How our packaging steel makes food cans even more sustainable

Thanks to their high recycling rate, tinplate food cans are already the stars of the circular economy and are considered a model material when it comes to sustainable packaging. But our experts at thyssenkrupp Steel think there's an even better way. At thyssenkrupp Rasselstein's production site for packaging steel in Andernach, experts from Production and Research & Development are working together with universities and industry partners to make the tinplate manufacturing process even more sustainable - among others in the FlexHeat2Anneal and H2-DisTherPro research projects.

Jörn Lochstampfer has been working at thyssenkrupp Steel for over 25 years. Today, in the Center of Decarbonization, he is responsible for decarbonization in the company's downstream processes - i.e. all the processes in which steel is further processed. "In addition to the overarching goal of producing climate-friendly steel based on, for example, hydrogen from 2027, thyssenkrupp Steel also wants to identify and utilize savings potential throughout its entire process chain," explains the expert. "For example at thyssenkrupp Rasselstein."

Andernach: The town that supplies the world with packaging steel

Dr. Peter Kirchesch is the sustainability officer here at thyssenkrupp Rasselstein and coordinates the sustainability strategy for packaging steel, among other things. The sustainability expert knows that this is an area with huge savings potential: "As a subsidiary of thyssenkrupp Steel based in Andernach, Rhineland-Palatinate, we are the only tinplate manufacturer in Germany and one of the largest producers of packaging steel in the world." The company has an annual production capacity of 1.5 million tons of the packaging material.

null — The starting material for packaging steel, as used in food cans, is hot-rolled steel strip 1.5 mm to 3.8 mm thick. Delivered in coils, it can weigh between 6 tons and 28 tons!

"In order to achieve the climate targets we have set ourselves, we will produce our packaging steel in a completely climate-neutral way by 2045," explains Jörn Lochstampfer. "The transformation of production of thyssenkrupp Rasselstein is an important part of thyssenkrupp's decarbonization strategy. This is because we can save around 400,000 tons of CO₂ emissions in the production of packaging steel." Kirchesch adds that both the resources used for steel production and the carbon footprint of the process steps in further processing are relevant to achieving this goal.

The experts see the energy-intensive continuous annealing and the batch annealing processes in particular as an opportunity to reduce CO₂ emissions. "thyssenkrupp Rasselstein uses two annealing processes, discontinuous batch annealing and continuous annealing. The conversions in both processes bring their own technical challenges, which we are currently examining in two research projects funded by the Federal Ministry for Economic Affairs and Climate (BMWK)," explains Kirchesch.

One of the research projects is called FlexHeat2Anneal. "It deals with continuous annealing process that is part of tinplate steel production," says Lochstampfer. "These processes are needed to restore the crystalline structure of the material that has been destroyed during cold rolling." It is only through these annealing processes that the packaging steel regains its form ability and can later be processed into cans for food packaging, for example. To do this, the steel strip is currently heated to up to 750 °C using natural gas. This is set to change in the future – with sustainable heat treatment.

The second research project is called "H2-DisTherPro" and deals with the batch annealing process, another method for recrystallizing tinplate. The aim of H2-DisTherPro is to completely replace the traditionally used carbon-containing fuel gases with hydrogen. "Here, too, safe operation must be guaranteed, and consistently high product quality ensured," emphasizes Dr. Peter Kirchesch. "As part of the research project, a test facility for the development of a suitable burner technology is being set up at the VDEh Betriebsforschungsinstitut technical center in Duisburg." At the same time, the plant's internal energy processes are already being adapted for later use in Andernach.

Bye-bye Natural Gas, Hello Hydrogen

More sustainable annealing processes, such as those being tested in the two research projects FlexHeat2Anneal and H2-DisTherPro, mean that green hydrogen will completely replace currently used fossil fuels such as natural gas. However, as hydrogen burns hotter than natural gas, among other things, components of the production process must be adapted to the use of hydrogen as part of the research projects - for example the burner and the radiant tubes, but also the safety concepts. "The aim is to influence the existing production processes as little as possible by switching to green hydrogen," explains Dr. Peter Kirchesch. "And the high quality of our packaging steel must also be guaranteed with sustainable annealing."

FlexHeat2Anneal & H2-DisTherPro: More sustainable packaging steel thanks to green hydrogen

The FlexHeat2Anneal and H2-DisTherPro research projects will run for three years. In addition to thyssenkrupp Rasselstein, the Department for Industrial Furnace Construction and Heating Technology at RWTH Aachen University and WS Wärmeprozesstechnik GmbH are also involved in the FlexHeat2Anneal project. In the H2-DisTherPro project, the colleagues from thyssenkrupp Rasselstein are working together with experts from VDEh-Betriebsforschungsinstitut GmbH, DSD Automation GmbH and thyssenkrupp Steel Europe. Kirchesch is optimistic: "The research projects are already showing promising initial results in the laboratory." The next step is to carry out tests on actual production facilities, for which the infrastructure is currently being prepared.

"It is important for the success of sustainable annealing processes that sufficient green hydrogen is available in the near future," emphasizes Lochstampfer, and Kirchesch agrees: "Initiatives such as the national hydrogen strategy are already addressing this need. The decisive factor now is the pace." Both agree that the expansion of production capacities and infrastructure must be massively driven forward so that the enormous demand for hydrogen can be met in the future. thyssenkrupp Steel Europe alone will be one of the largest European customers for hydrogen.

Research that benefits everyone

The research is not only important for thyssenkrupp. "This is basic research with a high level of practical relevance," explains Jörn Lochstampfer. "Because burner and annealing processes are used in various industries and production processes." The knowledge gained at thyssenkrupp Rasselstein with hydrogen in the annealing processes for the production of packaging steel can also be used later for other industrial processes. In this way, the findings can contribute to successful decarbonization in many other industries and other thyssenkrupp sites. Working on this important transformation is the greatest motivation for Jörn Lochstampfer and Dr. Peter Kirchesch every day.

You can find more exciting insights into our research and technologies for the decarbonization of steel production and other industries in our stories.