Torben Daun and Johannes Voß on dynamic methanol synthesis

Interplay between digitalization and experimental work

Interview of 12.12.2022

Torben Daun (li.) und Johannes Voß
© Fraunhofer UMSICHT
Torben Daun (l.) and Johannes Voß

Torben Daun and Johannes Voß are working on their doctorates at Fraunhofer UMSICHT and are researching methanol production from metallurgical gases as part of the Carbon2Chem® project. Their research concerns the behavior of the catalyst system and process under changing conditions or gas compositions. They also intend to digitally model the entire dynamic synthesis of methanol.

Before we get onto the specific area of research, what is methanol used for?

Torben Daun: As an end product, methanol can be used, for example, in the form of a solvent or as a refrigerant. It can also be used as an energy source or as fuel. Methanol is already being used in ships instead of diesel or crude oil, and methanol-powered cars are also an entirely real future possibility.

Johannes Voß: Methanol is the simplest alcohol. As a result, it is very important for the chemical industry as numerous other intermediate or end products can be synthesized from it.

Why is there a need for new manufacturing methods?

Torben Daun: Industry is currently predominantly based on fossil raw material sources. Carbon sources that have been created over millions of years are being depleted within a short space of time and end up as CO2 in the atmosphere. In line with the motto “Keeping carbon in the loop”, the aim is to reuse carbon and not let it escape into the atmosphere. New synthesis routes that do not rely on fossil raw materials as the source need to be created for this, e.g., for methanol. Instead, we should process those carbon-containing waste products that are in the main unavoidable, for example from steel mills, waste incineration or cement works.

What exactly are you working on at Fraunhofer UMSICHT?

Johannes Voß: As part of my PhD, I am investigating the dynamic synthesis of methanol in the lab so I am in charge of the experimental side. Methanol plants are normally supplied with a constant and fixed fresh gas composition. This cannot be guaranteed in our case as we use off-gases from a steel mill. Metallurgical gas changes depending on the upstream process and how this is carried out. I conduct experiments to see how the catalyst system and the process behave under changing conditions or gas compositions. What can harm the catalyst? What might be advantageous? It is also important to find out how we can react to fluctuating conditions.

Torben Daun: My PhD is based on a very similar subject: I also deal with the synthesis process under fluctuating feed compositions. In my case, however, I am focusing on the framework that can be used to digitally model the methanol plant.

To what extent does your research complement each other?

Torben Daun: My work is seamlessly linked to that of Johannes Voß. My objective is to predict how the plant will behave when using real gases or under dynamic conditions. Beyond the simulation, however, I also investigate other aspects: How do the controllers in the plant work? And how do they influence the behavior? This is something that is not taken into account in “typical” simulations, where often only snapshots are calculated.

Research is already being carried out with real gas in a technical center pilot plant at a steel mill in Duisburg. How does this differ from your work in Oberhausen?

Johannes Voß: The main difference lies in fact in the gases: At the lab in Oberhausen, we are using cylinder gases with deliberately varied states and fluctuations. For example, we can bring about extreme states in order to see certain effects. By contrast, in Duisburg real gases are being used to investigate the long-term stability of the catalyst system for methanol production, for example. We want to compare the real process with the artificial one.

What are currently the biggest challenges?

Johannes Voß: The catalyst systems run for years. Since we cannot measure every test point over such a long period, however, it is definitely a challenge to make long-term predictions within a relatively short time.

Torben Daun: One big issue is coordinating simulations and measurements. We are currently discussing the discrepancies and possible causes. Another issue is that the simulations are also meant to run at the same time as plant operation. This requires a certain speed, which we are constantly optimizing.

What does your typical working day look like?

Torben Daun: I spend most of my time working from home on my computer. On average, I go to the institute once a week. I mainly use the programs COMSOL and Ansys to perform the simulations, and I also model smaller procedures in Python. I am also involved in monitoring during extensive measurement campaigns at the demonstration plant.

Johannes Voß: Unlike my colleague, I am on site at Fraunhofer UMSICHT most days. If the demonstration plant is running, we have to be there round the clock which involves a classic three-shift operation. If the demonstration plant isn’t running, the lab is usually my first port of call, to check the plant there. Has everything gone to plan during longer test series or were there problems? In rare cases, there may be compressed air or gas failures, for example, which we then need to remedy.

What are the next steps?

Johannes Voß: The conversion of my plant is now complete. This means that the plant is running with precisely the configuration that I had planned. I will now work through the test plan to model the dynamic states and then evaluate the results.

Torben Daun: My main objective is also the project goal: We are ultimately aiming to create an industry standard plant. It should be possible to digitally model this plant. There are still several challenges ahead of us. For example, at the moment we are conducting the experiments on a single-tube reactor. On the industrial scale, there will be many individual tubes that are connected to form a bundle of several thousand.

Finally, can you give us some idea of the quantities produced?

Johannes Voß: The catalyst test bench in Duisburg produces around 200 milliliters of methanol per week. In the laboratory plant, it is about 1 liter a day. The demonstration plant produces a good 70 liters of methanol-water mixture a day. Industrial methanol production plants produce up to 5,000 metric tons a day.