oxyfuel makes the cement industry more sustainable

The cement industry is one of the world's largest CO₂ emitters. Nevertheless, it is impossible to imagine our everyday lives without cement, for example, in the construction industry. A switch to more sustainable processes is essential to protect the climate and remain competitive. The solution from our experts at thyssenkrupp Polysius is called polysius® pure oxyfuel.

Understanding oxyfuel: How it works

Large quantities of carbon dioxide (CO₂) are released during cement production. "Only one third of these CO₂ emissions result from the combustion of fossil fuels such as coal or petroleum coke," explains Jost Lemke, Process Engineer at thyssenkrupp Polysius. "While the largest part is released by the decomposition of limestone – calcination." Limestone is the most important raw material for cement production and, depending on quality, consists of around 35% to 44% CO₂.

But without limestone, no cement. That's why Lemke and his colleagues at thyssenkrupp Polysius came up with the oxyfuel technology. "Instead of burning the limestone in ambient air as in the conventional clinker burning process, pure oxygen is added in the polysius® pure oxyfuel process," explains the engineer. This eliminates the need for atmospheric nitrogen and produces highly concentrated, pure CO₂ in the flue gas. "Due to the high concentration, we can separate and capture almost 100% of the climate-damaging carbon dioxide instead of allowing it to escape unhindered into the atmosphere," the expert continues.

Determined towards sustainability: Catch4climate & CI4C

An efficient solution to make the cement industry more sustainable. Which has also attracted the interest of the research company Cement Innovation for Climate (CI4C) of the four cement manufacturers Buzzi Unicem SpA - Dyckerhoff GmbH, HeidelbergCement AG, SCHWENK Zement GmbH & Co. KG and Vicat S.A. As part of its catch4climate project, the research company has commissioned thyssenkrupp Polysius to build a polysius® pure oxyfuel kiln system.

For Frank Ruoss, CSO of thyssenkrupp Polysius, the cooperation with CI4C (Cement Innovation for Climate) has two major advantages: "On the one hand, a pioneering new process technology is being introduced or implemented here in the field of cement production that could have a disruptive character for the cement industry. Secondly, in this project we have successfully pursued an unusual partnership approach between thyssenkrupp Polysius and a customer consortium comprising no less than four major customers," says the manager.

The road to a more sustainable cement industry is long

But the cement experts are still a long way from reaching their goal. Currently, numerous technical concepts are being tried out, which will first have to establish themselves on the market in the coming years. "In addition to the technical challenges, I see an extremely high investment and financing requirement on the part of our customers," Ruoss gives as an outlook. "Here, the next steps must be taken in very close coordination and partnership with our customers." In addition, most projects will have to be accompanied and supported politically and in terms of approval law. "These are framework conditions that go beyond the normal Polysius range of experience," says Ruoss.

Challenges of the transformation of the cement industry

The cement industry is dependent on many factors. Global changes – whether in the economy or politics – affect the cement industry in almost all areas of the process chain, starting with raw materials and continuing through finished cement and concrete to recycling. "Raw materials, energy demand and CO₂ emissions are three topics in which important further developments must now be made at the same time. Our polysius® solutions offer improvements for many of these areas," explains Process Engineer Jost Lemke.

Intelligent production planning, together with optimized plants, can increase the consumption of renewable energies. This would reduce the need for electricity from coal and natural gas. "The polysius® booster mill gets the maximum output out of the cement clinker, and polysius® activated clay can further reduce CO₂ emissions in cement production," Lemke elaborates. "Added to this, of course, is the separation of CO₂ by the polysius® pure oxyfuel process. This makes it possible to avoid a very large proportion of CO₂ emissions," says the expert

Outlook: The future of sustainable cement production

A major step is the introduction of CO₂ separation in the cement industry. Our experts agree that this will play a significant role in shaping the cement industry of tomorrow over the next few years. In this context, it is also necessary to consistently develop the overall concept in parallel with the testing of the processes, taking into account other trends, such as the increased use of renewable energies. With CO₂ separation, thyssenkrupp Polysius lays an important foundation stone for optimum concrete recycling. As it is one of the next big issues for the cement industry.

Become part of the transformation

Are you already working in the cement industry and would like to help make it more sustainable, or would you like to get started? Then you can find all our current vacancies on our career platform. Want to read more about sustainability topics from the thyssenkrupp Group? Then look at our sustainability stories.