. If we had to develop a new catalyst, this would take a lot of time, but we want to find a solution quickly.

What exactly are you responsible for?

Kai Girod: My job is to check whether the catalysts that were originally developed for methanol synthesis based on fossil raw materials and that are currently in use can also be used for methanol synthesis with purified process gases from the steel industry. The resulting synthesis gas is the starting material for a new methanol synthesis route. Through experimental work, I evaluate the catalyst’s stability which directly affects the efficiency of the process.

In doing so, I pay attention to how the catalysts act with impurities. I exchange information with colleagues from industry partners, including plant manufacturer thyssenkrupp Industrial Solutions and catalyst producer Clariant, and provide test results that are needed to evaluate the various use possibilities.

Fraunhofer UMSICHT has several test plants of varying sizes. What do each of them do?

Kai Girod: The test plants must be seen as complementary. In one of the plants we work with small amounts of catalyst so that certain effects can be viewed in a more targeted manner. Is the gas purification in the technical center working well enough that the catalysts are not “poisoned”? It might be the case, for example, that impurities cannot be separated from the steel mill off-gases. With the larger plant, it is then a question of scaling up. Conditions are similar there to those in a technical plant.

In the lab plant where I work, there are currently a few grams of catalyst. In a future industrial plant, we would be talking about many metric tons. The amount of gas that I need is about 1 liter per minute. That seems like very little, but the temperature and pressure, i.e., the actual reaction conditions, correspond to those in a large plant. The pressures are in the range between 60 and 90 bar, the temperatures between 240 and 290 °C.

You use real gas. How does that differ from cylinder gas?

Kai Girod: Some of the real gases are fed to our laboratory so that we can experiment with them. There are certain factors that could certainly also be tested in other labs. The main components carbon dioxide and carbon monoxide, nitrogen and hydrogen could also be mixed together manually. However, real gases also contain trace substances and impurities that come from the raw materials used in steelmaking — coal or ore. These can damage the catalysts and “poison” them. Therefore, we also have a gas purification plant on site which purifies the gases. We analyze whether this is enough. The real gases need to be purified so that the process works stably. However, investing too much time and effort into it would be unprofitable. It’s all about getting the balance right.

Where does the real gas that is used come from?

Kai Girod: There are several sources of gas on the steel mill site: gas from the blast furnace, converter and coke plant. Firstly, there is the steelmaking process in which the raw iron is converted into steel. Then we have the blast furnaces. Their gas composition is different, however, so we test the gases separately. If you look at the whole picture, it is not just the composition of the gases that matters, but also their availability. Ultimately, the blast furnace provides the biggest quantity. Our aim is to avoid CO₂ emissions, which is why we focus on using particularly large gas streams.

Can you tell us about the initial milestones?

Kai Girod: So far we have managed to produce methanol in our plant for several thousand hours. This works well. Now we need to investigate how efficient the process is. How stable are the catalysts and how long do they last in reality? We are working on optimizing the process and on ensuring long life cycles of the catalysts used in a future large-scale plant so as to make the process even more economically viable.

What next? What challenges lie ahead?

Kai Girod: One big challenge is assessing how stable the process is. To do this, the tests have to run for weeks and months without a break. This is a major practical undertaking as many different plants all have to operate at the same time. If there are problems, we need to ascertain if they have impaired the outcome of the test. It is often difficult to judge in retrospect if the results can still be used. The goal is to obtain continuous results over months.

Moving on to the actual product: What can the resulting methanol be used for?

Kai Girod: Methanol is a basic chemical that can be converted into a wide variety of products. Examples of important chemical products made from methanol are formaldehyde, which is used to produce adhesives and synthetic resins for manufacturing chipboard or crockery, or acetic acid, which is predominantly used to produce polymers. However, methanol can also be converted into fuels such as gasoline, diesel and kerosene, or be used as a fuel itself. The major shipping companies are starting to order ships that run on methanol. However, one big production challenge is that hydrogen is needed, even to use the steel mill off-gases. This obviously has to come from renewable sources, otherwise it is pointless. Providing the huge amounts of hydrogen required is another major challenge.

Is this type of methanol production limited to metallurgical gases or can it also be adapted to other branches of industry?

Kai Girod: Off-gases from the various industries have different compositions and impurities, so gas purification has to be adapted to these. We are trying to separate off pure CO₂. If we succeed and develop a technical process for methanol production, it can also be transferred to other branches of industry. Waste incineration plants or cement works for instance could be suitable for a similar synthesis process.

Steel production is set to become green in the future by switching over to hydrogen. So why is there a need for the process you have researched for synthesizing methanol from metallurgical gases?

Kai Girod: The steel industry wants to save CO₂ very quickly. Using metallurgical gases is one way of achieving this in the near future. We are talking about a timescale of a few years. In principle, however, the steel industry would like to switch completely to hydrogen by means of direct reduction plants. Until then, we will accompany the industry’s transformation journey and will keep reducing CO₂ and use it to also reduce the dependency on natural gas. After switching to direct reduction plants, the steel mill will still produce CO₂-containing gases in the ballpark of 10 to 20 percent of the amounts currently emitted. This means that the technology we are now developing is a way of avoiding CO₂ emissions in the short and long term. Without our work, enormous amounts of CO₂ would be produced in the meantime, which is what we want to prevent.

But even if the steel mill switches to hydrogen in the future, there will still be many branches of industry which emit CO₂. CO₂ will always be released in cement production, for instance, because of the chemical reaction that takes place when burning lime. So the technologies that we are developing are a sustainable investment.